PETRONAS TECHNICAL STANDARDS DESIGN AND ENGINEERING PRACTICE
TECHNICAL SPECIFICATION
SPLASH ZONE COATING FOR RISER PIPES
PTS 20.149 FEBRUARY 1984
PREFACE
PETRONAS Technical Standards (PTS) publications reflect the views, at the time of publication, of PETRONAS OPUs/Divisions. They are based on the experience acquired during the involvement with the design, construction, operation and maintenance of processing units and facilities. Where appropriate they are based on, or reference is made to, national and international standards and codes of practice. The objective is to set the recommended standard for good technical practice to be applied by PETRONAS' OPUs in oil and gas production facilities, refineries, gas processing plants, chemical plants, marketing facilities or any other such facility, and thereby to achieve maximum technical and economic benefit from standardisation. The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance where PTS may not cover every requirement or diversity of condition at each locality. The system of PTS is expected to be sufficiently flexible to allow individual operating units to adapt the information set forth in PTS to their own environment and requirements. When Contractors or Manufacturers/Suppliers use PTS they shall be solely responsible for the quality of work and the attainment of the required design and engineering standards. In particular, for those requirements not specifically covered, the Principal will expect them to follow those design and engineering practices which will achieve the same level of integrity as reflected in the PTS. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the Principal or its technical advisor. The right to use PTS rests with three categories of users : 1) 2) 3)
PETRONAS and its affiliates. Other parties who are authorised to use PTS subject to appropriate contractual arrangements. Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) and 2) which requires that tenders for projects, materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards.
Subject to any particular terms and conditions as may be set forth in specific agreements with users, PETRONAS disclaims any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any PTS, combination of PTS or any part thereof. The benefit of this disclaimer shall inure in all respects to PETRONAS and/or any company affiliated to PETRONAS that may issue PTS or require the use of PTS. Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, PTS shall not, without the prior written consent of PETRONAS, be disclosed by users to any company or person whomsoever and the PTS shall be used exclusively for the purpose they have been provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of PETRONAS. The copyright of PTS vests in PETRONAS. Users shall arrange for PTS to be held in safe custody and PETRONAS may at any time require information satisfactory to PETRONAS in order to ascertain how users implement this requirement.
CONTENTS 1.0
SCOPE
2.0
RESPONSIBILITY
3.0
MATERIALS
4.0
PROCEDURES
5.0
INSPECTION, TESTING AND REPAIRS
6.0
PIPE IDENTIFICATION
1.0
SCOPE
1.1
This Specification covers the plant or yard application of the external protective coating of riser pipe to be used in the splash zone. This Specification includes the performance of all work necessary to receive, stockpile, clean and coat externally the riser pipe and repair damaged or defective coating and loadout of the coated riser pipe.
1.2
The CONTRACTOR shall furnish all the required coating materials, supervision, labour, equipment, testing, inspection, the work site, plant space, stockpile areas, services and expenses incidental to and necessary for the activities enumerated herein and in a manner satisfactory to the COMPANY.
1.3
The CONTRACTOR shall fully comprehend and adhere to the subject as referred to in the following standards and specifications:British Standard BS2451 Chilled Iron Shot and Grit -
-
Swedish Standard SIS 05 5900 1967 Pictorial Surface Preparation Standards for Painting Steel Surfaces American Standard ASTM D2240-81 Indentation Hardness of Rubber and Plastics by means of a Durometer. American Society for Testing and Materials Annual Book of ASTM Standards, Part 37.
2.0
RESPONSIBILITY
2.1
The CONTRACTOR shall comply with all the requirements for receiving, hauling, handling, unloading, storage and loading of riser pipe and other associated materials as given in Standard Engineering Specification No. 55.1, Unloading, Stockpiling, Hauling and Handling of Line Pipe Materials.
2.2
The CONTRACTOR shall be fully responsible for the riser pipe and for the external coating after the coating has been applied. Any damage to the riser pipe and/or the coating shall be handled as described in Standard Engineering Specification No. 55.1, unloading, Stockpiling, Hauling and Handling of Line Pipe Materials.
2.3
The CONTRACTOR shall submit his system Of operations and application of the coating to inspection(s) representatives of the COMPANY or by others so designated by the COMPANY.
3.0
MATERIALS
3.1
RISER PIPE Uncoated pipe shall be supplied by the COMPANY.
3.2
COATING REQUIREMENTS The splash zone coating has to meet the following requirements:
Hardness Rating
-
A55 - 65 (Shore A Durometer)
Tensile Strength
-
> 12 MPa
Tear Resistance
-
> 20 kN/m
Working Temperature
-
0 - 100º C
Elongation at break
-
> 400 %
Thermal Expansion Coefficient
-
< 60 x 10-5 / ºC
Density
-
> 1250 kg/m3
Volume Resistivity
-
> 10 12 Ohm.m
(specimen C of ASTM D624)
3.3
COATING MATERIALS The Elastomer Coating required is a synthetic rubber containing the - CH2 - CCL = CH - CH2 - repeating unit. The general name for this compound is polychloroprene or neoprene. The neoprene coating shall hereafter be referred to as rubber coating. The materials may be:
3.4
Rubber Applicator
-
RA-517-70
Good Year
-
LS-575
Arco Rubber
-
AR-881
Gates Rubber
-
1570-0521
Firestone
-
NS-327
STORAGE PROPERTIES The materials shall be stored by the CONTRACTOR at the CONTRACTOR'S expense and shall be stored and use in such manner so as to prevent damage or deterioration to the satisfaction of the COMPANY. The materials which have become contaminated with foreign matter or has deterioration shall not be used and shall be removed immediately from the coating yard at the CONTRACTOR'S expense. After storage in containers as supplied by the manufacturer for at least 12 months, the components of coating material shall remain in excellent condition. Materials older than 12 months shall not be used.
FIGURE 1 SPLASH ZONE COATING APPLICATION
1
BEFORE TEAR RESISTANCE TEST
2
AFTER TEAR RESISTANCE TEST
4.0
PROCEDURES
4.1
PIPE SURFACE PREPARATION The CONTRACTOR shall thoroughly clean and dry the riser pipe. Before applying any coating, the riser pipe surface shall be dry and free of dirt dust, rust, scale, mill lacquer, moisture, oil, grease or any other contaminants, The following conditions shall be compiled with during this riser pipe surface preparation stage : (1)
Oil, grease and wax shall be completely removed with a suitable volatile solvent. All line pipe cleaned by chemical means shall have no residue left on the riser pipe which might impair the bonding of the rubber coating.
(2)
All rust, scale, dirt and other contaminants shall be completely removed by blast cleaning using abrasives no coarser than 16 mesh BS, no finer than 35 mesh BS. See British Standard BS 2451. The blast cleaning abrasive used shall be a manufactured iron grit or copper slag. Sand shall not be used as a blast cleaning abrasive. The cleaning of the riser pipe shall be so controlled as to prevent burnishing or injurious abrasion of the riser pipe metal. After the blast cleaning is completed, the entire surface of the riser pipe shall conform to the blast-cleaning profile of Grade Sa 2.5 of the Swedish Standard No. SIS 05 59 00 1967.
(3)
During blasting CONTRACTOR shall protect the interior of the pipe by means of plugs placed in the ends to prevent the entry of abrasive onto the pipe interior surface.
(4)
Grit blasting shall be performed in a weather protected area where the relative humidity does not exceed 85 percent. The blast cleaning operation shall not be conducted on surfaces that are less than 5°C above the ambient dew point. Blast cleaning under these conditions may be performed provided the riser pipe can be warmed to a temperature (not to exceed 50 °C sufficient to perform the blasting operation.
(5)
All surface imperfections, such as slivers, scabs, burrs, weld splatter, gouges, slag, laminations and foreign matter shall be removed by grinding.
(6)
All ground areas shall be blast cleaned with the use of a portable blast cleaner.
(7)
Pipe containing a dent shall be set aside for the COMPANY to determine disposition.
(8)
After abrasive blast cleaning and prior to the coating application, the exterior pipe surface shall be thoroughly inspected under adequate lighting.
(9)
The permissible degree of surface roughness or "maximum profile" after blastcleaning shall not exceed 0.1 mm. The "maximum profile" is defined as the greatest vertical distance between the summit of any peak on the blast-cleaned surface and the bottom of an immediately adjacent trough.
(10)
All dust and detrimental residue shall be removed by the use of compressed air which is free of oil and moisture.
(11)
Before any primer is applied, the riser pipe surface shall be completely dry clean and free from all traces of blast cleaning products, abrasives, etc. Any surface, which shows signs of contamination from handling after blast cleaning, shall be cleaned and re-blast cleaned.
(12)
All blasted areas are to be primed 4 hours after they are blasted. All blasted areas remaining overnight without priming shall be reblasted. See also section 4.2.
4.2
COATING APPLICATIONS The neoprene sheet material is to be applied utilizing the vulcanization method or process to a thickness of 12.7 mm. The application is to be performed in accordance with the terms of this Specification, good rubber coating practice and the MANUFACTURER's recommendations, and will include the following steps. (1)
Apply one coat of base metal primer, heptic type, to clean abrasive blasted steel. This first coat of base metal primer shall be applied to the riser pipe surface as soon as possible and no later than 4 hours after blast cleaning, before any contamination of the surface has occurred.
(2)
Apply one coat of metal adhesive, triplic type, to primed steel plate.
(3)
Apply one coat of tack cement to primed steel and one to rubber coating. Additional coats may be applied.
(4)
Apply the rubber coating to the metal surface under pressure of rubber coated rollers.
(5)
The rubber coating material is to be cured in an autoclave. Application of coating shall be done in a covered area. Ambient temperature during application and curing shall not fall below 15°C. Further temperature of the riser pipe shall always be kept at 5°C above the ambient dew point. The coating shall not be contaminated by sand, dust, moisture, rain or other substance during its curing period The rubber coating shall be applied up to 150 mm from each end of the riser pipe. Unless otherwise specified in the Scope of work. The coating applied shall be of uniform thickness and of satisfactory smoothness and shall be free from cracks, pinhole or other defects. Each coat shall be firmly bonded to the previous one, while the complete coating shall adhere firmly to the line pipe. When fully cured, a piece of 50 mm will be torn off at each end of the applied rubber coating during the tear resistance test. See Section 5.2.2. The torn off area shall be machine flushed with the outside diameter of the riser pipe and remainder rubber at this section shall not exceed a thickness of 1 mm. A section of 60 mm next to the torn off areas of the rubber coating have to be machine tapered as shown, in figure 1. Blast-cleaned bevels and pipe ends shall be protected against corrosion during storage and transport. The CONTRACTOR shall either apply Shell ENSIS fluid or euqivalent or a suitable masking tape over the pipe bevel at no additional cost to the COMPANY.
4.3
LIGHTING A proper lighting system shall be provided in the pipe surface preparation and coating and inspection areas. Minimum light intensities required shall be as follows :(a)
Generally
300 Lux
(b)
Surface Inspection Area
500 Lux
5.0
INSPECTION, TESTING AND REPAIRS
5.1
INSPECTION COMPANY shall have full access to all phases of the CONTRACTOR's bonding process and shall have the right to reject any finished product not meeting the requirements of this Specification. CONTRACTOR shall be familiar with the manufacturer's recommendation for use of any chemical or material used in the bonding process and he shall follow those recommendations. Failure to allow manufacturer's recommendations shall be caused for rejection. On all rejected products the steel surfaces shall be cleaned and new sheets of elastomer applied, at CONTRACTOR's expense. COMPANY shall be furnished with copies of all test results and material certifications.
5.2
TESTING The following tests shall be performed by the CONTRACTOR to delivery.
5.2.1
Visual Inspection The rubber coating shall be inspected for imperfections, lack of bond at joints and ends, blisters, laminations and apparent irregularity. Any visually detected flaws shall be clearly marked with waterproof coloured crayon and brought to the attention of the COMPANY. The colour of the crayon shall be in contrast with the colour of the rubber coating. For black rubber coating the yellow colour will be preferable, for yellow rubber coating is black the suitable colour. Acceptance of the rubber coating shall be the responsibility of the COMPANY. Any additional testing and the costs incurred, as requested by the COMPANY, shall be the responsibility of the CONTRACTOR. Failure to satisfy the COMPANY as to the integrity of the coating will be grounds for rejection.
5.2.2
Tear Resistance Test For each pipe a cut shall be made through to base metal around the circumference of the pipe 50 mm from each end of the rubber Coating. Each 50 mm portion shall then be cut transversely through to metal and steel grips placed on one side of the transverse cut. Each 50 mm strip of rubber coating shall then be torn from the pipe around its complete circumference. The removal of the strip shall be entirely due to tearing of the stock material and the metal should remain 100% covered by rubber coating. Any presence of base metal will be considered as bonding failure and will result in rejection of the whole coated pipe section by the COMPANY. The Tear Resistance shall be greater than 40 kN/m.
5.2.3
Hardness Test The hardness test shall be generally in accordance with ASTM D2240-81. Four equally spaced, diametrically opposed pairs of hardness measurements shall be taken and quoted as Shore Hardness measurements. These hardness measurements shall fall between the specified limits of A55-65 on the Shore A Durometer scale. Failure to comply with the specified limits will result in rejection by the COMPANY.
5.2.4
Holiday Detection Test The rubber coating shall be entirely tested with a rolling spring electrode of suitable size. The voltage to be employed shall be in excess of 15 KV. The CONTRACTOR shall furnish, operate and maintain holiday detectors, type and voltage subject to approval by the COMPANY, to locate all defects not detectable by visual inspection. The CONTRACTOR shall provide necessary devices for calibrating the holiday detectors. The CONTRACTOR shall also ensure that spare holiday detectors are available on the operation at all times as well as spare fully charged batteries and spare detector spring rings, in order to allow dirty and clogged rings to be changed and cleaned. The COMPANY may choose to furnish holiday detectors if it so desires, but this in no way shall relive the CONTRACTOR from his responsibility of furnishing his own holiday detectors. The CONTRACTOR shall provide at no additional cost to the COMPANY labour to carry and operate the holiday detector(s) provided by the COMPANY. Any failure during holiday detection will result in rejection of that section of the rubber coating by the COMPANY. Rejection will required either complete retreatment or repair at COMPANY's discretion. Any costs or delay incurred resulting from the need for repairs shall be the sole responsibility of the CONTRACTOR.
5.2.5 Thickness Measurement A magnetic or electronic coating thickness measurement device shall be used to determine the rubber coating thickness. Four equally spaced sets of four measurements shall be taken in four equal planes along the length of the pipe. Any variation outside the specified tolerance will be caused for rejection by the COMPANY.
5.2.6
Tensile Strength Test A tensile strength test shall be performed on the coating material of every fifth coated joint. A minimum tensile strength of 17 MPa is required.
5.2.7
Elongation An elongation test shall be performed on the coating of every fifth coated joint. That elongation at breaking strength shall be greater than 400 %. This test is to be performed concurrently with the tensile strength test.
5.3
REPAIRS Any defective part of the coating such as holidays, tears or damaged spots shall be clearly marked with waterproof coloured crayon (See Section 5.2.1) and repaired by the CONTRACTOR immediately after it is detected to the satisfaction of the COMPANY. Repairs shall be effected using procedures previously approved by the COMPANY. Repairs shall be at least equal in effectiveness to the coating applied to the principal part of the line pipe. All repairs shall successfully pass testing by the holiday detector.
6.0
PIPE lDENTIFICATION
6.1
The identity of each riser pipe joint shall be preserved during and after the coating operation. Each joint of riser pipe shall be identified after coating by a consecutive numbering system and the length of each riser pipe joint, in millimetres together with the original pipe mill and heat numbers recorded inside the riser pipe at each end of the riser pipe joint. Thus 64 (38/108) - 12103 means that the riser pipe joint number 64 (pipe mill number 38 and heat number 108) is 12103 mm long.
6.2
A certified permanent record shall be supplied to the COMPANY showing the serial number, pipe mill number, heat number, joint length and date of coating for each riser pipe joint.
