ISO/TC 138/SC 4 - Plastics pipes and fittings for the supply of gaseous fuels

This document specifies the requirements and test methods for mechanical fittings intended to join plastic pressure piping systems including transition fittings to metal pipes for the following: — supply of gaseous fuels (GAS); — supply of water for human consumption (W), including raw water prior to treatment and for the supply of water for general purposes, as well as underground drainage and sewerage under pressure (P); — supply of water for irrigation (I); — industrial applications (IS). This document is applicable only to mechanical fittings with operating-temperature and pressure limits as indicated in the relevant systems standards. NOTE A list of International Standards for plastic pipes for which mechanical fittings can be used can be found in Annex A. Flanges are not covered by this document. Mechanical fittings for hot and cold water systems inside buildings, as well as for district heating applications, are not covered by this document.

This document specifies an encoding system for data of components, assembly methods and jointing operations for polyethylene (PE) piping systems for gas, water and other industrial applications. These data can be used in a traceability system and/or used to perform the fusion of components by using equipment as specified in ISO 12176‑1 and in ISO 12176‑2. This encoding system is explained in ISO/IEC 16022, ISO/IEC 18004 and ISO/IEC 24778 which refer to established code types, e.g. QR code. Data to be encoded are: fusion cycle(s), traceability of manufactured products, other manufacturer’s information that can also be given on websites such as voluntary certificates of quality and approvals. This document specifies the export of data (type, format and sequence) from a data retrieval system. Provisions of this document are applicable to polyethylene components conforming to ISO 4427‑2, ISO 4427‑3, ISO 4437‑2, ISO 4437‑3, ISO 4437‑4 and ISO 15494, and can also be applicable to any other components used in PE systems. ISO 13950 and ISO 12176‑4, which partly cover the fields of application of this document, can be used in parallel.

This document specifies the requirements of fitness for purpose of unplasticized polyamide (PA-U) piping system, intended to be buried and used for the supply of gaseous fuels. It also specifies the definitions of electrofusion and butt fusion joints. This document specifies the method of preparation of test piece joints and the tests to be carried out on these joints for assessing the fitness for purpose of the system under normal and extreme conditions. It also specifies the test parameters for the test methods to which it refers. The ISO 16486 series is applicable to PA-U piping systems, the components of which are connected by fusion jointing and/or mechanical jointing. In conjunction with the other parts of ISO 16486, it is applicable to PA-U fittings, their joints and to joints with components of PA-U.

This document specifies the physical and mechanical properties of pipes made from unplasticized polyamide (PA-U) in accordance with ISO 16486-1, intended to be buried and used for the supply of gaseous fuels. It also specifies the test parameters for the test methods to which it refers. The ISO 16486 series of standards is applicable to PA-U piping systems, the components of which are connected by fusion jointing and/or mechanical jointing. In addition, this document lays down dimensional characteristics and requirements for the marking of pipes. Pipes conforming to this document are jointed typically by using mechanical, electrofusion or butt fusion techniques.

This document specifies the physical and mechanical properties of fittings made from unplasticized polyamide (PA-U) in accordance with ISO 16486‑1, intended to be buried and used for the supply of gaseous fuels. It also specifies the test parameters for the test methods to which it refers. The ISO 16486 series is applicable to PA-U piping systems, the components of which are connected by fusion jointing and/or mechanical jointing. In addition, it lays down dimensional characteristics and requirements for the marking of fittings. In conjunction with the other parts of the ISO 16486 series, this document is applicable to PA-U fittings, their joints, joints with components of PA-U and joints with mechanical fittings of other materials, and to the following fitting types: — fusion fittings (electrofusion fittings and butt fusion fittings), and — transition fittings.

This document specifies the general properties of unplasticized polyamide (PA-U) compounds for the manufacture of pipes, fittings and valves made from these compounds, intended to be buried and used for the supply of gaseous fuels. It also specifies the test parameters for the test methods to which it refers. The ISO 16486 series is applicable to PA-U piping systems, the components of which are connected by fusion jointing and/or mechanical jointing. This document establishes a calculation and design scheme on which to base the maximum operating pressure (MOP) of a PA-U piping system.

ISO 21307:2017 establishes general principles regarding the procedure used in the construction and quality assessment of butt fusion jointing of polyethylene (PE) piping system components specified in accordance with relevant ISO standards. These components are installed in accordance with the relevant codes of practice, national regulations or industry guidance. Specifically, this document specifies three butt fusion jointing procedures for PE pipes and fittings. These are: - single low-pressure fusion jointing procedure; - dual low-pressure fusion jointing procedure; - single high-pressure fusion jointing procedure. ISO 21307:2017 takes into consideration the materials and components used, the fusion jointing procedure and equipment and the quality assessment of the completed joint. It can be applied in conjunction with appropriate national regulations and standards.

ISO 12176-1:2017 specifies the general characteristics of, and performance requirements for, equipment for butt fusion jointing of polyethylene (PE) piping systems using electrically powered heater plates. ISO 12176-1:2017 is applicable to mechanical and pressure-activated equipment for butt fusion jointing of PE pipes and fittings either intended to be used for the supply of gaseous fuels, conforming to ISO 4437‑2[1] and ISO 4437‑3[2], or intended for the conveyance of water for human consumption (including raw water prior to treatment) and for the conveyance of water for general purposes, conforming to ISO 4427‑2[3] and ISO 4427‑3[4]. Butt fusion machines with an automatic controller are subject to additional requirements as given in Annex A. NOTE This document is also applicable to butt fusion machines for larger nominal pipe diameters and nominal wall thicknesses than given in this document.

ISO 17484-1:2014 specifies the general requirements and the performance requirements for multilayer pipe systems based on pipes, fittings and their joints intended to be used for gas supply within buildings. PE-X and PE pipes composed of one stress-designed layer, adhesive and a barrier layer are also covered by ISO 17484-1:2014. ISO 17484-1:2014 gives guidance for the design of piping systems consisting of multilayer pipes based on thermoplastics, for which at least 60 % of the wall thickness is polymeric material. Polymeric materials intended for stress-designed layers and all inner layers are required to be polyethylene (PE) and/or crosslinked polyethylene (PE-X) in accordance with Annex A of ISO 17484-1:2014. ISO 17484-1:2014 applies to systems that operate at temperatures of −20 °C up to +60 °C. For the purpose of ISO 17484-1:2014, crosslinked polyethylene (PE-X) and adhesive layers are considered as thermoplastic materials. For sizes greater than 63 mm the requirements of ISO 18225 have to be fulfilled in addition. ISO 17484-1:2014 is applicable for piping systems used in buildings to supply gas with a maximum operating pressure up to and including 500 kPa (5 bar). ISO 17484-1:2014 applies to the following fuels: Category D gaseous fuel: natural gas; Category E gaseous fuel: LPG vapour, and natural gas or LPG vapour.

ISO 4437-3:2014 specifies the characteristics of fusion fittings made from polyethylene (PE) as well as of mechanical fittings for piping systems in the field of the supply of gaseous fuels. It also specifies the test parameters for the test methods referred to in this part of ISO 4437. In conjunction with ISO 4437‑1, ISO 4437‑2, ISO 4437‑4, and ISO 4437‑5, it is applicable to PE pipes, fittings and valves, their joints, and joints with components of PE and other materials intended to be used under the following conditions: the maximum operating pressure (MOP) is based on the design stress, determined from the compound minimum required strength (MRS) divided by the C factor, and taking into account rapid crack propagation (RCP) requirements; and a temperature of 20 °C is taken as reference temperature for the design basis. ISO 4437-3:2014 is applicable for fittings of the following types: electrofusion socket fittings; electrofusion saddle fittings; spigot end fittings (for butt fusion using heated tools and electrofusion socket fusion); socket fusion fittings; and mechanical fittings.

ISO 4437-1:2014 specifies the general properties of polyethylene (PE) compounds for the manufacture of pipes and fittings intended to be used for the supply of gaseous fuels. It also specifies the test parameters for the test methods referred to in this International Standard. In conjunction with ISO 4437-2, ISO 4437-3, ISO 4437-4, and ISO 4437-5, it is applicable to PE pipes, fittings and valves, their joints, and joints with components of PE and other materials intended to be used under the following conditions: the maximum operating pressure (MOP) is based on the design stress determined from the compound minimum required strength (MRS) divided by the C factor, and taking into account rapid crack propagation (RCP) requirements; and a temperature of 20 °C is taken as reference temperature for the design basis.

ISO 4437-5:2014 specifies the requirements of fitness for purpose of the polyethylene (PE) piping system to be used for the supply of gaseous fuels. It specifies the definitions of electrofusion, socket fusion, butt fusion, and mechanical joints. It specifies the method of preparation of test piece joints and the tests to be carried out on these joints for assessing the fitness for purpose of the system under normal and extreme conditions. It specifies the test parameters for the test methods referred to in this part of ISO 4437. In conjunction with ISO 4437‑1, ISO 4437‑2, ISO 4437‑3, and ISO 4437‑4, it is applicable to PE pipes, fittings, valves, their joints, and joints with components of PE and other materials intended to be used under the following conditions: the maximum operating pressure (MOP) is based on the design stress, determined from the compound minimum required strength (MRS) divided by the C factor, and taking into account rapid crack propagation (RCP) requirements; and a temperature of 20 °C is taken as reference temperature for the design basis.

ISO 4437-2:2014 specifies the characteristics of pipes made from polyethylene (PE) for piping systems in the field of the supply of gaseous fuels. It also specifies the test parameters for the test methods referred to in this International Standard. In conjunction with part of ISO 4437-1, ISO 4437-3, ISO 4437-4, and ISO 4437-5, it is applicable to PE pipes, fittings and valves, their joints, and joints with components of PE and other materials intended to be used under the following conditions: the maximum operating pressure (MOP) is based on the design stress determined from the compound minimum required strength (MRS) divided by the C factor, and taking into account rapid crack propagation (RCP) requirements; and a temperature of 20 °C is taken as reference temperature for the design basis. ISO 4437-2:2014 covers three types of pipes: PE pipes (outside diameter dn) including any identification stripes; PE pipes with co-extruded layers on either or both the outside and/or inside of the pipe (total outside diameter dn), where all PE layers have the same MRS rating; and PE pipes (outside diameter dn) with a peelable and contiguous thermoplastics additional layer on the outside (coated pipe).

ISO 18225:2012 specifies general and performance requirements for multilayer pipe systems based on pipes made from thermoplastics and intended to be used for gas supply outdoors. It gives requirements for the design of pipe systems consisting of multilayer pipes based on thermoplastics and for which at least 60 % of the wall thickness is of a polymeric material. The polymeric material used for stress design layers and all inner layers must be polyethylene (PE) and/or crosslinked polyethylene (PE-X), in accordance with Annex A. The outer layers of metal multilayer pipes must be of either PE or PE-X. NOTE For the purposes of ISO 18225:2012, PE-RT is considered as PE, while PE-X and adhesive layers are considered as thermoplastics materials. ISO 18225:2012 is applicable to systems intended to be operated at temperatures ranging from −20 °C to 40 °C. It is applicable to pipes in these systems having a nominal diameter up to and including 630 mm, and to the supply of gaseous fuels of categories D (natural gas) and E (LPG vapour and natural gas or LPG vapour) (see ISO 13623).

ISO 16486-6:2012 specifies a code of practice dealing with unplasticized polyamide (PA-U) piping systems intended to be buried outside buildings and used for the supply of gaseous fuels. It addresses the common basic principles for gas supply systems. ISO 16486-6:2012 is intended to be applied in association with national standards or codes of practice related to the above-mentioned basic principles. It is applicable to mains and service lines, the components of which are prepared for jointing by scraping and/or machining, and gives instructions for the design, storage, handling, transportation, laying conditions and fusion quality control of PA-U pipes and fittings up to and including 250 mm outside diameter, as well as subsequent joint testing, backfilling, pipe system testing, commissioning and decommissioning. It covers butt fusion jointing and electrofusion jointing.

ISO 12176-3:2011 describes the format and the contents of a fusion operator's badge, which is used during the construction of polyethylene (PE) piping systems for the supply of gaseous fuels or water to identify the fusion operator and to activate or deactivate the fusion-jointing equipment. The objective of ISO 12176-3:2011 is to achieve international interoperability between the operator's badge and the card-reading equipment of fusion-jointing equipment conforming to ISO 12176‑1 or ISO 12176‑2. The fusion-jointing equipment is required to read either the bar code or the magnetic-stripe code of the badge and to call up the corresponding data within the equipment in a standard format.

ISO 14531-3:2010 specifies the physical properties and mechanical-performance requirements for full-end-load-resistant mechanical fittings for use in the connection of crosslinked polyethylene (PE‑X) pipes conforming to ISO 14531‑1 and in the construction of transition assemblies for joining PE‑X pipes to metal pipes having plain spigot, screw thread, compression socket and flange terminations. In addition, it lays down dimensional requirements and specifies some general material properties (including chemical resistance) together with a classification scheme for PE‑X fitting materials produced in the form of pipe. ISO 14531-3:2010, when used in conjunction with the other parts of ISO 14531, provides the basis for the design, manufacture and installation of PE‑X piping systems (PE‑X pipes, PE‑X fusion fittings and mechanical fittings) for the supply of category D and category E hydrocarbon-based fuels.

ISO 17484-2:2009 specifies the recommended practice for the installation of multilayer pipe systems in accordance with ISO 17484-1:2006. It is applicable to piping systems used in buildings to supply gas with a maximum operating pressure up to and including 500 kPa (5 bar).

ISO 12176-2:2008 specifies performance requirements for electrofusion control units for use with polyethylene (PE) electrofusion fittings for the supply of gaseous fuels or for the conveyance of water for human consumption, including raw water prior to treatment and for the conveyance of water for general purpose or other fluids. The control units are divided into three input voltage classes: SVLV [safety, very low voltage (up to 50 V)], LV [low voltage (50 V to 250 V)] and HV [higher voltage (250 V to 400 V)]. ISO 12176-2:2008 is applicable to electrofusion control units designed for use in the construction of joints between PE pipes and fittings conforming to International Standards for the supply of gaseous fuels or for the conveyance of water, where the normal operating temperature of the control unit is in the range -10 °C to + 40 °C. If temperatures outside this range are expected, suitable operating limits are subject to agreement between manufacturer and purchaser. ISO 12176-2:2008 is applicable to control units with current or voltage control for fitting systems based on standard resistance wire heating technology.

ISO 13950:2006 specifies the characteristics of automatic recognition systems (numerical recognition by means of bar codes or magnetic cards, electromechanical recognition using implanted-resistor connectors and self-regulation systems) that enable the energy supply to be delivered automatically to the thermoplastic electrofusion fittings used in pipe jointing. It is applicable to electrofusion fittings intended to be used for plastics piping systems for the conveyance of gaseous fuels, water for human consumption (including raw water prior to treatment) and for general purposes, or of other fluids.

ISO/TS 18226:2006 describes the use of reinforced thermoplastics pipe (RTP) systems for transmission of gaseous fuels at maximum operating pressures up to and including 40 bars, and service temperatures in the region - 50 °C to 120 °C, depending on the liner and cover materials. ISO/TS 18226:2006 relates to transmission systems in which wear and damage to the liner are restricted by limiting pigging operations to soft pigging only. The recommendations in ISO/TS 18226:2006 are confined to RTP and its associated in-line fittings and end-fittings. Where the other system components (elbows, tees, valves, etc.) are of conventional construction, they will be governed by existing standards and codes of practice. ISO/TS 18226:2006 specifies a qualification testing procedure for RTP systems. It also provides a procedure for reconfirmation of the design basis that may be used for product variants where changes have been made in design, materials or the manufacturing process.

ISO 6993-4:2006 specifies a code of practice for the design, handling and installation of high-impact poly(vinyl chloride) (PVC-HI) pipes and fittings intended to be used for the supply of gaseous fuels through buried pipelines having an operating temperature range of 0 degrees Celsius up to and including +30 degrees Celsius and a maximum operating pressure of 1 bar (100 kPa).

ISO 6993-3:2006 gives the requirements for full-end load-resistant fittings and saddles made of high-impact poly(vinyl chloride) (PVC-HI) intended to be used for the supply of gaseous fuels through buried pipelines having an operating temperature range of 0 degrees Celsius up to and including +30 degrees Celsius and a maximum operating pressure of 1 bar (100 kPa). It is applicable only to fittings and saddles manufactured from the high-impact PVC materials PVC-A, PVC-CPE and PVC-EPR. It is applicable to joints with elastomeric sealing elements and of the solvent cement type. The fittings and saddles are suitable for those gases not containing potentially damaging components in such concentrations as to impair the properties of the fitting/saddle material.

ISO 6993-1:2006 specifies the requirements for pipes made of high-impact poly(vinyl chloride) (PVC-HI) intended to be used for the supply of gaseous fuels through buried pipelines having an operating temperature range of 0 degrees Celsius up to and including +30 degrees Celsius and a maximum operating pressure of 1 bar (100 kPa). It is applicable only to pipes manufactured from the high-impact PVC materials PVC-A, PVC-CPE and PVC-EPR. The pipes are suitable for those gases not containing potentially damaging components in such concentrations as to impair the properties of the pipe material.

ISO 6993-2:2005 gives the requirements for non-end load-bearing fittings made of high-impact poly(vinyl chloride) (PVC-HI) intended to be used for the supply of gaseous fuels through buried pipelines having an operating temperature range of 0 degrees Celsius up to and including +30 degrees Celsius and a maximum operating pressure of 200 mbar (20 kPa).

ISO 14531-4:2006 provides guidance for the design, construction, installation and on-site testing of PE-X pipeline systems. The standard deals with trenchless and open-trench installation methods. ISO 14531-4:2006, when used in conjunction with the other parts of ISO 14531, provides the basis for the design, manufacture and installation of PE-X piping systems (PE-X pipes, and PE-X and PE heat-fusion fittings and mechanical fittings) for the supply of category D and category E hydrocarbon-based fuels.

ISO/TR 19480:2005 gives guidance and other provisions for the training, assessment and approval of fusion operators, with the aim of establishing and maintaining their competency in the construction of polyethylene (PE) piping systems for the supply of gaseous fuels in accordance with ISO 10839, for the supply of water, or in the construction of such systems used in other pressure applications. It covers the butt fusion, electrofusion and socket fusion jointing techniques and considers both the theoretical and practical knowledge necessary to enable high-quality fusion joints to be produced.

ISO 14531-2:2004 specifies the physical properties and mechanical performance requirements of crosslinked polyethylene (PE-X) and polyethylene (PE) socket, saddle and spigot fittings for the connection by socket or saddle heat-fusion jointing techniques of PE-X pipes manufactured in accordance with ISO 14531-1. In addition, it lays down dimensional requirements and specifies some general material properties (including chemical resistance) together with a classification scheme for PE-X fitting base materials produced in the form of pipe. When used in conjunction with the other parts of ISO 14531, it provides the basis for the design, manufacture and installation of PE-X piping systems (PE-X pipes, PE-X fusion fittings and mechanical fittings) for the supply of category D and category E gaseous fuels.

ISO 12176-4:2003 specifies an encoding system for data on components, assembly methods and jointing operations for polyethylene (PE) piping systems for gas supply, for use in a traceability system. Reading of the codes can be carried out using alphanumeric or numeric data-recognition systems such as bar-code, magnetic-stripe card or microchip card readers. This part of ISO 12176 is applicable to PE pipes, fittings and valves conforming to ISO standards for gas supply piping systems and also to the assembly operation utilizing methods such as fusion using a heating tool (butt, socket and saddle fusion), electrofusion (socket and saddle fusion), induction fusion and mechanical jointing.

ISO 14531-1:2002 specifies the physical properties and mechanical-performance requirements for crosslinked polyethylene (PE-X) pipes intended for use in the supply of gaseous fuels. In addition, it lays down dimensional requirements and specifies some general material properties (including chemical resistance) together with a classification scheme for PE-X produced in the form of pipe. ISO 14531-1:2002, when used in conjunction with the other parts of ISO 14531, is applicable as the basis for the design, manufacture and installation of PE-X piping systems (PE-X pipes, PE-X fusion fittings and mechanical fittings) for the supply of category D and category E hydrocarbon-based fuels.

This Technical Specification presents a code of practice dealing with polyethylene (PE) pipes and fittings for buried pipeline systems outside buildings and designed to distribute gaseous fuels within the temperature range ? 20 °C to + 40 °C and gives appropriate temperature-related requirements. The code of practice covers mains and service lines whose components are prepared for jointing by scraping and/or machining, and gives instructions for the design, storage, handling, transportation, laying conditions and fusion quality control of PE pipes and fittings up to and including 630 mm outside diameter, as well as subsequent joint testing, backfilling, pipe system testing, commissioning and decommissioning. The jointing methods covered by this Technical Specification are heated-tool fusion jointing (butt, socket and saddle fusion), electrofusion jointing and mechanical jointing. No special precautions are necessary for areas exposed to the influence of mining and earthquakes other than those precautions mentioned in this code of practice. Existing and new national regulations take precedence over this Technical Specification.

ISO 17885:2015 specifies the requirements and test methods for mechanical fittings intended to join plastic pressure piping systems including transition fittings to metal pipes for the following: ? supply of gaseous fuels (GAS); ? supply of water for human consumption (W), including raw water prior to treatment and for the supply of water for general purpose, as well as underground drainage and sewerage under pressure (P); ? supply of water for irrigation (I); ? industrial applications (IS). ISO 17885:2015 is applicable only to mechanical fittings with operating-temperature and pressure limits as indicated in the relevant systems standards.

ISO 17467-3:2012 specifies the physical and mechanical characteristics of fittings made from unplasticized polyamide (PA-U) in accordance with ISO 17467-1, intended to be buried and used for the supply of gaseous fuels for maximum operating pressure up to and including 4 bar. It also specifies the test parameters for the test methods to which it refers. ISO 17467-3:2012 also lays down requirements for dimensions and the marking of fittings. In conjunction with ISO 17467-1 and ISO 17467-2, ISO 17467-3 is applicable to PA-U fittings, their joints and to joints with components of PA-U. These fittings can be of the following types solvent cement socket fittings, solvent cement spigot fittings, and solvent cement saddle fittings.

ISO 17467-1:2012 specifies the general properties of unplasticized polyamide (PA-U) compounds for the manufacturing of pipes, fittings and valves made from such compounds, intended to be buried and used for the supply of gaseous fuels for maximum operating pressure up to and including 4 bar. It also specifies the test parameters for the test methods to which it refers, and specifies a calculation and design scheme on which the maximum operating pressure (MOP) of piping systems is based.

ISO 17467-2:2012 specifies the physical and mechanical properties of pipes made from unplasticized polyamide (PA-U) in accordance with ISO 17467-1, intended to be buried and used for the supply of gaseous fuels for maximum operating pressure up to and including 4 bar. It also specifies the test parameters for the test methods to which it refers, and lays down dimensional characteristics and requirements for the marking of pipes.

ISO 16486-5:2012 specifies the requirements of fitness for purpose of the unplasticized polyamide (PA-U) piping system, intended to be buried and used for the supply of gaseous fuels. It also specifies the definitions of electrofusion and butt fusion joints. ISO 16486-5:2012 specifies the method of preparation of test piece joints and the tests to be carried out on these joints for assessing the fitness for purpose of the system under normal and extreme conditions. It also specifies the test parameters for the test methods to which it refers. ISO 16486 is applicable to PA-U piping systems the components of which are connected by fusion jointing and/or mechanical jointing. In conjunction with the other parts of ISO 16486, ISO 16486-5:2012 is applicable to PA-U fittings, their joints and to joints with components of PA-U.

ISO 16486-1:2012 specifies the general properties of unplasticized polyamide (PA-U) compounds for the manufacture of pipes, fittings and valves made from these compounds, intended to be buried and used for the supply of gaseous fuels. It also specifies the test parameters for the test methods to which it refers. ISO 16486 is applicable to PA-U piping systems the components of which are connected by fusion jointing and/or mechanical jointing. ISO 16486-1:2012 establishes a calculation and design scheme on which to base the maximum operating pressure (MOP) of a PA-U piping system.

ISO 16486-2:2012 specifies the physical and mechanical properties of pipes made from unplasticized polyamide (PA-U) in accordance with ISO 16486-1, intended to be buried and used for the supply of gaseous fuels. It also specifies the test parameters for the test methods to which it refers. ISO 16486 is applicable to PA-U piping systems the components of which are connected by fusion jointing and/or mechanical jointing. In addition, it lays down dimensional characteristics and requirements for the marking of pipes. Pipes conforming to ISO 16486-2:2012 are jointed typically by using mechanical, electrofusion or butt fusion techniques, but not by solvent cement jointing.

ISO 16486-3:2012 specifies the physical and mechanical properties of fittings made from unplasticized polyamide (PA-U) in accordance with ISO 16486-1, intended to be buried and used for the supply of gaseous fuels. It also specifies the test parameters for the test methods to which it refers. ISO 16486 is applicable to PA-U piping systems the components of which are connected by fusion jointing and/or mechanical jointing. In addition, it lays down dimensional characteristics and requirements for the marking of fittings. In conjunction with the other parts of ISO 16486, ISO 16486-3:2012 is applicable to PA-U fittings, their joints, to joints with components of PA-U and to joints with mechanical fittings of other materials, and to the following fitting types: fusion fittings, electrofusion fittings and butt fusion fittings; transition fittings.

ISO 21307:2011 establishes general principles regarding the procedure used in the construction and quality assessment of butt fusion joints incorporating fittings (ISO 8085-2) and pipes used in the construction of gas (ISO 4437) and water (ISO 4427) distribution systems made with equipment that complies with ISO 12176-1 and installed in accordance with ISO/TS 10839, relevant codes of practice, national regulations or industry guidance. Specifically, ISO 21307:2011 specifies a number of proven butt fusion jointing procedures for pipes and fittings with a wall thickness up to and including 70 mm. ISO 21307:2011 takes into consideration the materials and components used, the fusion jointing procedure and equipment and the quality assessment of the completed joint. It can be applied in conjunction with appropriate national regulations and standards.

ISO 22621-6:2010 specifies a code of practice dealing with polyamide (PA) piping systems, intended to be buried outside buildings and used for the supply of gaseous fuels. It is applicable to mains and service lines, the components of which are prepared for jointing by scraping and/or machining, and gives instructions for the design, storage, handling, transportation, laying conditions and fusion quality control of PA pipes and fittings up to and including 250 mm outside diameter, as well as subsequent joint testing, backfilling, pipe system testing, commissioning and decommissioning. The jointing methods covered by ISO 22621-6:2010 are butt fusion jointing and electrofusion jointing.

ISO 22621-5:2010 specifies the requirements of fitness for purpose of the polyamide (PA) piping system, intended to be buried and used for the supply of gaseous fuels at maximum operating pressures (MOP) up to and including 20 bar (2 MPa). It specifies the definitions of electrofusion and butt fusion joints. It also specifies the method of preparation of test piece joints and the tests to be carried out on these joints for assessing the fitness for purpose of the system under normal and extreme conditions. In addition, it specifies the test parameters for the test methods to which it refers. In conjunction with the other parts of ISO 22621, it is applicable to PA fittings, their joints and to joints with components of PA.