(Msia) Guide to Sewer Selection and Installation (Dec2006)_VC Pipe pg17～

AAGuide Guidetoto Sewer Selection Sewer Selection and Installation and Installation

ISSUE: 01 REVISION: 0 NOVEMBER 2006

PED/SDQS/ST018/GLD/1106/001

TABLE OF CONTENT 1.0

2.0

3.0

INTRODUCTION

1

1.1 1.2 1.3

1 1 1

SEWER PIPELINE - REGISTRATION AND APPROVAL

2

2.1 2.2

General Pipes Submission and Evaluation 2.2.1 General 2.2.2 Submission Procedures 2.2.3 Evaluation Process

2 2 2 3 3

SEWER PIPELINE - SELECTION GUIDE

5

3.1 3.2

General Selection Criteria 3.2.1 Material 3.2.2 Joint 3.2.3 Structural Design 3.2.4 Quality Assurance Selection Process 3.3.1 Exclusions of Use Explanations

5 5 6 6 7 7 7 12

SEWER PIPELINE – MATERIAL SELECTION

15

4.1

15 15 15

3.3

4.0

Purpose of This Guide Who Should Use This Guide How to Use This Guide

Gravity Sewerage System 4.1.1 General 4.1.2 Definition 4.1.3 Precautions and Principal Applications of Sewerage Gravity Pipeline System

15

ii

4.2

Vitrified Clay (VC) Pipe 4.2.1 Manufacture 4.2.2 Protective Coatings/Linings 4.2.3 Sizes/Classes

17 18 20 20

4.2.4 4.2.5 4.2.6 4.2.7

21 22 24 25

Joints Fittings Pipeline Hydraulic Design Application of Pipes

4.3

Reinforced Concrete (RC) Pipe 4.3.1 Manufacture 4.3.2 Protective Coatings/Linings 4.3.3 Sizes/Classes 4.3.4 Joints 4.3.5 Fittings 4.3.6 Pipeline Hydraulic Design 4.3.7 Application of Pipes

26 27 28 28 29 31 32 33

4.4

Ductile Iron (DI) Pipe 4.4.1 Manufacture 4.4.2 Protective Coatings/Linings 4.4.3 Sizes/Classes 4.4.4 Joints 4.4.5 Fittings 4.4.6 Pipeline Hydraulic Design 4.4.7 Application of Pipes

34 35 37 37 38 40 41 42

4.5

Glass-fibre Reinforced Plastic (GRP) Pipe 4.5.1 Manufacture 4.5.2 Protective Coatings/Linings 4.5.3 Sizes/Classes 4.5.4 Joints 4.5.5 Fittings 4.5.6 Pipeline Hydraulic Design 4.5.7 Application of Pipes

43 44 45 45 46 47 48 49

iii

4.6

5.0

Profile Wall High Density Polyethylene (HDPE) Pipe 4.6.1 Manufacture 4.6.2 Protective Coatings/Linings 4.6.3 Sizes/Classes 4.6.4 Joints 4.6.5 Fittings 4.6.6 Pipeline Hydraulic Design 4.6.7 Application of Pipes

50 51 55 55 55 58 58 59

FORCE MAIN

63

5.1

General 5.1.1 Definition 5.1.2 Pipe Materials and Application Conditions

63 63 63

5.2

Ductile Iron (DI) Pipe 5.2.1 Manufacture 5.2.2 Protective Coatings/Linings 5.2.3 Sizes/Classes 5.2.4 Joints 5.2.5 Fittings 5.2.6 Pipeline Hydraulic Design 5.2.7 Application of Pipe

64 65 65 65 65 67 68 68

5.3

Steel Pipes 5.3.1 Manufacture 5.3.1.1 Mild Steel 5.3.1.2 Stainless Steel 5.3.2 Protective Coatings/Linings 5.3.2.1 Mild Steel 5.3.2.2 Stainless Steel 5.3.3 Sizes/Classes 5.3.4 Joints 5.3.5 Fittings 5.3.6 Pipeline Hydraulic Design 5.3.7 Application of Pipes

69 71 71 72 72 73 73 72 74 75 76 76

iv

6.0

5.4

Glass-fibre Reinforced Plastics (GRP) Pipe 5.4.1 Manufacture 5.4.2 Protective Coatings/Linings 5.4.3 Sizes/Classes 5.4.4 Joints 5.4.5 Fittings 5.4.6 Pipeline Hydraulic Design 5.4.7 Application of Pipes

77 78 78 78 78 80 80 81

5.5

Acrylonitrile Butadiene Styrene (ABS) Pipe 5.5.1 Manufacture 5.5.2 Protective Coatings/Linings 5.5.3 Sizes/Classes 5.5.4 Joints 5.5.5 Fittings 5.5.6 Pipeline Hydraulic Design 5.5.7 Application of Pipes

82 83 84 84 85 86 87 87

5.6

Solid Wall HDPE Pipe 5.6.1 Manufacture 5.6.2 Protective Coatings/Linings 5.6.3 Sizes/Classes 5.6.4 Joints 5.6.5 Fittings 5.6.6 Pipeline Hydraulic Design 5.6.7 Application of Pipes

88 89 90 90 90 92 92 93

VACUUM SEWERAGE SYSTEMS

94

6.1 6.2

94 95 96 96 96 97 97 97

General Acrylonitrile Butadiene Styrene (ABS) Pipe 6.2.1 Manufacture 6.2.2 Protective Coatings/Linings 6.2.3 Sizes/Classes 6.2.4 Joints 6.2.5 Fittings 6.2.6 Pipeline Hydraulic Design

v

6.3

7.0

8.0

Solid Wall HDPE Pipe 6.3.1 Manufacture 6.3.2 Protective Coatings/Linings 6.3.3 Sizes/Classes 6.3.4 Joints 6.3.5 Fittings 6.3.6 Pipeline Hydraulic Design

98 99 99 99 99 99 99

PIPE JACKING

100

7.1 7.2

General Vitrified Clay (VC) Pipe 7.2.1 Manufacture 7.2.2 Protective Coatings/Linings 7.2.3 Sizes/Classes 7.2.4 Joints 7.2.5 Pipeline Hydraulic Design

100 101 102 102 102 103 103

7.3

Reinforced Concrete (RC) Pipe 7.3.1 Manufacture 7.3.2 Protective Coatings/Linings 7.3.3 Sizes/Classes 7.3.4 Joints 7.3.5 Pipeline Hydraulic Design

104 105 105 105 106 106

SEWER PIPELINE - DESIGN GUIDE

107

8.1 8.2

107 107 107 107 108 110 110 111

General Rigid Pipe 8.2.1 Vitrified Clay (VC) Pipe 8.2.1.1 Pipeline Structural Design 8.2.1.2 Pipeline Embedment 8.2.2 Reinforced Concrete (RC) Pipe 8.2.2.1 Pipeline Structural Design 8.2.2.2 Pipeline Embedment

vi

8.3

9.0

Flexible Pipe 8.3.1 Flexible Pipeline Structural Design 8.3.2 Flexible Pipeline Embedment 8.3.3 DI Pipe 8.3.4 GFRP Pipe 8.3.5 Profile Wall HDPE Pipe 8.3.6 ABS Pipe 8.3.7 Steel Pipe 8.3.7.1 Pipeline Structural Design 8.3.7.2 Pipeline Embedment 8.3.8 Solids Wall HDPE Pipe 8.3.8.1 Pipeline Structural Design 8.3.8.2 Pipeline Embedment

113 113 114 116 117 118 118 119 119 119 120 120 120

SEWER PIPELINE – TESTING GUIDE, SITE HANDLING AND INSTALLATION 123 9.1 9.2

General Field Testing 9.2.1 General Pipeline Testing Guide 9.2.2 Test for Straightness, Obstruction and Grade 9.2.3 Low Pressure Air Test 9.2.4 Hydrostatic Test 9.2.5 High Pressure Water Test 9.2.6 High Pressure Leakage Test 9.2.7 Vacuum Test 9.2.8 Infiltration Test 9.2.9 CCTV Inspection

123 123 124 124 124 124 125 125 126 126 126

9.3 9.4

Factory Testing Site Handling and Installation Guide 9.4.1 Dos and Don’ts

127 128 128

9.5

Handling and Installation Practice 9.5.1 Storage 9.5.2 Excavation 9.5.3 Pipe Cutting 9.5.4 Pipe Jointing 9.5.5 Pipe Inspection

133 133 133 134 134 135

vii

APPENDIX A :

Checklist B

APPENDIX B :

Product Details: Sewer Pipes and Fittings Form

APPENDIX C :

Evaluation Criteria Form

APPENDIX D :

Summary of Approved Suppliers/Manufacturers

viii

LIST OF TABLES Table 3.1 Table 3.2 Table 3.3 Table 3.4 Table 4.1 Table 4.2 Table 4.3 Table 4.4 Table 4.5 Table 4.6 Table 4.7 Table 4.8 Table 4.9 Table 4.10 Table 4.11 Table 4.12 Table 4.13 Table 4.14 Table 4.15 Table 4.16 Table 4.17 Table 4.18 Table 4.19 Table 4.20 Table 4.21 Table 4.22 Table 4.23 Table 4.24 Table 4.25 Table 4.26 Table 4.27 Table 4.28 Table 4.29 Table 4.30 Table 4.31 Table 4.32 Table 5.1 Table 5.2 Table 5.3 Table 5.4 Table 5.5 Table 5.6 Table 5.7 Table 5.8 Table 5.9 Table 5.10 Table 5.11 Table 5.12 Table 5.13 Table 5.14 Table 5.15 Table 5.16 Table 5.17 Table 5.18

Type of Pipelines for Various Sewerage Systems Application of Various Types of Pipes in Sewerage Systems Limit on Use for Various Types of Pipes for Sewerage Systems Exclusion of Use Gravity Sewer Pipeline Materials and Application Precautions and Principal Applications of Gravity Sewer Pipeline System Summary of VC Pipes Design and Specifications for Gravity Sewerage System Preferred Nominal Lengths of VC Pipes Crushing Strength (FN) in kN/m for Various Sizes of VC Pipes Allowable Angular Deflection of VC Pipes Colebrook-White Roughness Coefficient, ks for VC Pipes Various Pipeline Hydraulic Design Equations of VC Pipes for Gravity Sewerage System Advantages and Disadvantages of VC Pipes Summary of RC Pipes Design and Specifications for Gravity Sewerage System Crushing Test Loads of RC Pipes for Gravity Sewerage System Allowable Angular Deflection of RC Pipes Colebrook-White Roughness Coefficient, ks for RC Pipes Various Pipeline Hydraulic Design Equations of RC Pipes for Gravity Sewerage System Advantages and Disadvantages of RC Pipe Summary of Ductile Iron Pipes Design and Specifications for Gravity Sewerage System HAC Lining Thickness of Various Sizes of DI Pipes Standard Pipe Lengths of Various Sizes of DI Pipes Allowable Angular Deflection of Jointing for DI Pipes Various Pipeline Hydraulic Design Equations of DI Pipes for Gravity Sewerage System Advantages and Disadvantages of Ductile Iron Pipes Summary of GFRP Pipes Design and Specifications for Gravity Sewerage System Nominal Sizes of GFRP Pipes Angular Deflection Limits Relative to the Nominal Size of the GFRP Pipework Methods of Hydraulic Design of GFRP Pipe Advantages and Disadvantages of GFRP Pipe Summary of Profile Wall HDPE Pipes Design and Specifications for Gravity Sewerage System Classifications of Profile Wall HDPE Pipe Colebrook-White Roughness Coefficients (ks) for Profile Wall HDPE Pipe Advantages and Disadvantages of Profile Wall HDPE Pipe Technical Comparison of Various Types of Pipe for Gravity Sewerage System Summary of Comparison for Various Types of Pipe for Gravity Sewerage System Pressure Sewer Pipe Materials and Application Summary of DI Pipes Design and Specifications for Force Main Colebrook-White Roughness Coefficient, ks for DI Pipes Advantages and Disadvantages of DI Pipes for Force Main Summary of Mild Steel Pipes Design and Specifications for Force Main Summary of Stainless Steel Pipes Design and Specifications for Force Main Colebrook-White Roughness Coefficient (ks) for Steel Pipes Advantages and Disadvantages of Steel Pipes Summary of GRP Pipe Design and Specifications for Force Main Angular Deflection Limits Relative to the Nominal Size of GRP Pipelines Colebrook-White Roughness Coefficient, ks for GRP Pipes Advantages and Disadvantages of GRP Pipes for Force Main Summary of ABS Pipes Design and Specifications for Force Main Dimensions of ABS for Force Main Classifications of ABS Pipes for Force Main Colebrook-White Roughness Coefficients (ks) of ABS Pipes Advantages and Disadvantages of ABS Pipes Summary of Solid Wall HDPE Pipe Design and Specifications for Force Main B

B

B

B

B

B

B

B

B

B

B

B

B

B

Table 5.19 Table 5.20 Table 6.1 Table 6.2 Table 6.3 Table 6.4 Table 7.1 Table 7.2 Table 7.3 Table 7.4 Table 7.5 Table 7.6 Table 8.1 Table 8.2 Table 8.3 Table 8.4 Table 8.5 Table 8.6 Table 8.7 Table 8.8 Table 9.1 Table 9.2

Colebrook-White Roughness Coefficient (ks) for Solid Wall HDPE Pipes Advantages and Disadvantages of Solid Wall HDPE Pipe Summary of ABS Pipes Design and Specifications for Vacuum Sewerage System Dimensions Of Abs For Vacuum Sewerage System Classifications of ABS Pipes for Vacuum Sewerage System Summary of Solid Wall HDPE Pipe Design and Specifications for Vacuum Sewerage System Summary of VC Pipes Design and Specifications for Pipe Jacking Tolerance on Internal and External Diameter of VC Pipes for Pipe Jacking Allowable Angular Deflection of VC Pipes for Pipe Jacking Summary of RC Pipes Design and Specifications for Pipe Jacking Crushing Loads of RC Pipes for Jacking Pipe Minimum Angular Deflection and Straight Draw Joints of RC Pipes for Pipe Jacking Compositions of Fill Material for RC Pipeline Embedment Bedding Factors for Working Dead Loads for Various Types of Support Typical Flexible Pipe Materials Maximum Particle Size of Embedment Material for Flexible Pipeline Minimum Relative Compaction of Embedment Material for Flexible Pipeline Notations Applicable in the Guidelines Minimum Cover (H) for Flexible Pipeline Minimum Embedment Zone Dimensions Summary of Field Testing for Sewer Pipelines Summary of Factory Testing for Various Types of Sewer Pipe

LIST OF FIGURES Figure 2.1 Figure 3.1 Figure 4.1 Figure 4.2 Figure 4.3 Figure 4.4 Figure 4.5 Figure 4.6 Figure 4.7 Figure 4.8 Figure 4.9 Figure 4.10 Figure 4.11 Figure 4.12 Figure 4.13 Figure 4.14 Figure 4.15 Figure 4.16 Figure 4.17 Figure 4.18 Figure 4.19 Figure 4.20 Figure 4.21 Figure 4.22 Figure 4.23 Figure 4.24 Figure 4.25 Figure 4.26 Figure 4.27 Figure 4.28 Figure 4.29 Figure 4.30 Figure 4.31 Figure 4.32 Figure 4.33 Figure 4.34 Figure 4.35 Figure 4.36 Figure 4.37 Figure 4.38 Figure 5.1 Figure 5.2 Figure 5.3 Figure 5.4 Figure 5.5 Figure 5.6 Figure 5.7 Figure 5.8 Figure 5.9 Figure 5.10 Figure 5.11 Figure 5.12 Figure 5.13 Figure 5.14 Figure 5.15 Figure 5.16

Flow Chart of Product Registration and Approval Procedures Steps of Preliminary Selection of Sewer Pipeline Types of VC Pipes Typical Manufacturing Process for VC Pipes Spigot Socket with Rubber ‘O’ Ring Joint for VC Pipes Skid Type Sealing Joints for VC Pipes Typical Range of Fittings for VC Pipes Types of RC Pipes Typical Flexible Joint of Spigot Socket RC Pipes Typical Flexible Joint of Rebated/Ogee RC Pipes Typical Double Spigot Joint with Collar of RC Pipes Typical Range of Fittings for RC Pipes Types of DI Pipes Typical Manufacturing Process of Centrifugal Casting for DI Pipes Typical Push in Joints for DI Pipes Typical Self-anchoring Push-in Joint for DI Pipes Typical Ranges of Flange for DI Pipes Various Range of Fittings for DI Pipes Typical Filament Wound GRP Pipes Typical Centrifugally Cast GRP Pipes Definition of Stiffness for GRP Pipes Typical Integral Socket and Spigot Joint of GRP Pipes Typical Loose Collar Joint of GRP Pipes Typical Rigid Joints of GRP Pipe Various Ranges of Fittings for GRP Pipe Types of Profile Wall HDPE Pipe for Gravity System Various Forms of Profile Wall HDPE Pipe Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes (Option 1) Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes (Option 2) Helical Pattern of Profile Wall HDPE Pipe Typical Manufacturing Process of Annular Profile Wall HDPE Pipe Annular Pattern of Profile Wall HDPE Pipe Spigot Socket with Rubber Ring Seals Joint for Profile Wall HDPE Pipes Typical Socket Fusion Welding for Profile Wall HDPE Pipes Butt Weld Joint of Profile Wall HDPE Pipe Butt Welded Joint of Spigot Socket Profile Wall HDPE Pipe Flange Ends Joint of Profile Wall HDPE Pipe Screwed Fittings for Jointing of Profile Wall HDPE Pipe Plastic Fittings for Jointing of Profile Wall HDPE Pipe Various Ranges of Fittings for Profile Wall HDPE Pipe for Gravity System Typical Bolted Mechanical Joint of DI Pipes for Force Main Typical Flange Adapters of DI Pipe for Force Main Typical Self-anchoring Flange Adapters of DI Pipe for Force Main Typical Self -anchoring Bolted Mechanical Joints of DI Pipe for Force Main Typical Slip-on Coupling for DI Pipes Typical Self-anchoring Tie-bar Joints for DI Pipes Additional Ranges of DI Fittings for Force Main Typical Manufacturing Process of Mild Steel Pipes for Force Main Typical Manufacturing Process for Stainless Steel Pipes for Force Main Butt-welded Joint Preparation of Steel Pipes Sleeve Welded Joints of Steel Pipes Slip-on Type Coupling of Steel Pipes Threaded and Coupled Joints Recessed for Bitumen Lining Various Ranges of Fittings for Steel Pipes Typical slip-on coupling Typical stepped slip-on coupling

Figure 5.17 Figure 5.18 Figure 5.19 Figure 5.20 Figure 5.21 Figure 5.22 Figure 5.23 Figure 5.24 Figure 5.25 Figure 5.26 Figure 5.27 Figure 5.28 Figure 5.29 Figure 5.30 Figure 5.31 Figure 5.32 Figure 5.33 Figure 6.1 Figure 6.2 Figure 7.1 Figure 7.2 Figure 7.3 Figure 7.4 Figure 8.1 Figure 8.2 Figure 8.3 Figure 8.4 Figure 8.5 Figure 8.6 Figure 8.7 Figure 9.1

Typical band coupling Typical flange adapter Typical flange joints Various Ranges of DI Fittings for GFRP Pipes Typical Manufacturing Process Flow of ABS Pipes Types of ABS Pipes Typical Spigot-socket with Solvent Cement Joint of ABS Pipes Typical Spigot-socket with Elastomeric Seal Joint of ABS Pipes Typical Stub Flange Joint for ABS Pipes Various Ranges of Fittings for ABS Pipes Typical Manufacturing Process of Solid Wall PE Pipe Typical Butt Fusion Welding for Solid Wall HDPE Pipes Butt Fusion Welding of Spigot socket Joints for Solid Wall HDPE Pipes Typical Flange Joints of Solid Wall HDPE Pipes Fabricated Fittings for Butt Fusion of Solid Wall HDPE Pipes Stub End and MS Flange Fittings for Solid Wall HDPE Pipes Plastics Compression Fittings for Solid Wall HDPE Pipes Typical Spigot-socket with Solvent Cement Joint of ABS Pipes Typical Stub Flange Joint for ABS Pipes Type of VC Pipe for Pipe Jacking Types of RC Pipes for Pipe Jacking Typical Flexible Joint of Rebated/Ogee RC Pipes Typical Double Spigot Joint with Collar of RC Pipes Construction Method of Class ‘A’ Bedding Construction Method of Class ‘B’ Bedding Construction Method of Concrete Encasement Construction Method of Type H1 and Type H2 Support Construction Method of Type H3 Support Construction Method of Type HS Support Terminology and Typical Construction of Pipe Support for Flexible Pipeline Typical Field Pressure Test Equipment Layout

Section 1 Introduction

1.0

INTRODUCTION

1.1

Purpose of This Guide

This Guide provides guidelines to material selection of sewers for appropriate application as well as some recommendation for proper pipe handling, installation and testing practices. It draws on a wide base of knowledge and experience from operators and manufacturers. The Guide also contains reference information on pipe registration requirements and the approval status of the pipe manufacturers/suppliers. Product information such as pipe material, sizes and limitation on use of sewer pipes available in Malaysia and information on pipe handling, installation and testing are included in the Guide. The Guide does not cover the installation of internal plumbing systems to buildings as these procedures are managed by Local Authorities.

1.2

Who Should Use This Guide

This Guide is primarily for owners, developers, consulting engineers, manufacturers, suppliers and Public Authorities whose developments or products involved sewer pipes.

1.3

How to Use This Guide

The information in this Guide is listed in five main categories described in the following sections: •

Sewer Pipeline - Registration & Approval

Section 2.0

•

Sewer Pipeline - Selection Guide

Section 3.0

•

Sewer Pipeline - Material Selection -

Gravity Sewerage System

Section 4.0

-

Force Main

Section 5.0

-

Vacuum Sewerage System

Section 6.0

-

Pipe Jacking

Section 7.0

•

Sewer Pipeline - Design Guide

Section 8.0

•

Sewer Pipeline - Testing Guide, Site Handling and Installation

Section 9.0

A Guide to Sewer Selection and Installation 13th November 2006

1

Section 2 Sewer Pipeline - Registration and Approval

2.0

SEWER PIPELINE APPROVAL

2.1

General

-

REGISTRATION

AND

All manufacturers/suppliers must obtain approval from the Director General of Sewerage Services (DGSS) for the ranges of pipes, which they intend to supply to the sewerage industries in Malaysia.

2.2

Pipes Submission and Evaluation

2.2.1

General

Flow chart of the sewer pipe submission and evaluation process is shown in Figure 2.1.

2.2.2

Submission Procedures

The following are procedures for the preparation and submission of document to DGSS: 1. Obtain submission forms of a. Checklist B (see Appendix A); and b. Product Details – Sewer Pipes and Fittings Form (see Appendix B) from DGSS offices or from the DGSS website at www.jpp.gov.my. Photocopies of the submission forms attached in this Guide are acceptable, however a confirmation shall be made with the relevant authority if there is any latest revision being issued. 2. Prepare a complete set of document as per Checklist B including company profile and technical details of the products. All the submission documents shall be bound neatly. 3. Submit two (2) copies of the submission documents together with the Checklist B and the Product Details – Sewer Pipes and Fittings Form to DGSS for evaluation. 4. The manufacturer/supplier will be notified on the status of evaluation within 1 month of the date of submission received whether: •

Additional information/clarification may be requested;

•

The product has been approved with or without conditions;

•

The product has been rejected.

5. The manufacturer/supplier shall give the feedback on additional information/clarification requested within two (2) months; if not the DGSS will close the submission file and any respond after that will be considered as a new submission. 6. The manufacturer/supplier, whose product has been rejected, may appeal to the DGSS by providing valid reasons.


2


2.2.3

Evaluation Process

The following are steps of evaluation adopted by the technical evaluation committee: 1. Check if the submission of the document contains all the necessary information for evaluation. If not, the manufacturer will be requested to submit the outstanding information. 2. Evaluate the submission of the document based on a set of evaluation criteria as attached in Appendix C, the DGSS Guidelines and other relevant standards. 3. Notify the manufacturers/suppliers within 3 months of the date of submission received whether: • • •

Further information/clarification is required; The product has been approved, with or without conditions; The product has been rejected.

4. Check if there were problems associated with the pipe/brand encountered at site.


3


Figure 2.1: Flow Chart of Product Registration and Approval Procedures

Start

Obtain Checklist B and Product Details-Sewer Pipes and Fittings Form from DGSS (Sample in Appendix A & B)

Prepare & submit two (2) complete sets of documents to DGSS

Manufacturer/supplier to complete the submission

Notify manufacturer/supplier

DGSS initial check

Submission Complete?

No

Yes DGSS Technical Committee evaluating the submission

Notify the manufacturer/supplier that the submission's rejected

No

Submission Satisfactory

Evaluation Criteria (See Appendix C)

DGSS Design Guidelines & Policy

Yes Notify the manufacturer/supplier on the approval granted


Related Reference Material

4

Section 3 Sewer Pipeline - Selection Guide

3.0

SEWER PIPELINE - SELECTION GUIDE

3.1

General

Within the past few decades there has been a growing choice of sewerage system. There is an increased range of materials available for sewerage applications and there may be significant economic advantages to a more informed approach to materials selection. New sewerage systems are being introduced as a result of the utilisation of various plastic materials while traditional systems are being improved to overcome deficiencies. A greater choice of sewerage systems means more sewer materials can be applicable. The selection of suitable pipe material for the sewerage system and particular application requires knowledge outside the normal training of the designer with some complex issues requiring specialist materials and structural knowledge. Handling, installation and testing methods could also vary for different pipe materials. An increasingly competitive market place has made it more difficult to formulate objective technical decisions on materials. Information from suppliers is fragmented and focuses on the advantages rather than the disadvantages of a particular material. The section provides a summary of necessary information to lead to the accurate selection of sewer pipeline system.

3.2

Selection Criteria

The fundamental requirements of a piping selection for sewage conveyance system are: •

Availability of complete range of components to suit the system’s design, function and repair, e.g. where service connections are required, appropriate fittings must be available

•

Achieving the specified design life within the specified level of maintenance. Specified design life may be for the length of time that a service is to be provided to an area of customers or shorter time if there is plan to renovate, upgrade or replace the piping system in future. The design life generally sought by authorities for most instances is at least 100 years with special circumstances permitting a shorter life. Specified level of maintenance that would be desirable by most authorities at a minimum as to require infrequent cleaning of silts and slimes.

The design life, maintenance level and ranges of product form the basis for establishing criteria for selecting sewer material. The main criteria identified for the purposes of selecting sewer material are as follows: • Material; • Joint; • Structural design; and • Quality assurance.


5


3.2.1

Material

Materials to be used in sewer pipe, fittings, elastomeric seals, pipe coatings and other accessories must have the following properties: • Good corrosion resistance at the internal wall to hydrogen sulphide and sulphuric acid produced in septic sewage, and any industrial discharges attacks; • External wall to remain chemically stable when exposed to aggressive soils and groundwater; • Resist microbiological attack from the internal and external environment; • Good resistance to abrasion caused by sewage flow and any maintenance cleaning; • Remain sufficiently impermeable; • Suitable for the site condition; Factors to be taken into account in selecting materials should include: • The nature of the effluent and the possibility of chemical attack or mechanical damage; • The nature of the ground conditions and the possibility of subsidence or chemical attack; • The quality of workmanship which may be expected and the degree of supervision to be provided; • Third party interference to the pipe surrounding.

3.2.2

Joint

The pipe and fittings jointing systems and access chamber connections need to have the following characteristics: • Able to be consistently constructed in the specified manner under field conditions; • Resist groundwater infiltration; • Resist sewage exfiltration; • Resist root intrusion; • Resist pullout for an elastomeric sealing joint; • Have sufficient tensile, shear and bending strength for welded joints; • Not cause excessive snagging and fouling; • Not significantly affect the hydraulic flow roughness, through mismatching of surfaces and joint gap; • Not impede routine maintenance operations; • Resistance to damage due expansion; and • Able to joint two pipes of different materials. For elastomeric sealing joints, such performance is required for one and a combination of configurations that are possible with the joints such as: • Axial displacement (minimum insertion of spigot); • Axial deflection (relative deflection of one pipe length to adjoining pipe length); • Ring misalignment (shear); • Ring ovalisation (for flexible pipe); The elastomer properties affecting long term sealing performance are: • Hardness; • Rate of compression; • Stress relaxation; • Water absorption; • Resistance to ageing; • Resistance to chemicals; and • Resistance to microbiological deterioration.


6


3.2.3

Structural Design

The selected sewer at most installation conditions should not result in excessive complication in the installation process, e.g. internal bracing of flexible pipe, but capable to offer the following structural properties: • Resist ring cracking or crushing, where rigid pipe is used; • Resist excessive ring deflection, circumferential strain and ring buckling where flexible pipe is used; • Resist shearing and longitudinal bending where sufficient or uniform underlying support cannot be provided to the pipeline or excessive ground movement is expected; • For rising mains, resist cyclic pressure loading; and • The shape of the pipe should not deform easily.

3.2.4

Quality Assurance

Assurance is required that the material, pipe and fittings are manufactured and supplied so that they will consistently meet nominated standards/specifications. Such assurance is achieved by requiring the manufacturer to have a quality management system certified to comply with the International standard ISO 9001 or 9002 and an approved inspection and test plan to ensure conformance with the nominated material, pipe and fittings standards/specifications.

3.3

Selection Process

Compliance to the selection criteria may vary among the pipeline systems under various installation conditions. The following steps shown in Figure 3.1 below can be adopted for preliminary selection of suitable pipeline systems using this guideline: Figure 3.1: Steps of Preliminary Selection of Sewer Pipeline

Identify the type of systems

Identify the type of pipeline from Table 3.1

Check the suitability of the selected pipeline to the design condition from Table 3.2 and 3.3

Identify the exclusion of use in certain pipeline system under specific condition from Table 3.4

Identify the approved manufacturers/suppliers from Appendix D, Table D1

Getting the product information of the selected pipeline from Section 4.0, 5.0 and 6.0


7


Table 3.1: Type of Pipelines for Various Sewerage Systems System Gravity Sewer

Force Main

Vacuum Sewer

Type of Pipelines VC Pipe RC Pipe GRP Pipe DI Pipe Profile Wall HDPE Pipe DI Pipe Steel Pipe GFRP Pipe ABS Pipe Solid Wall HDPE Pipe Solid Wall HDPE Pipe ABS Pipe

Available Size (Diameter) 100 mm to 600 mm (locally made) 400 mm to 600 mm (imported) 150 mm to 3600 mm 50 mm to 3000 mm 80 mm to 1200 mm 100 mm to 3000 mm 80 mm to 1200 mm 100 mm to 2200 mm 50 mm to 3000 mm 10 mm to 630 mm 20 mm to 900 mm 20 mm to 900 mm 10 mm to 630 mm

Table 3.2: Application of Various Types of Pipes in Sewerage Systems Type of Pipe VC

RC

Application • • • • • • •

GRP

• • • • • • • •

DI

• •

All sizes are applicable. Short pipe lengths can be specially used in mine subsidence areas. Applicable as trenchless technology of pipe. Longer pipe length is not recommended because the pipe is likely to suffer beam failure due to the loss of flexibility since less flexible joints will be required for longer pipe. Where VC pipes is not available. Under local context, only RC pipes with DN375 mm and above is allowed. Applicable as trenchless technology of pipe. As an alternative to large diameter flexible pipes where: a. Native ground modulus inadequate to provide structural support. b. Inadequate geotechnical data available. c. Inadequate control over embedment placement and compaction. d. Likely third party interference to the pipe surrounding. Only for nominated projects or as permitted by the relevant authority. Under local context, only size DN 600mm or above are allowed. Allowed for above ground use where pipeline is protected from vandalism. Applicable as trenchless technology of pipe. Use under railways only with encasing pipe. Ends of cut pipe shall be sealed with resin. Pipes and couplings used above ground to have power and water approved UV protection. Only on sewers that would not require provision of junction for future pipeline extension. Suitable for above ground use, i.e where bridging support is provided such as water course, culvert, drain and exposed bridge crossings. Only for area where superimposed loading are excessive for other types of pipe.


8


Table 3.2: Application of Various Types of Pipes in Sewerage Systems (continued) Type of Pipe DI (continued)

Steel

ABS

Profile Wall PE Solid Wall PE

Application • Pipe lining of high alumina cement or sulphate resisting cement or PPFA cement such as Mascrete is required to minimise corrosion possibility by septic sewage. All linings shall be hydraulically proven of conveying the sewage inside the pipe. • Where there is potential for excessive differential settlement such as in fill ground (specify DI pipes with locking flexible joints to prevent joint pull out). • Where minimum pipe covers are not possible. • Where superimposed loadings are excessive for other pipe types. • Only use in corrosive soil conditions, tidal zones, anaerobic ground conditions and aggressive groundwater when it has an external polyethylene sleeving. • When used in unstable ground, locking gasket must be provided. • Use restraining elastomeric seals where buried service congestion prevents the use of thrust blocks or is subject to extreme ground movement. • Fittings for the pipe shall be made of mild steel. • Only use under or near DC traction systems with appropriate stray current insulation. • Suitable for use as conduit pipe for high loading applications. • Only allow for pressure sewer larger than DN 600mm and with relevant authority approval. • Not to be used near electricity transmission lines. • Suitable for above-ground use and inverted siphon application. • Welding of joints to be performed by qualified welders • Welded joints to have reinstatement of protection systems on site • Polyethylene coating should not be used where there is extended exposure to direct sunlight. • Only for specified depths of cover • Applicable for above ground use (within conduits) where DI or steel are not suitable. • Applicable in aggressive groundwater and tidal zone. • Applicable as inverted siphon under watercourse crossings. • Where VC or RC are not suitable • Only on sewers that would not require provision of junction for future pipeline extension. • • • • •

Applicable in aggressive groundwater and tidal zone. Suitable in soils with differential movement. Applicable as trenchless technology of pipe. Applicable as syphon under watercourse crossings. Not suitable for crossing under railways or major roadways unless within an encasing pipe.


9


Table 3.3: Limit on Use for Various Types of Pipes for Sewerage Systems Type of Pipe VC

RC

Limit on Use • • • • • •

GRP

• • • • • • • • • • • •

DI

• • •

Profile Wall PE and Solid Wall PE

ABS

• • • • • • • • •

Steel

• • •

Not in unstable ground, i.e refilled ground, tidal zone. Not suitable for above ground installation. Not in the vicinity of trees with aggressive root systems. Not use for crossing under water courses. Not suitable for high H2S levels unless good lining such as HDPE lining is provided. Not in aggressive soils/groundwater or tidal zone unless sulphate resistant cement is used. Not in area where future works may affect the pipe side support. Not in ground contaminated or possibly contaminated by certain chemicals in concentrations deleterious to GRP resin. Do not use pipes/couplings with chips, cracks, crazing, layer delamination or exposed fibres. Ends of cut pipe shall be sealed with resin. Do not use pipe and couplings, stored unprotected from sunlight for more than 9 months. Do not use in ground conditions having low stiffness, e.g. tidal zone. Not in location subjected to vehicular load and has insufficient cover. Not in areas subjected to third party interference, e.g. excavations within 2m of pipeline by other parties. Not in ground subject to differential settlement or extreme movement Not in ground offering low side support strength to the pipe. Do not use when control of construction practices is not adequate to ensure quality of embedment for flexible pipes. Not suitable for uncertainties in geotechnical analysis to determine if flexible pipe structurally suitable. Not to be used near electricity transmission lines. Corrosion may occur when installed above ground because of the tendency of temperature rise at the pipe and sewage, which thus promotes septicity and corrosive conditions. Externally coated bitumen pipes not suitable for use in extreme marine environment Not in location subjected to vehicular load and has insufficient cover. Not in areas subjected to third party interference, e.g. excavations within 2m of pipeline by other parties. Not in ground offering low side support strength to the pipe Not in ground which allows migration of pipe embedment material into it Not in ground contaminated with chemicals deleterious to HDPE Not suitable for above ground installation Not suitable as reticulations systems except for special applications. Not suitable for crossing under railways or major roadways unless within an encasing pipe. Not in areas subjected to third party interference, e.g. excavations within 2m of pipeline by other parties. Not in ground offering a low side support strength to the pipe Not in ground which allows migration of pipe embedment material into it. Not to be used near electricity transmission lines.


10


Table 3.4: Exclusion of Use Exclusion of Use

Condition • • • Conditions conducive to septic sewage • (e.g. low flows, shallow grades, sewers receiving old • sewage or turbulence is expected etc.) • • Environment corrosive to metals • • Minimum coverage not provided. • • Crossing under railway • • Above ground installation

Extreme Ground Movement

Very low pipe gradient Ground contaminated with chemicals deleterious to plastic Crossing under water courses


• • • • • • • •

Pipeline System VC GRP HDPE RC DI Steel DI Steel VC GRP HDPE VC (unencased) GRP (unencased) HDPE (unencased) VC GRP RC, Steel, DI with elastomeric joint RC HDPE ABS Any pipes with elastomeric joint

Reason Subject to low impact damage. Subject to impact damage. Excessive change in length with change in temperature. Potential for cement mortar corrosion subsequent metallic corrosion. Potential for metallic corrosion. Subject to low impact damage Side support might be interfered with due to the impact. Subject to low impact damage (shallow cover). Difficult to guarantee that side support will not be interfered with. Vulnerable to beam and shear failure due to low beam and shear strength. Susceptible to elastomeric joints pullout. Vulnerable to have septic sewage which generate high hydrogen sulphide and cause corrosion at the cement mortar. The plastic will degrade if the chemical present is deleterious to the plastic. The ground is susceptible to settlement, which may lead to potential pullout of the joint and caused infiltration.

11


3.3.1

Exclusions of Use Explanations

1. Above ground installation Pipelines above ground are in many instances exposed to vandalism, so the pipeline material and any corrosion protection coatings must have high resistance to impact and abrasion damage. Direct exposure to sunlight is another concern as this may cause degradation to some plastic materials. 2. Conditions conducive to septic sewage Under these conditions, the sewage may become septic and produce hydrogen sulphide which may convert to sulphuric acid when released to the atmosphere. Sulphuric acid will corrode concrete pipes and cement mortar used to line ductile iron and steel pipelines and cause subsequent corrosion at the reinforcement bars or other metal parts. 3. Environment corrosive to metals Environments corrosive to metals include marine environments and may also include some types of atmospheric industrial discharges. A marine environment is an environment in proximity to sea spray or wash. 4. Cover less than minimum Installation with less than minimum cover may be considered where a downstream sewer level needs to be tied into, where it is not possible to go under existing pipelines, where crossing a watercourse or where installing with minimum cover will result in considerable increase in construction depth elsewhere. Prior approval must be obtained from the relevant authority. 5. Crossing under railway The following factors limit the suitable pipeline systems and method of support of the pipeline under railways in general: • Catastrophic consequence from train derailment - pipelines and support conditions having a low risk of deformation or collapse are required • Railways are generally active - pipelines suitable for installation by boring or tunnelling/jacking are required • Trains generally pass frequently - cased boring or pipe jacked in closely behind the bore or tunnel excavation is required to prevent ground collapse (not required for excavations 100 mm diameter or less where the size of any collapse generally would not be expected to cause significant overburden subsidence) The following factors limit the pipeline systems and method of support in special circumstances: • Trains apply high impact loading - pipelines with good impact resistance is required • Disturbance during maintenance of rails and ballast - for shallow cover, pipelines that require negligible side support required. • Catastrophic consequence from train derailment - blow out of a sewage rising main from joint, corrosion or material fatigue failure leading to erosion of rail support For pressure pipelines, such as sewerage rising mains, it is required to encase the carrier pipeline with either another pipeline or reinforced concrete. For non-pressure pipelines, such as gravity sewers, encasement will lower the risk of failure and is thus recommended. High stiffness pipelines with high corrosion resistance (using appropriate coatings and linings and other means as required) offer the most foolproof solution.


12


Plastic pipelines should be encased either with concrete or cementitious grout (whilst ensuring the pipeline does not substantially deform during the grouting process) or with a very stiff pipeline of reinforced concrete, ductile iron or steel. Low ductility pipelines, such as GRP and VC at shallow cover should be similarly encased. 6. Extreme ground movement All pipelines will be subject to some downward (and unusually upward) movement due to underlying material movement. The degree of movement will vary with the magnitude of loading and the movement modulus of the underlying material. Along a pipeline the degree of movement will be different due to variations in dead loads (depth of covered soil density) and live loads and variation in the movement modulus due to variations in bedding thickness/compaction and foundation composition. Upward movement may occur due to swelling clay types (depending on the season) or by tree root growth. The ability of a pipeline to accommodate differential movement of the support depends on the maximum angular deflection at the joints, pipe length bendability and pipe length beam strength and shear strength. All pipeline systems have either joint angular deflection capability and for pipe length bendability and/or sufficient beam strength/shear strength to accommodate some degree of differential movement. Each pipeline system will have different limits and this needs to be determined for the particular loading and underlying modulus movement conditions on the pipeline. Where there is large differential movement over short distances, the beam strength and shear strength of individual pipe lengths and the ability to resist joint failure will determine the pipeline system to use. VC and GRP pipes are the most vulnerable to beam and shear failure within a length. RC, steel and DI pipes will withstand greater beam and shear load but will be susceptible to elastomeric joint pullout (ductile iron pipelines are available with a lock-in elastomeric joint to counter pull out). uPVC will flex to a degree but its low beam strength will eventually cause failure. Solid wall polyethylene pipe is much more flexible than the other plastic sewerage pipeline systems so will accommodate much greater differential movement over short distances. In additional solid wall PE pipeline systems having welded joints will not be subject to joint pullout like elastomeric sealing joints. It may be difficult to determine the possible level of movement of a ground. Therefore it is advisable, where ground known to have potential for large movement such as fill sites, soft sands, and silts, saturated sands and silts and clays renowned for substantial swelling; to select a welded PE pipelines if structural design is favourable. Otherwise where design shows that the soft soils do not provide sufficient side support to PE, below certain depths of cover, a steel pipeline with welded joints should be used or pipes supported on piles. 7. Pipeline grading affected critically Loss of gradient may be so severe that it may lead to surcharge and spillage of sewage upstream. Also with the loss of gradient, sewage may stagnate and become septic. Septic sewage which can produce hydrogen sulphide and subsequently sulphuric acid is not a concern with plastic pipelines recommended in such conditions but consideration needs to be given to downstream assets such as large diameter concrete pipelines.


13


8. Ground contaminated with chemicals deleterious to plastics The chemicals which can be deleterious to plastics in general are principally organic solvents and for some plastics, strong acids and alkalis. The likelihood of damage depends on the contact time, chemical concentration, and temperature and for some plastics the strain in the plastics. However it is difficult to analyse the ground conditions to determine the degree of hazard at sites that may be a concern. Plastics like HDPE and ABS are therefore excluded outright from use near petrol stations, oil storage sites, land fill sites with known or suspected chemical dumping and chemical manufacturing sites. For other sites suspected of being contaminated or may be contaminated in the future with specific chemicals deleterious to plastics, the designer must obtain further advise and chemical resistance charts from pipe suppliers and undertake some site sampling to roughly gauge the likely hazard. 9. Crossing under water courses Infiltration into a sewer under a watercourse is a major concern. Rehabilitation of such sewer is also relatively difficult and costly. Therefore pipeline system which offers the least chance of infiltration and failure needs to be selected. Welded joints pipeline system is also preferred because as the elastomeric joints are likely to fail of under such condition the ground conditions are generally more prone to differential settlement (permitting joint pullout), and greater external water pressure (particularly in extreme wet weather conditions). Pipeline systems with welded joints therefore offer the safest solution. (Note: Where pipeline are installed under watercourses using directional drilling techniques, a welded pipeline must be used anyway).


14

Section 4 Sewer Pipeline - Material Selection

4.0 SEWER PIPELINE – MATERIAL SELECTION 4.1

GRAVITY SEWERAGE SYSTEM

4.1.1 General This section provides the product data and information on manufacturers of the approved products for gravity pipeline system. The data is a summary of the information provided by the manufacturers during submission for approval and may not represent the latest products available. Minimum design requirements of gravity sewerage system in Malaysia as stated in MSIG Volume 3 are summarised as follows: • Domestic connection sewer DN 150 minimum • Public sewer DN 200 and above Table 4.1 showed the pipe materials and application conditions as approved by DGSS: Table 4.1: Gravity Sewer Pipeline Materials and Application Pipe Material VC RC GRP DI Profile Wall PE

Application DN100 and above DN375 and above DN600 and above with prior approval from DGSS High load application For special circumstances with prior approval from DGSS

4.1.2 Definition A pipeline system is considered as gravity system when: a. It can operate at atmospheric pressure; b. There is no differential pressure; or c. There is no any additional internal pressure inside the system; and d. There is no additional force inside the system to assist the flow of the sewage. The gravity pipelines shall be able to withstand a buoyancy effect.

4.1.3 Precautions and Principal Applications of Sewerage Gravity Pipeline System The precautions and basic principal applications of the pipe for sewerage gravity systems are shown in Table 4.2 below: Table 4.2: Precautions and Principal Applications of Gravity Sewer Pipeline System GENERAL PRECAUTION

• All pipelines may be damaged, rendered structurally unsound or have inadequate joint performance due to incorrect installation practices. • All pipes and fittings may be damaged prior to installation by inappropriate transportation, storage and handling practices. • All pipelines shall be constructed by trained and certified pipelayers with a system of documentation for quality control of installation in place.


15

Section 4 Sewer Pipeline - Material Selection

Table 4.2: Principal Application of Gravity Sewer Pipeline System (continued) GENERAL PRECAUTION

GENERAL LIMITATIONS

GENERAL ADVANTAGES

GENERAL DISADVANTAGES

• All pipelines can be adversely affected in both the short and long term by third party damage to the pipe or corrosion protection system. • All pipelines shall be installed with proper methods of pipeline embedment and haunches. • All pipes require verification of the internal diameter for hydraulic design – the nominal size does not necessarily represent accurately the internal diameter. • Larger diameter flexible pipelines require knowledge of the soil properties along the route of the pipeline and at the intended depth of the pipeline for accurate structural design. • All pipelines require detailed site investigation and special designs for installations in contaminated land and sites where the ground is subject to significant movement or subsidence. • All pipes and fittings may be damaged by inappropriate cleaning practices and maintenance equipment. • All pipeline systems have components that can be damaged by illegal discharges of trade waste. • Plastic pipes are resistant to H2S gas attack, impervious to groundwater and resistant to corrosion by almost all chemicals found in sewage except some specific organic compounds. • Thermoplastic pipes allow handling of much longer lengths and larger sizes than VC and GRP pipes, and are easier to cut. • Rubber ring jointed pipes are easily jointed and tolerate some joint deflection. • All pipes can be used as slip liners inside microtunnelled/jacked encasing pipe. • GRP, RC, VC and DI pipes can be supplied in designs for pipe jacking in microtunnelling installations. • Rigid pipes have one or more pipe classes that have sufficient ring strength to not rely on side support for achieving structural adequacy. • Metallic pipe are easy to trace and, when fully welded, are impermeable to organic contaminants and gases. • Flexible pipes may be susceptible to deflection after placement and compaction of embedment and fill. • Plastic pipes may be susceptible to permeation and degradation by certain organic contaminants in soils. • Plastic pipes and plastic coating or sleeving on metal pipes may be susceptible to degradation by certain organic contaminants in soils. • Plastic pipelines are sensitive to point loading. • Rubber rings may be susceptible to degradation by certain organic contaminants in soils and exposure to the sunlight and UV. • Flexible pipes rely on support for embedment and adjacent native soil to achieve structural adequacy in buried installations (except for some shallow installations without live loadings) • Non-black plastic pipes and fittings and plastic pipe coatings suffer UV degradation on prolonged exposure to direct sunlight (generally 12 to 24 months depending on the local condition)


16

Section 4 Sewer Pipeline – Material Selection (Gravity Sewerage System)

4.2

Vitrified Clay (VC) Pipe

The design data and specifications of VC pipes for gravity sewerage system are summarised in Table 4.3 below: Table 4.3: Summary of VC Pipes Design and Specifications for Gravity Sewerage System

Material Nominal Size (DN), mm Nominal Length, m Classes • Crushing Strength (FN) Jointing Methods Protective Coating • External • Internal Standards

Malaysian Sewerage Industry Guidelines (MSIG) • Intercepting sewer • Public gravity sewer Approved Manufacturers/Suppliers

Summary Vitrified clay DN100 to DN1200 mm 1.5, 1.75, 2.0, 2.5, 3.0 m • Conform to MS 1061:1999 and BS EN 295: 1991 • Refer to Table 4.5 • Spigot and socket with rubber ‘O’ ring • Spigot and socket with skid type (prefabricated) seals With or without glazing (depends on the product) With or without glazing (depends on the product) MS 1061:1999 Manufacture BS EN 295-1:1991 BS EN 295-2:1996 BS 65:1991 BS EN 752:1997 Design BS EN 752:1997 Installation ASTM C12-91

• 150 mm minimum diameter • 200 mm minimum diameter Refer to Table D1 and DGSS latest approval list


17


4.2.1 Manufacture Material compositions of VC pipes as in accordance with MS 1061:1999 comprise blends of suitable clays source from different locations and/or strata in a form of grog and fired to vitrification. The clays may contain shale, sand, prefired material of such a quality and homogeneity. Calcine clays shall be included to minimize pipe wall permeability. Recycle materials are not allowed in producing the VC pipes. The VC pipes can be manufactured into two different types of pipe as shown in Figure 4.1 below: Figure 4.1: Types of VC Pipes

Spigot-socket pipe

Double spigot pipe


18


Typical manufacturing process of VC pipes is shown in Figure 4.2 below: Figure 4.2: Typical Manufacturing Process for VC Pipes

Selection of raw material

Mixing /Blend

Dry clay is crushed, grounded and screened to achieve desired fine particles

The selected fine particles of dry clay is blended with water

Extrusion

Blend clay is extruded to form the pipes or bends

Cut and joints

Pipes are cut and jointed to form junctions and fittings

Trim and dry

Pipes, bends and fittings are trimmed and dried with hot air

Glazing (optional)

Pipes, bends and fittings are coated with a solution of salts to form ceramic glaze to reduce permeability

Firing 1050ºC to 1250ºC

Cooling 650ºC to 450ºC

Check on soundness, straightness and sizes

Final Inspection

Store


19


4.2.2 Protective Coatings/Linings External and internal glazing is a mean of improving impermeability of VC pipes. The process involves coating the dried pipes prior to firing stage with a solution of salts to form ceramic glaze on pipe wall. Glazing is not compulsory so long the products perform to requirements. When glazed they need not be glazed on the jointing surfaces of the spigot and socket.

4.2.3 Sizes/Classes Nominal size (DN) is a numerical designation of the minimum internal diameter of VC pipes. It is a convenient round number approximately equal or equal to a manufacturing dimension and the bore of the pipe shall not deviate from the nominal size beyond the set limits in MS 1061: 1999. Nominal length of VC pipes for DN 200 and greater either shall be as in Table 4.4 or they shall be whole multiples of 250mm. There are no preferred nominal lengths for DN 100 and DN 150 pipes. The pipes length other than the offered standard length can be obtained by cutting the pipes with pipe cutting chain. Table 4.4: Preferred Nominal Lengths of VC Pipes Nominal Size (DN), mm 200 225 250 300 ≥ 350

Length, m 1.5, 2.0 1.5, 1.75, 2.0 1.5, 2.0 1.5, 2.0, 2.5 1.5, 2.0, 2.5, 3.0

(Ref: MS 1061: Part 1: 1999, page 4) Classes of VC pipes is defined by the ring crushing strength (FN), which can be directly used in structural design calculations. The crushing strengths (kN/m) for various sizes of VC pipes as recommended in MS 1061: 1999 are shown in Table 4.5 below: Table 4.5: Crushing Strength (FN) in kN/m for Various Sizes of VC Pipes Nominal Sizes (DN) ≤ 150* 200 225 250 300 350 400 450 500 600 700 800 1000 1200

#

L N.A N.A N.A N.A N.A N.A N.A N.A N.A 48 60 60 60 60

95 N.A N.A N.A N.A N.A N.A 38 43 48 57 67 76 95 N.A

Class Number 120 22 24 28 30 36 42 48 54 60 72 84 N.A N.A N.A

160 28 32 36 40 48 56 64 72 80 N.A N.A N.A N.A N.A

200 34 40 45 50 60 70 N.A N.A N.A N.A N.A N.A N.A N.A

#

Lower strength pipe * Class numbers do not apply for DN ≤ 150 pipe. Higher crushing strengths may be declared, provided that the increase is in steps of 6 kN/m. (Ref: MS 1061: Part 1: 1999, page 5)


20


Crushing strength (FN) of the VC pipes shall be batch tested using either three-edge bearing test or segmented bearer test as described in MS 1061: 1999. Rigid bearer test may only be used for pipes of nominal length lower than 1.10m. The crushing strength of VC pipes may vary slightly but not significantly between batches. Only pipes of the same class and jointing system are compatible.

4.2.4 Joints Joints method of VC pipes is basically of the type of flexible joints. The types of jointing available from the approved manufacturers are generally of the following types: 1. Rubber ‘O’ ring joint - Spigot-socket with rubber ‘O’ ring type is available from all approved manufacturers and is the recommended type to be used in most applications. Figure 4.3 shows an example of spigot socket with rubber ‘O’ ring joint. Figure 4.3: Spigot Socket with Rubber ‘O’ Ring Joint for VC Pipes

2. Skid type sealing joint - This is another type of push-in flexible mechanical joint which is already prefabricated into the spigot/socket. There are two main types of skid type sealing joint: a. L-Joint by Sunway Keramo Sdn. Bhd. and GBH Clay Pipes Sdn. Bhd. and b. K-Joint by Sunway Keramo Sdn. Bhd. and JPC-Intan Sdn. Bhd. The samples of skid type sealing joint are shown in Figure 4.4 below: Figure 4.4: Skid Type Sealing Joints for VC Pipes

L-Joint

K-joint

Sealing material used for the joints is varies depending on the type of joints used and shall be in accordance with BS EN 681-1: 1996. It shall be made of elastomeric compounds comprising suitable polymers that need to ensure long term sealing of the joint.


21


There are two common types and materials used as a joint seals for VC pipes that are approved by DGSS in Malaysia, which are: 1. Rubber ring seals – The rubber ring seals shall be made of EPDM or styrene butadiene rubber (SBR). When placed at the correct position over the end of the spigot, it will roll 360° (one full turn) into place when the joint is pushed in. It is critical that the ring is not twisted and the joint shall be cleaned before jointing to avoid loose joint. The limitation of the rubber ‘O’ ring is that it cannot fill the gap between the spigot and socket completely because of its circular profile. It allows higher point compression and deteriorates with time. Therefore proper control of the spigot-socket diameters is crucial to prevent very high rubber compression (cause difficulty in jointing or additional cracking force on the socket) and very low compression (not effective jointing). 2. Rubber or polyurethane seals - These sealing elements is used in skid type sealing. The prefabricated lip ring (L-Joint) has a rubber lip ring fixed in the pipe socket with an epoxy sealant bonded to the pipe socket. No joint in the spigot is required. Light lubrication of the seal is needed before the spigot skids in. The conical joint (K-Joint) consists of a hard polyurethane compound cast inside the socket and a soft polyurethane element on the spigot end, providing a tight and flexible connection. Lubrication on the seals is required before jointing. Control of spigot and socket diameters during manufacture is less critical as the polyurethane seal can be cast to tighter tolerances. Angular deflections of the joints in the field achieving two thirds of that specified in MS 1061: 1999 are acceptable. Table 4.6 lists the acceptable angular deflections for various sizes of VC pipes. Table 4.6: Allowable Angular Deflection of VC Pipes Nominal Size (DN) DN 100 to DN 200 DN 225 to DN 500 DN 600 to DN 800 > DN 800

Angular Deflection 4.6° or 80mm per metre length 1.7° or 30mm per metre length 1.1° or 20mm per metre length 0.6° or 10mm per metre length

(Ref: MS 1061: Part 1: 1999, page 10)

4.2.5 Fittings Fittings for VC pipes to BS EN 295-1: 1991 has a minimum internal diameter closely approximating the nominal size. The deviation of the minimum internal diameter from the nominal size increases as pipe diameter increases. Fittings are prone to unusual loading, which can cause differential loads and settlement. Therefore it is necessary to encase the fittings in concrete to prevent bending and shear failures which VC fittings are vulnerable to. Figure 4.5 shows the typical range of fittings available for VC pipes. Figure 4.5: Typical Range of Fittings for VC Pipes

Socket-spigot reducer taper A Guide to Sewer Selection and Installation 13th November 2006

Socket-spigot increaser taper 22


Figure 4.5: Typical Range of Fittings for VC Pipes (continued)

Spigot-spigot taper

Stopper

Spigot-socket bend

Spigot-spigot bend

Single T joint

Single Y joint

Double T joint

Double Y joint

Backdrop

Tumbling bay

Riley slope junction

Slope junction

Spigot oblique saddle* *Note: Saddles are only used for tapping into the waterline.


Spigot square saddle*

23


Figure 4.5: Typical Range of Fittings for VC Pipes (continued)

Coupling with elastomeric seal

4.2.6 Pipeline Hydraulic Design Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 4.7 shall be referred to when determining discharge capacity of the VC pipes for gravity sewer application. Table 4.7: Colebrook-White Roughness Coefficient, ks for VC Pipes Pipe Condition New Old

Roughness, ks (mm) 0.06 1.5

Whilst, the selection of the VC pipes diameter and gradient for gravity sewer application to cope with the peak flow, can be also based on the one of the following equations as shown in Table 4.8 below.

Table 4.8: Various Pipeline Hydraulic Design Equations of VC Pipes for Gravity Sewerage System Design Equations Manning Equation Hazen-Williams Equation

Name of Coefficient

Pipeline Condition

Manning Coefficient, n

Good Bad

Typical Value of Coefficient 0.010 0.017

Hazen-Williams Coefficient, C

N/A*

110

*N/A – not applicable Frictional head losses at the joints between VC pipes could be higher than other types of pipe due to its relatively short length but it could be minimised by proper jointing. Head losses due to pounding along the barrel should be minima provided that the VC pipes barrel is manufactured within straightness tolerances given in the manufacturing specification.


24


4.2.7 Application of Pipes The application of VC pipes for the gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. The advantages and disadvantages of the VC pipes for this application are listed in Table 4.9 below. Table 4.9: Advantages and Disadvantages of VC Pipes

• • • • • • • • • • • •

• •

Advantages Installation requirements are less stringent than flexible pipes. Less imported granular material needed. Resistant to H2S attack, unlike RC. More resistant to abrasion than RC. Most resistant material to chemical corrosion found in sewage. Not degraded by UV radiation, unlike plastics without carbon black. No significant variation in dimensions or shape with temperature variation, unlike plastics. Proven long term performance, unlike plastics. Jointing procedure relatively simple. A rolling rubber ring requires no lubricant, unlike skid joints. Some rotational movement of the joint is possible, unlike the uPVC solvent cement joint. Disturbance of pipe side support does not substantially impair structural performance unlike flexible pipe. VC pipe is not buoyant like plastic pipe, therefore is not likely to move off line and grade due to water in the trench. VC pipe will not bend along its length, unlike plastic pipe, which can bend along its length from loading or from temperature variations during storage. Such bending lends to pounding of flows. VC pipes do not need special procedures to retain a round profile unlike low stiffness large diameter plastic pipe. High ring strength.


• • •

• • • • • •

• • •

Disadvantages Heavier than plastic pipes. Mechanical lifting equipment is required in sizes DN 225 and above. Shorter pipe lengths than plastic pipes, thus more joints. Rougher bore than plastics, requiring steeper grades or larger diameter pipes. Slime adheres to VC more readily than plastics and is less easily washed off. Care is required in handling as pipes are susceptible to lower the impact damage. Pipes may fracture under differential settlement within a pipe length. Where poor bedding results in support only at the socket, pipes may fracture, depending on the load magnitude. Low shear strength. Beam strength may be insufficient if pipe barrel is not offered continuous support (load dependent). High protrusion of socket requires more careful preparation of bedding to prevent a pipe length just being supported at the socket. No longitudinal pipe barrel flexibility to accommodate any loss of pipe bedding continuity. Even minor cracks can lead to penetration and chokes by aggressive root systems. Fittings in riser structures more prone to failure than thermoplastic fittings.

25


4.3

Reinforced Concrete (RC) Pipe

The design data and specifications of RC pipes for gravity sewerage system are summarised in Table 4.10 below: Table 4.10: Summary of RC Pipes Design and Specifications for Gravity Sewerage System

Material

Nominal Size (DN), mm Effective Length, m Classes • Crushing Strength (FN) Jointing Methods

Protective Coating • External • Internal

Summary • Cement • Aggregates • Water • Reinforced steel with hard drawn wire DN 150 to DN 3000 • ≤ DN 600 : 3.0m maximum • > DN 600 : 0.45m to 5.0m • Conform to MS 881:1991 • Class L, M, H, 1.5H, 2H and 2.5H • Higher strengths available upon request • Spigot and socket joint with rubber ‘O’ ring • Spigot and socket joint with cement mortar filling • Rebated/ogee joint with rubber ‘O’ ring • Rebated/ogee joint with cement mortar filling • Double spigot joint with collar/ butt joint with collar

Standards

• Bare • DN < 1000 : High alumina cement mortar lining • DN ≥ 1000 : HDPE/PVC lining is preferred • Sacrificial concrete lining is an alternatives MS 881:1991 Manufacture BS 5911-1:2002 BS 5911: Part 100: 1998 BS 5911: Part 120: 1998 AS 3725-1989 Design AS 3725-1989 Installation

Malaysian Water Sewerage Industry Guidelines (MSIG) • Other gravity sewer • Pipe strength Approved Manufacturers/Suppliers

• •

DN375 mm and above Class L as a minimum strength class

Refer to Table D1 and DGSS latest approval list.


26


4.3.1

Manufacture

Material compositions for RC pipes comprise blends of cement, aggregates and water and reinforced with hard drawn wire. Ordinary Portland cement compliance to MS 522 shall be used, unless other types of cement are specified by the suppliers/manufacturers. The fully compacted concrete shall contain not less than 360kg cement/m3 and shall have a maximum water/cement ratio of 0.45. The coarse aggregates shall have the flakiness index of not more than 35 and 10% fines value of not less than 100kN. The maximum nominal size of aggregate shall not exceed 20mm. The RC pipes can be manufactured into two different types of pipe as shown in Figure 4.6 below: Figure 4.6: Types of RC Pipes

Spigot socket pipe

Rebated pipe

The manufacturing processes that have been adopted by local manufacturers to produce RC pipes are as follows: 1.

Centrifugal spinning process In this process, the concrete and steel reinforcement is placed inside a mandrel, which is then spun. The compaction of concrete is achieved by combining centrifugal force and vibration to spin pipe horizontally.

2.

Vertical cast process The basic principle of this process is to feed the dry concrete into a vertically placed mould, which is vibrated at high frequency to compact the concrete. This process can be classified broadly into two sub-categories, which are: a. Dry vertical cast process The process uses the principle of core vibration to vibrate concrete and hydraulic compaction to form close tolerance joint profiles. The pipes are produced vertically at various machine stations using low slump concrete. b. Wet vertical cast process This process is mainly to produce large diameter of pipes. The process is using the principle of outer form vibration to compact the concrete. The pipes are being produced vertically with individual mould sets using high slump concrete.

3. Roller suspension process This is an alternative process, which is currently on used in Malaysia. In this process, a horizontal roller is placed inside the pipe steel-reinforcing cage. While rolling the cage, concrete is added to form the pipe. For the RC pipes that are manufactured with elliptically reinforcement, the load line shall be clearly marked to identify the laying orientation of the pipes.


27


4.3.2 Protective Coatings/Linings External coating is not required for RC pipe. However, where corrosion is likely to occur from external aggressive soil, the pipes shall be manufactured using sulphate-resisting Portland cement complying with MS 1037. The other types of cements that can be used with the approval from the DGSS are: a. Portland pulverised fuel ash cement complying with MS 1227; or b. Portland blast furnace cement complying with MS 1389; or c. Supersulphated cement complying with BS 4248. The types of internal protective linings that shall be applied to RC pipes for sewerage application are as following: 1. High alumina cement mortar lining (HAL) This type of lining is recommended in the MSIG 3 to be used with the RC pipes with nominal size less than DN 1000 mm. The layer of HAL with minimum thickness of 12 mm (to comply with MS 881: Part 1) shall comprise one part of high alumina cement and 3 parts of fine sand as a secondary process. High alumina cement is coated on the pipe while the concrete is still wet to ensure firm adhesion of the lining to the pipe. However, deterioration of high alumina cement concrete is directly influenced by increased in heat and humidity, which accelerates conversion of the unstable calcium aluminate decahydrate. For this reason, pipe lined with high alumina cement concrete should not be steam cured. 2. PVC/HDPE lining This type of lining is preferred to be used with the RC pipes with the nominal size more than or equal to DN 1000 mm. The layer of the lining shall have a minimum thickness of 5 mm. It is suitable for sewers experiencing serious corrosion problem. The lining is projected by keying a PVC/HDPE sheet from one face around the inner of pipe before the concrete is cured. Continuity of the lining is provided by heat welding or fusing each individual sheet to the next. Continuous longitudinal stud of lining is not allowed. The stud shall be of spirally arrangement to prevent water sipping into the area between the pipes and the lining. The lapping of PVC/HDPE at jointing shall be provided with stainless steel or other non-coated corrosion resistant metal ring. PVC/HDPE lining may only be required on the wall above the lowest sewage level where sulphuric acid will react with the wall. 3. Sacrificial concrete lining This type of lining is an alternative protection lining to the pipe offered by all the manufacturers. Pipe with this lining is designed to sacrifice part of their walls up to 38 mm without affecting their designed strengths. If pulverised fuel ash cement is used to produce the RC pipes, no protective lining is required.

4.3.3

Sizes/Classes

Nominal size (DN) is commonly used as a numerical designation of the size of RC pipes. It is a convenient round number approximately equal to a manufacturing dimension and the bore of the pipe shall not deviate from the nominal size beyond the set limits in MS 881: 1991. The use of RC


28


pipe for 300mm and less is handicapped by the lack of fittings for junction requirements, further the use of RC pipe smaller than DN 375mm is not recommended by DGSS. Effective length of pipes shall be between 0.45m and 5m inclusive with a maximum of 3m for pipes DN 600 or less. Pipe cannot be cut on site. Classes of RC pipe are defined in terms of the crushing strength in kN/m of the pipe cross section as tested according to MS 881: 1991. RC pipes are categorised into three main crushing strength classes, which are Low (L), Medium (M) and High (H). The crushing strength of RC pipe is varied by the strength of the concrete, the thickness of the wall and the amount and placing of reinforcement. The crushing test load of RC pipes for gravity sewerage system in kN/m is shown in Table 4.11 below. Table 4.11: Crushing Test Loads of RC Pipes for Gravity Sewerage System Nominal Size of Pipe, mm DN 300 375 450 525 600 675 750 825 900 975 1050 1125 1200 1350 1500 1650 1800

Class L Works proof load 20 20 20 20 20 20 38 41 46 48 51 53 58 63 69 75 82

Maximum load 25 25 25 25 25 25 48 52 58 60 64 67 72 79 87 94 103

Class M Works proof load 23 31 35 38 46 50 53 58 67 72 76 82 87 96 104 116 124

Maximum load 29 39 44 48 58 63 67 72 84 90 95 103 109 120 130 145 155

Class H Works proof load NA 36 41 46 54 60 65 69 85 91 96 106 110 122 132 146 158

Maximum load NA 45 52 58 68 75 81 86 106 114 120 133 138 153 165 183 198

(Ref: MS 881: Part 3: 1991, page 15) Pipes with crushing strength higher than Class H is also available and defined by the figure in front of the alphabet. As an example Class 2.5H, indicates that the pipe crushing strength is 2.5 times stronger than Class H pipe.

4.3.4

Joints

The joint methods for RC pipes in accordance with BS 5911 are generally of the following types: 1. Flexible joint of spigot-socket with rubber ‘O’ ring type is the recommended type to be used in most applications. Manufacturing tolerances with the spigot and socket of RC pipe are not as wide as with VC pipe since RC pipe shrinkage during manufacturing is relatively smaller. Typical flexible joint of spigot-socket with rubber ‘O’ ring is shown in Figure 4.7.


29


Figure 4.7: Typical Flexible Joint of Spigot Socket RC Pipes

Spigot socket joint with rolling rubber ring (Ref: BS 5911: Part 100: 1998, page 9)

Spigot socket joint with confined rubber ring

2. Rigid joint of spigot socket with cement mortar filling is commonly used where flexibility is not an issue. It can be applied both for normal gravity and jacking pipe installation. 3. Flexible rebated/ogee joint with rubber ‘O’ ring is used to joint the rebated pipes as shown in the following Figure 4.8. Figure 4.8: Typical Flexible Joint of Rebated/Ogee RC Pipes

Rebated joint with rolling rubber ring (Ref: BS 5911: Part 120: 1988, page 8)

Rebated joint with confined rubber ring

4. Rigid rebated/ogee joint with cement mortar filling is more commonly used for rigid pipeline installation, like jacking pipe where flexibility is not required. 5. Double spigot joint with collar/ butt joint with collar is usually used for pipe jacking application. Figure 4.9 shows the typical double spigot joint with collar. Figure 4.9: Typical Double Spigot Joint with Collar of RC Pipes

Double spigot joint with collar and rolling rubber ring (Ref: BS 5911: Part 120: 1988, page 8)

Double spigot joint with collar and confined rubber ring

The collars shall be fabricated from stainless steel 316 plate or glass reinforced plastic (GRP) or other non-coated corrosion resistant metal and shall not be attached to reinforcement. Sealing materials used for the joints are varies depending on the type of the joints used. The descriptions and requirements of each types of sealing material that have been approved by DGSS to be used with RC pipes are as following: 1. Rolling rubber O ring is used in spigot-socket joint and rebated joint to allow flexibility of the pipeline. Normally it has circular cross section. When placed at the correct position over the end of the spigot, it will roll 360° (one full turn) into place when the joint is pushed in. It is critical that the ring is not twisted and the joint is cleaned before jointing to avoid loose joint. A Guide to Sewer Selection and Installation 13th November 2006

30


Instead of rubber O ring with circular cross section, a triangular shaped rubber ‘O’ ring is also available. When the gasket is placed around the spigot end, it rests firmly against the spigot shoulder and is placed at the centre in the bell. The top section of the gasket will roll over and rest in the annular space after the spigot is pushed in. The limitation of the rubber ‘O’ ring is that it cannot fill the gap between the spigot and socket completely because of its circular profile although it allows higher point compression. Therefore proper control of the spigot-socket diameters is crucial to prevent very high rubber compression (cause difficulty in jointing or additional cracking force on the socket) and very low compression (not effective jointing). 2. Cement mortar can be used to fill the gap in a rebated joint. However, this will induced rigidity at the joint and thus only suitable for application where flexibility is not required. Angular deflections of the joint for RC pipes shall be in accordance with BS 5911: Part 100: 1998. The allowable angular deflections of RC pipes are shown in Table 4.11 below: Table 4.12: Allowable Angular Deflection of RC Pipes Nominal Size (DN), mm DN 150 to DN 600 DN 675 to DN 1200 DN 1350 to DN 1800 Above DN 1800

Angular Deflection 2° or 35 mm per metre length 1° or 17.5 mm per metre length 0.5° or 9 mm per metre length to be stated by the manufacturer

(Ref: BS 5911: Part 100: 1988, page 15)

4.3.5

Fittings

Fittings are not a stock item with RC pipes manufacturers and any junctions or bends are made up as specials. Specifications of fittings like bends and junctions are provided in MS 881: 1991. The typical ranges of fitting for RC pipes are shown in Figure 4.10. Figure 4.10: Typical Range of Fittings for RC Pipes

Bends

Right angle socket junction


Right-angle tumbling bay junction

31


Figure 4.10: Typical Range of Fittings for RC Pipes (continued)

Oblique-angled socket junction

4.3.6

Oblique-angled tumbling bay junction

Pipeline Hydraulic Design

Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 4.12 shall be referred to when determining discharge capacity of the RC pipes for gravity sewer application. Table 4.13: Colebrook-White Roughness Coefficient, ks for RC Pipes Pipe Condition New Old

Roughness, ks (mm) 0.15 3.0

Whilst, the selection of the RC pipes diameter and gradient for gravity sewer application to cope with the peak flow, can be also based on the one of the following equations as shown in Table 4.13 below.

Table 4.14: Various Pipeline Hydraulic Design Equations of RC Pipes for Gravity Sewerage System Design Equations

Name of Coefficient

Colebrook-White Equation

Roughness Coefficient, ks

Manning Equation Hazen-Williams Equation

Manning Coefficient, n Hazen-Williams Coefficient, C

Pipeline Condition N/A* Good Bad

Typical Value of Coefficient 0.3 to 3.0 0.012 0.016

N/A*

120

*N/A – not applicable


32


4.3.7

Application of Pipes

The application of RC pipes for gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. The advantages and disadvantages of the RC pipes for this application are listed in Table 4.14 below. Table 4.15: Advantages and Disadvantages of RC Pipe •

•

• • • •

• •

Advantages For the same loading and ground conditions, installation requirements are not as stringent as for flexible pipes like HDPE and GRP. High beam and ring crushing strength permits RC to bridge lengths without support and tolerate a degree of subsidence and differential settlement. Not degraded by UV radiation, unlike plastics without carbon black. No significant variation in dimensions or shape with temperature variation, unlike plastics. Not degraded by some chemicals, such as solvents that degrade HDPE and GRP. Where installed with an embedment that is not designed to give side support, there is no concern of structural failure where there may be third party interference, unlike flexible pipes. Rolling rubber ring requires no lubricant, unlike skid joints used with GRP and HDPE pipe. Available as microtunnelling and jacking pipe.

• • • • •

• •

•

• •


Disadvantages Subject to H2S related corrosion. Field welding of PVC/HDPE liner at pipe joints is required to ensure integrity of liner for resistance to H2S attack. Heavier than HDPE and GRP. Mechanical lifting is always required. Pipe lengths are shorter than lengths available with HDPE and GRP thus more joints are required. Rougher bore than HDPE and GRP, requiring a steeper sewer grade or larger pipe diameter. Slime adheres more readily to RC than plastics and is less easily washed off. Less abrasion resistant than plastic pipes and VC. Risk of structural failure is increased where design requires side support. It is possible this side support may be disturbed from third party interference. When using only haunch support for RC pipe, then disturbance of the ground adjacent to the pipeline is not likely to affect the pipeline performance, unlike flexible pipe. Fittings are not readily available. Retrospective installation of fittings / repair is complicated.

33


4.4

Ductile Iron (DI) Pipe

The design data and specifications of DI pipes for gravity sewerage system are summarised in Table 4.15 below: Table 4.16: Summary of Ductile Iron Pipes Design and Specifications for Gravity Sewerage System Material Nominal Diameter (DN), mm Standard Length Classes • Wall thickness •

Pressure Class

Jointing Methods

Protective Coating • External • Internal Standards

Malaysian Sewerage Industry Guidelines (MSIG) • Public gravity sewer

Approved Manufacturers/Suppliers

Summary Scrap ductile iron, steel, ferrosilicon, coke, limestone and magnesium DN 100 to DN 2000 mm 5.0 to 8.15 m • • • • • • • • •

Conform to BS EN 545 Minimum Class K9 Conform to BS EN 598 For pipes with operating pressure up to 6 bar (0.6 MPa) Push-in joints with rubber ring Self-anchoring push-in joints Slip-on couplings Flange end joints with rubber gasket Self-anchoring tie-bar joints

• Metallic zinc coating with bitumen finished coat. • Extra HDPE sleeving for severe ground conditions • High alumina cement mortar lining is preferred BS EN 598 Manufacture BS EN 545 BS 8010 ISO 2531 AS 3680 HDPE Sleeving AS/NZS 2566.1 Design BS EN 598 Annex C AS 2566.2 (basic) Installation BS 8010 section 2.1 (detail) • • • •

For high load applications For above ground installation Pipe protection linings and coatings are required Polyethylene sleeving is required for all buried application.

Refer to Table D1 and DGSS latest approval list


34


4.4.1

Manufacture

Material used is basically ductile iron. Some may include certain percentages of recycled material produced during the casting process. Ductile iron is also known as spheroidal or nodular graphite (SG) cast iron. The casting material, i.e iron and carbon based, and the latter element is being present principally as graphite in spherical nodular form to improve the tensile, bending strength and fracture toughness of the material. It is also incorporated some of the miscellaneous components such as silicon, manganese, magnesium, phosphorus, sulphur. The raw materials are normally sourced from outside Malaysia. The DI pipes can be manufactured into two types of pipes as shown in Figure 4.11 below: Figure 4.11: Types of DI Pipes

Spigot socket pipe

Flanged pipe Flanged pipes are used only where restrained DI joints are required and spigot-socket restrained DI joints are inappropriate. The common manufacturing process to manufacture DI pipes is centrifugal cast, while the DI fittings are cast using traditional gravity casting. The flanged DI spun pipes are manufactured by centrifugally casting the pipe barrel and then the DI flanges is welded or screwed loose on to specially prepared ends. Figure 4.12 shows the typical flow manufacturing process of centrifugal cast DI pipes.


35


Figure 4.12: Typical Manufacturing Process of Centrifugal Casting for DI Pipes

Melting Raw materials are melted and chemically analysed Chemical analysis

Nodularisation treatment

Centrifugally force moulding

Pipes are formed by introducing the treated molten into a revolving, water cooled steel mould with centrifugal force

Annealing

External coating

Internal lining

Finishing

Curing


Metallic zinc coating is applied on the external wall of the pipes

Cement mortar or bitumen is placed in slowly rotating pipes which is then spun rapidly

Bitumen paint is applied at the external wall to provide a bare protection to external corrosion

Inspection

Storage

36


4.4.2

Protective Coatings/Linings

The types of external protective coatings available for DI pipes are as follows: 1. Metallic zinc coatings and prime layer with bitumen paint as finished layer is commonly used and recommended by DGSS. 2. Epoxy coating is to be used for all fittings and accessories as required by DGSS. 3. Bitumen paint can also be used as the protective coating for the pipes and fittings. However, this is not commonly used and prior approval from DGSS is required. 4. Polyethylene sleeving can be used as a final layer to provide extra protection when installed in corrosive ground. DGSS requires this sleeving to be used for all buried application. Polyethylene sleeve can be applied in the factory during pipe production or installed on site. 5. Cathodic protection is an alternative to the other protection system but is not normally preferred. Bonding across the joints is necessary to guarantee electrical continuity when this system is to be installed. The types of internally protective lining available for DI pipes are as follows: 1. High alumina cement mortar lining is commonly used in sewage application and recommended by DGSS. The smooth cement mortar surface protects the pipe against corrosion and allows a smoother flow pattern. Epoxy-based coating on the end surfaces is required if this lining is used. The HAC lining shall be in accordance with BS EN 598: 1994 as shown in Table 4.16 below: Table 4.17: HAC Lining Thickness of Various Sizes of DI Pipes Nominal Size, DN DN 100 to 300 DN 350 to 600 DN 700 to 1200 DN 1400 to 2000

Nominal Thickness 3.5 5.0 6.0 9.0

Dimensions in milimetres Maximum crack width Tolerance and radial displacement -1.5 0.6 -2.0 0.7 -2.5 0.8 -3.0 0.8

(Ref: BS EN 598: 1994, page 10) 2. Other cement lining using Portland cement or sulphate resistant cements are also available. However the usage of this cement lining is limited by the characteristic of the medium to be conveyed.

4.4.3

Sizes/Classes

Nominal size (DN) for ductile iron pipes have dimensions based on imperial sizing. As a result, the metric nominal sizing relates only roughly to the internal diameter of the pipe after cement lining. The bore of the pipe is governed by the classes and pressure load to the pipe, which will then affect the iron wall thickness. The minimum iron wall thickness of the pipe shall not be less than the minimum values given in BS EN 598:1995.


37


Pipe Lengths are standardized according to BS EN 598:1995 and are within ±150 mm of the standard lengths as Table 4.17 below: Table 4.18: Standard Pipe Lengths of Various Sizes of DI Pipes Nominal Size (DN) DN 100 to 600 DN 700 to 800 DN 900 to 1400 DN 1500 to 2000

Standard Length, m 5.0, 5.5 or 6.0 5.5, 6.0 or 7.0 6.0, 7.0 or 8.15 8.15

(Ref: BS EN 598: 1994, page 7) Classes of DI pipe have not been defined in the European Standard BS EN 598:1995 for sewerage applications. However, the standard has set specific requirements on pipe performance to ensure the pipes are capable to operate with pressures up to 6 bar (0.6 MPa). The approved DI pipes manufactured in Malaysia are classified according to BS EN 545:2002 – Ductile iron pipes, fittings, accessories and their joints for water pipeline. In this standard, the DI pipe is classified based on wall thickness and not pressure rating. Class K9 is the minimum class of ductile iron pipes. The wall thickness (e) of this class is determined from the formula e = K (0.5 + 0.001 DN) as given in BS EN 545:2000 for pressurized water pipelines and can withstand pressures up to 60 bar (6MPa) for DN 200 and below, decreasing to 30 bar (3MPa) for DN 600 and above for spigot-socket pipes. As a result the minimum wall thickness is almost doubled those set in BS EN 598:1995. Hence Class K9 is acceptable in sewerage application including gravity sewer system.

4.4.4

Joints

The joints for DI pipe are generally of a type using elastomeric gaskets as a sealing medium. Joint methods used in DI pipe installation for gravity system are as follows: 1.

Push-in joints are made on pipes having a chamfered plain spigot at one end and especially formed socket at the other. The sockets shall be grooved to capture elastomeric seals. The seal is affected by means of a gasket placed within the socket before jointing. Figure 4.13 shows the typical push in joints for DI pipes. Figure 4.13: Typical Push in Joints for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 18) 2.

Self-anchoring push-in joints have a special gasket in respect of dimensions and shape but stainless steel toothed inserts are moulded into the gasket. The locking mechanism is added to prevent pull out of the joint, which may result from internal pressure or movement of the pipeline due to external forces.


38


These joint types lend themselves for use in ground that may allow significant pipeline settlement, for steep slopes, for watercourse crossings and for above ground. Tyton-Loc is an example of this type of joint. The typical self-anchoring push-in joint of DI pipes is shown in Figure 4.14 below. Figure 4.14: Typical Self-anchoring Push-in Joint for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 18) 3. Flange joints are made on pipes by welding, screwing or integrally casting flanges onto the end of the standard pipe with a seal of 3mm flat elastomeric full face gasket compressed between the flanges by means of bolts. Figure 4.15 shows the typical ranges of flange of DI pipes. Figure 4.15: Typical Ranges of Flange for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 22) Sealing materials are to be of elastomeric compounds comprising suitable polymers such as: 1. Ethylene propylene diene monomer (EPDM) with 40% minimum volume of compound for IRHD of >=55<85; or 2. Styrene butadiene rubber (SBR) with 50% minimum volume of compound for IRHD of >=55<85. The design of the seal’s profile and the compounding of the elastomer needs to ensure long term sealing of the joint. The elastomer seals shall be protected from unnecessary exposure to the effects of ultra-violet light and ozone. A Guide to Sewer Selection and Installation 13th November 2006

39


Jointing lubricant of water based emulsion is required in the application of elastomeric seals to achieve the following: • Provide sufficient lubrication to prevent damage to joint seals or surfaces of jointing; • Enable correctly configured jointing; • To remain as an effective lubricant under wet conditions. Allowable angular deflections of flexible joints for DI pipes include push-in joint and mechanical joint according to BS EN 598: 1995 is shown in Table 4.18 below: Table 4.19: Allowable Angular Deflection of Jointing for DI Pipes Nominal Size (DN) DN 100 to DN 300 DN 350 to DN 600 DN 700 to DN 2000

Deflection 3.5° 2.5° 1.5°

(Ref: BS EN 598: 1998, page 12) Angular deflections of the self-anchoring push-in joints however could be slightly higher depending on manufacturing tolerance of particular manufacturers.

4.4.5

Fittings

For gravity sewer applications, the exact fittings required for junctions and manhole drops are not available. The configurations of fittings also vary from those normally used in VC fittings. The fittings come with either Tyton joint, flange joint or other joints. Figure 4.16 shows the various ranges of fittings available for DI pipe. Figure 4.16: Various Range of Fittings for DI Pipes

Flange-flange bend

Spigot-spigot bend

Socket-socket bend

Socket-socket-flange tee

Spigot-spigot-flange tee

Flange-flange-flange tee

Spigot-spigot-spigot tee


Socket-socket-socket tee

40


Figure 4.16: Various Range of Fittings for DI Pipes (continued)

Flange-flange offset taper

Flange-flange taper

Spigot-flange taper

Spigot-spigot taper

Socket-flange taper

Socket-socket taper

Flange-spigot connector

4.4.6

Flange-socket connector

Socket-socket connector

Cap

Plug

Socket-socket slip collar


The selection of the DI pipes diameter and gradient for gravity sewer application to cope with the peak flow, can be based on one of the following equations as shown in Table 4.19 below. Table 4.20: Various Pipeline Hydraulic Design Equations of DI Pipes for Gravity Sewerage System Name of Coefficient

Pipeline Condition

Typical Value of Coefficient

Colebrook-White Equation

Roughness Coefficient, ks

N/A*

0.046

Manning Equation

Manning Coefficient, n

Good Bad

0.012 0.015

Hazen-Williams Coefficient, C

N/A*

130 to 140

Design Equations

Hazen-Williams Equation *N/A – not applicable


41


4.4.7


The application of DI pipes for gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. The advantages and disadvantages of the DI pipes for this application are listed in Table 4.20 below. Table 4.21: Advantages and Disadvantages of Ductile Iron Pipes

• • • •

•

•

• • •

Advantages Higher beam, ring and shear strength than VC and plastic pipes Not affected by UV radiation. Slight change in length with temperature variations, unlike plastic pipes. High ring stiffness permits use with very shallow cover and up to unusually large superimposed loads unlike VC and plastic pipes. High beam and shear strength permits use in ground subject to substantial differential settlement. Also use of Tyton-Loc joint prevents joint pullout in such conditions. Not subject to damage from substantial impact loads making it suitable for rail, over dimensional highway and bridge crossings unlike unencased GRP and VC High resistance to shock or impact due to improper handling, water hammer or unstable condition. Able to deform when stressed beyond yield point. Superior tensile strength to withstand severe loads and high internal pressure.


• • • • • • • •

• •

Disadvantages More expensive than plastics, RC and VC. Heavier than plastics. Mechanical lifting is required. External polyethylene (PE) sleeving required for buried application in corrosive soil conditions. Care is required to ensure sleeving completely wraps the pipe and is sealed. PE sleeving is easily damaged. Where sleeving is damaged in certain aggressive soils (pH ≤5 and ≥9), corrosion will occur. Internally less corrosion resistant than VC and plastics. Less abrasion resistant than plastic pipes and VC. Rougher bore than plastics thus require steeper grades or larger diameter pipes. Slime adheres more readily to DICL than plastics and is less easily washed off. Cement mortar lining is corroded by sulphuric acid produced from hydrogen sulphide generated in septic sewage. Ductile iron is corroded by hydrogen sulphide and sulphuric acid produced in septic sewage conditions.

42


4.5

Glass-fibre Reinforced Plastic (GRP) Pipe

The GRP pipes are classified as a composite pipe where it is a heterogeneous combination of two or more materials (reinforce agent and matrix), differing in form or composition on a macro-scale. The design data and specifications of the GRP pipes for gravity sewerage system are summarised in Table 4.21 below: Table 4.22: Summary of GRP Pipes Design and Specifications for Gravity Sewerage System Summary Material • Filament Wound Pipe

•

Centrifugally Cast Pipe

Nominal Diameter (DN), mm Effective Length, m Classes • Stiffness Classes (SN) • Pressure Class Jointing Methods


Malaysian Sewerage Industry Guidelines (MSIG)

Approved Suppliers/Manufacturers

• • • •

Thermosetting resin or polyester resin Roving or woven fabrics of E-glass filaments Surface tissues Additional material such as additives and colourants

• Thermosetting resin or polyester resin • Chopped strand mat of E-glass filaments • Surface tissues • Aggregates and fillers • Additional material such as additives and colourants DN 100 to 4000 mm 3.0 and 6.0 m • Conform to BS 5480: 1990 • SN 1250, 2500, 5000, 10 000, 15 000, 20 000 • G – can withstand internal hydrostatic pressures up to 0.5 bar • Integral socket and spigot joint with rubber ring • Loose collar joint • Butt joint • Flange joint • •

Thermosetting resin Resin rich lining with superficial layers of C glass material BS 5480: 1990 Manufacture AS 3571: 1989 BS 8010: Section 2.5: 1989 ASTM D 3262 AS/NZS 2566.1: 1998 Structural Pipeline Design AS/NZS 2566.2: 2002 Installation • Only pipe with DN600 mm and above is allowed at where VC and RC pipes are not suitable. • Under special circumstances with prior approval from DGSS Refer to Table D1 and DGSS latest approval list


43


4.5.1

Manufacture

Material compositions of the GRP pipes consist mainly of thermosetting resin, normally isophthalic polyester, or vinyl ester resin for special chemical resistance requirements. It is incorporated with a fibrous reinforcement derived from continuously drawn filaments of E-glass and shall be used in the following forms alone or in any combination subject to compatibility with the resin used: a. Roving; b. Chopped strand mat; c. Woven fabric. A surface tissue shall be incorporated into the superficial layers of the internal surfaces of a GRP pipe or fittings to enhance chemical resistance. They shall be made of: a. Glass material of C-glass; or b. Woven textiles based on polyester or acrylic fibres; or c. Non-woven textiles based on polyester or acrylic fibres. An aggregates and fillers can also be incorporated into the GRP pipe as a part of the composite structure to enhance the stiffness of the pipe. The aggregates shall be of inert granular material with the size range between 0.05mm and 5mm and the inert fillers shall be of a fine material with a particle size below 0.05mm. The resin may incorporate the additives for modifying the properties of the resin, and pigments or dyes as a colourant. There are two types of manufacturing process for GRP pipes, which are: 1. Filament winding 2. Centrifugally casting The filament wound GRP pipe is constructed of two layers. The inner layer is the superior chemical resistance made by a resin rich hand laid liner and backed by the tremendous strength offered by a continuous filament helical wound on the outside (the outer layer). The inner liners provide very smooth surfaces. The outer layers that give the strength to the pipe are constructed by filament winding machine. The manufacturing process involves a band of continuous resin impregnated roving (fiberglass), which is wrapped around a rotating mandrel and then cured at room temperature to produce the final product. The technique offers high speed and precise method for placing the composite layers. The mechanical strength of the filament wound products/components parameters are winding angle, fiber tension, resin chemistry and curing cycle. The outer liner protects the resin rich chemical resistant liner from mechanical damage and preventing sagging between supports. The typical filament wound GRP pipe is shown in Figure 4.17 below. Figure 4.17: Typical Filament Wound GRP Pipes


44


The centrifugally cast GRP pipe is a combination of two materials. An inner and outer liner of GRP is a combination of chopped strand of E-glass filament reinforcement and synthetic resin sandwiching a core of composite structure. Whilst the composite structure is a combination of aggregates of inert granular material such as graded silica sands and the inert fillers of a fine material as used in concrete mixed with synthetic resin. The typical form of centrifugally cast GRP pipe is shown in Figure 4.18 below: Figure 4.18: Typical Centrifugally Cast GRP Pipes

4.5.2


External protection of GRP pipe is by a layer of thermosetting resin. The layer provides scratch resistance and also acts as a barrier against ultraviolet. Internal protection of GRP pipe is by a smooth resin rich lining free of glass filament that has good corrosion resistance across a wide pH range. It also enhances a smooth flow in the pipe. The surface tissue shall be incorporated to the pipe to enhance chemical resistance.

4.5.3 Sizes/Classes Nominal size (DN) of GRP pipe is a numerical designation of size designated by outside diameters or by thread size. It is a convenient round number for reference purposes and is only loosely related to manufacturing dimensions. The GRP pipes shall be designated by a nominal size (DN) selected from the values given in Table 4.22 below: Table 4.23: Nominal Sizes of GRP Pipes Nominal size (DN) ≥ 100mm to 500mm >500mm to 2600mm >2600mm to 4000mm

Increment 50 100 200

(Ref: BS 5480: 1990, page 7) Pipe Lengths should show the effective length of the pipes. The pipes shall comprise a straight length of either 3m or 6m with the permissible deviations of ± 25mm. The GRP pipes can be cut and chamfered to the desirable length by water-fed petrol driven abrasive disc cutter. Sealing of cut pipe ends is not required. Classes of GRP pipes for gravity system as in accordance with BS 5480: 1990 are defined by the pressure class and stiffness class of the pipe, as described below: 1. Pressure – GRP pipes is classified for use under gravity, indicated by G, imply that the component is capable of withstanding internal hydrostatic pressure up to 0.5 bar.


45


2. Stiffness – GRP pipes is classified according to their minimum initial specific stiffness. This shall be referred to the preferred numbers (SN values) for nominal minimum initial stiffness in N/m2 of SN 1250, 2500, 5000, 10000, 15000 and 20000. The ring bending stiffness is increased as the wall thickness of the GRP pipe is increased. Figure 4.19 defines the stiffness of the GRP pipe. Figure 4.19: Definition of Stiffness for GRP Pipes External loading

Circumferential deflection

4.5.4 Joints Joints for GRP pipe are generally of a type of flexible joints using elastomeric sealing rings as a medium to allow a deflection for the pipe. The most commonly used types of joint for GRP pipe for gravity system are as following: 1. Integral socket and spigot joint is a push-in joint incorporating a specially formed socket and spigot with the seal is effected by means of an elastomeric gasket. Spigots are to have witness marks to identify the insertion depth. Figure 4.20 shows the typical integral socket and spigot joint of GRP pipes.

Figure 4.20: Typical Integral Socket and Spigot Joint of GRP Pipes (Ref: BS 8010: Section 2.5: 1998 Appendix A, page 15) 2. Loose collar joint is a simple push-in joint consisting of a full-width elastomeric profile, usually of an EPDM rubber, overwrapped with GRP. The typical of this joint is shown in Figure 4.21 below.

Figure 4.21: Typical Loose Collar Joint of GRP Pipes (Ref: BS 8010: Section 2.5: 1998 Appendix A, page 15) A Guide to Sewer Selection and Installation 13th November 2006

46


Meanwhile, Figure 4.22 shows the methods of jointing for GRP pipes that can also be applied when the flexibility is not the major concern. Figure 4.22: Typical Rigid Joints of GRP Pipe

Butt Joint (Ref: MI Pipe Catalogue, Appendix 1)

Flange Joint

Sealing materials are to be of elastomeric compounds comprising suitable polymers such as: 1. Ethylene propylene diene monomer (EPDM) with 40% minimum volume of compound for IRHD of >=55<85; or 2. Styrene butadiene rubber (SBR) with 50% minimum volume of compound for IRHD of >=55<85. The design of the seal’s profile and the compounding of the elastomer needs to ensure long term sealing of the joint. Jointing lubricant of water based emulsion is required in the application of elastomeric seals to achieve the following: • Provide sufficient lubrication to prevent damage to joint seals or surfaces of jointing; • Enable correctly configured jointing; • To remain as an effective lubricant under wet conditions. Allowable angular deflections of flexible joint for the GRP pipes for gravity system such as rolling or restrained ring joints relative to the nominal size of the pipework according to BS 5480: 1990 are as Table 4.23 below: Table 4.24: Angular Deflection Limits Relative to the Nominal Size of the GRP Pipework Nominal Size (DN) < 500 ≥ 500 to < 900 ≥ 900 to < 1800 ≥ 1800

Angular Deflection (°) 3 2 1 0.5

(Ref: BS 5480: 1990, page 10) 4.5.5 Fittings Fittings of the GRP pipe for gravity system are made of continuous glass rovings with either chopped strand mat or chopped rovings (E-glass) with coupling agent to bond to resin. The chopped rovings coupling shall be coated with pigmented resin or acrylic paint for above ground use. Figure 4.23 shows the various ranges of fittings for GRP pipe, to be used for gravity system.


47


Figure 4.23: Various Ranges of Fittings for GRP Pipe

Bends

Tees

Y Junction

Tapers

4.5.6 Pipeline Hydraulic Design There are two methods of hydraulic design for the GFRP pipes as indicated in the Table 4.24 below: Table 4.25: Methods of Hydraulic Design of GRP Pipe Methods Colebrooke-White Hazen-Williams


Coefficient Roughness, Ks = 0.003mm C = 150

48


4.5.7 Application of Pipes The application of GRP pipes for the gravity systems may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 4.25 below lists the advantages and disadvantages of the GRP pipe for this application. Table 4.26: Advantages and Disadvantages of GRP Pipe • • • •

• • • • • •

Advantages Lighter than VC and RC. Longer than VC and RC, thus less joints. Immune to H2S attack unlike RC. Smoother bore than VC and RC permits flatter grades or smaller diameter pipes. Slime does not build up as readily as with VC and RC and is more easily washed off. Greater internal diameter than the equivalent size and class for other pipes permits greater flow. Resistant to more chemicals than RC. Resin liner type can be altered to suit chemical resistance required Pipes can be cut to length on site and joined with coupling (resin seal coat over cut surface is required). Thermoset GRP pipe does not distort with ambient temperature increase like thermoplastic HDPE pipe. Available as microtunnelling and jacking pipe.


• • • •

• • •

• • •

Disadvantages Heavier than HDPE. Sides fill support is required to prevent excessive pipe flexure. Easily damaged by impact with hard objects, particularly during backfill. External impacts can result in star cracking of the inner liner. This can go undetected in small diameter pipes where internal inspection is difficult. Degraded by high concentrations of certain chemicals after long contact. Badly damaged pipe is difficult to repair and must be replaced. Damaged sections require cutting out or repair using couplings or clamps; in-situ repair using epoxy patching not advisable as methods not proven. Branch connections to existing pipelines more difficult than other pipe types. Low beam shear strength makes it unsuitable in ground subject to large movements or subsidence. Short lengths of pipe are required immediately out of fixed structures, to prevent pipe shearing from differential settlement.

49

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System)

4.6

Profile Wall High Density Polyethylene (HDPE) Pipe

The design data and specifications of profile wall HDPE pipes for gravity sewerage system are summarised in Table 4.26 below: Table 4.27: Summary of Profile Wall HDPE Pipes Design and Specifications for Gravity Sewerage System

Nominal Diameter (ID), mm Effective Length, m Classes • Nominal Stiffness (SN) • Material Type Jointing Method

Summary • High Density Polyethylene • Carbon Black • Antioxidants 100 to 3000 mm 4.0, 6.0, 9.0 and 12.0 m • Conform to AS/NZS 2566.1:1998 and DIN 16961-1 • SN 1250, SN 2500 • PE 80, PE 100 • Spigot-socket with rubber ring seals • Thermofusion welding a. Welded spigot-socket b. Welded plain ends using a fillet or butt weld c. Welded spigot socket using a butt weld d. Flange end joint


• Not applicable • Not applicable Manufacture

Material

Malaysian Sewerage Industry Guidelines Approved Manufacturers/Suppliers


DIN 16961-1 CAN/CSA-B182.6-M92 ISO TC 138 SC1 CEN/TC 155/WG 13 SFS 3453 ASTM D 3350 ASTM D 3212 AS/NZS 2566.1:1998 Design AS/NZS 2566.1:2002 Installation Only for special circumstances with prior approval from DGSS Refer to Table D1 and DGSS latest approval list

50


4.6.1

Manufacture

Material composition of the profile wall HDPE pipes shall be a high density polyethylene (HDPE) plastic in the form of powders, granules or pellets with no more than 10% of recycled materials. The materials shall be as uniform in composition and size and as free of contamination. Some carbon black or titanium dioxide, about 2-3% may be added as ultraviolet stabiliser. Other additives added are lubricants, antioxidants and pigments. The profile wall HDPE pipes that are allowed for gravity system application shall be doubled wall or triple wall corrugated as shown in Figure 4.24 below. Figure 4.24: Types of Profile Wall HDPE Pipe for Gravity System

Double Wall Corrugated HDPE Pipe

Cross Sectional Area of the Pipe

Triple Wall Corrugated Pipe

Cross Sectional Area of the Pipe

The profile wall HDPE pipes can be manufactured into various forms of pipes depending on their jointing method as shown in Figure 4.25 below: Figure 4.25: Various Forms of Profile Wall HDPE Pipe

Spigot socket pipe

Threaded pipe

Double spigot pipe

Flanged pipe


51


Manufacturing processes of profile wall HDPE pipes can be by injection moulding or rotational moulding. The steps of manufacturing process of profile wall HDPE pipe is varied, depending on the patterns of the profile wall pipe, which is helical or annular. Figure 4.26: Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes (Option 1)

Extrusion of hollow rib PE Strips

Helical Winding

A molten PE is pass through a die to form a hollow rib PE strips

An extruded strip of PE is helically winded on a revolving heated mandrel

Overlapping Next winding overlapping on part of the previous winding

Thermofusion Bond

Formation of Profile Wall

Formation of Spigot Socket

Positions of Rubber Ring

The overlapping molten layers is fused together

Polypropylene tribes are inserted to hollow ribs to maintain the round profile

The ends of the mandrel are of special shapes to form spigot and socket ends of solid wall contrition

Rubber seal with keys is placed around the mandrel end that forms the socket, so that it is mechanically bonded to the inside of the socket

Cooling

Inspection

Marking


Storage

52


Figure 4.27: Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes (Option 2)

Extrusion of hollow rib PE strips

Helical winding

Thermofusion

Formation of spigot socket

A molten PE is pass through a die to form a hollow rib PE strips

An extruded strip is helically winded about a mandrel. However, the cross section of the extruded strip can only have one hollow rib

The next winding fuses to the edge of the previous winding

A socket shape on the pipe end is mould at the end of the mandrel. A rubber ring is not bonded to the socket

Cooling

Inspection

Marking

Storage

Figure 4.28: Helical Pattern of Profile Wall HDPE Pipe


53


Figure 4.29: Typical Manufacturing Process of Annular Profile Wall HDPE Pipe

Extrusion of Solid PE Pipe

Co-extrusion of Large Diameter Pipe

Thermofusion

A molten PE is extruded using continuos vacuum moulding through a circular die.

A molten larger diameter pipe is molded with annular corrugation by travelling mould blocks and co-extended around the smaller diameter of solid wall PE pipe.

The two pipes is are fused together.

Formation of Socket

A socket of solid wall construction is formed on the pipe end on the outside pipe wall.

Cooling

Inspection

Marking

Storage

Figure 4.30: Annular Pattern of Profile Wall HDPE Pipe


54


4.6.2


External and internal protection for profile wall HDPE pipe is not required.

4.6.3

Sizes/Classes

Nominal size (DN) is commonly used as a numerical designation of the internal diameter of HDPE profile wall pipes. It is a convenient round number approximately equal to a manufacturing dimension. In some cases, two internal diameters may be assigned to one nominal size. Pipe Lengths should show the effective length of the pipe. HDPE profile wall pipes can be cut on site using most types of saws. However, it is not desirable to cut helically wound profile pipe, as it is difficult to cut square and need to seal open end of profile. Classes of HDPE profile wall pipes for gravity sewer are classified according to: 1. AS/NZS 2566.1:1998 This standard defined the HDPE profile wall in terms of nominal stiffness of pipe, which is governed by the HDPE grade, wall thickness and cross-section geometry. The minimum pipe ring stiffness is determined using must not be less than SN 1250 and SN 2500 corresponding to a value between 1250 N/m2 and 2500 N/m2. The minimum value between these limits depends on the installation conditions. 2. MS 1058:1994 According to this standard, the HDPE profile wall pipes for gravity sewer are defined by the material type and the level of minimum required strength as shown in Table 4.27. The design stress of the pipe is obtained by applying a design coefficient of 1.25 to the minimum required strength value of the pipe. Table 4.28: Classifications of Profile Wall HDPE Pipe Type of Material PE 80 PE 100

Minimum Required Strength, MPa 8.0 10.0

Max. Allowable Design Stress, MPa 6.3 8.0

The wall thickness of profile wall HDPE pipe shall not be less than 2.3mm.

4.6.4

Joints

The jointing methods for the profile wall HDPE pipes are of the following: a. Spigot-socket with rubber ring seals type as shown in Figure 4.31 below. Figure 4.31: Spigot Socket with Rubber Ring Seals Joint for Profile Wall HDPE Pipes


55


b. Thermofusion Welding is formerly known as fusion welding. This method uses heated tools to weld the joint faces together and can be applied to specially make moulded socket fittings and also to those made for butt jointing. The thermofusion welding can be carried out to the following: e. Welded spigot-socket The socket fusion welding or known as extrusion welding is recommended for low pressure application only. The method can be employed when using moulded polyethylene fittings and spigot and socket joints. Figure 4.32: Typical Socket Fusion Welding for Profile Wall HDPE Pipes

f.

Welded plain ends using a fillet or butt weld Butt fusion welding is suited to the jointing of HDPE for all sizes of pipe. The joint is produced by heating the faces of the components against a heated flat plate, which is usually coated with PTFE and then bringing them together under controlled pressure. An example of butt fusion welded is shown in Figure 4.33 below. Figure 4.33: Butt Weld Joint of Profile Wall HDPE Pipe

•

Welded spigot socket using a butt weld One end of the pipe is opened up to act as the socket of a moulded fitting and thereafter the butt fusion welding is carried out. Figure 4.34 shows an example of this type of jointing. Figure 4.34: Butt Welded Joint of Spigot Socket Profile Wall HDPE Pipe


56


c. Flange end joint Flange joints are most commonly used for larger diameter pipes. It consist either a full face or stub flanges welded to the pipe or alternately can be formed on the pipe. Figure 4.35: Flange Ends Joint of Profile Wall HDPE Pipe

(Ref: Weholite Spiro Pipe System Catalogue) The jointing of the profile wall HDPE pipes can also be enhanced with the application of certain type of fittings such as: 1. Metal fittings These fittings are based on the type of compression fittings commonly used with copper tube such as: a. Compression fittings - The dimensions of the pipe are generally unaltered, the joint being effected by the use of an internal liner and a compression ring or sleeve which distorts and compresses the pipe wall onto the liner, thus gripping the wall of the pipe. b. Screwed fittings used to joint the profile wall HDPE pipe is shown in Figure 4.36 below. Figure 4.36: Screwed Fittings for Jointing of Profile Wall HDPE Pipe

2. Plastic Fittings – The types of plastic fittings for jointing of profile wall HDPE pipe is shown in Figure 4.37 below. Figure 4.37: Plastic Fittings for Jointing of Profile Wall HDPE Pipe

Compression fittings

Flange fittings

(Ref: www.hdpefittings.com) Sealing material of rubber ring seal type shall be used for profile wall HDPE pipes. The rubber seal can be positioned and bonded in the socket prior to jointing or placed between the outer


57


corrugations at the spigot end. All joints are of the skid type where application of lubricant is required at the jointing surfaces. The bonded rubber seals to the socket are to prevent displacement on jointing. However the seals have tendency to collect dirt. Rubber seal that retained between ribs can prevent sideways stress relaxation of the rubber and the rubber seal is less likely to be displaced from its correct sealing location. However, extra efforts are required to place the seal between the corrugations correctly as there is a tendency for it to twist. Maximum allowable vertical deflection for profile wall HDPE pipes shall not be more than 5% and 2° horizontal misalignment at 30 days from completion of placement and compaction of all trench and embankment fill material.

4.6.5

Fittings

The fittings for profile wall HDPE can be moulded or fabricated. The fabricated fittings are less compact than the moulded fittings and are thus less convenient for handling and installation. They will also require a greater support area. For junctions, only the Y fitting need be of HDPE materials. An appropriately dimensioned spigot or socket end on the Y or the adaptor to the Y is permitted to be in another material. Figure 4.38 below shows the various ranges of fittings for profile wall HDPE pipe that can be used in gravity system. Figure 4.38: Various Ranges of Fittings for Profile Wall HDPE Pipe for Gravity System

4.6.6


The profile wall HDPE pipe has limiting design criteria of deflection at joints and compressive strain that can be buckling. Colebrook-White roughness coefficients (ks) is recommended to be applied in hydraulic designs of profile wall HDPE pipes for gravity sewer pipelines are as Table 4.28 below: Table 4.29: Colebrook-White Roughness Coefficients (ks) for Profile Wall HDPE Pipe Pipe Condition New Old


Roughness Coefficient, ks 0.06 0.6

58


Old pipe can refer as a plastic pipeline with proper joints having sliming and light silting, as this would occur generally within 2 years of installation.

4.6.7


The application of profile wall HDPE pipes for gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 4.29 lists the advantages and disadvantages of the profile wall HDPE pipe for this application. Table 4.30: Advantages and Disadvantages of Profile Wall HDPE Pipe

• • • • • • • • • • • • •

Advantages Lighter than VC, RC and GRP. Longer than VC and RC thus less joints. Immune to H2S attack. Smoother bore than VC and RC, permits flatter grades or smaller diameter pipes. Resistant to more chemicals than RC and uPVC. Not degraded by UV radiation if carbon black additive is added. More abrasion resistant than RC. Pipes can be manufactured to any length, however this increases pipe cost per metre. Save on the amount of polyethylene used while still achieving the same pipe ring stiffness. Can easily be curved to eliminate need for bends. Suitable for directional drilling, e.g. water courses crossings for syphon. Available joint welding provides higher confidence in achieving long-term leakfree system. Resistant to failure from differential settlement or pipe longitudinal flexibility accommodates large differential ground settlement.

• • •

• • •

•

• •

•

•


Disadvantages Side fill support required to prevent excessive pipe flexure. PE degraded by high concentrations of certain chemicals, such as solvents over long contact times. Welding in the field to repair or add branch off-takes requires dry, clean conditions to be effective. Special equipment and trained equipment operators are required. Pipes susceptible to damage from heavy impact loads. Spigot ends are especially sensitive to damage. Pipes can be distorted in hot weather, that is, ovalisation and bending along the length. Pipe length changes significantly with temperature. Pipes laid in hot weather can decrease in length sometime after backfilling, causing some pull out at joints and fixed structures. Material can collect under the rubber seal, which can affect the seal if not removed. Cleaning under the seal can be overlooked or not done properly. Helical pipes cannot be cut to length. Special puddle flanges are required to achieve a watertight seal when connecting to concrete manholes. Proper sealing is depended on satisfactory vibration of concrete. Fusion repair is difficult to be successfully achieved due to high cleanliness/dryness requirements and heating controls. Requires much thicker wall than uPVC solid wall pipe to achieve equivalent stiffness.

59


Table 4.31: Technical Comparison of Various Types of Pipe for Gravity Sewerage System Description

VCP

Corrosion Resistance

Resistant to acid

Chemical Resistance

Moderate

Impact Resistance Fire Resistance Abrasion Resistance

RC

DI Material Properties Can corrode; requires Resistant to acid with proper protection in some acidic lining soils and septic waters Susceptible to acids (i.e: Resistant to organic sulphuric acid); solvents solvents; requires may cause dissolution protection from acids

GRP

Resistant Good; not affected by salt and hydrogen sulphide attack High; not subject to brittle failure

Profile Wall HDPE

Resistant to acid

Very good

Moderate

Moderate

High

Will not sustain combustion



Will sustain combustion

Will sustain combustion

High

High; moderate under acidic conditions

Moderate; reduce

High

High

Soil Stress Resistance

Withstands high soil loads




Flexible; withstands stress with sidefill support

Hydrostatic Strength

Low

Low

High

High

Moderate

Tensile Strength

High

High; rigid sections; flexibility in system due to shorter lengths

High

Higher than steel and plastic pipe

Has less strength to volume ratio

Pipe Stiffness

Rigid

Rigid

Flexible; bends slightly

Handling, weight

Heavy

Heavy

Heavy

Joining

Push on joint

Push on joint; more joints

Push on joints most common; mechanical joints possible

Rigid on vertical, flexible on horizontal Light; better weight to strength ratio than concrete Push on joints most common; butt joint and flanged joints possible

Moderate

Flexible Light Butt-fusion above ground mostly, bolted flange for equipment connections

(Ref: http://www.healthybuilding.net) A Guide to Sewer Selection and Installation 13th November 2006

60


Table 4.31: Technical Comparison of Various Types of Pipe for Gravity Sewerage System (continued) Description

VCP

Bedding

Lower half support may be necessary

Durability

High; long lifespan

Joint Integrity Water Flow

Temperature Range

Long-term reliability with proper installation Smooth wall; low friction Wide range application

RC

DI Installation Factors More rigid at lower Lower half support may be diameters; still requires necessary careful bedding Service High (with corrosion Moderate control as required) Long-term reliability with proper installation

Long term reliability

Slightly higher friction factor,

Slightly higher friction factor,

Wide range application

Handles very high and low temperatures

GRP

Profile Wall HDPE

Generally requires more sidefill support to control deflection

Generally requires more sidefill support to control deflection

High; long lifespan

Decades

Long-term reliability with proper installation

Butt-fusion results in tight seals

Smooth walls; low friction factor Low impact resistance with decreasing temperatures; lower tensile strength with increasing temperatures

Smooth walls; low friction factor Better low temperature resistance

(Ref: http://www.healthybuilding.net)


61


Table 4.32: Summary of Comparison for Various Types of Pipe for Gravity Sewerage System

No Properties 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Type of Pipe

Service Life Corrosion Resistance Abrasion Resistance Chemical Resistance Degradation by long contact with chemical Temperature Resistance Impact Resistance Hydraulic Smoothness Structural Strength Impermeability Length Sizes (Diameter) Degradation by UV radiation Weight Slime formation Level of wash off Level of bore roughness


VCP *

*

*

* *

*

*

Concrete

* * * *

* * * *

*

*

* * * * *

* * * * *

* *

* * * *

* * * * * * * * * * * *

*

* * * * * * * * * * * * * * * * *

*

*

* * *

* *

* *

* *

* *

* *

* *

* *

*

*

*

DI/Steel * * * * * * * * * * * * * * *

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

HDPE * * *

GRP

* *

* * * * * * * *

* * * * * * * *

* * * *

* * * *

*

*

* * * *

* * * *

*

*

*

*

*

* * *

*

*

*

* * * * * * * * * * * * * * * * *

* * *

* * * *

* * * * *

* * * * *

* * * * *

* * * * *

* * *

* * * * * * *

* * * * * * * * * * *

* * * * * * * * * * *

* * * * * * * * * * *

* *

* *

62

Section 5 Sewer Pipeline - Material Selection (Force Main)

5.0

FORCE MAIN

5.1

General

Minimum design requirements of pressure sewerage pipeline system in Malaysia as stated in MSIG Volume 3 are as summarised below: • Minimum diameter DN 100 minimum • Maximum hydraulic retention time 2 hours • Minimum design pressure 1.5 times working pressure

5.1.1

Definition

Force main means a pipeline facility through which sewage moves in transportation, forcing by: a. Positive pressure created by pumping effect; or b. Differential pressure in the pipeline created by siphon effect.

5.1.2

Pipe Materials and Application Conditions

Pipe materials and application conditions as approved by DGSS for pressure sewerage pipeline system is as Table 5.1 below: Table 5.1: Pressure Sewer Pipe Materials and Application Pipe Material Non-plastic DI Pipe Steel Pipe Plastic GFRP Pipe ABS Pipe

Solid Wall HDPE Pipe


Application Preferred material. DN 100 and above DN 600 and above DN 600 and above for special circumstances with prior approval from DGSS For special circumstances with prior approval from DGSS, which require the benefits of such pipes Prior approval from DGSS is required

63


5.2

Ductile Iron (DI) Pipe

The design data and specifications of DI pipes for force main are summarised in Table 5.2 below: Table 5.2: Summary of DI Pipes Design and Specifications for Force Main

Material Nominal Diameter (DN), mm Standard Length, m Classes • Wall thickness •

Pressure Class

Jointing Methods


Malaysian Sewerage Industry Guideline Vol.3



Summary Scrap ductile iron, steel, ferrosilicon, coke, limestone and magnesium DN 100 to DN 2000 mm 5.0 to 8.15 m • • • • • • • • • • • • •

Conform to BS EN 545 Minimum Class K9 Conform to BS EN 598 For pipes with operating pressure up to 6 bar (0.6 MPa) Push-in joints with rubber ring Self-anchoring push-in joints Slip-on couplings Flange end joints with rubber gasket Self-anchoring tie-bar joints Bolted mechanical joints Flange adapters Self-anchoring flange adapters Self-anchoring bolted mechanical joints

• Metallic zinc coating with bitumen finished coat. • Extra HDPE sleeving for severe ground conditions • High alumina cement mortar lining is preferred BS EN 598 Manufacture BS EN 545 ISO 2531 AS 3680 HDPE Sleeving AS/NZS 2566.1 Design BS EN 598 Annex C AS 2566.2 (basic) Installation BS 8010 section 2.1 (detail) • For high load applications • For above ground installation • Pipe protection linings and coatings are required • Polyethylene sleeving is required for buried application subjected to soil condition. Refer to Table D1 and DGSS latest approval list

64


5.2.1

Manufacture

Material compositions and manufacturing process of DI pipes for force main is identical with DI pipes applied for gravity sewerage system as described in Section 4.4.1.

5.2.2


The protective coatings and linings of the DI pipe for force main has the same components with the DI pipe used for gravity system, as described in Section 4.4.2.

5.2.3

Sizes/Classes

Nominal size (DN) and pipe lengths of DI pipe for force main shall be in accordance with BS EN 598:1995 as described in Section 4.4.3. Classes of DI pipe have not been defined in the European Standard BS EN 598:1995 for sewerage applications. However, the standard has set specific requirements on pipe performance to ensure the pipes are capable to operate with pressures up to 6 bar (0.6 MPa), the assumed maximum for pressure sewer applications. The approved DI pipes manufactured in Malaysia are classified according to BS EN 545:2002 – Ductile iron pipes, fittings, accessories and their joints for water pipeline. In this standard, the DI pipe is classified based on wall thickness and not pressure rating. Class K9, K10 and K12 are the classes of ductile iron pipes that can be used as a force main. The minimum class of DI pipe, i.e Class K9 can withstand pressures up to 60 bar (6.0 MPa) for DN 200 and below, decreasing to 30 bar (3MPa) for DN 600 and above for spigot-socket pipes. The minimum wall thickness of DI pipes is almost doubled those set in BS EN 598:1995, thus increasing the operating pressure of the pipes.

5.2.4

Joints

Joint methods used for DI pipes installation for force main is basically same as the jointing methods recommended for gravity system as described in Section 4.4.4. The additional methods of jointing that can be used for force main are as following: 1. Bolted mechanical joints are made on pipes having a plain spigot at one end and a specially formed socket at the other. The seal is affected by the compression of wedge-shaped gasket between a seating on the inside of the socket and the external surface of the spigot. The typical bolted mechanical joint for DI pipe is shown in Figure 5.1 below. Figure 5.1: Typical Bolted Mechanical Joint of DI Pipes for Force Main

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 18) 2. Flange adapters are designed to connect flange pipe or any flanged fitting to plain-ended pipe. They consist of a flange and sleeve piece, a wedge-shaped rubber gasket and a loose gland fastened to the main body by bolts. Figure 5.2 shows the typical flange adapters for DI pipe that can be used in force main. A Guide to Sewer Selection and Installation 13th November 2006

65


Figure 5.2: Typical Flange Adapters of DI Pipe for Force Main

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 19) 3. Self-anchoring flange adapters consist of a loose flange, bolts and one or more rubber seals carrying anchoring segments. The typical self-anchoring flange adapter is shown in Figure 5.3. Figure 5.3: Typical Self-anchoring Flange Adapters of DI Pipe for Force Main

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 20) 4. Self-anchoring bolted mechanical joints is incorporating a ductile iron circlip which is located in a chamber or groove cast in the socket and which registers with a groove specially machined in the spigot. Figure 5.4 shows the typical self-anchoring bolted mechanical joints of DI pipe that can be used for force main. Figure 5.4: Typical Self -anchoring Bolted Mechanical Joints of DI Pipe for Force Main

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 21) 5. Slip-on couplings are designed for use with plain end pipes. The coupling consists of a sleeve, at the ends of, which are wedge-shaped rubber gaskets and flanges held together by bolts. The typical slip-on coupling for DI pipes is shown in Figure 5.5 below: Figure 5.5: Typical Slip-on Coupling for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 19)


66


6. Self-anchoring tie-bar joints have a special loose anchor ring placed behind the socket and a special anchor ring welded onto the outer surface of the spigot. Figure 5.6 shows the typical self-anchoring tie-bar joints used for DI pipes. Figure 5.6: Typical Self-anchoring Tie-bar Joints for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 20) Sealing materials and jointing lubricant requirements of DI pipes for force main shall follow to that recommended for gravity system as stated in Section 4.4.4. Allowable angular deflections of DI pipes for force main application shall meet the requirements recommended for DI pipes used for gravity system, as described in Section 4.4.4.

5.2.5

Fittings

The range of fittings for DI pipes applied for force main is basically same as the fittings used for gravity system except for the tapers. Figure 5.5 shows the additional ranges of DI fittings that can be applied into the force main, other than those listed in Section 4.4.5. Figure 5.7: Additional Ranges of DI Fittings for Force Main

Socket-socket flange scour tee

Spigot-spigot flange scour tee

Socket-spigot-flange tee

Spigot-spigot-flange tee

Non-thrust dismantling joint (Ref: Power and Water – Water Supply and Sewerage Approved Products Manual/ www.powerwater.com.my)

Thrust dismantling joints (Ref: Power and Water – Water Supply and Sewerage Approved Products Manual/ www.powerwater.com.my)


67


5.2.6


Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 5.3 shall be referred to when determining discharge capacity of the DI pipes for force main. Table 5.3: Colebrook-White Roughness Coefficient, ks for DI Pipes Mean Velocity, V (m/s) 0.8 ≤ V ≤ 1.5 1.5 ≤ V ≤ 2.0 V ≥ 2.0

5.2.7

Roughness, ks (mm) 0.6 0.3 0.15

Application of Pipe

The application of DI pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.4 lists the advantages and disadvantages of the DI pipes for this application. Table 5.4: Advantages and Disadvantages of DI Pipes for Force Main

• • • • • •

• • •

Advantages Higher beam, ring and shear strength than plastic pipes Not affected by UV radiation. Slight change in length with temperature variations, unlike plastic pipes. High ring stiffness permits use with very shallow cover and up to unusually large superimposed loads unlike plastic pipes. High beam and shear strength permits use in ground subject to substantial differential settlement Not subject to damage from substantial impact loads making it suitable for rail, over dimensional highway and bridge crossings unlike unencased GFRP. High resistance to shock or impact due to improper handling, water hammer or unstable condition. Able to deform when stressed beyond yield point. Superior tensile strength to withstand severe loads and high internal pressure.


• • • • • • • •

•

Disadvantages More expensive than plastics pipe. Heavier than plastics. Mechanical lifting is required. External polyethylene (PE) sleeving required for buried application in corrosive soil conditions. Care is required to ensure sleeving completely wraps the pipe and is sealed. PE sleeving is easily damaged. Where sleeving is damaged in certain aggressive soils (pH ≤5 and ≥9), corrosion will occur. Internally less corrosion resistant than VC and plastics. Less abrasion resistant than plastic pipes. Rougher bore than plastics thus require steeper grades or larger diameter pipes. Slime adheres more readily to DI than plastics and is less easily washed off. Ductile iron is corroded by hydrogen sulphide and sulphuric acid produced in septic sewage conditions.

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5.3

Steel Pipes

There are two types of steel pipe approved by DGSS that can be applied as force main pipeline system, which are mild steel and stainless steel. The design data and specifications of mild steel pipes for force main are summarised in Table 5.5 below: Table 5.5: Summary of Mild Steel Pipes Design and Specifications for Force Main

Material Nominal Diameter (DN), mm Standard Length, m Classes • Operating Pressure Jointing Methods




Summary Carbon steel DN 100 to 2200mm 6.0, 9.0 and 12.0 m. Longer lengths are available on special request • Conform to BS 534:1990 • Varies with pipe diameter, wall thickness and material grade • Butt-welded joint • Sleeve joints for welding • Slip-on type coupling • Flange joint • Threaded and coupled joint • Coal tar enamel, bitumen enamel, asphalt enamel and glass fibre. • High alumina cement mortar, coal tar enamel, coal tar epoxy, sulphate resistant cement or bitumen. BS 534:1990 Manufacture BS 3600:1976 BS 3601:1987 AS/NZS 2566.1:1998 Design BS EN 10025:1993 ISO 559:1991 AS/NZS 2566.2:2002 Installation • Approval for use from the DGSS is required • Pipe is allowed only for sizes 600mm and above • Pipe protection linings and coatings are required. • Permitted for inverted siphons (depressed sewers) and internal pump station pipework. Refer to DGSS latest approval list in Table D1


69


The design data and specifications of stainless steel pipes for force main are summarised in Table 5.6 below: Table 5.6: Summary of Stainless Steel Pipes Design and Specifications for Force Main

Material Nominal Diameter (DN), mm Standard Length, m Classes • Operating Pressure Jointing Methods


Malaysian Sewerage Industry Guidelines Approved Manufacturers/Suppliers

Summary Stainless steel DN 21.34 to 273.05m Pipe length may be specified as long as transportable. • Conform to BS 3600: 1976 • Varies with pipe diameter, wall thickness and material grade • Butt-welded joint • Sleeve joints for welding • Slip-on type coupling • Flange joint • Threaded and coupled joint None None Manufacture: BS 3600:1976 Design: AS/NZS 2566.1:1998 Installation: AS/NZS 2566.2:2002 • Approval for use from the Director General is required • Pipe is allowed only for sizes 600mm and above Refer to DGSS latest approval list in Table C1


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5.3.1

Manufacture

5.3.1.1 Mild Steel Material compositions for mild steel pipes is carbon steel that shall consist of structural or analysis grade steel comply with BS EN 10025: 1993 and BS 3601: 1987. The most common manufacturing process that can be applied to produce all sizes of mild steel pipes is by using helical winding method as shown in Figure 5.8 below. Figure 5.8: Typical Manufacturing Process of Mild Steel Pipes for Force Main

Helical Winding

A steel strip is helically winded and continuously welded to the adjacent windings Welding

Formation of Socket

Hydrostatic Testing

Storage

Socket is formed on the pipe end

X-ray Inspection

Inspection

Blasting and Priming

Lining

Coating

The mild steel pipes can also be manufactured using other methods of manufacturing processes that is dependent on the sizes of the pipe, such as: 1. Steel pipes with diameter less than DN 500 • Hot rolling billets, bars, or ingots into a seamless tube; and • Involves cold rolling steel strip through rollers into the pipe shape and then welding. 2. Steel pipes with diameter DN 500 and up to DN 1050 The manufacturing process for these sizes of pipes involves a formation of steel plates into a circular shape using a ‘U’ press followed by an ‘O’ press. Then the joint is welded along the pipe barrel by submerged arc welding. 3. For sizes up to DN 3000 The production for these sizes of pipes involves a cold rolling of steel plates into a circular or half-circular shape. One circular shaped steel plate is then welded along the barrel. For larger diameter pipes two half-circular shapes will be welded together along the barrel.


71


5.3.1.2 Stainless Steel Material compositions of stainless steel pipes is consist of stainless steel mother coils, which their grades and compositions shall comply with BS 3600:1976 The manufacturing process of stainless steel pipes is shown in the flow chart of Figure 5.9 below. Figure 5.9: Typical Manufacturing Process for Stainless Steel Pipes for Force Main

Uncoiling

Mother coils are slitted into required width with slitter machine

Forming

Slit coils are cold formed into pipes

Welding

Pipes are formed to precise dimension using tri-cathode welding technology

Cutting

Annealing

Pipes are cut into the required length

Pipes are annealed to further upgrade the quality of the pipes

Water Quenching

Sizing

Pipes to undergo acid pickling process to obtain superior corrosion resistance and a silver grey finish

Straightening

Acid Pickling

Hydrostatic Test

Packing


Marking

Inspection

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5.3.2


5.3.2.1 Mild Steel External coating for mild steel pipes that commonly applied for the pipe’s protection is bitumen whereas a coal tar enamel, asphalt enamel and glass fibre still can also be used in accordance with BS 534:1990. The polyethylene coating is applied by rotating a preheated pipe in a bath of polyethylene powder. For exposed steel at the joints, the polyethylene can be wrapped manually, around the ends to finish under the later applied cement mortar lining. Internal lining is applied at the end of the manufacturing process. High alumina cement mortar, sulphate resistant cement mortar, coal tar enamel, coal tar epoxy or bitumen shall be used as the internal lining protection to the pipes. In accordance with BS 534:1990, the minimum cement content shall be 330kg/m3 and the maximum water:cement ratio shall not exceed 0.46:1. The steel pipe is subjected for priming before the internal coal tar or bitumen protection is applied. For cement mortar lining, the cement mortar is applied by feeding the mortar into a slowly rotating pipe. With the mortar in place the pipe is rotated rapidly in order to densely compress the mortar and form a uniformly thick lining with as smooth as possible flow characteristics. Thermosetting (epoxy paint or powder or epoxy tar resin) and thermoplastic (polyethylene, polyurethane) shall be applied to the internal and external surfaces of the pipe.

5.3.2.2 Stainless Steel Protective coatings and linings are not applicable for stainless steel pipe.

5.3.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the outer diameter of steel pipes. It is a convenient round number approximately equal to a manufacturing dimension. The bore of the pipe, which is affected by the wall thickness will govern the pressure load to the pipe. Pipe sizes are not restricted to these nominal sizes and can be made to any outside diameter upon request from the purchaser. Effective length of steel pipe is referred to the actual length that a pipe contributes when correctly assembled in a run of piping. This dimension excludes the additional length contributed by a slipon type coupling when this is used. The pipes shall be supplied in either random lengths or cut lengths. Where cut length is specified, the maximum variation in length shall be +6, -0mm for lengths up to and including 6m. For every 3 m increase in length above 6 m, the plus tolerance shall increase by 1.5 mm to maximum of 12.5 mm. The pipe can also be cut on site by oxy-cutter. Classes of the steel pipe have not been defined in BS EN 534:1990. The classification of grades and qualities of steel pipe are derived in BS EN 10025:1990.


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5.3.4

Joints

Jointing of steel pipes can be achieved with the following methods: 1. Butt-welded joints This is commonly used but is not suitable for lined steel pipes in sizes 610mm OD and smaller. Figure 5.10 shows the preparation of butt-welded joint for steel pipes. Figure 5.10: Butt-welded Joint Preparation of Steel Pipes

(Ref: BS 534: 1990, page 9) 2. Sleeve joints for welding The steel pipes are supplied with the spigot end and the sleeve end. These joints are the preferred type of DGSS but it is exceptional for pump station pipe work and valve connections where flange joints shall be used. Types of sleeve joints for welding are shown in Figure 5.11 below. Figure 5.11: Sleeve Welded Joints of Steel Pipes

Parallel sleeve

Collar sleeve (Ref: BS 534: 1990, page 11)

Taper sleeve

Surface sleeve

3. Slip-on type coupling This type of coupling is to be applied with plain end pipe as shown in Figure 5.12. Figure 5.12: Slip-on Type Coupling of Steel Pipes

(Ref: BS 534: 1990, page 12) A Guide to Sewer Selection and Installation 13th November 2006

74


4. Flange joint In accordance with MSIG, flange joint is compulsory to use for pump station pipe work and valve connections 5. Threaded and coupled joint Where bitumen lined pipes required with threaded and coupled joints, the thread shall have a taper thread on both the pipe and the coupling. The coupler shall be recessed in the centre to take the lining as shown in Figure 5.13. Figure 5.13: Threaded and Coupled Joints Recessed for Bitumen Lining

(Ref: BS 534: 1990, page 12) Mechanical joints are only permitted for cut pipe lengths, where internal cement mortar lining at joint is not possible and where movement of the pipeline is to be allowed for.

5.3.5

Fittings

Fittings are fabricated by welding together sections of steel pipe and are tailor-made which have been hydraulically tested before coating. Hence, they are considered as steel pipe specials. The end fittings produced are prepared to match those of the pipes to which they are to be joined. Steel fittings are much more costly because fabrication is labour intensive with the need to manually weld and apply cement mortar lining. Figure 5.14 shows the various ranges of fittings for steel pipe. Figure 5.14: Various Ranges of Fittings for Steel Pipes

Long radius bend

Short radius bend

Gusseted bend

Plain end tee

Sleeve joint tee

Tee with flange

Concentric reducer

Eccentric reducer

Stub flange


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5.3.6


Colebrook-White roughness coefficients (ks) recommended for hydraulic design of steel pipes for force main are as recommended in Table 5.7 below: Table 5.7: Colebrook-White Roughness Coefficient (ks) for Steel Pipes Mean velocity, V (m/s)

Roughness Coefficient (ks,), mm 0.6 0.3 0.15

0.8 ≤V≤ 1.5 1.5 ≤V≤ 2.0 V≥ 2.0

5.3.7


The application of steel pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.8 lists the advantages and disadvantages of the steel pipes for this application. Table 5.8: Advantages and Disadvantages of Steel Pipes Advantages • •

• •

• • • • •

More flexible than DI pipe. Polyethylene external coating makes it resistant to aggressive soils and is more reliable than PE sleeving used with DI pipe. Longer pipe lengths. Polyethylene internal coating is inert to chemical attack from hydrogen sulphide and is resistant to the maximum sulphuric acid concentrations that could be developed from septic sewage conditions. Less change in length with temperature variations compared with PE and uPVC. Hard, smooth surfaces resist scratches and impact damage. Better strength and safety. No corrosion, resulting in lasting durability. Thinner gauge material is used, resulting in lasting durability. Have a longer life-span, saving maintenance and replacement costs in the long term.


Disadvantages • • • •

If the PE internal coating is damaged to expose the steel, corrosion may result. Heavier than thermoplastic pipes. A range of fittings as required for sewer reticulation is not available. Careful checking for pinholes in the internal lining is required to ensure possible points of steel corrosion do not exist.

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5.4

Glass-fibre Reinforced Plastics (GRP) Pipe

The design data and specifications of GRP pipes for force main are summarised in Table 5.9 below: Table 5.9: Summary of GRP Pipe Design and Specifications for Force Main Summary Material • Filament Wound Pipe

•

Centrifugally Cast Pipe

Standard Nominal Diameter Standard Effective Length Jointing Method

Classes • Stiffness Classes (SN) • Pressure Classes (PN) Protective Coating • External • Internal Standards

Malaysian Sewerage Industries Guidelines (MSIG) Approved Suppliers/Manufacturers

• • • •

Thermosetting resin or polyester resin Roving or woven fabrics of E-glass filaments Surface tissues Additional material such as additives and colourants

• Thermosetting resin or polyester resin • Chopped strand mat of E-glass filaments • Surface tissues • Aggregates and fillers • Additional material such as additives and colourants 100mm to 1000mm 3.0 and 6.0m • Integral socket and spigot joint • Loose collar joint • Butt Joint • Flange Joint • DI coupling a. Slip-on coupling b. Stepped slip-on coupling c. Band coupling d. Flange adapters e. Flange joints • •

SN 1250, 2500, 5000, 10 000, 15 000, 20 000 PN 12.5, 16, PN 20

Thermosetting resin Resin rich lining with superficial layers of C glass material BS 5480: 1990 Manufacture AS 3571: 1989 ASTM D 3262 AS/NZS 2566.1: 1998 Structural Pipeline Design AS/NZS 2566.2: 2002 Installation Under special circumstances with prior approval from DGSS Refer to Table D1 and DGSS latest approval list


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5.4.1

Manufacture

The material compositions and manufacturing processes of GRP pipe for force main are identical with the GFRP pipe applied for gravity system as described in Section 4.5.1.

5.4.2


The protective coatings and linings of GRP pipes for force main are generally same with those recommended for the GRP pipe applied for gravity system as described in Section 4.5.2.

5.4.3

Sizes/Classes

Nominal size (DN) of GRP pipes for force main is same with the nominal sizes for GRP pipes applied for gravity system as described in Section 4.5.3. However, the application of the GRP pipes for force main is limited for diameter up to 1000mm due to the higher pressure rating that need to be catered inside the pipe. Pipe lengths of the GRP pipe for force main has the same value with those recommended for GRP pipe applied for gravity system as described in Section 4.5.3. Classes of the GRP pipes for force main are defined by both pressure class and stiffness class as following: 1. Pressure – GRP pipe that classified for use under pressure is capable of withstanding internal hydrostatic pressure more than 0.5 bar. The pressure classes are referred as PN 12.5, PN 16 and PN 20 that corresponding to 12.5, 16 and 20 bar of working pressure. The pressure rating of the GRP pipe is not dependent on the wall thickness but the GRP composite through wall is the component that increases the pressure rating of the GRP pipe. 2. Stiffness – GRP pipe shall be classified according to their minimum initial specific stiffness. This shall be referred to the preferred numbers (SN values) for nominal minimum initial stiffness in N/m2 of SN 1250, 2500, 5000, 10000, 15000 and 20000. The ring bending stiffness is increased as the wall thickness of the GRP pipe is increased.

5.4.4

Joints

Jointing methods that are recommended for GRP pipes used in gravity system described in Section 4.5.4 are also can be applied for force main. The GRP pipes for force main is also compatible to be jointed with the application of DI couplings, as follows: 1. Slip-on coupling is designed for use with plain-ended pipes. It consists of a sleeve, at the ends of, which are wedge-shaped elastomeric gaskets and flanges held together by bolts as shown in Figure 5.15 below.

Figure 5.15: Typical slip-on (Ref: BS 8010: Section 2.5: 1989, page 15)


78


2. Stepped slip-on coupling is a special slip on couplings used to connect pipes of different diameters or materials as shown in Figure 5.16 below.

Figure 5.16: Typical stepped slip-on coupling (Ref: BS 8010: Section 2.5: 1989, page 15) 3. Band coupling is designed for used with plain-ended pipes. It consists of a metallic band encasing a shaped elastomeric profile as shown in Figure 5.17 below.

Figure 5.17: Typical band coupling (Ref: BS 8010: Section 2.5: 1989, page 16) 4. Flange adapters as shown in Figure 5.18 is designed to connect flanged pipe or any flanged fitting to plain-ended pipe. It consists of a flange and sleeve piece, a wedge-shaped elastomeric gasket and a loose gland fastened to the main body by bolts.

Figure 5.18: Typical flange adapter (Ref: BS 8010: Section 2.5: 1989, page 16) 5. Flange joints are made by integral forming or attaching a preformed GRP flange or forming a stub flange with metallic backing flange. The assemblies of this joint is shown in Figure 5.19 below.

Figure 5.19: Typical flange joints (Ref: BS 8010: Section 2.5: 1989, page 17) A Guide to Sewer Selection and Installation 13th November 2006

79


However, the jointing of GRP pipe for force main shall be carefully done to ensure that it can stand the pressure rating of the system. Sealing material and jointing lubricant for the GRP pipe applied for force main shall follow the requirements described in Section 4.5.4. Allowable angular deflections of flexible joint for the GRP pipe for force main such as rolling or restrained ring joints or clamped joints relative to the nominal size of the pipework according to BS 5480: 1990 are as Table 5.10 below: Table 5.10: Angular Deflection Limits Relative to the Nominal Size of GRP Pipelines Nominal Size (DN) < 500 ≥ 500 to 1000

Angular Deflection (°) 3 2

5.4.5 Fittings The GRP pipe for force main shall be used with the ductile iron fittings. The DI fittings shall have the allowable operating pressure of PN 16 and PN 35 with thermal bonded polymer of internal lining and external coating. The requirements to joint these fittings to the GRP pipe shall be as follows: 1. The sockets shall be grooves to capture elastomeric seals. 2. Spigot ends shall be chamfered over 10 to 20mm at approximately 20º to pipe barrel. 3. Flange shall be equipped with 1.5mm or 3mm flat elastomeric full face gasket depending on the pressure rating of the pipe. Figure 5.20 shows the various ranges of DI fittings that can be used with GRP pipe for the application of force main. Figure 5.20: Various Ranges of DI Fittings for GRP Pipes

Flange-socket connector

Socket-socket connector

Cap

Socket-socket bend

Socket-socket-flange scour tee

5.4.6 Pipeline Hydraulic Design Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 5.11 shall be referred to when determining discharge capacity of the GRP pipes for force main.


80


Table 5.11: Colebrook-White Roughness Coefficient, ks for GRP Pipes Mean Velocity, V (m/s) 0.8 ≤ V ≤ 1.5 1.5 ≤ V ≤ 2.0 V ≥ 2.0

Roughness, ks (mm) 0.6 0.3 0.15

5.4.7 Application of Pipes The application of GRP pipes for the force main may subject to certain conditions and limitations as described in Table 3.2 and 3.3, Section 3. Table 5.12 lists the advantages and disadvantages of the GRP pipe for this application. Table 5.12: Advantages and Disadvantages of GFRP Pipes for Force Main

• • • • • • • • • •

Advantages Lighter than DI. Less joints. Immune to H2S attack. Smoother bore permits flatter grades or smaller diameter pipes. Slime does not build up and is more easily washed off. Greater internal diameter than the equivalent size and class for other pipes permits greater flow. Resistant to more chemicals than HDPE. Resin liner type can be altered to suit chemical resistance required Pipes can be cut to length on site and joined with coupling (resin seal coat over cut surface is required). Compatible to use with ductile iron fittings. Thermoset GFRP pipe does not distort with ambient temperature increase like thermoplastic HDPE pipe.

• • • •

• • •

• • •


Disadvantages Heavier than HDPE. Sides fill support required to prevent excessive pipe flexure. Easily damaged by impact with hard objects, particularly during backfill. External impacts can result in star cracking of the inner liner. This can go undetected in small diameter pipes where internal inspection is difficult. Degraded by high concentrations of certain chemicals after long contact. Badly damaged pipe is difficult to repair and must be replaced. Damaged sections require cutting out or repair using couplings or clamps; in-situ repair using epoxy patching not advisable as methods not proven. Branch connections to existing pipelines more difficult than other pipe types. Low beam shear strength makes it unsuitable in ground subject to large movements or subsidence. Short lengths of pipe are required immediately out of fixed structures, to prevent pipe shearing from differential settlement.

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Section 5 Sewer Pipeline – Material Selection (Force Main)

5.5

Acrylonitrile Butadiene Styrene (ABS) Pipe

The design data and specifications of ABS pipes for force main are summarised in Table 5.13 below: Table 5.13: Summary of ABS Pipes Design and Specifications for Force Main

Material Nominal Diameter, mm Standard Effective Length, m Classes: • Pressure Class (PN) Jointing Method


Malaysian Sewerage Industry Guidelines (MSIG) Approved Manufactures/Suppliers

Summary Acrylonitrile, Butadiene and Styrene DN 10 to 200 mm 6.0 m Conform to MS 1419:Part 1: 1997 Class 4.5, 6, 9, 12, 15, T • Spigot-socket with solvent cement welding joint • Spigot-socket with elastomeric seal joint • Stub flange joint • Not applicable • Not applicable Manufacture

MS 1419:Part 1 to 3: 1997 MS 1419: Part 4 : 1998 AS 3518: Part 1 & 2: 1988 AS 3690: 1989 AS 3691: 1989 BS 5391: Part 1 BS 5392: Part 1 Design AS 2566.1: 1998 Installation AS 2566.2: 2002 For special circumstances with prior approval from DGSS, which require the benefits of such pipe Refer to Table D1 and DGSS latest approval list


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5.5.1

Manufacture

Material compositions of ABS pipes are consist of a copolymer of the monomers acrylonitrile, butadiene and styrene. Each monomer brings to the copolymer different properties, such as: a. Acrylonitrile is to provide resistance to chemicals and ageing (ultraviolet light) and rigidity; b. Butadiene provides impact strength, toughness and abrasion resistance; and c. Styrene contributes to strength and ease of processing. Varying the quantities of each monomer will modify the performance properties of ABS pipes. For pipe applications as a pressure sewerage system, appropriate quantities of each monomer are selected to optimise the performance properties of tensile strength, chemical resistance, ductility and weatherability. Material suitable for pressure pipe applications shall be Type 12142 in conformance with MS ISO 2580-1. Manufacturing process of ABS pipes is much the same as used for other extruded thermoplastic pipe as shown in Figure 5.21 below: Figure 5.21: Typical Manufacturing Process Flow of ABS Pipes

Blending

Raw material (compounded ABS) is fed into a screw Melting

Mixing

Extrusion of pipe

Homogeneous molten ABS is then passed through a series of dies to be extruded to a certain diameter and wall thickness

Sizing

Pipes are sized and cooled using water Cooling

Cutting

Pipes are marked and cut to size Marking

Formation of socket

Inspection

Storage

Sockets are formed on the pipes using a belling machine


83


The ABS pipes for pressure system can be manufactured into various forms of pipe depending on their jointing method as shown in Figure 5.22 below. Figure 5.22: Types of ABS Pipes

Plain ended pipe

Spigot end pipe

Spigot socket pipe

5.5.2


The protective coating and lining is not required for ABS pipe since the material itself can resist the corrosion attack from the sewage.

5.5.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the outside diameter of ABS pipe. ABS pipe is extruded with a fixed outside diameter while the inside diameter is varied to achieve the range of pipe classes. The ABS pipe without couplings shall conform to the dimensions recommended in MS 1419: Part 1-1997 as given in Table 5.14. Table 5.14: Dimensions of ABS for Force Main Nominal Size (DN) 10 15 20 25 32 40 50 80 100 150 200


Mean Outside Diameter, Dm Min Max 17.0 17.3 21.2 21.5 26.6 26.9 33.4 33.7 42.1 42.4 48.1 48.4 60.2 60.5 88.7 89.1 114.1 114.5 168.0 168.5 218.8 219.4

84


Pipe lengths should show the standard overall length of the pipe, exclusive of coupling, of 6 + 0.05, - 0m. All measurements shall be adjusted to an equivalent length at 20ºC. The ABS pipe can be cut at site to the desirable length by handsaw or powersaw. However, care must be taken to ensure squareness of cut ends. Classes of ABS for force main are defined according to maximum static working pressure at a pipe material temperature of 20°C, as Table 5.15 below: Table 5.15: Classifications of ABS Pipes for Force Main Class of Pipe Class 4.5 Class 6 Class 9 Class 12 Class 15 Class T

Maximum Static Working Pressure, MPa 0.45 0.60 0.90 1.2 1.5 1.2 after threading

(Ref: MS 1419: Part 1: 1997, page 3)

5.5.4

Joints

The methods of jointing ABS pipes for force main are as following: 1. Spigot-socket with solvent cement welding joint This jointing as shown in Figure 5.23 is commonly used for ABS pipe. The jointing process shall be properly performed to provide an ideal joint for the elimination of infiltration and root intrusion. Figure 5.23: Typical Spigot-socket with Solvent Cement Joint of ABS Pipes

2. Spigot-socket with elastomeric seal joint Spigot and socket pipe for elastomeric seal jointing shall carry a witness mark such that when the spigot is inserted into a matching pipe socket to the witness mark, the joints are confined to the socket and jointing seal as shown in Figure 5.24 below. Figure 5.24: Typical Spigot-socket with Elastomeric Seal Joint of ABS Pipes


85


3. Stub flange joint The flange is required to be solvent cemented onto a spigot end. The stub flange requires the use of a backing plate and a rubber gasket between the flanges for specific joint application. Figure 5.25 shows the typical stub flange for ABS pipes. Figure 5.25: Typical Stub Flange Joint for ABS Pipes

(Ref: Azeeta Pipe System Catalogue) The jointing of ABS pipe requires special trainings because of the care required to make a solvent cement joint, particularly in large diameters. Solvent cement shall consist of one or more solvents and a sufficient quantity of base ABS material dissolved in the solvents to give the cement the body and consistency required for proper application. Small amounts of inert fillers are added to control shrinkage during drying.

5.5.5

Fittings

ABS fittings for making of junction connections are available and it can be injection moulded or fabricated. Figure 5.26 shows the various ranges of fittings for ABS pipe that can be applied into force main. Figure 5.26: Various Ranges of Fittings for ABS Pipes

Socket

Reducing socket

90° elbow

Equal tee

Reducing tee

Reducing bushes

Long radius plain bend (Ref: Azeeta Pipe System Catalogue)

Short radius plain bend

Saddle


86


5.5.6


Colebrook-White roughness coefficients (ks) recommended for hydraulic design of ABS pipes for force main are as Table 5.16 below: Table 5.16: Colebrook-White Roughness Coefficients (ks) of ABS Pipes Mean velocity, V (m/s) 0.8 ≤V≤ 1.5 1.5 ≤V≤ 2.0 V≥ 2.0

5.5.7

Roughness Coefficient Ks, mm 0.6 0.3 0.15


The application of ABS pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.17 lists the advantages and disadvantages of ABS pipes for this application. Table 5.17: Advantages and Disadvantages of ABS Pipes

• • • • • • • • • • • • • • • • • • •

Advantages Lighter than DI and steel pipes. Resistant to corrosive soils and ground water. Pipes can be cut to length on site. Simpler to cut than non-plastics. Higher impact resistance than PE. Excellent abrasion resistance. Range of working temperature is wider compare to PE. Resistant to more chemicals than PE. Better resistant to UV degradation than other thermoplastics like HDPE. Infiltration and root intrusion eliminated with solvent cement joints. Tolerant of ground subsidence. Pipe lengths can be assembled out of the trench. Solvent cement welding permits continuous pipe lengths for slip lining. Narrower trench is permissible than DI and steel pipes. Mode of failure Weather resistance Homogeneous joint Non-toxic/taint free Smooth bore Minimal maintenance


• • • • • •

• •

Disadvantages Thermal expansion less than HDPE. Side fill support required to prevent pipe flexure. Bedding requirements more stringent than for rigid pipes. Any later disturbance of pipe side support may affect pipe performance. Pipes can be distorted in hot weather, that is, ovalisation and bending along length. Pipe length can change significantly with temperature change. Pipes laid in hot weather can decrease in length sometime after backfilling. No rotational movement of solvent cement pipe joints to accommodate any ground movement. Fumes from solvent cementing, depending on contact time and ventilation may have a toxic effect. Solvent cement may also cause skin and eye irritation.

87


5.6


The design data and specifications of solid wall HDPE pipe for force main are summarised in Table 5.18 below: Table 5.18: Summary of Solid Wall HDPE Pipe Design and Specifications for Force Main Summary Material

Nominal Diameter (ID), mm Standard Length, m Classes • Material Type • Pressure Class (PN) Jointing Method



Approved Manufactures/Suppliers

• High Density Polyethylene • Carbon Black • Antioxidants DN 16 to DN 900 mm 6.0 and 12.0 m PE 80, PE 100 PN 2.5 to a maximum of PN 16 • Thermofusion welding a. Butt fusion welding b. Butt fusion welding of spigot socket joints • Electrofusion • Flange joints • Mechanical metal couplings Not applicable Not applicable Manufacture

CP 312: Part 1 & 3: 1973 SFS 3453 WIS 04-32-15 WIS 04-24-01 WIS 04-32-14 AS/NZS 2566.1: 1998 Design AS/NZS 2566.2: 2002 Installation • Prior approval from DGSS is required • Shall not be used in ground contaminated with high concentration of chemicals that can degrade the pipes • Shall not accept any industrial or other aggressive discharges that may affect the pipe integrity. Refer to Table D1 and DGSS latest approval list


88


5.6.1

Manufacture

Material compositions of the solid wall HDPE pipes pipe is polyethylene (PE) resins with density range of 950-965 kg/m3 containing no more than 10% of recycled materials. The PE plastic can be in the form of powders, granules or pellets. Some carbon black or titanium dioxide, about 2-3% shall be added as ultraviolet stabiliser. Other additives added are lubricants, antioxidants and pigments. Manufacturing process of HDPE solid wall pipes is shown in typical flow chart of Figure 5.27. Figure 5.27: Typical Manufacturing Process of Solid Wall PE Pipe

Preheating

Pelletised raw materials is preheated to remove volatile and moisture

Melting, compressing and degassing

Raw materials are fed to an extruder where a helical screw mechanism moves the granules along the extruder through zone

Formation of pipe

Molten PE is passed through a die at the end of the extruder to form the pipes

Sizing

1st stage cooling

Pipes are cooled by external vacuum or internal pressure while passing through the forming sleeves

2nd stage cooling

Pipes are passed through water bathing of even lower temperatures till it reaches ambient temperatures

Cutting

Pipes are cut into the required length

Inspection

5.6.2

Storage


External protection and internal protection is not required for solid wall HDPE pipes.


89


5.6.3

Sizes/Classes

Nominal Outside Diameter, dn of solid wall HDPE pipes is a numerical designation of size to HDPE piping system other than flanges and components designated by thread size. It is a convenient round number for reference purposes. This diameter is fixed while the internal diameter varies depend on the classes. The increment is not constant and the sizing follows the adopted international standards for thermoplastic pipe for pressure applications. Standard length of pipe indicated the overall effective length of the pipe. HDPE solid wall pipes can be cut on site using most types of saws. Classes of solid wall uPVC pipes is designated by the material types, PE 100 and PE 80, which correspond to the level of minimum design strength at 20°C for up to 50 years. PE 80 and PE 100 show the capabilities of the pipes to withstand 80 bar (8 MPa) and 100 bar (100 MPa) of strength respectively. The maximum design stress is obtained by applying a design coefficient of 1.25 to the strength. PE is available in various compounds of different density and this alters the allowable stress that a pipe can withstand. The higher the allowable design stress, the thinner the wall for the same working pressure. Ring stiffness of 8 kN/m2 (8000 MPa) is generally taken as the minimum stiffness for smaller diameter pipe. Hence PE 80 with typical resins density of 950 to 955 kg/m3 is recommended for use in pressure sewerage. Working pressure is increased by increasing the wall thickness (to ensure pipe bores align at joints requires that each pipe have the same pressure class).

5.6.4 Joints The jointing methods for solid wall HDPE pipe shall be as follows: 1. Thermofusion welding is formerly known as fusion welding. This method uses heated tools to weld the joint faces together and can be applied to specially made moulded socket fittings and also to those made for butt jointing a. Butt fusion welding is suited for the jointing of HDPE for all sizes of pipe. The joint is produced by heating the faces of the components against a heated flat plate, which is usually coated with PTFE and then bringing them together under controlled pressure. Butt welding also leaves a raised bead about the joint inside the pipe which will interfere with the flow. Tools are available to remove this internal bead but because this is not easily inspected for, installers may avoid this operation. Figure 5.28 shows the typical butt fusion welding for solid wall HDPE pipes. Figure 5.28: Typical Butt Fusion Welding for Solid Wall HDPE Pipes

b. Spigot socket joints – For this joint one end of the pipe is opened up to act as the socket of a moulded fitting and thereafter the butt fusion welding is carried out as shown in Figure 5.29. Figure 5.29: Butt Fusion Welding of Spigot Socket Joints for Solid Wall HDPE Pipes A Guide to Sewer Selection and Installation 13th November 2006

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2. Electrofusion is simpler than butt fusion but only applicable for small diameter of pipe up to 315 mm only. The heating and timing operations are all automatically undertaken by a control unit of the following procedures: - Electrofusion coupling slipped over the ends of the pipe to join - Resistance wires in the coupler are heated by a controlled electrical current - The coupler and pipe are melted and then fused to each other. The main deterrent to the use of electrofusion joints is their greater cost compare to the method of thermofusion welding. 3. Flange joints can be used when require jointing to fittings or pipes of other material and most commonly used for larger diameter pipes. It consist either a full face or stub flanges welded to the pipe or alternately can be formed on the pipe. The rotational flexibility that this joint type provides is however compensated for by the longitudinal flexibility of polyethylene pipe. Figure 5.30 shows the typical flange joints of solid wall HDPE pipes. Figure 5.30: Typical Flange Joints of Solid Wall HDPE Pipes

Flange joint for HDPE-HDPE pipes

Flange joint for HDPE-steel pipes

4. Mechanical metal couplings do not provide the strength or long term performance as compare to a properly made fusion joint and are only considered for some repair operations. There are wide ranges of plastic (acetal and GRP used) fittings for small diameters that use mechanical (compressed rubber seal) joints and development continue on larger sizes.

5.6.5

Fittings

The fabricated fittings for solid wall HDPE pipes are available in sizes 225 and larger. It comprise of pipe sections that are fillet welded together to form the fitting configuration. Like the pipes,


91


fittings are also jointed by butt fusion. The various ranges of fabricated fittings for solid wall HDPE pipes are shown in Figure 5.31 below. Figure 5.31: Fabricated Fittings for Butt Fusion of Solid Wall HDPE Pipes

The stub end and MS flange fittings are also available to jointing the HDPE pipes as shown in Figure 5.32. Figure 5.32: Stub End and MS Flange Fittings for Solid Wall HDPE Pipes

Stub end

MS flange

There are several types of plastic fittings available, some of, which require the pipe to be specially form such as compression fittings and flange fittings. The compression fittings are effected by the use of components of plastics or rubber material. Schematics of typical plastic compression fittings are shown in Figure 5.33. Figure 5.33: Plastics Compression Fittings for Solid Wall HDPE Pipes

Straight coupler

5.6.6

Elbow coupler

Tee coupler

Saddle


Colebrook-White roughness coefficients (ks) recommended for hydraulic design of profile wall HDPE pipes as force main are as Table 5.19 below: Table 5.19: Colebrook-White Roughness Coefficient (ks) for Solid Wall HDPE Pipes Mean velocity (V ), m/s 0.8 ≤V≤ 1.5 1.5 ≤V≤ 2.0 V≥ 2.0

5.6.7

Roughness (Ks,), mm 0.6 0.3 0.15



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The application of solid wall HDPE pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.20 below lists the advantages and disadvantages of solid wall HDPE pipes for this application. Table 5.20: Advantages and Disadvantages of Solid Wall HDPE Pipe

• • • • • • • • • •

Advantages Lighter than DI and steel pipes. Longer pipe lengths than DI pipe is available. Immune to H2S attack. Pipes can be cut to length on site. Simpler to cut than non-plastics. Infiltration and root intrusion eliminated with electrofusion and butt welded joints properly made. Pipeline will bend to conform to subsidence under pipe. Resistant to UV degradation (due to carbon black light stabiliser). Pipe lengths can be assembled out of the trench, where welded. Welding permits continuous pipe lengths to be made for slip lining. Narrower trench than with DI and steel pipes is permissible.

•

• • • •

• • •

•

•


Disadvantages Side fill support required to prevent excessive pipe flexure and Any disturbance of pipe side support may affect performance. Bedding requirements more stringent than for rigid pipes. PE degraded by high concentrations of certain chemicals, such as solvents after long contact. For PE welding to be effective, the welding area must be clean and dry. Where butt or fillet welding is required, special welding equipment is used. Trained equipment operators are required to ensure a satisfactory weld. Pipes are susceptible to damage from heavy impact loads. Pipes can be distorted in hot weather, that is, ovalisation and bending along length. Pipe length changes more with temperature change than other plastics. Pipes laid in hot weather can shorten after backfilling causing possible damage. Butt welding leaves an internal bead to cause sewer snagging and fouling. Remote controlled devises are available overseas to remove beads but not readily obtainable in Malaysia. Welding between different grades of polyethylene is not possible.

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Section 6 Sewer Pipeline – Material Selection (Vacuum Sewerage System)

6.0

VACUUM SEWERAGE SYSTEMS

6.1

General

Vacuum sewerage system shall only be considered where the life-cycle costs of a conventional gravity sewerage system are clearly shown to be higher. The application of this system is considered when all sewage transportation modes have been identified, their respective feasibilities evaluated against technical, environmental, financial, economic and other relevant criteria over the design life of the asset and that the vacuum sewerage system has been confirmed as the best option. The net present value (NPV) calculations shall be submitted to DGSS for all options prior to approving construction of a vacuum sewerage system. Vacuum sewerage system is suitable for application in the following conditions: • Unstable soil likely to settle • Restricted construction access Typical sizes of the pipelines of the system are as follows: • Branch lines dn 90 mm to dn 150 mm • Main lines dn 150 mm to dn 250 mm Pipeline types approved for vacuum sewers are mainly from the plastic pipes which are: • ABS pipe (for internal use) • Solid wall HDPE pipe (for external use)


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6.2

Acrylonitrile Butadiene Styrene (ABS) Pipe

The design data and specifications of ABS pipes for vacuum sewerage system are summarised in Table 6.1 below: Table 6.1: Summary of ABS Pipes Design and Specifications for Vacuum Sewerage System

Material Nominal Diameter, mm Standard Effective Length, m Classes: Pressure Class (PN) Jointing Method

Summary Acrylonitrile, Butadiene and Styrene DN 10 to 200 mm 6.0 m Conform to MS 1419:Part 1: 1997 Class 4.5, 6, 9, 12, 15, T • Spigot-socket with solvent cement welding joint • Stub flange joint


• Not applicable • Not applicable Manufacture

Malaysian Sewerage Industry Guidelines (MSIG) Approved Manufactures/Suppliers

MS 1419:Part 1 to 3: 1997 MS 1419: Part 4 : 1998 AS 3518: Part 1 & 2: 1988 AS 3690: 1989 AS 3691: 1989 BS 5391: Part 1 BS 5392: Part 1 Design AS 2566.1: 1998 Installation AS 2566.2: 2002 For special circumstances with prior approval from DGSS, which require the benefits of such pipe Refer to Table C1 and DGSS latest approval list


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6.2.1

Manufacture

Material compositions and manufacturing process of ABS pipes for vacuum sewerage system are same as the compositions and method to produce ABS pipe for force main as described in Section 5.5.1. The various forms of ABS pipes is produced depending on their jointing method and application as shown in Figure 5.22, Section 5.5.1.

6.2.2


The protective coating and lining is not required for ABS pipe since the material itself can resist the corrosion attack from the sewage.

6.2.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the outside diameter of ABS pipe. The ABS pipe without couplings shall conform to the dimensions recommended in MS 1419: Part 1-1997 as given in Table 6.2 below. Table 6.2: Dimensions of ABS for Vacuum Sewerage System Nominal Size (DN) 10 15 20 25 32 40 50 80 100 150 200

Mean Outside Diameter, Dm Min Max 17.0 17.3 21.2 21.5 26.6 26.9 33.4 33.7 42.1 42.4 48.1 48.4 60.2 60.5 88.7 89.1 114.1 114.5 168.0 168.5 218.8 219.4

Pipe lengths show the standard overall length of the pipe, exclusive of coupling, of 6 + 0.05, - 0m. All measurements shall be adjusted to an equivalent length at 20ºC. The ABS pipe can be cut at site to the desirable length. However, care must be taken to ensure squareness of cut ends. Classes of ABS for force main are defined according to maximum static working pressure at a pipe material temperature of 20°C, as Table 6.3 below: Table 6.3: Classifications of ABS Pipes for Vacuum Sewerage System Class of Pipe Class 4.5 Class 6 Class 9 Class 12 Class 15 Class T

Maximum Static Working Pressure, MPa 0.45 0.60 0.90 1.2 1.5 1.2 after threading

(Ref: MS 1419: Part 1: 1997, page 3)


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6.2.4

Joints

The methods of jointing ABS pipes for vacuum sewerage system are as following: 1. Spigot-socket with solvent cement welding joint This jointing as shown in Figure 6.1 is commonly used for ABS pipe. The jointing process shall be properly performed to provide an ideal joint for the elimination of infiltration and root intrusion. Figure 6.1: Typical Spigot-socket with Solvent Cement Joint of ABS Pipes

2. Stub flange joint The flange is required to be solvent cemented onto a spigot end. The stub flange requires the use of a backing plate and a rubber gasket between the flanges for specific joint application. Figure 6.2 shows the typical stub flange for ABS pipes. Figure 6.2: Typical Stub Flange Joint for ABS Pipes

(Ref: Azeeta Pipe System Catalogue) The jointing of ABS pipe requires special trainings because of the care required to make a solvent cement joint, particularly in large diameters. Solvent cement shall consist of one or more solvents and a sufficient quantity of base ABS material dissolved in the solvents to give the cement the body and consistency required for proper application. Small amounts of inert fillers are added to control shrinkage during drying.

6.2.5

Fittings

ABS fittings for making of junction connections are available and it can be injection moulded or fabricated. The various range of fittings for ABS pipe for vacuum sewerage application are same as shown in Figure 5.26, Section 5.5.5.

6.2.6


Colebrook-White roughness coefficients (ks) recommended for hydraulic design of ABS pipes for vacuum sewerage system shall be in accordance with those recommended for force main application described in Section 5.5.6.


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6.3


The design data and specifications of solid wall HDPE pipe for vacuum sewerage system are summarised in Table 6.4 below: Table 6.4: Summary of Solid Wall HDPE Pipe Design and Specifications for Vacuum Sewerage System Summary Material

Nominal Diameter (ID), mm Standard Length, m Classes • Material Type • Pressure Class (PN) Jointing Method



Approved Manufactures/Suppliers

• High Density Polyethylene • Carbon Black • Antioxidants DN 16 to DN 900 mm 6.0 and 12.0 m PE 80, PE 100 PN 2.5 to a maximum of PN 16 • Thermofusion welding a. Butt fusion welding b. Butt fusion welding of spigot socket joints • Electrofusion Not applicable Not applicable Manufacture

CP 312: Part 1 & 3: 1973 SFS 3453 WIS 04-32-15 WIS 04-24-01 WIS 04-32-14 AS/NZS 2566.1: 1998 Design AS/NZS 2566.2: 2002 Installation • Prior approval from DGSS is required • Shall not be used in ground contaminated with high concentration of chemicals that can degrade the pipes • Shall not accept any industrial or other aggressive discharges that may affect the pipe integrity. Refer to Table C1 and DGSS latest approval list


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6.3.1

Manufacture

Material compositions and manufacturing process of the solid wall HDPE pipes are same with those specified for solid wall HDPE pipes applied for force main described in Section 5.6.1.

6.3.2


External protection and internal protection is not required for solid wall HDPE pipes.

6.3.3

Sizes/Classes

Nominal Outside Diameter, dn of solid wall HDPE pipes is a numerical designation of size to HDPE piping system other than flanges and components designated by thread size. It is a convenient round number for reference purposes. This diameter is fixed while the internal diameter varies depend on the classes. The increment is not constant and the sizing follows the adopted international standards for thermoplastic pipe for pressure applications. Standard length of pipe indicated the overall effective length of the pipe. HDPE solid wall pipes can be cut on site using most types of saws. Classes of solid wall uPVC pipes is designated by the material types, PE 100 and PE 80, which correspond to the level of minimum design strength at 20°C for up to 50 years. PE 80 and PE 100 show the capabilities of the pipes to withstand 80 bar (8 MPa) and 100 bar (100 MPa) of strength respectively. The maximum design stress is obtained by applying a design coefficient of 1.25 to the strength. PE is available in various compounds of different density and this alters the allowable stress that a pipe can withstand. The higher the allowable design stress, the thinner the wall for the same working pressure. Ring stiffness of 8 kN/m2 (8000 MPa) is generally taken as the minimum stiffness for smaller diameter pipe. Hence PE 80 with typical resins density of 950 to 955 kg/m3 is recommended for use in pressure sewerage. Working pressure is increased by increasing the wall thickness (to ensure pipe bores align at joints requires that each pipe have the same pressure class).

6.3.4 Joints The solid wall HDPE pipes and fittings less than DN 160 shall be jointed using electrofusion fittings. Pipes and fittings DN 160 and larger shall be jointed with electrofusion fittings or butt fusion welding.

6.3.5

Fittings

The fabricated fittings for solid wall HDPE pipes are available in sizes 225 and larger. It comprise of pipe sections that are fillet welded together to form the fitting configuration. The various ranges of fabricated fittings for solid wall HDPE pipes are shown in Figure 5.31 to Figure 5.33, Section 5.6.5.

6.3.6


Colebrook-White roughness coefficients (ks) recommended for hydraulic design of solid wall HDPE pipes for vacuum sewerage system shall be in accordance with those recommended for force main application described in Section 5.6.6.


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Section 7 Sewer Pipeline – Material Selection (Pipe Jacking)

7.0 Pipe Jacking 7.1

General

Jacking method of pipe laying shall be employed only when the conditions or the requirements of the responsible authorities require such a method. The pipes used for jacking shall be able to withstand the laterally induced jacking stresses of 2000 psi without damage. The setting out of the guide rails for the pipe and the actual jacking operation shall maintain a high accuracy level of line and grade. The direction and grade for jacked sewer shall not deviate from the designed alignment for more than 100 mm for every 100 meters of sewer. All the joints used for connecting the jacked pipes shall be watertight and durable. The types of the pipe that approved by DGSS to use as the pipe jacking are of the following: • Vitrified Clay (VC) Pipe • Reinforced Concrete (RC) Pipe


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7.2


The design data and specifications of VC pipes for pipe jacking are summarised in Table 4.3 below: Table 7.1: Summary of VC Pipes Design and Specifications for Pipe Jacking

Material Nominal Size (DN), mm Nominal Length, m Classes Jointing Method Protective Coating • External • Internal Standards


Summary Vitrified clay DN300 to DN600 mm Not specified in BS EN 295-7: 1995 Conform to BS EN 295-7: 1995 Double spigot flexible joints with sleeve/collar With or without glazing (depends on the product) With or without glazing (depends on the product) • BS EN 295-1:1991 • BS EN 295-2:1996 • BS EN 295-2:1991 • BS EN 295-7:1995 Refer to Table D1 and DGSS latest approval list


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7.2.1 Manufacture Material compositions and manufacturing process of VC pipes for pipe jacking is same as applied for gravity sewerage system as described in Section 4.2.1. Only double spigot type of VC pipe can be used for the pipe jacking application as shown in Figure 7.1 below. Figure 7.1: Type of VC Pipe for Pipe Jacking

Double spigot pipe

7.2.2 Protective Coatings/Linings The protective coatings and linings of the VC pipes for pipe jacking has the same components with the VC pipes used for gravity sewerage system, as described in Section 4.2.2.

7.2.3 Sizes/Classes Nominal size (DN) is a numerical designation of the internal diameter of VC pipes. The internal and external diameter of the barrel of a pipe shall not deviate from the manufacturer’s stated value by an amount greater than that shown in Table 7.2 below: Table 7.2: Tolerance on Internal and External Diameter of VC Pipes for Pipe Jacking Nominal Size (DN), mm ≤ 300 400 500 600 800 > 800

Tolerance on Stated Diameter Internal ±5 ±6 ± 7.5 ±9 ± 12 ± 15

External - 10 - 12 - 15 - 18 - 24 - 30

Length of VC pipes for pipe jacking shall have the tolerance of ± 2 mm on the manufacturer’s stated nominal length. The length shall be measured at 90º intervals around the circumference. The tolerance applies to the mean of these measurements. Classes of VC pipes for pipe jacking is defined by the various types of strength specified herein, which used in structural design calculations. a. Crushing strengths (FN) of VC pipes or pipe sections shall be not less than 28 kN/m for pipes of nominal size DN 100 and DN 150. The crushing strength for VC pipes with nominal sizes greater than DN 150 shall be same as specified for gravity sewerage system as tabulated in Table 4.5, Section 4.2.3. b. Compressive strength of VC pipes for pipe jacking shall not be less than 75 N/mm2.


102


c. Jacking strength shall be determined in accordance with BS EN 295-7:1995 by applying the load without shock and increase it at a convenient rate not exceeding 35.0 N/mm2.min up to half the maximum anticipated load. The test shall be done of at least 10 specimens cut from the same pipe. d. Design jacking load shall be declared by the manufacturer. This will depend on jacking strength and on the specific design of the joint and packing ring. e. Maximum working jacking load shall be determined by using factors of safety of either 1.6 for automatically steered jacking machines or 2.0 for manually steered systems.

7.2.4

Joints

Jointing materials of VC pipes for pipe jacking are of the following types: 1. Rubber sealing elements Rubber sealing elements shall be in accordance with BS EN 295-1: 1991 as described in gravity sewerage system, Section 4.2.4. 2. Polyurethane sealing elements Polyurethane sealing elements shall be in accordance with BS EN 295-1: 1991 as described in gravity sewerage system, Section 4.2.4. 3. Stainless steel sleeves The corrosion resistance of stainless steel shall be equal or greater than the resistance of austenitic stainless steel with minimum chrome content of 17% and minimum nickel content of 8%. The sleeves shall be edge dressed and free from sharp edges. The internal surface of the sleeve shall be finished to provide a sealing surface. 4. Polypropylene sleeve couplings Polypropylene sleeve couplings shall meet the requirements of BS EN 295-1: 1991 as following: • Melt flow index ≤ 1.5 times nominal value • Tensile strength ≥ 20 N/mm2 • Elongation at break ≥ 200% 5. Materials of other components Components of other materials shall comply with the relevant European Standards or the manufacturer’ declared specifications, which shall also include requirements for long term behaviour. Angular deflections of the joints assembly shall be deflected by the method described in BS EN 295-3:1991 by the values in Table 7.3 and when so deflected shall withstand constant pressure of not less than both 5 kPa (0.05 bar) and 50 kPa (0.5 bar) for 5 min without visible leakage. Table 7.3: Allowable Angular Deflection of VC Pipes for Pipe Jacking Nominal Size (DN), mm ≤ 800 > 800

Minimum deflection per meter of deflected pipe length, mm 20 10

(Ref: BS 295-7: 1995, page 6)

7.2.5


The pipeline hydraulic design of VC pipes for pipe jacking shall have a low hydraulic roughness and shall be in accordance with BS EN 295-7:1995 as described in Section 4.2.6.


103


7.3


The design data and specifications of RC pipes for pipe jacking are summarised in Table 7.4 below: Table 7.4: Summary of RC Pipes Design and Specifications for Pipe Jacking

Material

Nominal Size (DN), mm Effective Length, m Classes Jointing Methods

Protective Coating • External • Internal

Standards Approved Manufacturers/Suppliers

Summary • Cement • Aggregates • Water • Reinforced steel with hard drawn wire DN 300 to DN 3000 • ≤ DN 600 : 3.0m maximum • > DN 600 : 0.45m to 5.0m • Conform to BS 5911-1:2002 and AS 4058:1992 • Rebated/ogee joint with rubber ‘O’ ring • Rebated/ogee joint with cement mortar filling • Double spigot joint with collar/ butt joint with collar • Bare • DN < 1000 : High alumina cement mortar lining • DN ≥ 1000 : HDPE/PVC lining is preferred • Sacrificial concrete lining is an alternatives Manufacture BS 5911-1:2002 Refer to Table D1 and DGSS latest approval list.


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7.3.1

Manufacture

Material compositions and manufacturing processes of RC pipes for pipe jacking is same as applied for gravity sewerage system as described in Section 4.3.1. The RC pipes for pipe jacking shall be compacted so that when hardened they shall be free from honeycombing and from any individual large void greater than 6mm. Surface of the pipes shall be free from voids of less than 12mm deep. The RC pipes for the pipe jacking can be manufactured into two different types of pipe as shown in Figure 6.3 below: Figure 7.2: Types of RC Pipes for Pipe Jacking

Pipe with rebated joint

Pipe with butt-end joint and collar

7.3.2 Protective Coatings/Linings External coating and internal linings of RC pipes for pipe jacking shall be in accordance with those specified for gravity sewerage system as described in Section 4.3.2.

7.3.3

Sizes/Classes

Nominal size (DN) and effective length of RC pipes for pipe jacking is similar to the RC pipes used for gravity sewerage system as described in Section 4.3.3. Crushing strength of RC pipes shall be tested in compliance to BS 5911-1: 2002. The maximum, work proof and ‘no-crack’ crushing load of RC pipes for pipe jacking shall be as Table 7.5 below: Table 7.5: Crushing Loads of RC Pipes for Jacking Pipe Nominal Size (DN), mm 900 1050 1200 1350 1500 1650 1800 1950 2100 2250 2400 2550 2700 2850 3000

‘No-crack’ Load Works Proof Load Maximum Load Kilonewtons per metre of effective length 55 88 110 60 96 120 70 112 140 80 128 160 85 136 170 95 152 190 100 160 200 100 176 220 100 184 230 105 200 250 105 216 270 105 224 280 110 240 300 110 256 320 110 264 330

(Ref: BS 5911: Part 120: 1989, page 10) A Guide to Sewer Selection and Installation 13th November 2006

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7.3.4

Joints

The joint methods for RC pipes are generally of the following types: 1. Flexible rebated/ogee joint with rubber ‘O’ ring is used to joint the rebated pipes as shown in the following Figure 7.3. Figure 7.3: Typical Flexible Joint of Rebated/Ogee RC Pipes

Rebated joint with rolling rubber ring (Ref: BS 5911: Part 120: 1988, page 8)

Rebated joint with confined rubber ring

2. Rigid rebated/ogee joint with cement mortar filling is more commonly used for rigid pipeline installation, like jacking pipe where flexibility is not required. 3. Double spigot joint with collar/ butt joint with collar is usually used for pipe jacking application. Figure 7.4 shows the typical double spigot joint with collar. Figure 7.4: Typical Double Spigot Joint with Collar of RC Pipes

Double spigot joint with collar and rolling rubber ring (Ref: BS 5911: Part 120: 1988, page 8)

Double spigot joint with collar and confined rubber ring

The collars shall be fabricated from stainless steel 316 plate or glass reinforced plastic (GRP) or other non-coated corrosion resistant metal and shall not be attached to reinforcement. Angular deflections of the RC pipes for pipe jacking shall be tested in accordance with BS 59111:2002 which is not less than that given in Table 7.6 below. Table 7.6: Minimum Angular Deflection and Straight Draw Joints of RC Pipes for Pipe Jacking Nominal Size (DN), mm

Minimum Angular Deflection

DN 900 to DN 1200 DN 1350 to DN 1800 DN 1900 to DN 3000

Minimum Straight Draw, mm 20 1° 20 1/2° to be stated by the manufacturer

(Ref: BS 5911: Part 120: 1988, page 11)

7.3.5


The pipeline hydraulic design of RC pipes for pipe jacking shall have a low hydraulic roughness and shall be in accordance with BS 5911-1:2002 as described in Section 4.3.6.


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Section 8 Sewer Pipeline - Design Guide

8.0

SEWER PIPELINE - DESIGN GUIDE

8.1

General

This section provides general guides on good practice and general concept on sewer pipeline structural design and pipeline embedment. Detail requirements and procedures shall be referred to the MSIG Volume 3 and DGSS Design Manual series as well as other relevant standards. General concept and requirements on the pipeline structural design and pipeline embedment of each type of pipe material are provided in this section. The purpose of this section is to serve as a quick guide to the designer for the selection of sewer pipeline system.

8.2

Rigid Pipe

8.2.1


8.2.1.1 Pipeline Structural Design The basis of structural design for VC pipeline is to determine whether the crushing strength of the pipe, enhanced by a field supporting strength can support the working loads under actual field conditions. The field supporting strength of VC pipe is materially affected by the method of installation. It is dependent upon two factors: 1. The inherent strength of the pipe; 2. The bedding of the pipe. The factor of safety of greater than 1.0 and less than or equal to 1.5 shall be applied to the field supporting strength to determine a safe supporting strength for the installed VC pipe. The allowable working load to the crushing strength of the VC pipe under the actual field condition is determined by the bedding factor. The magnitude of the bedding factor is depended on the type of bedding. The higher the bedding factor, the higher the height of support from material placed at the side of the pipe. Thus, the permissible loading on VC pipe increases as the bedding factor increases. The types of working loads considered on installed VC pipe are due to: a. Materials covering the pipes; b. Superimposed dead load; and c. Superimposed live loads. The working loads, due to the dead load of trench fill or in-situ material is proportionately to the trench width. It is increases as the trench width, measured at the top of the pipe, increases. So, the trench width shall be kept as narrow as possible. The live loads may be produced by wheel loading, construction equipment or by compaction effort. The impact factor of 2.0 shall be applied for wheel or tracks loads including construction and other equipment. The working load on pipes due to the mass of water carried by the pipe may be disregarded. The compaction method shall be properly selected so that the combined dead load and live load does not exceed the field supporting strength of the pipe, or cause a change in its properties or grade.


107


Structural design of VC pipe is to be performed in accordance to: a. MSIG Volume 3; b. BS EN 752:1997 – Drain and sewer systems outside buildings; c. AS 4060:1992 – Loads on buried vitrified clay pipes; and d. ASTM C 12 – 9: Standard practice for installing vitrified clay pipelines.

8.2.1.2 Pipeline Embedment The pipeline embedment method as described in the ASTM C 12 – 91 recommended four classes of bedding (Class ‘A’, Class ‘B’, Class ‘C’ and Class ‘D’) and two encasement (concrete encasement and crushed stone encasement) for VC pipe installation in trenches to achieve improvements in allowable loading. However, there are only two bedding and one encasement for pipeline embedment defined in ASTM C 12 – 9 have been used for the installation of VC sewer pipeline, in line with those recommended in MSIG 3, which are: 1. Class ‘A’ bedding; 1. Class ‘B’ bedding; and 2. Concrete Encasement The constructions of this pipeline embedment method for VC pipe installation are described below. 1. Class ‘A’ bedding This class of bedding can be achieved by either of two construction methods as shown in Figure 8.1 below: Figure 8.1: Construction Method of Class ‘A’ Bedding OD

OD Compacted Selected Backfill Material

300mm (min)

ID 0.25 OD

Grade 20 Concrete

0.25 ID or 100mm (min)

Transverse Steel

Bedding Factor: 3.4, p:

Concrete Cradle OD Transverse Steel

Compacted Selected Backfill Material 0.25 ID or 100 mm (min)

Grade 20 Concrete

ID 0.5 OD

Granular Well Compacted Material

0.25 OD or 100 mm (min)

Bedding Factor: 3.4, p: 0.4%

Concrete Arch Note: p is the ratio of the area of steel to the area of concrete. (Ref: ASTM C 12 – 91, page 8) A Guide to Sewer Selection and Installation 13th November 2006

108


2. Class ‘B’ bedding The typical drawing of this class of bedding is shown in Figure 8.2 below: Figure 8.2: Construction Method of Class ‘B’ Bedding OD Compacted Selected Backfill Material

30mm (min)

ID Granular Well Compacted Material

0.5 OD 0.125 ID or 100 mm (min)

Bedding Factor: 1.9

(Ref: ASTM C 12 – 91, page 9) 3. Concrete Encasement The typical drawing of this concrete encasement is shown in Figure 8.3 below: Figure 8.3: Construction Method of Concrete Encasement OD

VC Pipe

ID ID

Grade 20 Concrete

0.25 OD or 100mm (min)

Bedding Factor: 3.0

In the installation of VC sewer pipeline under the circumstances of: • Crossing a drain; or • Crossing a road; or • Installation depth ≥ 900mm and < 1200mm only the Class ‘A’ bedding and concrete encasement is permitted for the installation of VC pipe. Otherwise, Class ‘B’ bedding is permissible to be applied for the installation of the VC pipe. The concrete support and encasement shall have strength grade not less than Grade 20. It is recommended that wire mesh reinforcement or uniformly distributed small diameter reinforcement bar be used in the concrete support design. A compacted selected backfill material shall be of finely divided material free of debris, organic material and large stones.


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A granular well-compacted material for pipe support shall mean material that has been spaded or shovel-sliced so that the material fills and supports the haunch area and encases the pipe to the limits. It shall be using of well-grade not more than 20 mm particles size of crushed stone or other non-consolidating bedding material not subject to migration. This particle size is effective because it can readily achieve a density close to its optimum with little compacting effort. The granular support may require cement stabilisation for certain in situ conditions such as on steep slopes. The degree of compaction for the granular bedding and haunch support, measured by the density index (ID), shall not be less than 60 percent to prevent any damage to the pipe.

8.2.2


8.2.2.1 Pipeline Structural Design The basis of the structural design of RC pipeline is to determine whether the cracking load of RC pipe, enhanced by pipe support and bedding can withstand of the following types of the vertical load: 1. Working load due to the fill material; 2. Working load due to superimposed dead load; 3. Working load due to superimposed live load. The assessment of working loads on the RC pipe is dependent on the factors of: 1. Height of the fill material above the top of the pipe; 2. Assessed unit weight of the fill material; 3. Magnitude and nature of any superimposed loads; 4. Type of bedding, support and foundation materials; 5. Pipe installation conditions; 6. Width of trench; 7. External diameter of pipe. A bedding factor shall be applied to working loads, for the purpose of test load of the RC pipeline. The bedding factor of 1.5 is taken for all live loads irrespective of the type of pipe support provided. The bedding factor for working dead load is dependent on the type of pipe support provided. The higher the bedding factor, the higher the height of support from material placed at the side of the pipe. Thus, the permissible loading on the RC pipe increases as the bedding factor increases. The working dead loads due to fill or in-situ materials are dependent on the trench width measured at the top of the pipe. The narrower the trench width, the lesser the working dead loads on the pipeline. An impact effects shall be taken into account for all live loads imposed by wheel loads, vehicle loads, railway loading, construction equipment loads and other equipment loads. An appropriate impact factor shall be applied to the live loads for the installation of the RC pipe. The vertical working load on pipes due to the mass of water carried by the pipe may be disregarded for pipe less than 1800 mm diameter but should be considered for larger diameter pipe. Structural design of RC pipe is to be performed in accordance to MSIG Volume 3 and AS 3725 – 1998 – Loads on Buried Concrete Pipe.


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8.2.2.2 Pipeline Embedment The pipeline embedment method of RC pipe as described in AS 3725:1989, recommended three major types of pipe supports of RC pipe, which are: 1. Type U support; 2. Type H support comprises of type H1, H2, H3; and 3. Type HS support comprises of type HS1, HS2, HS3. However, only type H and HS support defined in AS 3725:1989 have been normally used for the embedment of RC sewer pipeline, in line with those recommended in MSIG 3, which are: 1. Type H Support The typical drawing of type H1 and type H2 support is shown in Figure 8.4 below: Figure 8.4: Construction Method of Type H1 and Type H2 Support

Haunch Zone, y Bed Zone, x

Type 1 Compacted Select Fill Material

(Ref: AS 3725-1989, page 16) The typical drawing of type H3 support is shown in Figure 8.5 below: Figure 8.5: Construction Method of Type H3 Support

Haunch Zone, y Bed Zone, x

Grade 20 Concrete

(Ref: AS 3725-1989, page 17)


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2. Type HS Support The typical drawing of type HS support is shown in Figure 8.6 below: Figure 8.6: Construction Method of Type HS Support

Type 2 Type 1

(Ref: AS 3725-1989, page 17) The compositions of fill material for RC pipeline embedment are shown in Table 8.1 below: Table 8.1: Compositions of Fill Material for RC Pipeline Embedment Type of Fill Select Fill

Ordinary Fill

Particle/Aggregate Composition Size (mm) Type 1 Type 2 Conforms with the following soil classes: 1. SC – clayey sands with fines of low plasticity; ≤ 75 ≤ 20 2. SP – poorly graded sand; 3. SW – well graded sand; 4. GC – clayey gravels with fines of low plasticity 5. GW – well graded sand and gravel mixtures with little or no plastic fines; 6. GP – poorly graded sand and gravel mixtures with little or no plastic fines 75 to 150 Mass of stone is not more than 20%

The bedding factors for dead loads for various types of pipe support shall be not greater than the values in Table 8.2 as recommended in AS 3725-1989. Table 8.2: Bedding Factors for Working Dead Loads for Various Types of Support Minimum Depth, mm Support Type H

HS

H1 H2 H3 HS1 HS2 HS3

Bed Zone X O.D ≤ 1500 : 100 O.D > 1500 : 150 0.25O.D but not less than 100 O.D ≤ 1500 : 100 O.D > 1500 : 150

Haunch Zone Y 0.1D 0.3D 0.3D 0.1D

0.3D 0.3D

Maximum Bedding Factor (f) 1.5 2.0 2.5 2.0 2.5 4.0

(Ref: AS 3725-1989, page 18)


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The compressibility of the side support will affect the loading. The lower the compressibility of that side support, the higher the possible loading, i.e. the more densely the embedment is compacted, the higher the load. Embedment materials need to be placed in layers not exceeding 250 mm in depth to ensure that any compaction will achieve a uniform increase in density throughout the depth of the layer. Concrete cradle could also be used to achieve a high enhancement of pipe strength. The use of concrete support is not desirable due to difficulties achieving the close fitting of the concrete to the pipe. Concrete undergoes shrinkage, and if the concrete is too wet, it can result only in point support of the concrete for the pipe. With the high strengths to which reinforced concrete pipes can be made today it is normally not necessary to use concrete support for the type of trench installation loadings encountered by sewerage pipes.

8.3

Flexible Pipe

The pipeline structural design and pipeline embedment method of flexible pipeline recommended in this part of the section is applicable for all types of flexible pipes conveying sewage for both pressure and non-pressure applications that are manufactured from the materials listed in Table 8.3, and that are: 1. Homogeneous or composite; 2. Creep affected (plastics) or unaffected (metallic); or 3. Plain or structural wall Table 8.3: Typical Flexible Pipe Materials Plastics Acrylonitrile butadiene styrene (ABS) Glass filament reinforced plastics (GFRP) Polyethylene (PE)

Metallic Ductile Iron (DI) Steel

Additional requirements on the pipeline design and pipeline embedment for the specific type of pipe material are described in the following clause of this section.

8.3.1

Flexible Pipeline Structural Design

The basis of flexible pipeline structural design is to select appropriate embedment material densities and pipe stiffness for the particular loading and native soil stiffness so that values for vertical ring deflection, circumferential pipe wall strain and ring buckling resistance do not exceed allowable longer long term values. The structural design of flexible pipelines relies primarily upon side support to resist vertical loads without excessive deformation by adopting an elliptical shape. The basis design of the pipeline for flexible pipe is to determine whether: 1. The loads acting on the pipe due to fill and superimposed load can causes vertical diametral deflection in the pipe resulting in bending stresses; and 2. The effect of internal pressure in a pipe can introduce a uniform stress in the wall of the pipe. The installation of pipeline shall be designed to give no more than 5% vertical diametral deflection in the empty pipe condition.


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For carrying out a pipeline design of flexible pipe, it is dependent on the factors of: 1. The height of the fill material above the top of the pipe; 2. The maximum density of the fill material; 3. The magnitude of any loads superimposed on the fill material and the nature of the loads, e.g whether the loads are distributed or concentrated, static or dynamic. 4. Pipe installation condition; 5. The width of the trench; 6. The mean outside diameter of the pipe; 7. The type of bedding as defined by the bedding factor value. The effect of impact causes by the dynamic superimposed loads, road vehicle loading and railway loading shall also be taken into the consideration for designing the sewer pipeline for flexible pipe. Floatation of the pipeline shall be prevented before any further pipe laying by either, placement and compaction of sufficient height of fill material over the installed pipeline, or by filling the pipeline with water to prevent floatation. Compaction equipment or methods that produce horizontal or vertical earth pressures on the pipeline, which can cause damage or excessive distortion to the pipeline, shall not be used. Structural design of flexible pipe is to be performed in accordance to MSIG Volume 3 and AS 2566.1- 1992 – Structural Design for Buried Flexible Pipelines.

8.3.2

Flexible Pipeline Embedment

The typical drawing of the embedment method for flexible pipe as described in Australian Standard AS/NZS 2566.2:2002 – Installation for Buried Flexible Pipelines is shown in Figure 8.7. The embedment material for the flexible pipe shall be in accordance with AS/NZS 2566.2:2002 which: 1. Comply with the maximum particles size of Table 8.4 and be of particle size and grading that will allow the specified relative compaction to be achieved with the intended compaction methods; Table 8.4: Maximum Particle Size of Embedment Material for Flexible Pipeline Nominal pipe diameter, DN < 100 > 100 ≤ 150 > 150

Maximum particle size, mm 10 14 20

2. Contain no organic material that will affect embedment material performance; 3. Be free of materials that would be physically and chemically harmful to any pipeline component, including any protective coating; and 4. For unprotected metallic pipes, be a granular fill with a resistivity greater than 50 ohm.m. The higher the granular content of the embedment material, particularly higher gravel content, the more supportive it becomes to the pipe, where an equivalent compactive method is used. Sharp granular embedment material should not be used with some pressure pipe materials as it can either score the external surface of the pipe, or damage the protective coatings and sleeving.


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The materials for flexible pipeline embedment shall be of the following: 1. Native soils, especially cohesionless soils containing of sand or coarse-grained soil with less than 12% fines and particles size less than 20mm. Sand prone to ‘bulk’ when moist shall be avoided. Whatever materials are used, ensure that the required density is to be met. 2. Imported cohesionless material containing of processed aggregates with nominal size of graded aggregate not more than 20mm. Graded aggregates are considered more susceptible to segregation in transport and handling. Particular care shall be taken to remix or wash this material to minimize the effect of segregation. 3. Other materials containing the gravel gradings of: a. Well graded crushed rock with particles size not more than 20mm; b. Crushed rock dust with particles size not more than 10mm; and c. Sand with particles size not more than 5 mm. The application of this type of material embedment is to facilitate the achievement of the soil moduli. Where there is a possibility of migration of fines between the native soil and the embedment zone, a geotextile filter fabric, such as non-woven fabric made from filaments of synthetic fibres shall be provided to ensure that the integrity of the side support to the pipe is not compromised. The compacted bedding material surface shall be continuous, smooth and free of stones larger than those 20mm, so as to provide a uniform support to the pipe. Following grading, and where required compaction, pockets for sockets, couplings, flanges or other projections shall be excavated in the bedding material, so as to ensure the pipeline is fully supported along the pipe barrels. The bedding shall be provided with joint holes to ensure that the pipe rests on the barrel and not the joint. The side support and overlay material shall be placed in layers of appropriate thickness for the method of compaction, to achieve the relative compaction or soil modulus specified. The side support material shall be brought up evenly on each side of the pipe. Ordinary fill shall be a material obtained from the excavation or imported and containing not more than 20% by mass of rock with size between 75mm and 150mm and none larger than 150mm. Control of the relative compaction of soils in the side support zone during pipe installation is the usual means for ensuring the soil moduli will be at least equal to those assumed at design stage. Each layer of the embedment material shall be compacted as recommended in Table 8.5 below in accordance with AS/NZS 2566.2:2002. Table 8.5: Minimum Relative Compaction of Embedment Material for Flexible Pipeline

Soil Type Cohesionless Cohesive

Test Method

Trafficable Areas Embedment Trench Fill Material % Material %

Density Index (ID) Standard dry density ratio (RD)


Non-Trafficable Areas Embedment Trench Fill Material % Material %

70

70

60

95

95

90

Compaction will depend on site requirements

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Embedment material is to be compacted in layers not exceeding 250 mm or 0.4 of the pipe external diameter, whichever is less. Bedding is to be compacted with a vibrating plate. Replacement of embedment material by alternative structural support may be required in the following circumstances: a. Pipes are laid on steep grades; b. Forces, due to hydrostatic or hydrodynamic pressure, may not be contained by the embedment material; c. The foundation for the pipeline is inadequate; d. The embedment material or native soil support may be washed away. The concrete encasement shall be considered as an alternative embedment material where: a. Gradients are 30% or greater; b. Additional embedment material stiffness is required; c. The trench foundation is inadequate; d. Buoyancy considerations could result in excessive uplift forces; and e. The risk of erosion is high (such as through water course) The requirements of the pipeline embedment for flexible pipe shall be in accordance with the Australian Standard AS/NZS 2566.2:2002 - Installation for Buried Flexible Pipelines.

8.3.3

DI Pipe

8.3.3.1 Pipeline Structural Design The structural design sewer pipeline used with ductile iron pipe is referred to as flexible pipe with high ring stiffness design. The design combines elements of rigid pipe design and flexible pipe design. The basis of structural pipeline design for DI pipe is to provide a high degree of security for the pipeline during its operating life. It is dependent on the factors of: 1. Pipe ovalization – is proportionately to diameter of pipe. It is limited to 4% for DN ≥ 800 with safety factor of 1.5 at minimum elastic limit in bending of 500MPa and maximum stress in the pipe wall of 330 MPa. 2. Pressure from earth loading; 3. Pressure from traffic loading; 4. Bedding factor – depends upon the soil pressure distribution at the top of the pipe; 5. Factor of lateral pressure; 6. Modulus of soil reaction – depends upon the nature of soil used in the pipe zone and upon the laying condition; and 7. Heights of cover. The failure mode of ductile iron pipe is from fracture through ring bending. The ductile iron cross section can deform considerably before fracture, but not as great a deformation as that with plastic pipe. Sufficient load provided over the pipe can help to provide some resistance to the pipe deformation. For the loading situations normally encountered for sewerage pipelines, the side support plays a negligible role in resisting the overburden loadings. The cement lining of ductile iron pipe can suffer cracking with small deformations of the pipe cross section. Hence, the limit placed on the vertical deflection due to cement lining governs the design and overrides any stress limit in the ductile iron due to bending.


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This deflection limit, however, although low compared to thermoplastic pipe, is not expected to be exceeded under the worst loading conditions for sewerage. It is therefore only necessary to undertake a structural design analysis for unusual loadings such as when a high load is superimposed over a pipeline with shallow cover. Structural design of DI pipe is to be performed in accordance with the British Standards BS 80102.1:1987 – Code of Practice for Ductile Iron Pipelines, BS EN 598:1995 (Annex C) – Ductile Iron Pipes, Fittings, Accessories and their Joints for Sewerage Applications. Other than what has been required here, the structural design of DI Pipe shall be in accordance with AS 2566.1-1992 as described in Clause 8.3.1.

8.3.3.2 Pipeline Embedment The main functions of the embedment with ductile iron pipe are to ensure that the pipeline retains any specified gradient and that the external corrosion protection system is not exposed to abrasion with sufficient coating or tear by providing a sleeving. The DI pipe is a flexible pipe that has a very high stiffness of most diameters, with maximum allowable vertical deflection of 1.5%. This high ring stiffness means that the pipe does not have a need for the embedment to function as side support unlike other more flexible pipe such as plastic pipe. However, the bedding is still required to give uniform continuous support to the pipeline. Crushed rock, even though it fulfils the side support requirements, is unsuitable as sharp rock edges can damage the external coating. Cohesive materials (e.g. clays, sandy clays, and silty clays) will not damage the coating but are difficult to place and compact to achieve sufficient side support. The preferred embedment medium is sand. The requirements of the pipeline embedment for DI Pipe other than what is required here shall be in accordance with the Australian Standard AS/NZS 2566.2:2002 as described in Section 8.3.2.

8.3.4

GRP Pipe

8.3.4.1 Pipeline Structural Design The structural design of GRP pipeline is to ensure that the assumptions made during design are achieved in the field. For non-pressure pipelines, the installed pipeline should be capable of taking the maximum external water pressure. The pressure pipelines should be capable of withstanding the combined effects of the maximum external water pressure and a complete internal vacuum. For external loading, when correctly installed, GRP pipes shall have sufficient strength for all normal conditions when operating at pressures up to their rated pressure. It is necessary to consider the combined effect of internal and external loads to determine the behaviour of the pipes. The factors taken into account should include the following: 1. Type of installation 2. Depth of burial; 3. Type of traffic loading; 4. Any additional surcharges; 5. Native soil type; 6. Height of water table; 7. Maximum and minimum working pressure; 8. Magnitude and frequency of any surge; 9. Minimum and maximum operating temperatures. A Guide to Sewer Selection and Installation 13th November 2006

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Because GRP pipes are flexible conduits which in the buried condition normally rely on the pipesoil structure interaction for their load bearing capacity, it is important that the pipes are bedded and surrounded in a material which is capable of transmitting lateral thrusts from the pipe to the native soil forming the trench wall and that the native soil does not become over-stressed. The backfill and compaction procedures are dependent on these factors: a. The classification and the density of the native soil; b. Groundwater levels along the length of the pipeline; c. Classes of pipe Heavy mechanical compactors shall not be used within 300mm of the pipe crown. Structural design of GRP pipe is to be performed in accordance with the British Standard BS 8010: Section 2.5: 1989 – Pipelines on land: design, construction and installation (Glass reinforced thermosetting plastics). Other than what has been required here, the structural design of GRP Pipe shall be in accordance with AS 2566.1-1992 as described in Clause 8.3.1.

8.3.4.2 Pipeline Embedment The GRP pipeline embedment method shall be in accordance with the AS/NZS 2566.2:2002 as described in Clause 8.3.2.

8.3.5

Profile Wall HDPE Pipe

8.3.5.1 Pipeline Structural Design The basis of the profiled wall HDPE pipeline structural design is to determine whether the pipe satisfies the deflection at joints, compressive strain and buckling pressure resistance limits. For the particular installation conditions, this requires the selection of the suitable combination of pipe class and embedment support. Structural design of the profiled wall HDPE pipeline is to be performed in accordance with AS/NZS 2566.1:1998 as described in Clause 8.3.1 and British Standard BS 8010 - Pipelines on land: design, construction and installation.

8.3.5.2 Pipeline Embedment The GRP pipeline embedment method and requirements shall be in accordance with AS/NZS 2566.2:2002 as described in Clause 8.3.2.

8.3.6

ABS Pipe

8.3.6.1 Pipeline Structural Design Structural design of ABS pipeline is to be performed in accordance with AS/NZS 2566.1:1998 as described in Clause 8.3.1.

8.3.6.2 Pipeline Embedment As with other flexible pipe, ABS pipe cannot support the soil overburden loading without the assistance of the material that surrounds the pipe. The embedment requirements as would apply to other thermoplastic pipe such PE are necessary.


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For underlay preparation, a minimum thickness of 75mm shall be provided in the bottom of the trench. The overlay material should be levelled and compacted in layers to a minimum height of 150mm above the top of the pipe trench. The ABS pipeline embedment method and requirements pipeline is to be performed in accordance with MS 1419: Part 4: 1998. Other than what has been required here, the structural design of ABS Pipe shall be in accordance with AS 2566.2-2002 as described in Clause 8.3.2.

8.3.7

Steel Pipe

8.3.7.1 Pipeline Structural Design Steel pipe in the wall thickness normally offered come within the flexible pipe designation. The ring stiffness (the measure of flexibility) decreases as the pipe size increases. When compare to equivalent sizes of plastic pipelines, steel pipe are much stiffer than plastic pipe. Steel pipes will not fail from circumferential tension like ductile iron pipe and unlined steel pipe require a limitation on deflection to prevent reverse curvature (buckling). The maximum vertical deflection limit to prevent reverse curvature of steel pipe is 4.0%. However, the cement lining of the steel pipe is prone to fracture and a deflection limitation of 2.5% is required for buckling. The deflection limits for steel pipe with elastomeric joint therefore becomes equivalent to that for cement lined ductile iron pipe, which is 1.5%. For small diameter flexible pipe of medium stiffness as the steel pipe, experience has shown that except for unstable ground conditions, the use of good quality embedment materials at the relative compactions will ensure acceptable deflection with no structural design of pipeline is necessary. It is therefore only necessary to undertake a structural design analysis for unusual loadings such as when a high load is superimposed over a pipeline with shallow cover. Structural design of steel pipe is to be performed in accordance with AS 2566.1-1992 as described in Clause 8.3.1.

8.3.7.2 Pipeline Embedment The embedment medium for steel pipe is governed by the need to protect the external coating of the pipeline while providing pipe side support without great care in placement of the embedment medium. Sand of equivalent density to crushed rock is less supportive than the crushed rock but the higher stiffness of steel pipe compared to plastic pipe, generally means that steel pipe will perform at least as well as plastic pipe in terms of ovalisation. The ABS pipeline embedment method and requirements pipeline is to be performed in accordance with AS/NZS 2566.2:2002 as described in Clause 8.3.2.


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8.3.8

Solids Wall HDPE Pipe

8.3.8.1 Pipeline Structural Design For a buried flexible pipe to have long term structural adequacy, it is required that the combined stiffness of the pipe ring and surrounding soil prevent pipe ring deformation and ring tension/compression/crushing stress limits being exceeded when external pressures (and possibly internal vacuum) are applied. Further, it is required that the flexible pipe have a minimum ring stiffness to prevent localised deformation when placing backfill around the pipe. Structural design of solid wall HDPE pipe is to be performed in accordance with AS 2566.1-1992 as described in Clause 8.3.1.

8.3.8.2

Pipeline Embedment

The use of polyethylene solid wall pipe is generally limited to special applications for pressure sewers. As with other flexible pipe, PE pipe cannot support the soil overburden loading without the assistance of the material that surrounds the pipe. Where the PE pipe chosen is of equivalent stiffness to other plastic pipe then the same embedment conditions would be appropriate. The solid wall HDPE pipeline embedment method shall be in accordance with AS/NZS 2566.2:2002 as described in Clause 8.3.2.


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Figure 8.7: Terminology and Typical Construction of Pipe Support for Flexible Pipeline

l

l l B

D

l

D


D

121


Table 8.6: Notations Applicable in the Guidelines

Symbol

Definition Width of trench or embedment zone measured at the springline of the pipe

B

Unit of measurement mm

De

Diameter of the most extreme external surface along the pipe barrel, averaged in two directions

mm

Di

(Minimum) mean internal diameter, which is the average of the maximum and minimum internal diameters

mm

H

Cover, vertical distance between the top of the pipe and the finished surface

mm

ID

Density index

lb

Depth of bedding below the bottom of the pipe

mm

lc

Horizontal distance between the spring line and the trench wall or permanent trench support (not distance to temporary trench supports)

mm

lo

Depth of overlay

mm

%

Ref.: Modified from AS/NZS 2566.2:2002, pg. 10

Table 8.7: Minimum Cover (H) for Flexible Pipeline

Not subject to vehicle loading

Minimum cover H m 0.30

Land zoned for agricultural use

0.60

Loading condition

Subject to vehicular loading – (a) no carriageway; (b) sealed carriageways; and (c) unsealed carriageways Pipelines in embankments or subject to construction equipment loads

0.45 0.60 0.75 0.75

Ref.: AS/NZS 2566.2:2002, pg. 16

Table 8.8: Minimum Embedment Zone Dimensions De ≥75, ≤150 >150, ≤300 >300, ≤450 >450, ≤900 >900, ≤1500 >1500, ≤4000

lb 100 100 100 150 150 150

Minimum dimension (mm) lc lo 100 100 150 150 200 150 300 150 350 200 300 0.25De

B = De + 2lc 275 – 350 450 – 600 700 – 850 1050 – 1500 1600 – 2200 2250 – 6000

Ref.: AS/NZS 2566.2:2002, pg. 17


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Section 9 Sewer Pipeline – Testing Guide, Site Handling and Installation

9.0

SEWER PIPELINE – TESTING HANDLING AND INSTALLATION

9.1

General

GUIDE,

SITE

This section specifies methods of test and their application to field testing of pipelines for the purpose of determining pipeline acceptability. Field testing includes leak or hydrostatic pressure testing and deflection testing, as appropriate, for pressure and non-pressure pipelines. It is very often that the pipelines are not handling properly at site during loading, unloading and installation, thus resulted in necessary pipe cracking, improper joints etc. This section does not provide details in handling and installation procedures and requirements as the information can be obtained from relevant standards and guidelines, but it emphasises on the good practices that should be adopted while handling various types of pipeline. The common errors and recommended practices for site handling and installation of pipelines are presented as an illustrated guide attached at the end of this section.

9.2

Field Testing

The types of field testing require for various sewer pipelines are summarised in Tables 9.1. Details of the testing requirements and constraints shall be referred to MSIG Volume 3. Table 9.1: Summary of Field Testing for Sewer Pipelines Pipeline System Gravity Sewer

Pressure Sewer

Vacuum Sewer

Type of Test Test for straightness and grade: - Laser beam with sighting targets; - Sight rails and boning rod; - Lamp and mirror; - Insertion of a smooth ball. Exfiltration test: - Hydrostatic test - Low pressure air test Infiltration test Deflection test CCTV Inspection Test for straightness, obstruction and grade: - Same as recommended for gravity sewer. Exfiltration test: - Same as recommended for gravity sewer. High pressure water test High pressure leakage test CCTV Inspection Check the SDR of the pipe before installation (SDR is the thickness to diameter ratio of the pipe). Vacuum test.


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9.2.1

General Pipeline Testing Guide

The following guides are generally applicable to all water, air and vacuum tests. • • • • • • • • • •

The testing should be conducted before and after the backfilling of the trench. The pipeline must be cleaned and cleared of obstruction before the test is conducted. All plugs must be installed securely. Concrete thrust blocks must be completed and cured before the test. If solvent welding is used, the joint must be cured for at least 24 hours before testing. Air test is easier to apply but results can be affected by small changes in temperature. Water test is less stringent than air test but it suffers from the disadvantage of providing and disposing of large quantities of water. If the pressure drop is above that allowable limit on air testing, it is recommended to conduct water test to confirm the result. All air and vacuum testing of pipes shall be carried under the shade away from direct sunlight to avoid temperature effects on the pipe. Do not over-pressurise the pipelines to prevent sudden expulsion of a poorly installed plug.

Brief description on the procedures and requirements of the testing are given below. Detailed information of the testing can be obtained from MSIG Volume 3 and relevant standards.

9.2.2

Test for Straightness, Obstruction and Grade

For gravity sewers and pressure sewers, the grade and straightness are important to achieve the design velocity. The laser beam with sighting targets and sight rails and boning rod methods will provide more exact assurance for both the grade and straightness, which shall be used whenever possible. The lamp and mirror and insertion of smooth ball methods will provide a rough idea on whether the sewers are laid graded or straight, which should be used only for a quick check.

9.2.3

Low Pressure Air Test

The procedure of low pressure air test shall be as follows: a. Pump in air slowly until a pressure of 25 +5,-0 kPa is reached. Where the pipeline is below the water table this pressure shall be increased to achieve a differential pressure of 25 kPa. In no circumstances should the actual pressure exceed 50 kPa. b. Maintain the pressure for at least 3.0 min. c. Where no leaks are detected, shut off the air supply d. Where the pipeline fails the test, repressurised to 25 +5,-0 kPa and check for leaks by pouring a concentrated solution of soft soap and water over accessible joints and fittings. The test length shall be acceptable, where the pressure drops by 7kPa, or less, over the required test period.

9.2.4

Hydrostatic Test

The procedure of hydrostatic test shall be as follows: a. The test pressure shall be not less than 20 kPa, or 20kPa above the ground water pressure at the pipe soffit at its highest point, whichever is the greater, and not exceed 60 kPa at the lowest point of the section.


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b. Steeply graded pipelines shall be tested in stages where the maximum pressure, as stated above, will be exceeded if the whole section is tested in one length. c. The pressure shall be maintained for at least 2 hrs by adding measured volumes of water where necessary. d. Any visible leaks detected shall be repaired and the pipeline shall be retested. The test length shall be acceptable, where the addition of make-up water shall be 0.5 L/hour per metre length per metre diameter.

9.2.5

High Pressure Water Test

The procedure of high pressure water test shall be as follows: a. Close all valves apart from the test pump input and pressurized the test length to the specified test pressure or 1.5 times the design operating pressure; b. Apply and then maintain the test pressure by the addition of measured and recorded quantities of make-up water at regular intervals over a period, within the range of 1 hr to 12 hr; c. Where pressure measurements are not made at the lowest part of the test length, make an allowance for the static head, between the lowest point of the pipeline and the point of measurement, to ensure that the test pressure is not exceeded at the lowest point. There must be a drop in test pressure during the pressurised filling and in the next 10 minutes after the required pressure is achieved.

9.2.6

High Pressure Leakage Test

The test is normally conducted immediately after the high-pressure water test, i.e. before the water is drained out. The test pressure mentioned in high water pressure test must be maintained for 24 hours. The measure the amount of additional fill water requires to maintain the test pressure. The measured amount must not exceed 0.1 litre per millimetre of pipe diameter per kilometre of pipe per day for each 3 bars of pressure applied. Also check for visible leakage. The typical field pressure test equipment in AS/NZS 2566.2:2002 shown in Figure 9.1 below is recommended for adoption: Figure 9.1: Typical Field Pressure Test Equipment Layout


125


9.2.7

Vacuum Test

The procedures of vacuum test shall be as follows: a. b. c. d.

Apply a vacuum until a negative pressure of 25kPa to 30kPa is achieved. Maintain the vacuum for at least 3.0 min. Where no leaks are detected, isolate the test section from the vacuum pump. Where the pipeline fails the test, reapply the vacuum and check for leaks. Pouring water over joints and fittings will improve the possibility of leaks detectable by auditory methods.

The test length shall be acceptable, where the vacuum drops by 7kPa, or less, over the test period.

9.2.8

Infiltration Test

The pipeline shall be observed for infiltration over a 24 hr period, or as appropriate. In all cases where infiltration is observed, the source shall be investigated, and any leak detected shall be repaired. This method is applicable where a freestanding water table exists at a level of at least 1.5m above the test section and 150mm above any sideline connections.

9.2.9

CCTV Inspection

Inspection by CCTV shall in accordance to the procedures:1. Coverage a. Initial CCTV testing & inspection shall be conducted for a minimum 10% random selection of sewer pipeline in accordance with standard procedure. b. If the mandatory requirement of clause 9.2.9-2 is less then 5% of the entire development area, the minimum CCTV testing & inspection is 10% as in 9.2.9-1a. If the mandatory requirement of clause 9.2.9-2 is more than 5%, the minimum CCTV testing & inspection shall have an additional of 10%. c. All new sewer pipeline shall undergo the CCTV inspection except: i) Development with sewer length < 500m long with no interval. ii) Vacuum sewer. iii) Existing network to be taken over by SSD under the concessionaire agreement. d. Prior to taking over existing network that has been approved from any owner or after rehabilitation works have been completed. 2. Characteristics of 100% CCTV Inspection A 100% CCTV inspection shall be conducted for sewer pipelines lay on ground with greater risk of failure and have the following characteristics. b. Deeper than average of 6m or more. c. Pipe diameter above 600mm. d. Areas that are restricted vehicular access for repair when encounter failure (e.g. central business district) e. Under buildings, lakes, rivers, roads and railway line. f. Ground slopes greater 30° inclination. g. All sewers installed using pipe jacking method. h. All diversion or re-alignment of existing sewer networks.


126


3. Stage of Inspection a. Stage 1 - All projects are to start with stage 1 inspection where 10% (by length) of sewer network and property connections involved, shall be randomly selected and CCTV inspected. b. Stage 2 - Should any Grade 3,4 and 5 conditions as defined in the Manual for Sewer Condition Classification approved by SSD, found in stage 1 inspection, the CCTV inspection shall proceed to stage 2 inspection. Stage 2 inspections shall include another 40% of the sewer network to be randomly selected for CCTV inspection. c. Stage 3 - Should any Grade 3,4 and 5 conditions as defined in the Manual for Sewer Condition Classification approved by SSD, found in stage 2 inspection, the CCTV inspection shall proceed to stage 3 where all the remaining network shall be CCTV inspected. After the CCTV inspection and recording have been completed for a project, a report on the CCTV inspection together with the recording and recommendations shall be prepared by the CCTV contractor and submitted to the relevant SSD branch office, 7 days after the date of inspection. The copy of the tape (or other recording media used to store the record) containing the CCTV inspection records shall be submitted together with the certificate duly signed by the qualified person responsible for the CCTV inspection. The qualified person shall declare the authenticity of the recording submitted and that the CCTV inspection has been done in accordance with the procedure.

9.3

Factory Testing

The types of factory testing require for various types of pipe for sewerage system are summarised in Tables 9.2 below. Table 9.2: Summary of Factory Testing for Various Types of Sewer Pipe Type of FactoryTesting Visual inspection Crushing test Dimensions test Deflection test Shear resistance Water absorption test Straightness of pipe Impermeability test Tensile test Brinell hardness test Strain corrosion resistance test Ovality test Specific stiffness test

VC √ √ √ √ √ √ √ √

RC √ √ √ √ √ √

DI

√ √

Types of Pipe GFRP Steel

√ √

√ √ √

√ √ √ √

ABS

HDPE

√ √

√ √

√ √

√

√

√

√ √

√

√

√

√

Note: The test methods shall be referred to their respective standards.


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9.4

Site Handling and Installation Guide

9.4.1

Dos and Don’ts DOs

DON’Ts Pipe Delivery

Site Handling

Site Unloading

Pipe Storage


128


DOs

DON’Ts Loading to Trench

Excavation


129


DOs

DON’Ts Pipe Bedding

Pipe Fitting RUBBER RING JOINTS


130


DOs

DON’Ts Placement

Pipe Embedment


131


Pipe Embedment

DOs

DON’Ts Protection


132


9.5

Handling and Installation Practice

9.5.1

Storage

9.5.2

Excavation


133


9.5.3

Pipe Cutting

9.5.4

Pipe Jointing


134


9.5.5

Pipe Inspection


135

APPENDIX A Checklist B

APPENDIX B Product Details: Sewer Pipes and Fittings Form

APPENDIX C Evaluation Criteria Form

APPENDIX C Summary of Approved Suppliers/Manufacturers

REFERENCES 1. Valve, Piping and Pipeline Handbook 2. Developer Guideline Volume III 3. Power and Water

( 3rd Edition ), T.C. Sewer Networks and Pump Station ( 2nd Edition ) May 2002 Water Supply and Sewerage Approved Products Manual

Malaysian Standards (MS) 1. MS 1058: 2002

2. MS 1061: 1999 3. MS 881: 1991 4. MS 1419

Specification for polyethylene (PE) Piping systems for water supply Part 1:General (Third revision) Part 2: Pipes (Third revision). Vitrified clay pipes and fittings and pipe joints for drains and sewers Specification for pre-cast concrete pipes and fittings for drainage and sewerage Part 1: 1997: Pipes Part 2: 1998: Guides for Installation of ABS Pipe System

British Standards (BS) 1. BS 5480:1990 2. BS 5911-1:2002

3. BS 6076:1996 4. BS 65:1991 5. BS 8010-2.1:1987 6. BS EN 295-1:1991 7. BS EN 295-7:1996

8. BS EN 545:2002 9. BS EN 598:1995

Specification for glass reinforced plastics (GRP) pipes, joints and fittings for use for water supply or sewerage Concrete pipes and ancillary concrete products. Specification for unreinforced and reinforced concrete pipes (including jacking pipes) and fittings with flexible joints(complementary to BSEN 1916:2002) Specification for polymeric film for use as a protective sleeving for buried iron pipes and fittings (for site and factory application) Specification for vitrified clay pipes, fittings and ducts, also flexible mechanical joints for use solely with surface water pipes and fittings Code of practice for pipelines. Pipelines on land: design, construction and installation. Ductile iron Vitrified clay pipes and fittings and pipe joints for drains and sewers. Requirements Vitrified clay pipes and fittings and pipe joints for drains and sewers. Requirements for vitrified clay pipes and joints for pipe jacking Ductile iron pipes, fittings, accessories and their joints for water pipelines. Requirements and test methods Ductile iron pipes, fittings, accessories and their joints for sewerage applications. Requirements and test methods

10. BS 8010

11. BS 5911

12. BS EN 752: 1997

British Standard Cord for practice for Pipeline: Part 1: 1987: Pipeline on Land: General Part 2: 1989: Pipeline on Land: Design, construction and installation. Section 2.1: 1987 Ductile Iron Section 2.5: 1989 Glass reinforced thermosetting plastics Precast Concrete Pipes, fittings and ancillary products: Part 100: Specification for unreinforced and reinforced pipes and fitting with flexible joints Part 200: Specification for reinforced jacking pipes with flexible joints Drain and sewer systems outside buildings.

International Organization for Standardisation (ISO) 1. ISO 2531: 1998 2. ISO TC 138 SC1 3. ISO TR 10465-1: 1993 4. ISO TR 10465-3: 1999

Ductile iron pipes, fittings, accessories and their joints for water or gas applications Plastics pipes and fittings for soil, waste and drainage (including land drainage) Underground installation of flexible glass-reinforced thermosetting resin (GRP) pipes - Part 1: Installation procedures Underground installation of flexible glass-reinforced thermosetting resin (GRP) pipes - Part 3: Installation parameters and application limits

Australian Standard (AS/NZS) 1. 2. 3. 4. 5. 6.

AS 3680-1989 AS 3725-1989 AS 4060-1992 AS/NZS 2280: 2004 AS/NZS 2566.1: 1998 AS/NZS 2566.2: 2002

Polyethelene sleeving for ductile iron pipelines Loads on buried concrete pipe Loads on buried vitrified clay pipe Ductile iron pipe and fittings Buried flexible pipelines-Structural design Buried flexible pipelines-Installation

American Society for Testing and Materials (ASTM) 1. ASTM D 3212 2. ASTM D 3262 3. ASTM D 3350 4. ASTM D-2321 5. ASTM F 894

Standard Specification for Joints for Drain and Sewer Plastic Pipes Using Flexible Elastomeric Seals Specification for “Fiberglass” Glass-Fiber-Reinforced ThermosettingResin Sewer Pipe Standard Specification for Polyethylene Plastics Pipe and Fitting Materials Practice for Underground Installation of Flexible Thermo Plastic Sewer Pipe. Specification for Polyethylene (PE) Large Diameter Profile Wall Sewer. and Drain Pipe.

German Institute for Standardization (DIN) 1. DIN 16961-1 (2000-03)

Thermoplastic pipes and fittings with profiled outer and smooth inner surfaces-Dimensions

Canadian Standards Association (CSA) 1. CAN/CSA-B182.6-M92

Profile Polyethylene Sewer Pipe and Fittings

Code of Practice 1. CP 312

Code of practice for plastics pipe work ( thermoplastics material ) Part 1: 1973: General principles and choice of materials Part 3: 1973: Polyethylene pipes for the conveyance of liquids under pressure

Water Industry Specifications (U.K) (WIS) 1. WIS 04-24-01 2. WIS 04-32-14

Specification for mechanical fittings and joints for polyethylene pipes for nominal sizes 90 to 1000 Specification for PE 80 and PE 100 electrofusion fittings for nominal sizes up to and including 630

Website 1. http://www.plasticpipes.com 2. http://www.pslc.ws 3. http://www.healthy building.net 4. http://www.powerwater.com.my

(Msia) Guide to Sewer Selection and Installation (Dec2006)_VC Pipe pg17～

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