Crosslinked polyethylene (PEX) piping systems for gas services

1.1 General

This Standard covers crosslinked polyethylene (PEX) pipe and fittings for use in gas mains and services, including gas gathering, gas transmission, and distribution of fuel gases.

1.2 Pipe

This Standard covers PEX pipes in metric nominal sizes DN 16 to DN 1000 or nominal pipe sizes NPS-3 to NPS-54 that are

a) pressure-rated using the hydrostatic design basis (HDB) rating method specified in ASTM D2837 or the minimum required strength (MRS) rating method specified in ISO 9080 and ISO 12162;

b) intended for operating temperatures between –50 and 110 °C; and

c) joined by PEX electrofusion fittings or by mechanical fittings, but not by butt fusion.

1.3 Joints

This Standard includes requirements for joints made between PEX pipe and PE electrofusion fittings compliant with ASTM F3373.

1.4 Pipe exclusions

This Standard does not cover pipes intended to be joined by butt fusion, socket fusion, or saddle fusion.

1.5 Fittings

Fittings to be used with PEX pipe manufactured to this Standard are in accordance with ASTM F2829. Fittings covered in this Standard include

a) plastic-to-metal transition fittings;

b) electrofusion fittings (e.g., couplings, elbows, tees, and end caps); and

c) mechanical couplings.

1.6 Requirements

This Standard specifies requirements for

a) primary properties of the PE compound;

b) physical properties of the finished PEX pipe;

c) on-line monitoring during production;

d) shipping and storage; and

e) markings.

Note: See CSA Z662 for design and installation limitations of products covered by this Standard.

1.7 Terminology

In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the Standard.

Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.

Notes to tables and figures are considered part of the table or figure and may be written as requirements.

Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.