SPECIFICATION FOR PIPE CORROSION COATING NEOPRENE

Transcription

1 SPECIFICATION FOR PIPE CORROSION COATING NEOPRENE Specification for Pipe Corrosion Coating Neoprene 1 of 9

2 TABLE OF CONTENTS 1.0 SCOPE REFERENCE DOCUMENTS MATERIALS EQUIPMENT AND LABOR SURFACE PREPARATION COATING APPLICATION INSPECTION AND TESTING REPAIRS STORAGE, HANDLING AND SHIPPING PERFORMANCE OF WORK 9 Specification for Pipe Corrosion Coating Neoprene 2 of 9

3 1.0 SCOPE 1.1 This specification shall govern the materials, application, inspection, repairs, handling of bare and coated pipe, and other requirements for external coating of pipe using neoprene rubber. The work includes the furnishing of all labor, materials, tools and equipment and the performance of all operations and incidentals necessary for the coating, handling, storing and shipping of coated pipe. Furthermore, the work shall meet any additional requirements stated elsewhere in the CONTRACT. As used in this specification, the following definitions shall apply: COMPANY: CONTRACTOR: The firm responsible by contract for the application of the neoprene to the pipe CONTRACT: Signed work agreement between COMPANY and CONTRACTOR. CONTRACTOR shall obtain COMPANY's written approval for any deviations from the requirements of this specification or specifications, standards and drawings referenced herein or elsewhere in the CONTRACT. In case of conflict between documents, the order of precedence given in the CONTRACT shall govern. This document is not intended to be all inclusive, and the use of the requirements set forth does not relieve the CONTRACTOR of his responsibility to supply a product capable of performing its intended service. 2.0 REFERENCE DOCUMENTS latest editions and addenda of the following codes and standards. Steel Structures Painting Council SSPC SP 1 Solvent Cleaning SSPC SP 5 White Metal Blast Cleaning SSPC VIS 1 Pictorial Surface Preparation for Painting Steel Surfaces National Association of Corrosion Engineers RP Recommended Practice, High Voltage Electrical Inspection of Pipeline Coatings Prior to Installation American Society for Testing and Materials ASTM D 2240 Standard Test Method for Rubber Property Durometer Hardness ASTM D 412 Standard Test Method for Rubber Properties in Tension ASTM D 624 Standard Test Method for Rubber Property Tear Resistance ASTM D 1149 Standard Test Method for Rubber Deterioration Surface Zone Cracking in a Chamber ASTM D 471 Standard Test Method for Rubber Property Effect of Liquids 2.2 Project Specifications 2.3 Project Drawings 2.1 Codes and Standards The coating shall be applied in accordance with the Specification for Pipe Corrosion Coating Neoprene 3 of 9

4 3.0 MATERIALS 3.3 Bonding Agents The CONTRACTOR shall supply all coating materials required by this specification. 3.1 Pipe Unless otherwise specified, all pipe will be furnished free of mill coating. 3.2 Elastomer The bonding agent shall be handled, stored and The elastomer shall be an unvulcanized pre shrunk applied in accordance with the manufacturer's material. It shall be compounded to meet or specifications, or as directed by an authorized exceed the following properties when vulcanized. representative of the bonding agent manufacturer. Each material container shall be marked with a Hardness Rating Shore A Durometer durable marking 63 6material 8 to display the date of (ASTM 2240) manufacture, manufacturer's material name, rubber and batch number. Tensile Strength 2000 psi minimum (ASTM 412) 3.4 Tape Ultimate Elongation (ASTM 412) Tear Resistance Angle Tear, Die C 200 lbs./in. (ASTM 624) Ozone Resistance (ASTM 1149) Water Absorption Volume Change 5% maximum (ASTM 471) The elastomer materials shall be handled, stored and applied in accordance with the manufacturer's specifications, or as directed by an authorized representative of the coating manufacturer. Each material container shall be marked with a durable marking material to display the date of manufacture, manufacturer's material name, number and batch number. Each batch of material shall be certified in writing, including the results of property tests that were conducted for quality assurance before packaging. The primer and other bonding agents shall be compatible with the elastomer material and shall be as recommended by the elastomer manufacturer. Full descriptions of the bonding agents to be used shall be submitted by CONTRACTOR to COMPANY prior to use. The descriptions shall include a statement from the elastomer manufacturer as to the suitability of the bonding agents for this application. Tape or other 500% exterior minimum molding devices shall meet with rubber manufacturer's approval, and shall be removed after rubber has cured. minimum 3.5 Abrasive 100 hrs. Material for abrasive cleaning shall be a steel grit and/or shot particle of a size that will produce an angular profile of not less than 1.5 mils nor more than 2.5 mils in depth. Worn abrasive shall be replaced with new material. The abrasive material and compressed air for blasting shall be free of impurities, water and oil. Adequate separators, dryers and traps shall be provided and kept empty of condensate. 4.0 EQUIPMENT AND LABOR 4.1 Condition of Equipment All equipment and tools furnished by the coating CONTRACTOR shall be of good quality, maintained in good operating condition and suitable for use to Specification for Pipe Corrosion Coating Neoprene 4 of 9

5 apply materials required by this specification. All equipment shall be subject to approval by the COMPANY. Equipment shall be capable of coating joint lengths up to 42 feet long. 4.2 Rubber Wheels All cleaning and coating machines (and pipe moving wheels or rollers) shall be equipped with rubber wheels or wheels overlayed with hard fiber to prevent marking or indenting of the pipe. Knurled steel or other type wheels, capable of marking or indenting the pipe or coating shall be prohibited. 4.3 Holiday Detector The electrical equipment used to test the coating shall be portable, low amperage, adjustable voltage, pulse type holiday detector employing an audible signaling device. The holiday detector shall be furnished with a coil spring electrode or a suitable brush type and pointed or tipped electrode. 4.4 Autoclave The autoclave shall be capable of vulcanizing the elastomer under raised temperature and pressure. It shall be large enough to accommodate each joint of pipe for curing as a monolithic piece. 4.5 Labor The CONTRACTOR shall provide supervision and labor for the entire coating operation from the time of receiving the pipe to loading out of transportation. The CONTRACTOR shall provide necessary facilities for COMPANY supervision and inspection of all the work. 5.0 SURFACE PREPARATION inspected and pre cleaned according to SSPC SP 1, to remove oil, grease and loosely adhering deposits. Visible oil and grease spots shall be removed by solvent wiping. Only COMPANY approved safety solvents which do not leave a residue shall be used. All pipe shall be preheated to a temperature 170EF before grit blasting in order to prevent oxidation of the cleaned surface. The heat source shall not leave a residue to contaminate the pipe surface. Ends of pipe shall be protected by plugs in such a manner as to prevent entry of abrasive into the pipe interior during blasting. Any abrasive entering pipe shall be removed prior to coating. 5.2 Blasting The pipe surface to be coated shall be cleaned to a "White Metal" finish in accordance with SSPC SP 5. The blast pattern shall be a uniform, angular anchor profile with a minimum depth of 1.5 mils to a maximum of 2.5 mils. For consistent surface finish, a stabilized working mix of the cleaning media shall be maintained by frequent small additions of a new grit commensurate with consumption; infrequent large additions shall be avoided. The cleaning media working mix shall be maintained clean of contaminants by continuous effective operation of blasting machine scalping and air wash separators. 5.3 After Blasting After blast cleaning, the pipe surface to be coated shall be examined. All surface imperfections, such as slivers, scabs, burrs, weld splatter or gouges shall be removed by grinding. Grinding is only allowed in so far as it will not reduce the wall thickness of the pipe beyond the minimum given by Project Specification / Pipe that cannot be repaired or that is dented shall not be coated. All ground areas shall be reblasted to the above requirements. 5.1 Preparation for Blasting Prior to blast cleaning, external surfaces shall be After blasting, the inside and outside of the pipe shall be left clean and free of abrasive materials, dust or other blasting residue. A brush off air blast Specification for Pipe Corrosion Coating Neoprene 5 of 9

6 or vacuum type cleaner shall be used to clean the entire pipe. A 10 percent solution of Oakite 33 or COMPANY approved equal shall be applied to the surface while surface is 110EF to 150EF. Rate of application to be 1 gallon of solution per 100 square feet of surface area. Dwell time to be minimum of 20 seconds. Spray at 600 to 800 psi pressure fresh water to remove acid residue. Minimum of 2½ gallons of water per 100 square feet of surface is required. Remove excess water by squeegee or air knife. The cleaned pipe surfaces shall be protected from conditions of high humidity, rainfall, or surface moisture. The cleaned pipe surface shall be coated within 2 hours after it is cleaned, and shall not be allowed to flash rust before coating. Total elapsed time between grit blasting and coating of the blast cleaned surface shall be kept to a minimum to avoid the formation of oxides on the surface. 6.2 Vulcanization Vulcanization shall take place within eight hours of elastomer application. Elastomer shall be vulcanized in an autoclave using a combination of temperature and pressure as recommended by the elastomer manufacturer. The CONTRACTOR shall submit a comprehensive description of the procedure for the vulcanization to the COMPANY for approval prior to coating. 6.3 Dimensions The pipe shall be coated with ½ inch thick neoprene and shall have a cut back of 6 inches from each pipe end. Each coating end shall be beveled at a 45E angle. 6.4 Field Joints 6.0 COATING APPLICATION 6.1 Application of Bonding Agents and Elastomer The primer shall be applied as soon after blasting as practicable. In no case shall more than 2 hours elapse between completion of blast cleaning and application of primer. Care shall be taken to ensure that the condition of the metal surface remains as per SSPC SP 5 until it is primed. Reblasting shall be required if these conditions are not met. From blasting on through the application of bonding agents and elastomers, the pipe shall be maintained at least 5EF above the dewpoint. The application of the bonding agents and elastomer shall be performed in accordance with manufacturer's recommendations. If an extruded coating process is used in the application, batch changes on any one pipe shall not be allowed. The CONTRACTOR shall submit comprehensive procedures for his proposed operations to the COMPANY for approval prior to application. The CONTRACTOR shall supply the COMPANY with neoprene split sleeves to be used for field joint coatings. The split sleeve, as shown in Project Drawing or , as applicable, shall be of the same material and thickness as the elastomers which is applied to the pipe. The circumferential ends of the split sleeve shall be configured so that it can overlap upon itself for a minimum of 3 inches. The minimum width of the split sleeve shall be 12 inches wide so that the sleeve can cover the entire cut back area of the pipe. 7.0 INSPECTION AND TESTING 7.1 COMPANY Access for Inspection COMPANY representative(s) shall be given ready access to inspect the CONTRACTOR's quality control procedures, methods and results of the coating materials, equipment, and the CONTRACTOR's work. All stages of the work shall be subject to full time inspection by the COMPANY. Such inspection shall Specification for Pipe Corrosion Coating Neoprene 6 of 9

7 not relieve the CONTRACTOR of his responsibility to provide materials and workmanship to this specification. 7.2 Inspection of COMPANY Supplied Pipe Upon receipt of line pipe or pipe bend material supplied by COMPANY, CONTRACTOR shall perform a thorough inspection. Any damage to the material such as dents, gouges, buckles, ovalization or damage to the weld bevels shall be recorded against the pipe mill number and reported to the COMPANY. COMPANY may request CONTRACTOR to make repairs at COMPANY's expense or instruct CONTRACTOR to set aside and not coat pipe pending COMPANY's further instructions. Any damage discovered during subsequent stages of the coating or inspection operations shall be made good by CONTRACTOR at his expense. 7.3 Joint Identification For each joint of pipe, the following measurements, information and pipe identification shall be recorded before coating operations commence. a. Pipe mill number b. Joint length c. Weight (bare pipe) d. Any other information stencilled on the outside or inside of the pipe. If the pipe mill number is not stencilled on the inside of the pipe it shall be paint stencilled there before coating. Pipe joint identification shall be preserved by the CONTRACTOR at all times. to the requirements as noted below: a. Hardness Rating, Shore A Durameter (ASTM 2240) b. Tensile Strength (ASTM 412) 2,000 psi minimum c. Ultimate Elongation (ASTM 412) 500% minimum d. Tear Resistance, Die C (ASTM 624) 200 lbs/in minimum Each batch of elastomer or fraction thereof shall be tested. A batch shall be defined as one load of the mixer used to compound the material or 700 lbs. whichever is less. Three samples from each batch shall be tested. The following tests may not be used for quality control, but shall be used for certification one time on a particular compound. Certification test results shall be supplied to verify that the elastomer meets the following requirements: a. Ozone Resistance (ASTM 1149) 100 hours b. Water Absorption, Volume Change 5% maximum Tests for the batch tests and the certification tests shall be performed on cured samples. All tested samples shall meet or exceed the specified requirements. Test certificates as per ASTM standards shall be provided to COMPANY for approval prior to use of the elastomer material. 7.4 Blasting Cleaning Inspection of the blasted surface shall be by comparison to the white metal blast cleaning standards in SSPC VIS Testing of Elastomer Materials Prior to delivery of the elastomer it shall be tested 7.6 Visual Inspection The coating shall be inspected for imperfections, lack of bond at joints and ends, blisters, laminations and any apparent irregularity. Any visually detected flaws shall be clearly marked with a waterproof crayon or marker using a contrasting color to the coating. COMPANY shall accept these flaws, reject the coating or request repairs or further tests at CONTRACTOR's expense. Specification for Pipe Corrosion Coating Neoprene 7 of 9

8 7.7 Sounding The coating shall be sounded over its entire length along lines spaced every 1 ft. around the circumference or every 90E whichever is less. A 2 lb. hammer shall be used. The hammer shall be brought to the elastomer surface through a vertical height of at least 3 ft. with a minimum of additional acceleration. CONTRACTOR shall exercise caution when hitting the hammer on the pipe so as not to damage the neoprene thereby causing loss of bond at the point of impact. Coating should produce a uniform pitch everywhere. Any marked difference in audible pitch or rebound response of the hammer shall be noted and the area marked as for visual flaws. COMPANY shall accept these areas, reject the coating or request repairs or further tests at CONTRACTOR's expense. 7.8 Electronic Holiday Inspection The entire coating shall be electronically spark tested in order to detect faults such as voids, cracks, thin spots or foreign inclusions. The coating shall be tested using a brush electrode except for the coating seams or joints which shall be tested with a pointed or tipped electrode. The test voltage shall be in accordance with NACE Standard RP In no case, however, shall the effective voltage be less than 15,000 volts. Because of variables, such as relative humidity and temperature, the detector voltage shall be adjusted no less than twice daily: once just before starting work in the morning and once just before starting work in the afternoon. To ensure proper inspection voltage, the equipment shall be grounded in accordance with the instructions of the equipment manufacturer. 7.9 Thickness Measurement A magnetic or electronic coating thickness measuring device shall be used to determine the coating thickness. Measurements shall be taken at four equally spaced locations along the length of the coating. At each location, four measurements (spaced 90E apart around the circumference) shall be made. For longitudinally welded pipe, the measurements shall include the longitudinal weld seam area of the pipe. Any variation greater than +1/16 inch shall be termed a defect Hardness Test Hardness tests shall be taken at the same locations as the coating thickness measurements. Tests shall be comparable or calibrated to match Shore A durometer test specified for the coating material. Tests shall fall within the range given in Section 3.2. Failure to meet these requirements will be grounds for rejection by the COMPANY Adhesion Test The CONTRACTOR shall provide an extra length of vulcanized elastomer on one end of each pipe joint for destruction testing. An adhesion test shall be carried out on these sections not less than 24 hours after vulcanization. The test shall be carried out at a temperature of 70EF + 10EF. The removal of the test strip shall be entirely due to tearing of the stock material and the metal should remain 100% covered by the rubber. Any presence of bare metal will be considered to be due to bond failure and shall result in rejection of the whole coated joint by the COMPANY. The test strip coating remaining on the pipe shall be completely removed. Any failure of the coating to pass holiday inspection shall result in rejection of that section of the coating by the COMPANY. Rejection will require either complete recoating or repair at COMPANY's discretion and of CONTRACTOR's expense. 8.0 REPAIRS All coating defects disclosed by visual inspection, hardness tests, sounding tests, thickness measurements, bond tests and the holiday Specification for Pipe Corrosion Coating Neoprene 8 of 9

9 detector and obvious defects that may occur as the result of mechanical damage, or any other causes, shall be marked by chalk or crayon and repaired by the CONTRACTOR. Procedure for repairing coating defects shall be submitted for approval to the COMPANY by CONTRACTOR prior to start of work. Repair shall be at discretion of COMPANY. No more than two repairs are allowed on any one coated joint. No defect greater than one square foot in size is eligible for repair. Repairs shall be as good as the rest of the coating and meet the provisions of this specification. Repairs shall undergo all tests mandated by this specification with the exception of the adhesion test. If repairs are disallowed by this specification or can not meet the provisions of this specification, the entire coating shall be removed and reapplied. compliance with existing shipping standards and regulations PERFORMANCE OF WORK CONTRACTOR shall guarantee that work performed on external coating of pipe shall be in accordance with this specification and that the application of the coating system shall be in accordance with the specifications of the coating material manufacturer. The COMPANY's representative shall have proper access rights to CONTRACTOR's plant and property to assure the COMPANY that the foregoing specifications are being followed. 9.0 STORAGE, HANDLING AND SHIPPING Pipe shall be handled and stored in a manner to prevent damage to pipe walls, beveled ends, and coating. Pipe shall be handled, transported and stored in accordance with Specification No CONST SPL/OSPL All pipe handling shall be with equipment approved by the COMPANY's representative. Pipe or coating damaged by the CONTRACTOR in handling or other operations shall be satisfactorily repaired at no expense to the COMPANY. The coated pipe shall be stacked in such a manner that the exterior coating does not contact a hard surface which will cause coating damage. Stacking height shall be reduced at COMPANY representative's request if he observes detrimental effects to the pipe or coating due to stacking. Pipe will be transported from the coating yard to the jobsite by truck, rail or barge, as specified in the CONTRACT. Pipe shall be shipped in such a manner as to adequately protect the pipe and its coating. Pipe shall be loaded for shipping in Specification for Pipe Corrosion Coating Neoprene 9 of 9