Preface 

This is the seventh edition of CSA/ANSI LC 1 • CSA 6.26, Fuel gas piping systems using corrugated stainless steel tubing. It supersedes the previous editions published in 2019, 2018, 2016, 2014, 2005, and 1997. This edition of this Standard has been updated to reflect current industry practice, and address CSA Group’s guide on drafting Standards. Major changes to this edition include the following: a) this Standard has been revised for accessibility; b) installation instructions using manifolds have been revised; c) in Clause 5.16.4, the test specimen sizes have been updated; and d) Annex C has been updated to bring the recommendations of this non-mandatory annex into agreement with the bonding requirements on the current editions of the US and Canadian model codes. This Standard is considered suitable for use for conformity assessment within the stated scope of the Standard. This Standard was prepared by the Joint Subcommittee on Corrugated Stainless Steel Tubing, under the jurisdiction of the Technical Committee on Gas Appliances and Related Accessories, the Z21/83 Technical Committee on Performance and Installation of Gas Burning Appliances and Related Accessories, and the Strategic Steering Committee on Fuels and Appliances, and has been formally approved by the Technical Committees and the Interprovincial/Territorial Gas Advisory Council. This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. This Standard has been approved by the American National Standards Institute (ANSI) as an American National Standard. 

Scope 

1.1 Inclusions 

This Standard applies to fuel gas piping systems using corrugated stainless steel tubing (CSST), intended for installation in residential, commercial, or industrial buildings, and including the following components as a minimum: a) corrugated stainless steel tubing (CSST) piping systems not exceeding a size of 2 in (50.8 mm), based on the nominal inside diameter of the tubing; b) fittings for connection to the CSST; and c) striker plates (see Clause 3) to protect the installed CSST from puncture threats. Other components of piping systems covered by this Standard include gas manifolds, gas pressure regulators, manual gas valves, quick-disconnect devices, excess flow valves, and gas convenience outlets (see Clauses 4.3, 4.4, and 4.5). 

Note: If such additional components are required to complete the piping system installation, they are either provided as part of the piping system or specified in the manufacturer’s installation instructions [see Clause 4.7n)]. 

1.2 Additional inclusions 

This Standard also applies to the following: a) CSST piping systems in which portions of the piping are exposed to the outdoors, as required, to make connections to outdoor gas meters or to outdoor gas appliances, which are attached to, mounted on, or located in close proximity to the building structure; and b) CSST piping systems that are used in conjunction with other approved fuel gas piping materials. 

1.3 Exclusions 

This Standard does not apply to the following: a) CSST, whether coated or uncoated, intended for direct burial underground. Tubing is installed underground only when encased inside either an approved conduit or as part of an approved engineered system and in accordance with local codes and the manufacturer’s instructions; and b) gas connectors for appliances. These connectors are covered by CSA/ANSI Z21.24 • CSA 6.10 and ANSI Z21.69 • CSA 6.16. 

1.4 Concealment of tube fittings 

This Standard includes criteria to establish the suitability of concealed mechanical tube fittings for use with concealed gas piping (see Clause 3). 

1.5 System pressure ratings 

This Standard applies to piping systems rated at a) 5 psi (34.5 kPa) and intended for exposure to maximum actual operating pressures (see Clause 3) not exceeding 6.5 psi (44.8 kPa); or b) 25 psi (172.5 kPa) and intended for exposure to maximum actual operating pressures not exceeding 30 psi (207 kPa). Note: The manufacturer has the option to certify its system to either pressure rating. 

1.6 Applicable fuels 

This Standard applies to piping systems intended for use only with fuel gas as defined in Clause 3, but does not apply to piping systems intended for use with propane in the liquid state. 

1.7 Pressure references 

All references to psi throughout this Standard are to be considered gauge pressure unless otherwise specified. 1.8 Measurement units If a value for measurement as given in this Standard is followed by an equivalent value in other units, the first stated value is to be regarded as the specification. 

Note: This Standard contains SI (metric) units corresponding to the yard/pound quantities, the purpose being to allow this Standard to be used in SI (metric) units. IEEE/ASTM SI 10 or ISO 80000-1 is used as a guide in making metric conversion from yard/pound quantities. If a value for a measurement and a corresponding value in other units are both specified as a quoted marking requirement, the first stated unit, or both, are to be provided. Given corresponding values might be approximate. See also Annex D. 

1.9 Terminology

In this Standard, "shall" Is used to express a requirement, i.e., a provision that the user shall 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.