Cross Linked PEX Line Pipe (PEX)

Transcription

1 Cross Linked PEX Line Pipe (PEX) API SPECIFICATION 15PX September 20

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4 Contents

5 Specification for Cross Linked PEX Line Pipe (PEX) 1 Scope 1.1 Purpose The purpose of this specification is to provide standards for cross linked PEX (PEX) line pipe suitable for use in conveying oil, gas, and non-potable water in underground, above ground and reliner applications for the oil and gas producing industries. The standard does not propose to address all of the safety concerns associated with the design, installation or use of products suggested herein. It is the responsibility of the user of the standard to utilize appropriate health and safety considerations. All pipe produced under this standard shall utilize pressure rated materials, but may be used in pressurized, non-pressure and negative pressure applications. The technical content of this document provides requirements and guidelines for performance, design, materials inspection, dimensions and tolerances, marking, handling, storing and shipping. 1.2 Applications Equipment This specification covers PEX line pipe utilized for the production and transportation of oil, gas and nonpotable water. The piping is intended for use in new construction, structural, pressure-rated liner, line extension and repair, of both above ground and buried pipe applications. Specific equipment covered by this specification is listed as follows: PEX line pipe; Fittings Service Conditions The standard service conditions for the API Spec15PX Standard Pressure Rating are as follows: Standard pressure ratings in non-chemically aggressive fluids Service temperature range: -50 C (-58 F) to 95 C (203 F) Note applications above 95 C (203 F) require special design consideration The fluid environment is oil, gas and non-potable water and combinations thereof (see Table 1) Axial loads shall include end loads due to pressure only Service conditions other than the standard API Spec 15PX conditions are discussed in Section 5 Design. 2 Normative References 2.1 General This specification includes by reference, either in total or in part, the most current issue of the following standards: ANSI B16.5, Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard API 15S, Second Edition, Spoolable Reinforced Plastic Line Pipe

6 API Q1, Specification for Quality Management System Requirements for Manufacturing Organizations for the Petroleum and Natural Gas Industry ASTM D22, Standard Test Method for Determining Dimensions of the Thermoplastic Pipe and Fittings ASTM D23, Standard Practice for Underground Installation of Thermoplastic Pipe for Sewers and Other Gravity-Flow Applications ASTM D2765, Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics ASTM D2774, Standard Practice for Underground Installation of Thermoplastic Pressure Piping ASTM D2837, Standard Test Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials or Pressure Design Basis for Thermoplastic Pipe Products ASTM F1055, Standard Specification for Electrofusion Type Polyethylene Fittings for Outside Diameter Controlled Polyethylene and Crosslinked Polyethylene (PEX) Pipe and Tubing ASTM F1668, Standard Guide for Construction Procedures for Buried Plastic Pipe ASTM F64, Standard Practice for Field Leak Testing of Polyethylene (PE) and Crosslinked Polyethylene (PEX) Pressure Piping Systems Using Hydrostatic Pressure ASTM F2786, Standard Practice for Field Leak Testing of Polyethylene (PE) Pressure Piping Systems Using Gaseous Testing Media Under Pressure (Pneumatic Leak Testing) ASTM F2788/F2788M, Standard Specification for Metric and Inch-sized Crosslinked Polyethylene (PEX) Pipe ASTM F2829/F2829M, Standard Specification for Metric- and Inch-Sized Crosslinked Polyethylene (PEX) Pipe Systems ASTM F2905/F2905M, Standard Specification for Black Crosslinked Polyethylene (PEX) Line Pipe, Fittings and Joints For Oil and Gas Producing Applications ASTM F2968/F2968M, Standard Specification for Black Crosslinked Polyethylene (PEX) Pipe, Fittings and Joints For Gas Distribution Applications ASTM F3203, Standard Test Method for Determination of Gel Content of Crosslinked Polyethylene (PEX) Pipes and Tubing ASTM F412, Standard Terminology Relating to Plastic Piping Systems ASTM F714, Standard Specification for Polyethylene (PE) Plastic Pipe (DR-PR) Based on Outside Diameter ASTM F876, Standard Specification for Crosslinked Polyethylene (PEX) Tubing ASTM F2657, Standard Test Method for Outdoor Weathering Exposure of Crosslinked Polyethylene (PEX) Tubing ASTM D4364, Standard Practice for Performing Outdoor Accelerated Weathering Tests of Plastics Using Concentrated Sunlight CSA Z662, Oil and Gas Pipeline Systems DIN 16892, Crosslinked polyethylene (PE-X) pipes - General requirements, testing DIN 16893, Crosslinked polyethylene (PE-X) pipes - Dimensions ISO 67, Thermoplastics pipes for the conveyance of fluids -- Resistance to internal pressure -- Test method

7 ISO 10147, Pipes and fittings made of crosslinked PEX (PE-X) Estimation of the degree of crosslinking by determination of the gel content ISO 162, Thermoplastics materials for pipes and fittings for pressure applications - Classification, designation and design coefficient ISO 13477, Thermoplastics pipes for the conveyance of fluids -- Determination of resistance to rapid crack propagation (RCP) -- Small-scale steady-state test (S4 test) ISO , Plastics pipes and fittings - Crosslinked polyethylene (PE-X) pipe systems for the conveyance of gaseous fuels - Metric series -- Specifications - Part 1: Pipes ISO , Plastics pipes and fittings -- Crosslinked polyethylene (PE-X) pipe systems for the conveyance of gaseous fuels -- Metric series -- Specifications -- Part 2: Fittings for heat-fusion jointing ISO , Plastics pipes and fittings -- Crosslinked polyethylene (PE-X) pipe systems for the conveyance of gaseous fuels -- Metric series -- Specifications -- Part 3: Fittings for mechanical jointing (including PE-X/metal transitions) ISO , Plastics pipes and fittings -- Crosslinked polyethylene (PE-X) pipe systems for the conveyance of gaseous fuels -- Metric series -- Specifications -- Part 4: System design and installation guidelines ISO 3126, Plastics piping systems -- Plastics components -- Determination of dimensions ISO 9001, Quality management systems - Requirements ISO 9080, Plastics piping and ducting systems - Determination of the long-term hydrostatic strength of thermoplastics materials in pipe form by extrapolation ISO TS 29001, Petroleum, petrochemical and natural gas industries - Sector-specific quality management systems - Requirements for product and service supply organizations ISO/IEC 020, Conformity assessment -- Requirements for the operation of various types of bodies performing inspection ISO/IEC 065, Conformity assessment - Requirements for bodies certifying products, processes and services PPI TR-3, Policies and Procedures for Developing Hydrostatic Design Basis (HDB), Hydrostatic Design Stresses (HDS), Pressure Design Basis (PDB), Strength Design Basis (SDB), Minimum Required Strength (MRS) Ratings, and Categorized Required Strength (CRS) for Thermoplastic Piping Materials or Pipe PPI TR-4, PPI Listing of Hydrostatic Design Basis (HDB), Hydrostatic Design Stress (HDS), Strength Design Basis (SDB), Pressure Design Basis (PDB) and Minimum Required Strength (MRS) Ratings for Thermoplastic Piping Materials or Pipe Title 49 CFR Part 192, Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards 2.2 Requirements Requirements of other standards included by reference in this specification are essential to the safety and interchangeability of the equipment produced. 2.3 Equivalent Standards Standards referenced in this specification may be replaced by other international or national standards that can be shown to meet or exceed the requirements of the referenced standard. Manufacturers who use other standards in lieu of standards referenced herein are responsible for documenting the equivalency of the standards. Where a standard is revised, the latest edition may be used on issue and

8 shall become mandatory 6 months from the date of the revision. 3 Definitions and Abbreviations 3.1 Definitions adapters Appurtenances that allow connecting components with different joining systems. component Any pressure line pipe, pipe connection, fitting, flange, adapter, reducer, or end of outlet connection covered by this specification. crosslinking The process by which the adjacent polymer chains of a PEX plastic are joined to produce a threedimension polymer network. PEX materials used in the manufacturing of PEX line pipe may be crosslinked by a number of industryproven means. These include: peroxide crosslinking (PEX-a); silane crosslinked (PEX-b); irradiation (PEX-c). Design Service Factor (DSF) A safety factor applied to the Hydrostatic Design Basis (HDB) to calculate the Standard Pressure Rating of the pipe. Design Coefficient When using the DIN 16892/3 design method, coefficient, with a value greater than 1, that takes into consideration service conditions as well as properties of the components of a piping system other than those represented in σ LPL NOTE pipes. See ISO 162 for information regarding the minimum permissible service (design) coefficient for PEX Dimension Ratio (DR) Equal to the ratio of a pipe s outside diameter to its wall thickness. fittings A piping component used to join or terminate sections of pipe or to provide changes of direction or branching in a pipe system. flanges Face flanges with bolt hole circle per ANSI B16.5. Flanges and flange adapter as used in this specification, incorporates use of PEX flange adapter and metallic backup ring utilizing ANSI B16.5 bolt hole pattern Metallic Flange couplers for field installations and PEX face flanges used as internal diameter adapters are also covered by this specification Fluid Service Factor (FSF) Factor applied in the determination of the Maximum Working Pressure to account for the impact of the transported fluid on pipe performance. Hydrostatic Design Basis (HDB) The categorized Long-term Hydrostatic Strength (LTHS) in the circumferential or hoop direction for a given set of end use conditions, as established by ASTM D2837. Long Term Strength Xxxxxxxxxxxx lot number Assignment of a unique code to each lot of manufactured pipe or fittings under the same conditions of production. Lot numbers are used to maintain production identification and traceability.

9 material designation code A set of letters and numbers used to identify stress-rated thermoplastic compounds. The code consists of two or three letters which describe the type of material (PE, or PEX). This is followed by three or four numbers to describe material and physical properties in accordance with PPI TR-4. Maximum Working Pressure The maximum anticipated, sustained pressure applied to the pipe in actual service when the Fluid Service Factor (FSF) and Temperature Service Factor (TSF) are considered. Minimum Required Strength (MRS) The categorized lower prediction limit (LPL) of the long-term hydrostatic strength at 20 C determined in accordance with ISO 9080 and ISO 162. In this standard (API 15PX), the equivalent MRS value is defined by reference curves in DIN and has a value of 9.5 MPa. out of roundness The maximum measured diameter, minus the minimum measured diameter, divided by the average measured diameter, times 100, expressed as a percentage. reducers Component fittings that allow two pipes of different diameters to be connected. Standard Pressure Rating (PR) The established maximum pressure that non-aggressive fluids such as water can exert continuously with a high degree of certainty that failure in the pipe will not occur. 3.2 Abbreviations ANSI American National Standards Institute API American Petroleum Institute ASTM American Society for Testing Materials CSA Canadian Standards Association DIN Deutsch Institute for Norms DR Dimension Ratio FSF Fluid Service Factor HDB Hydrostatic Design Basis ISO International Standards Organization LPL Lower Prediction Limit MRS Minimum Required Stress PEX Cross-linked Polyethylene PE Polyethylene PPI Plastics Pipe Institute, Inc. PR Pressure Rating QA Quality Assurance QC Quality Control RCP Rapid Crack Propagation TSF Temperature Service Factor UV Ultraviolet 4 Design 4.1 Long Term Strength The long-term strength shall be measured with water as the internal pressurizing medium. Either the HDB or DIN 16892/3 long term strength shall be used to establish the maximum working pressure of a PEX pipe. The design process shall include the effects of the internal and external chemical environment on the long-term strength which comprises the Design Service Factor for HDB method, or the Design Coefficient when using the DIN 16892/3 method; the operating temperature, and the chemical environment which is included in the Fluid Service Factor (FSF). The design process shall also include consideration of the

10 installation method. 4.2 Fluid Service Factors The Fluid Service Factors in Table 1 shall be used to compensate for possible effects of the transported fluid on the long-term performance of the piping and for the hazardous nature of some applications. Table 1 Fluid Service Factors (FSF) Environment Factor HDB DIN 16892/3 Produced water, seawater, brine, process water and other oilfield water based fluids excluding oilfield water containing > 2 % liquid hydrocarbons Table 2 Table 4 Dry gas gathering (no associated hydrocarbon liquids) Table 2 Table 4 Dry gas gathering that is subject to Canadian Federal Regulations Table 2 Table 4 Multiphase fluids, wet natural gas and liquid hydrocarbons 0.5 Table 3 Table 5 1 Water containing significant quantities of liquid hydrocarbons (> 2 %) shall be treated as liquid hydrocarbon. 2 Gas gathering in this standard refers to gas from a well or production source in a low population density area that is not subject to United States Department of Transportation, Office of Pipeline Safety, Title 49 CFR Part CSA Z662 Clause Determining the Maximum Working Pressure To use the HDB Pressure Rating System: 1) Determine the Fluid Service Factor (FSF) to determine whether to use Table 2 or Table 3. 2) Select the appropriate HDB based on the anticipated operating temperature and the material designation code as shown in the appropriate rows of Table 2 if the FSF is 1.0 or Table 3 if the FSF is ) Find the DR for the pipe in the column headings in Tables 2 or 3. 4) The value for the Maximum Working Pressure in water service is at the intersection of the DR column and the HDB row in Table 2 and includes the application of a design service factor of ) The value for the Maximum Working Pressure for multiphase fluids, wet natural gas and liquid hydrocarbons is at the intersection of the DR column and the HDB row in Table 3 and includes the application of a design service factor of ) When calculating a HDB between 23 C (73.4 F) and the elevated temperature at which the manufacturer has an established HDB, the HDB at any intermediate temperature shall be calculated by linear interpolation using the method described in PPI TR-3. Annex C provides guidance on the interpolation method. 7) For pipe sizes not listed in this standard the pressure ratings shall be calculated using the methods in Annex D.1.

11 Table 2 Standard Pressure Ratings (psi) of PEX pipe using the HDB method of design at various temperatures for non-chemically aggressive fluids. For the working pressure of multiphase fluids, wet natural gas and liquid hydrocarbons, refer to Table 3. Temperature C ( F) Material Designation Code HDB (psi) Maximum Working Pressures, psig, for the Indicated DR DR 7.4 DR 9 DR DR 13.6 DR 23 (73) PEX xx PEX xx (140) 82 (180) 93 (200) PEX xx PEX xx PEX xx06 PEX xx PEX xx PEX xx HDB was interpolated using the HDB values at 23 C and 82 C for the grades with the indicated Material Designation Code. Table 3 Working pressure (psi) of PEX pipe using the HDB method of design at various temperatures for multiphase fluids, wet natural gas, and liquid hydrocarbons. Temperature C ( F) Material Designation Code HDB (psi) Maximum Working Pressures, psig, for the Indicated DR DR 7.4 DR 9 DR DR 13.6 DR 23 (73) PEX xx PEX xx (140) 82 (180) 93 (200) PEX xx PEX xx PEX xx06 PEX xx PEX xx06 PEX xx HDB was interpolated using the HDB values at 23 C and 82 C for the grades with the indicated Material Designation Code To use the DIN 16892/3 Pressure Rating System: 1) Determine the fluid service factor (FSF) according to Table 1 to determine whether to use Table 4 or Table 5 to determine the Maximum Working Pressure. 2) Select the anticipated operating temperature from the row headings in Table 4 if the FSF is 1.0 or in Table 5 if the FSF is 0.5 3) Find the DR for the pipe in the column headings in Tables 4 or 5. 4) The value for the Maximum Working Pressure in water service is at the intersection of the DR column and the Temperature row in Table 4. 5) The value for the Maximum Working Pressure for multiphase fluids, wet natural gas and liquid hydrocarbons is at the intersection of the DR column and the Temperature row in Table 5.

12 6) For pipe sizes not listed in this standard the pressure ratings shall be calculated using the methods in Annex D.2. Table 5 shall be used for determining the Maximum Working Pressure for pipes transporting multiphase fluids, wet natural gas and liquid hydrocarbons. The values for the Maximum Working Pressure listed in Table 4 and Table 5 include the application of a design coefficient of 1.25, and are for a 20-year service life for all temperatures less than 90 C, a 15-year service life at 90 C and a 10-year service life at 95 C. NOTE The DIN standard does not specify service lifetimes of 20 years for PEX materials at 90 C and above. If the producer can show that they have completed testing to validate a longer lifetime that value may be used. NOTE The DIN standard pressure ratings are based on PEX pipe with 9.5 MPa equivalent MRS. Modern PEX materials meet those requirement as defined in detail in DIN and Table 4 Standard Pressure Ratings (psi) of PEX pipe using the DIN 16892/3 method of design at various temperatures for most fluids. For the working pressure of multiphase fluids, wet natural gas and liquid hydrocarbons, refer to Table 5. Temperature C ( F) Maximum Working Pressure (psig) for the indicated DR DR 7.4 DR 9 DR DR (50) (68) (86) (104) (122) (140) (158) (6) (194) (203) The DIN standard specifies that that the service life of PEX pipe is 15 years at 90 C and 10 years at 95 C at the indicated dimensions and pressures provided that there is additional regression data at 0 C for at least one year. NOTE Modern PEX products have undergone much more extensive testing, and the supplier is usually able to provide evidence for a 20-year service life.

13 Table 5 Maximum Working Pressure (psi) of PEX pipe using the DIN 16892/3 method of design at various temperatures for multiphase fluids, wet natural gas and liquid hydrocarbons. Temperature Maximum Working Pressure (psig) for the indicated DR C ( F) DR 7.4 DR 9 DR DR (50) (68) (86) (104) (122) (140) (158) (6) (194) (203) The DIN standard specifies that that the service life of PEX pipe is 15 years at 90 C and 10 years at 95 C at the indicated dimensions and pressures provided that there is additional regression data at 0 C for at least one year. NOTE Modern PEX products have undergone much more extensive testing, and the supplier is usually able to provide evidence for a 20 year service life External Collapse Rating Guidelines on the collapse rating of cross-linked PEX pipe are laid out in Annex B. 4.4 External Service Environment The design shall consider the effects of external UV exposure and external chemical environment on the durability of the pipe for the anticipated service life and the storage time prior to installation. 4.5 Dimensions and Tolerances Size Pipe furnished to this specification shall comply with the dimensions and tolerances given in Table 6 (Inch Dimensions) or Table 7 (Metric Dimensions) as specified on the purchase order. In applications where special conditions or requirements dictate diameters, wall thicknesses or dimensions other than those listed in these tables, those special sizes shall be acceptable upon agreement of the buyer and the seller provided that the PEX pipe is manufactured from PEX compounds meeting the requirements of this specification and the strength and design basis used to establish the working pressure are the same as those proscribed in tables 2 through 5. For diameters not shown in the tables, the tolerance shall be the same percentage as shown in the tables for the next smaller listed size. The dimensional requirements of ASTM F714 are also acceptable Toe-in The outside diameter when measured at the cut end of the pipe length shall not be more than 1.5 % smaller than the outside diameter specified in Table 6 or Table 7, when measured at any point within 1.5 pipe diameters or.8 in. (300 mm), whichever is less, to the cut end of the pipe length. Measurements shall be made using ASTM D22 Test Method Eccentricity The wall thickness variability as measured and calculated in accordance with ASTM D22 Test Method in any diametrical cross section of the pipe shall not exceed 12 % unless otherwise specified elsewhere in

14 this standard Length Pipe shall be furnished in cut lengths or coils as specified on the purchase order and agreed between the purchaser and the supplier Out of Roundness (Ovality) The out of roundness or ovality of the pipe shall not exceed the tolerance in ASTM F2788. NOTE Other factors such as installation, coiling, compaction, static soil loading, exposure to high ambient temperature and vehicular loads may increase ovality during use beyond the requirements of the standard. Table 6 Inch Dimensions and Tolerances Based on Outside Diameters Outside Diameter Wall Thickness Nominal Size (in.) in. mm DR in. mm ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

15 Table 6 Inch Dimension and Tolerances Based on Outside Diameters (Continued) Outside Diameter Wall Thickness, Tolerance is plus 12 % Nominal Size (in.) in. mm DR in. mm ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

16 Table 6 Inch Dimension and Tolerances Based on Outside Diameters (Continued) Outside Diameter Wall Thickness, Tolerance is +12 % Nominal Size (in.) in. mm DR in. mm ± ± ± ± ± ± ± ± ± ± ± ± ± ±

17 Table 6 Inch Dimension and Tolerances Based on Outside Diameters (Continued) Outside Diameter Wall Thickness, Tolerance is +12 % Nominal Size (in.) in. mm DR in. mm NOTES ± ± ± ± ± ± ± ± ) Pipe dimensions and schedules listed are most commonly used by the oil and gas industries. Additional sizes and schedules are available. The complete list of sizes and schedules are listed in the following ASTM standards: ASTM F2788, Standard Specification for Metric and Inch-sized Crosslinked PEX (PEX) Pipe ASTM F2829, Standard Specification for Metric-Sized Crosslinked PEX (PEX) Pipe Systems ASTM F2968/F2968M, Standard Specification for Black Crosslinked PEX (PEX) Pipe, Fittings and Joints for Gas Distribution Applications ASTM F2905/F2905M, Standard Specification for Black Crosslinked PEX (PEX) Line Pipe, Fittings and Joints for Oil and Gas Producing Applications

18 Diameter Nominal Table 7 Metric Dimensions and Tolerances Based on Outside Diameters Outside Diameter (mm) Minimum Wall Thickness, mm Tolerance is plus 12 %, rounded to the nearest 0.1 mm DR 7.4 DR 9 DR DR 13.6 DR ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Process of Manufacture Pipe furnished to this specification shall be produced by extrusion. Rework or recycled material shall not be used. Fittings shall be manufactured using polymers, metals, or composites and shall comply with the relevant product standards for that fitting type. PEX pipes shall be cross linked to the minimum level specified in this standard prior to installation. 5.1 Pipe Compound

19 PEX pipe shall be made from PEX compounds which have been crosslinked by means such that the pipe meets the performance requirements of this section. The manufacturing process shall result in a PEX pipe capable of obtaining the pressure ratings as shown in Section 4.3, when tested in accordance with procedures no less restrictive than those of PPI TR Pipe Compound Requirements Long Term Hydrostatic Strength The long-term strength of the material shall be established by the manufacturer in accordance with PPI TR-3 using ASTM D2837 or ISO 9080 methodology. PEX materials meeting the requirements of this specification shall be tested for long term hydrostatic strength witnessed or tested by a certified, third party, auditing agency that conforms to ISO/IEC 020 and/or ISO/IEC 065, or, have an HDB and/or MRS listed in PPI TR-4. If using the DIN standard for design, the material shall have a minimum LPL of 9.5 MPa at 20 C as shown by the reference curves presented in DIN Thermal Oxidative Stability For conformance to the 95 C temperature requirements of this standard, thermal stability of the pipe compound shall be demonstrated by one of the following methods: 2.8 MPa hoop stress at 230 F (0 C), survival to 8000 hours 2.5 MPa hoop stress at 230 F (0 C), survival to 8760 hours For applications with high potential for oxidative attack, the formulation shall sustain 2.4 MPa hoop stress at 230 F (0 C) survival to 15,000 hours. NOTE An engineering assessment is typically done to determine if the application requires this additional level of testing. If the compound has an ASTM F876 chlorine resistance cell value of 5 this requirement is waived. The indicated hoop stress values are used to calculate the test pressure using the following equation: 2e min p = 10σ d em e min Where: p is the test pressure (bars) σ - is the hoop stress to be induced by the applied pressure, in megapascals; d em - is the mean outside diameter of the test piece, in millimeters; e min - is the minimum wall thickness of the free length of the test piece, in millimeters. To calculate the test pressure in psi, multiply the result in bars by 14.5 To calculate the test pressure in MPa, divide the test pressure in bars by Rapid Crack Propagation (RCP) Resistance The critical temperature per ISO shall be lower than the minimum design temperature, but in no case higher than -20 C. Critical temperature shall be measured on nominal 4 in. (0 mm) DR pipe Considerations for Chlorinated Water Service PEX compounds shall have a chlorine resistance cell classification minimum value of 1 per ASTM F UV Weathering Protection The pipe shall be protected against UV weathering. The manufacturer shall determine retention of properties based on the testing of UV exposed pipe in accordance with ASTM F2657 or ISO

20 Annex C, or ASTM D4364. NOTE Color Pipe formulations containing N550 carbon black at 2.0 % meet this requirement. If the color of the pipe is black, the formulation shall contain carbon black as a colorant, and the formulation shall meet the requirements of Finish and Workmanship Pipe Ends Pipe ends shall be plain and squared or with flared ends for use with flange connections. Cut pipe ends shall be clean without ledges, shaving tails, burrs or cracks. Other pipe end conditions shall be agreed between purchaser and the seller Finish The interior and exterior of the pipe shall be uniform in finish without voids, cracks, crazing, foreign inclusions or deep scratches Workmanship The interior of the pipe shall be free of cuttings, shavings and other debris 5.4 Fittings All fittings, plastic or metallic, must be demonstrated by the pipe manufacturer to also meet or exceed the thermal and mechanical properties of the pipe Electrofusion Fittings Electrofusion fittings furnished for use with this specification shall meet the requirements of specification ASTM F1055 or ISO part 2. Electrofusion fittings shall not be used in services with H 2 S content of 100 ppm or higher. NOTE If the specified electrofusion fittings are HDPE fittings and do not have the same high temperature capabilities of the PEX pipe with which they will be used, the designer is cautioned that the system design pressure and temperature are limited by the lowest rated component Metallic Fittings Mechanical metallic fittings furnished for use with this specification shall meet the requirements of specification ISO part 3 and the requirements of sections , and of API 15S, 2 nd Edition PEX Fittings Non-cross-linked polyethylene shall not be used for thermoformed components. Thermoformed reducers and elbows made of PEX pipes may be used. If PEX fittings are used in a PEX pipeline the pressure and temperature rating of the pipeline shall be defined by the rating of the PEX fitting. Fabricated PEX fittings may be used. PEX fittings shall be manufactured according to applicable ASTM or ISO standards, or in compliance with the manufacturer s documented procedures approved by the customer, whichever is more restrictive. The PEX compound used for the fittings shall comply with all the compound requirements of this standard. When conflicts arise between standards or procedures, this document s requirements shall be followed. Pressure rating of the fabricated-fitting design is beyond the scope of this standard and shall be established by the fitting manufacturer. 6 Quality Management Program

21 Products meeting this specification shall be manufactured in a facility that maintains a written quality management system in accordance with API Q1 or ISO TS or ISO Quality Records Retention Quality records shall remain legible, readily identifiable and retrievable for a period of not less than 10 years. 6.2 Quality Control Tests Dimensional Analysis Samples for quality control testing shall be conditioned in accordance with ASTM D22 or ISO Physical Properties 1) Pipe: Refer to Table 8 for physical testing requirements for PEX pipe. 2) Fittings: Fittings intended for use with PEX pipe shall meet the dimensional, design, and performance requirements of the applicable fitting product standard and shall have dimensions that are compatible with the pipe manufactured to this standard. 3) Retesting: If the results of any test(s) do not meet the requirements of this specification, the test(s) may be conducted again in accordance with an agreement between the purchaser and the seller. There shall be no agreement to lower the minimum requirement of the specification by such means as omitting tests that are a part of the specification, substituting or modifying a test method, or by changing the specification limits. In retesting, the product requirements of this specification shall be met, and the test methods designated in the specification shall be followed. If, upon retest, failure occurs, the quantity of the product represented by the test(s) does not meet the requirements of this specification and shall be rejected.

22 Table 8 Test Description and Frequency for PEX Pipe Test Description Outside Diameter Wall Thickness Test Method/Conditions ASTM D22 or ISO 3126 ASTM D22 or ISO 3126 Frequency Once every 2 hours Once every 2 hours Minimum Requirements Must meet dimensions specified in Table 5 or 6. Must meet dimensions specified in Table 5 or 6. Out of Roundness ASTM F2905 Once/2 hours or once/coil, whichever is less frequent. For straight lengths of pipe, the requirements of ASTM F2905 shall be met. For coiled pipe, out of roundness shall be agreed on between the manufacturer and the buyer. Crosslinking degree ASTM F3203 or ASTM D2765 Method B, or ISO Once per day per extrusion line. PEX-a 70 % PEX-b 65 % PEX-c 65 % Sustained pressure test ISO psi (4.6 MPa) 1 hoop stress at 203 F (95 C) Once per week per Minimum time before failure: 165 hours and extrusion line. ductile behavior Sustained pressure test ISO psi (4.4 MPa) 1. hoop stress at 203 F (95 C) Once per year per extrusion line. Minimum time before failure: 1000 hours and ductile behavior 1. The indicated hoop stress values are used to calculate the test pressure using the following equation: 2e min p = 10σ d em e min p test pressure (bars) σ - is the hoop stress to be induced by the applied pressure, in megapascals; d em - is the mean outside diameter of the test piece, in millimeters; e min - is the minimum wall thickness of the free length of the test piece, in millimeters. To calculate the test pressure in psi, multiply the result in bars by 14.5 To calculate the test pressure in MPa, divide the test pressure in bars by Product Marking 7.1 General Pipe manufactured in conformance with this specification shall be marked by the manufacturer as specified. Pressure rating markings are prohibited. The pipe shall be marked with the maximum permissible UV weathering exposure time in years as determined by the manufacturer. The required print line markings on pipe shall be legible, visible and permanent, and spaced at intervals of not more than 5 ft. (1.5 m).

23 The permanency of the marking shall be such that it can only be removed by physically removing part of the pipe wall thickness. The marking shall not reduce the pipe wall thickness to less than the minimum value required for the pipe or tubing. It should not have an effect on the long-term strength of the pipe and it should not provide channels for leakage when elastomeric gasket compression fittings are used to make joints. The print string on each length of pipe or fitting shall include in any sequence: 1) Manufacturer s name, product name or trademarks; 2) API Spec 15PX; 3) Additional standards (optional) (e.g. ASTM F2788); API Spec 15PX is a stand-alone specification and is the primary manufacturing standard. If a manufacturer decides to dual mark a product it is permitted as long as the manufacturer meets the requirements of API Spec 15PX and the additional standard(s). 4) Size; 5) Dimension Ratio (DR); 6) If using the HDB method - Material Designation Code (PEX0006, PEX0008); 7) UV weathering exposure time allowed in years; 8) Date of manufacture in year-month-day format (e.g. 16 Mar 06); 9) Manufacturer s lot number; 10) Additional markings, except pressure ratings, as agreed upon between manufacturer and purchaser, are permitted. 8 Handling, Storage, and Installation 8.1 Storage PEX pipe products should be protected against deterioration from exposure to ultraviolet light and weathering effects to the time limit stated on the print line. Color and black products are typically compounded with antioxidants, thermal stabilizers, and UV stabilizers. Color products use sacrificial UV stabilizers that absorb UV energy, and are eventually depleted. In general, non-uv-protected products should not remain in unprotected outdoor storage. 8.2 Handling PEX piping materials are lightweight compared to similar piping materials made of steel but larger pieces and components can be heavy. Lifting and handling equipment shall have adequate rated capacity to lift and move components from the truck to onsite or temporary storage. Equipment such as a forklift, a crane, a side boom tractor, or an extension boom crane is used for unloading. When using a forklift, or forklift attachments on equipment such as articulated loaders or bucket loaders, lifting capacity shall be adequate at the load center on the forks. Before lifting or transporting the load, forks should be spread as wide apart as practical, forks should extend completely under the load, and the load should be as far back on the forks as possible. Care should be taken not to damage the load with the forks. 8.3 Installation Installation shall be done according to the manufacturer instructions and guidelines. 9 Integrity Management See Annex G for informative guidance on integrity management.

24 Annex A (informative) API Monogram

25 Annex B (informative) External Pressure Rating (Collapse Pressure) In certain applications, cross-linked PEX pipe may be subjected to a negative pressure that could cause the collapse of the pipe. A negative pressure situation exists where the external loading on the pipe is greater than the internal pressure in the pipe, which can result in pipe collapse if the external hydraulic pressure exceeds the flattening resistance of the pipe. Flattening resistance should be considered for gravity flow lines, vacuum lines, submerged lines and any line where the internal pressure is less than the static external hydraulic load. Flattening resistance is usually not a consideration where the end of the line is open to an external water environment. Open ended lines are pressure balanced and the static head in a full pipe crossing a water body will usually be the same or higher that the water height above the pipeline. A few examples of where negative pressure situations may occur are as follows. 1) Above or below ground gravity flow lines. 2) A vacuum line a water suction line submerged 23 ft in a lake (equivalent to 10 psi external loading) and is operating under a partial vacuum of 5 psi. The net negative pressure is 15 psi. 3) A water line going over a hill. The velocity of the water flow down the hill can exceed the velocity of the water coming up the hill and cause a negative pressure to occur. Excessive external pressure or nor net internal vacuum pressure can cause pipe flattening or collapse. The maximum external load is determined not by material strength but by the pipe s stiffness. The pipe will flatten if the bending moment due to the load exceeds the resisting moment due to the elastic stresses in the pipe. The critical external pressure above which round pipe will flatten or collapse can be estimated by using Love s Equation: P cr = 2E 1 μ 1 2 DR 1 3 P cr is the critical flattening pressure, lb./in. 2 ; E is the elastic modulus, lb./in. 2 ; is Poisson s ratio; (0.40 for PEX under long-term stress); (0.35 for PEX under short-term stress); DR is the pipe Dimension Ratio. An appropriate safety factor should be applied when using this equation for design. If short-term modulus is used in the calculation, a safety factor of 3 would be typical. If a long-term value of modulus is available, this may be reduced to 1.5. For above ground lines, increased temperatures will decrease the pipe s collapse resistance and in buried lines, pipe deflection will reduce flattening resistance.

26 Annex C (informative) Interpolation of the HDB HDB values at temperatures between two other temperatures at which HDBs have been experimentally determined can be calculated by interpolation. This method is similar to the method established in PPI TR-3 which uses the LTHS values for interpolation then categorizes the interpolated LTHS into the HDB. HDB T = HDB L (HDB L HDB H ) ( 1 T L 1 T T ) ( 1 T L 1 T H ) Where: HDB T = HDB at the interpolation temperature (psi) HDB L = HDB at the lower temperature (psi) HDB H = HDB at the higher temperature (psi) T T = interpolation temperature (K) T L = lower temperature (K) T H = higher temperature (K)

27 Annex D (normative) Calculation of Pressure Ratings for Pipe Sizes Not Listed in this Standard The various tables of pressure rating in this standard contain pressure ratings for limited range of wall thicknesses. The HDB and DIN 16892/3 methods provide a means of calculating the maximum working pressure for non-standard sizes that are not listed in this standard specification. In this annex methods are described to calculate maximum working pressure if certain information is available about the pipe and operating conditions. D.1 Pressure Rating Based on HDB Knowing the HDB and the Dimension Ratio (DR) enables calculation of the Maximum Working Pressure for a given fluid environment. The following equation defines the relationship between Maximum Working Pressure and the DR, the HDB and the Fluid Environment. MWP = 2HDB DF FSF DR 1 Where: MWP = Maximum working pressure (psi) HDB DR = Hydrostatic design basis (psi) = Dimension ratio = (average outside diameter) / (minimum wall thickness) DF = System Design Factor = 0.71 for this standard FSF = Fluid Service Factor = 1.0 for non-chemically aggressive fluids = 0.5 for multiphase fluids, wet natural gas and liquid hydrocarbons

28 D.2 Pressure Rating Based on DIN 16892/3 The DIN 16892/3 pressure rating method is based on the long term hydrostatic strength performance compared to reference lines published in the standard that relate the long term hydrostatic pressure resistance of the pipe to the measured rupture time. It is necessary to use the reference lines to calculate the maximum working pressure for a known pipe diameter and wall thickness. The equation below is derived from the equation in the DIN standard. MWP = 16σ t d t FSF Where: MWP = Maximum working pressure (bars) σ = Long term hydrostatic pressure resistance from reference lines (N/mm 2 ) t d DF = Minimum pipe wall thickness (mm) = Average pipe diameter (mm) = System Design Factor = 1.25 for this standard FSF = Fluid Service Factor = 1.0 for non-chemically aggressive fluids = 0.5 for multiphase fluids, wet natural gas and liquid hydrocarbons

29 Annex E (informative) Purchasing Guidelines Table E.1 provides recommended guidelines for inquiry and purchase of API Spec 15PX pipe or fittings. Table E.1 Purchasing General Guidelines Pipe Design Parameter Specification Material Design Conditions API 15PX PEX Design Pressure Maximum Operating Pressure Pressure cycles Design Temperature Maximum Operating Temperature Temperature Cycles Service Fluid Composition, (% liquid hydrocarbons) Above ground or buried Fittings Requirements Isometric drawing An important consideration for purchasing quality materials for application in oil and gas gathering is the selection of a quality vendor. Vendors should have an understanding of the necessary quality control testing and the capability to perform the testing required by standards. Vendors should be able to provide records showing that a detailed QA/QC program is in place that utilizes the testing required by API Spec 15PX. Appropriate records of in-plant inspection and testing and quality control/quality assurance testing should be available to demonstrate that the manufacturer s piping products meet the requirements of this specification. Vendors should have the ability to provide sound technical support for its products in field applications.