01-SAIP-01

Insp nspe ect ction ion Proc roce edur dure e 01-SAIP-01

31 July, July, 2004

Small Nipple Inspection Program Document Responsibility: Inspection Department

Saudi Saudi Aramco Aramc o Desk DeskTop Top Standards Standards Table of Contents 1 2 3 4 5 6 7 8 9 10 11

Scope.................... Scope.................................. ............................ .......................... .............. 2 Purpose............... Purpose............................... ............................. .......................... ............... 2 Safety.................. Safety................................. ............................ .......................... ............... .. 2 References.......... References.......................... ............................. .......................... ............... 2 Definitions and Abbreviations............. Abbreviations.... .................... ............. 4 Inspection Procedure Steps.................. Steps....... .................... ......... 6 Inspection Methods................. Methods...... ...................... ...................... ............. 7 Acceptance and Rejection Criteria................. Criteria....... .......... 8 Repairs................. Repairs................................ ............................ .......................... ............... 9 Inspection Interval............... Interval.... ..................... ...................... ............... ... 10 Documentation............ Documentation.. ..................... ....................... ...................... .......... 10

Appendix - I........................ I...................................... ........................... .................. ..... 11 Appendix - II....................... II..................................... ........................... .................. ..... 12 Previous Issue: 31 January, 1999 Next Planned Update: 1 August, 2009 Revised paragraphs are indicated in the right margin Primary contact: Supervisor, IEU on 874-6604

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Document Responsibility: Inspection Department Issue Date: 31 July, 2004 Next Planned Update: 1 August, 2009

1

2

01-SAIP-01 Small Nipple Inspection Program

Scope 1.1

This Saudi ARAMCO Inspection Procedure (SAIP) establishes the inspection requirements of in service (existing) small pipe nipples of up to 1-½ inch NPS within existing facilities. This procedure applies primarily to piping in hydrocarbon service but can be applied to other services as well.

1.2

Nondestructive Testing (NDT) should be performed only by individuals certified to level I or II in accordance with SAEP-1140 or SAEP-1142.

Purpose This SAIP is intended to assist the Plant and Equipment (PE) Inspectors of Operations Engineering Units in their selection, on stream evaluation, and tracking of existing nipple condition.

3

4

Safety 3.1

Radiographic examination personnel safety should be per SAEP-1143 para. 3.

3.2

All pressure testing should be in compliance with GI-0002.102, "Pressure Testing Safely".

References The following standards were used in the preparation of this procedure and should be carefully reviewed by the inspectors. All references should be the latest issued revision or edition. 4.1

Saudi Aramco References Saudi Aramco Engineering Standards SAES-A-004

General Requirements for Pressure Testing

SAES-A-206

Positive Material Identification

SAES-L-004

Pressure Design of Piping Components

SAES-W-011

Welding Requirements for On-Plot Piping

Saudi Aramco Engineering Procedures SAEP-20

Equipment Inspection Schedule

SAEP-302

Instructions for Obtaining a Waiver

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SAEP-1140

Qualification and Certification of Saudi Aramco NDT Personnel

SAEP-1141

Industrial Radiation Safety

SAEP-1142

Qualification and Certification of Non-Saudi Aramco NDT Personnel

SAEP-1143

Radiographic Examination

SAEP-1144

Magnetic Particle Examination of Welds and Components

SAEP-1145

Liquid Penetrant Examination of Welds and Components

Saudi Aramco Standard Drawing AB-036521

Bracing Detail on Small Connection

Saudi Aramco General Instructions GI-0002.102

Pressure Testing Safely

GI-0150.003

Radiation Safety

Saudi Aramco Inspection Procedures

4.2

01-SAIP-02

Retirement Thickness of In-Plant Piping

00-SAIP-07

Positive Material Identification Requirements

Industry Codes and Standards American Society of Mechanical Engineers ASME SEC V

Nondestructive Examination

ASME B 31.1

Power Piping

ASME B 31.3

Chemical Plant and Petroleum Refinery Piping

ASME B 31.4

Liquid Transportation System for Hydrocarbon, LPG, Anhydrous Ammonia, & Alcohol

ASME B 31.8

Gas Transmission and Distribution Piping System

American Petroleum Institute API RP 570

Piping Inspection Code

API RP 578

Material Verification

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5


Defini tions and Abbreviations Nipple: A pipe nipple is a small bore pipe attached to a main header by welding. The attachment may be by use of a welding boss or proprietary fitting/valve welded to the pipe header. Alloy Material: Any metallic material (including welding filler materials) that contains alloying elements such as chromium, nickel, or molybdenum, which are added to enhance mechanical or physical properties and/or corrosion resistance. Fabrication: The preparation of piping and small connection for assembly, including cutting, threading, grooving, forming, bending and joining of components into subassemblies. Face of the weld: The exposed surface of a weld on the side from which the welding was done. Filler material: The material to be added in making metallic or nonmetallic joints. Fillet weld: A weld of approximately triangular cross section joining two surfaces approximately at right angles to each other in a lap joint, tee joint, or corner joint. Crack: A fracture type discontinuity characterized by a sharp tip and high ratio of length to width to opening displacement. Lack of fusion: A weld discontinuity in which fusion did not occur between weld metal and base metal or adjoining weld beads. Incomplete Penetration: The weld beads unable to fill the weld bevel groove. Porosity: Cavity type discontinuities formed by gas entrapment during solidification of the weld metal. Rounded Indications: Indications with a maximum length of three times the width or less on the radiograph. Aligned Indications: A sequence of four (4) or more rounded indications should be considered aligned. Leg Length: is the thickness of a fillet weld, excluding any allowable reinforcement measured through the leg. tm: Minimum thickness required (t) is equal to the design thickn ess as calculated by the applicable ASME Code B31.3 formula.

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Hydrocarbon Services: Process streams of liquid or gaseous hydrocarbon (HC) materials, or HC streams that may contain phenols, carbon dioxide, and ammonia. Category "D" Fluid Service: A fluid service in which all the following apply:

1)

The fluid handled is nonflammable, non toxic, and not damaging to human tissues as defined in ASME B31.3 paragraph 300.2.

2)

The design gage pressure does not exceed 150 psi (1030 kpa)

3)

The design temperature is from -20°F (-29°C) through 366°F (180°C)

Low-Chrome Alloy Steels: Alloy materials with nominal chromium contents of 1% to 5% chrome. Repair: The work necessary to restore a nipple to a condition suitable for safe operation at the design conditions, without any deviation from the original configuration. Abbreviations: ADIP

Amino-Di-IsoPropanol

DEA

Di Ethanol Amine

DGA

Di Glycol Amine

HAZ

Heat Affected Zone

HC

Hydrocarbon

MEA

Mono Ethanol Amine

MSAER

Mandatory SA Engineering Requirements

MT

Magnetic Particle Testing

NDT

Non Destructive Testing

P&ID

Piping and Instrumentation Drawings

PFD

Process Flow Diagram

PMI

Positive Material Identification

PT

Penetrant Testing

PWHT

Post Weld Heat Treatment

RT

Radiography Testing

RTFI

Radiographic Film Interpretation

TEG

Tri Ethylene Glycol

UT

Ultrasonic Testing

VT

Visual Inspection

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6


Inspection Procedure Steps 6.1

Piping Categorization 6.1.1

A piping circuit will usually start and end at individual pieces of equipment and includes all lines of similar metallurgy and corrosion rate, same service, and design temperature and pressure. P&IDs or PFDs should be marked to designate to which corrosion circuit each line corresponds and line designation tables should be prepared for each unit.

6.1.2

Circuits should be categorized according to the anticipated corrosion and vibration potential of the process fluid they handle. Three (3) priorities of inspection have been assigned to the individual piping circuits based on the corrosion potential.

6.1.3

-

Priority 1: Vibrating service nipples at all operating temperatures including cryogenic service and all chemical injection points.

-

Priority 2: Non-vibrating service above 450°F or 230°C.

-

Priority 3: Non vibrating service below 450°F or 230°C.

Examples of pipe nipple inspection priorities are shown for the following services / equipment: 6.1.3.1

6.1.3.2

Priority-1 Nipples a.

Heater outlets

b.

Condenser outlets

c.

Steam including condensate pots

d.

Chemical Injection Point circuits

e.

H2S Streams

f.

Amine service

g.

Caustic service

h.

High temperature H2 streams

i.

Dead legs

j.

Mixed streams (hot and cold junction)

k.

Cryogenic services

l.

Vicinity of Pumps & Compressors

m.

Instrumentation Piping (Orifice, Flange & Gauges, etc.)

Priority -2 Nipples a.

Condenser outlets

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6.1.3.3

6.1.4

7


b.

Steam including condensate pots

c.

H2S Streams

d.

Amine service

e.

Caustic service

f.

H2 streams

g.

Dead legs

h.

Instrumentation Piping (Orifice, Flange & Gauges, etc.)

Priority –3 Nipples a.

Flare lines and header

b.

Off-gas lines and header

c.

Fuel gas

d.

Other process piping (L.P. steam and hydrocarbon)

e.

Dead legs

f.

Category "D" Fluids

Subsequent pipe nipple inspection priorities should be adjusted based on historical inspection findings, and inspection intervals adjusted according to paragraph 10.0.

Inspection Methods 7.1

Radiography should be used to inspect all pipe nipples for I.D./O.D corrosion on piping including cryogenic service. If, during the inspection of existing nipples or replacements, indications are found in welds, these indications should be evaluated per acceptance/rejection criteria of Table's 1 and 3.

7.2

The radiographic technique for small diameter nipples and to measure side wall thickness is shown in Appendix I & II.

7.3

Where questionable radiographs are produced, ultrasonic thickness (UT) gauging of the pipe nipple should be used as comparison.

7.4

Visual inspection should be performed on all pipe nipple systems to determine the need for replacement or repairs due to external corrosion, threads not covered by seal weld, vibration fatigue or possibility of overloading of the nipple. In cases where fatigue is suspected and radiography is not possible then liquid penetrant or magnetic particle inspection should be performed to determine if cracking has been initiated.

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Commentary Note: Over loading is usually associated with over stressing of the pipe nipple welds due to applied external forces such as people continuously using branch connection as a step.

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8


Acc eptance and Rejecti on Criteria Table 1 DEFECT ACCEPTANCE LIMITS IN SOCKET WELD RA DIOGRAPHY CRACK NONE

LACK OF FUSION, SLAG Length ≤ 0.4 x OD (note 1) Width ≤ 0.31 x "t" and 0.040" (1mm) (note 2)

LA CK OF PENETRATION

POROSITY

Acceptable provided the fused fillet leg and throat thickness meet the minimum acceptable value (note 4)

≤ 0.31

x "t" and 0.040" (note 2)

Notes: 1

OD is the actual outside diameter of the pipe. See Table 2 for lengths

2

The maximum permitted defect width shall be the lesser of 0.31 x "t" or 0.040" (1mm). "t" is the pressure design thickness of the pipe.

3

Aligned defects shall be considered as one defect if the separation distance is less than the length of the longer defect.

4

The minimum fused leg length (Cx ) is 1.25 x "t" (from ASME B31.3 328.5.2.C). The minimum effective throat thickness is 0.88 x "t". These are determined from radiography not physical measurement. "t" is the pressure design thickness of the pipe.

Table 2 MAXIMUM DEFECT LENGTHS FOR PIPE SIZES PIPE SIZE NPS

OUTSIDE DIAMETER (OD) (inches)

0.4 x OD (Inches)

½

0.840

0.34

¾

1.050

0.42

1

1.315

0.53

1 1/2

1.900

0.76

Table 3 ACCEPTANCE CRITERIA FOR OTHER CHARACTERISTICS GAP IN SOCKET WELDING BOSS NIPPLE WALL THICKNESS

FABRICATION TOLERANCES

Existing piping

New piping

Rejectable if gap is over 50% of the socket depth or ¼" whichever is less Rejectable if the corroded thickness is below "t" min. per design calculations NA

Rejectable if gap is over 50% of the socket depth or 3/16" whichever is less Rejectable if the corroded thickness is below "t" plus the corrosion allowance Must meet applicable industrial standards

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9


Repairs 9.1

Calculated retirement thickness (t) code tm and structural minimum thickness (which ever is greater) should be compared against original nipple thickness from the line specification. The structural minimum retirement thickness for carbon steel and chrome-moly alloy pipe nipples up to 1.5 NPS is 0.09 inch (2.25 mm) per 01-SAIP-02.

9.2

Pipe nipples should be removed at the retirement thickness indicated in paragraph 9.1. If the pipe nipple has not reached retirement thickness but shows a reduction in original wall thickness, the corrosion rate and remaining life should be calculated. The pipe nipples, which show a remaining life of less than the normal inspection frequency outlined in paragraph 10.2 or the next T&I inspection period, a temporary repairs (boxing) should be considered until replacement during scheduled T&I.9.3. All pipe nipples that have been identified as having the incorrect metallurgy for the piping system should be removed and replaced regardless of the remaining wall thickness. All alloy replacement nipples, valves and welds should be evaluated using an approved Positive Material Identification (PMI) instrument before installation p er SAES-A-206 using 00-SAIP-07 and API RP 578 as guides. Those nipples which are not braced and subjected to vibration should be adequately braced per SAES-L-004, paragraph 6.2.3 and Saudi Aramco Standard Drawing AB-036521 to prevent future fatigue failure. All repaired or replaced nipples should be radiographed and acceptance/ rejection criteria should be per Section 8.0, Tables 1 & 2. All nipple repairs / replacement associated with MEA, DGA, TEG and ADIP service piping should be Post Weld Heat Treated (PWHT) per SAES-W-011, section 13.0. All low alloy steel material should be PWHT per SAES-W-011, section 13.0. All low alloy steel material should be radiographed a nd MT or PT inspected after Post Weld Heat Treatment (PWHT) and acceptance/rejection c riteria should be per Section 8.0, Tables 1, 2 & 3. All piping associated with repaired or replaced nipple should be hydrostatically tested per SIS requirements in accordance with SAES-A-004. NDT in-lieu of hydrostatic test is not acceptable unless approved by the responsible Plant Manager.

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If PWHT is a requirement of SAES-W-011, but is not feasible for any reason, obtain an engineering waiver against the applicable MSAER per SAEP-302.

10

Inspection Interval 10.1

Pipe nipples should be inspected based on the priority designation of the line and/or circuit in which they are installed. Each line should be identified as part of a circuit and should be prioritized according to corrosion class as defined per SAEP-20.

10.2

In general, radiographic inspection frequencies should be based on the corrosion rate in accordance with SAEP-20, Table-II, or the following Priority Table, whichever is less. Small nipples in vibrating service should be included in priority 1 category. Priority Table Priority 1 2 3

11

Inspection Frequency 3 Years max. (Chemical Injection Point only per API RP 570) 5 Years max. for all other 7 Years max. 10 Years max.

Documentation 11.1

All piping Nipples should be identified on each line in priority 1-3 piping circuits. These pipe nipples should be added to the OSI Program as additional data/inspection points.

11.2

Thickness measured from the radiographic film image should be entered into the OSI Program to track individual corrosion rates and remaining life of each pipe nipple.

Revision Summary 31 July, 2004 Major revision.

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Appendix - I Radiographic Technique 90° Elbow

Radiographic Technique Tee

Notes: 1. 2. 3. 4.

SFD to be 12" with the source lined up in the middle. Shoot with one MX & one AX type film, MX closest to the weld. Only one weld per shot, with the number next to the weld on the pipe. Use three times the pipe wall thickness fro the shot exposure time - MX film.

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Appendi x - II Profile Radiographic Technique for Pipe Wall Measurements NDT Unit Procedure No. 32.60.2.001 Dated 2/28/96

1.

Purpose The purpose of this Operations Inspection Division Procedure is to define a recommended method of performing Radiographic Corrosion Analysis using Profile Radiography with a comparator reference.

2.

Scope This procedure should be applied to determine the pipe wall thickness using a reference comparator on line and/or process piping with or without content and with or without insulation. It is not intended to replace present methods of radiographically calculating wall thickness, but to offer an alternate method with improved accuracy.

3.

4.

References 3.1

Saudi Aramco General Instruction GI-0150.003

3.2

Saudi Aramco General Instruction GI-0150.003, Supplement 8

3.3

Saudi Aramco Engineering Procedure SAEP-1141

3.4

Saudi Aramco Engineering Procedure SAEP-1143

Definitions 4.1

Profile Radiography - A tangential radiograph produced by alignment of the radiographic technique such that the radiation passes through or adjacent to the chord of the pipe producing an image of the ID and OD surfaces.

4.2

SFD - Source to Film Distance. For the purposes of this procedure, the minimum source to film distance should be 3 times the outside diameter of the pipe being radiographed.

4.3

Comparator - A 1.000" carbon steel, nickel or chrome plated, spherical ball.

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Document Responsibility: Inspection Department Issue Date: 31 July, 2004 Next Planned Update: 1 August, 2009 5.


Procedure 5.1

Radiation Safety Handling and use of industrial radioactive isotopes should be in accordance with the safety requirements of 00-SAIP-08 and GI0150.003. Particular caution should be applied due to the inherent long exposure times and/or use of Cobalt60 when performing profile radiography.

5.2

Technique (Without Insulation) Figure 1, provides a layout of the technique for the profile radiography of pipe without insulation. Particular notice should be given to the orientation of the source, and film in relation to the pipe and comparator. The source is to be placed on a plane exactly level with the surface of the pipe and 90° (perpendicular) to the film. With masking tape, the comparator is to be positioned such that it is exactly on the radius of the pipe parallel with the film and 90° (perpendicular) to the central direction of radiation (see paragraph 5.5, Note 2).

5.3

Technique (With Insulation) Figure 2, provides a layout of the technique for the profile radiography of pipe with insulation. Particular notice should be given to the orientation of the source, and film in relation to the pipe and comparator. The source is to be placed approximately mid point of the insulation and 90° (perpendicular) to the film. With masking tape, the comparator is to be positioned such that it is exactly on the radius of the pipe parallel with the film and perpendicular to the central direction of radiation (see paragraph 5.5, Note 2).

5.4

Calculating Results In either technique, measure comparator height film image and the film image of the pipe wall thickness. Because of the geometric relationship of either technique, the radiographic images will be an enlargement of the comparator and pipe wall actual dimension. The comparator will provide a percentage of image enlargement to serve as correction of the pipe wall image thickness. Using a 1.00" comparator ball, the correction factor is the measured height of the comparator and used as indicated in the following formula:

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Actual w.t. = image w.t. of pipe X Comparator actual w.t. / comparator image

Comparator Image

w

c

Pipe wall image

actual w .t. = w * c actual /c 5.5

Technical Notes Note-1: Position of the film is critical. As close as possible, the film is to be held 90° (perpendicular) to the central beam of radiation as indicated in either technique. Failure to hold the perpendicular position of the film will cause the image of the comparator to appear oval and reduce accuracy. Note-2: Position of the source in relationship to the tangent of the pipe is critical. Consider an imaginary radius line drawn from the center of the pipe to the pipe O.D. surface. The imaginary line drawn must be 90° (perpendicular) to the central beam of radiation as indicated in either technique. Position the ball off this imaginary line either too close the film or too close to the source will result in an overlap of images of the pipe wall and comparator reducing accuracy and increase difficulty in taking measurements.

5.6

Technique Acceptance The following technique acceptance criteria is based on empirically established values. Accuracy of this technique is dependent on adherence to the following technique acceptance criteria. 5.6.1

Radiographic Quality as defined by SAEP-1143 for film density and film artifacts should be applied. Film should not be less than 2.0 or greater than 4.0 in density. Film should be free of film artifacts such as watermarks, smudges, light leaks, etc. that would Page 15 of 17



interfere with interpretation. Given that this type of radiography is not to be used for weld quality examination, minor scratches or finger nail marks should not be cause for rejection of the film.

w

Im a g e

h

% O v a l ity = w /h 5.6.2

Comparator Image - The image of the comparator should be round. However, variations in the technique and in particular, the technique for pipe with insulation will result in the comparator image being oval. Ovality is determined by comparing the height and width of the comparator image. A measured image height 7% greater than the measured image width is an indication that the film was not properly aligned 90° (perpendicular) to the central beam of radiation (see Note 1) and must be radiographed again.

5.6.3

Comparator Image Enlargement - The maximum image enlargement of the comparator should not exceed 20% (1.20"). A measured comparator image greater than 1.20" is an indication that the SFD was insufficient. To correct, increase the SFD in the technique and re-shoot. In the event the enlargement exceeds 20%, the SFD may be increased to reduce the image enlargement.

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Min SFD = 3 x O.D. Note 2 1.000" Sphere

Note 2

Fig 1 Technique Without Insulation Note 1 Min SFD = 3 x O.D. Note 2 1.000" Sphere

Note 2

Note 1

Fig 2 Techniqu e With Insu lation

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01-SAIP-01

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