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Publications ANSI NGV 3.1-2014/CSA 12.3-2014

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ANSI NGV 3.1-2014/CSA 12.3-2014 - Fuel system components for compressed natural gas powered vehicles

Publication Year:

  • 2014

Total Pages:



  • CSA


This is the third edition of ANSI NGV 3.1 - CSA 12.3, Fuel system components for compressed natural gas powered vehicles. It supersedes the previous editions published in 2012 and 1995.


This Standard establishes requirements for newly produced compressed natural gas fuel system components, intended for use on natural gas powered vehicles, as listed in Table 1, below:

Table 1 - Fuel system components - (See Clauses 1.1 and 1.5.)

Check valve
Manual valve
Manual container valve
Automatic valve
Gas injector
Pressure indicator
Pressure regulator
Gas flow adjuster
Gas/air mixer
Pressure relief valve
Pressure relief device
Excess flow valve
Gas tight housing and ventilation hoses
Rigid fuel line
Flexible fuel line, hoses and assemblies
Discharge line closures

This Standard applies to devices that have a service pressure of either 16 500 kPa (2 400 psi), 20 700 kPa (3 000 psi), or 24 800 kPa (3 600 psi), hereinafter referred to in this Standard as the following:

"P24" - 16 500 kPa (2 400 psi)
"P30" - 20 700 kPa (3 000 psi)
"P36" - 24 800 kPa (3 600 psi)

The Standard also applies to components downstream of the first stage of pressure reduction with a working pressure designated by the manufacturer in kPa (psi).

The construction of the noted components whether specifically covered by the various provisions of this Standard or not, is to be in accordance with reasonable concepts of safety, performance and durability.

All specifications as to construction set forth herein are to be satisfied by the construction actually prescribed or such other construction as will provide at least equivalent performance.

This Standard emphasizes the pressure containment, performance and safety characteristics of components listed in Table 1.

It is recognized that other components not specifically covered herein can be examined to meet the criteria of this Standard and tested according to the appropriate functional needs.

This Standard does not apply to the following:

a) natural gas fuel system components incorporated during the manufacture of motor vehicles originally manufactured in compliance with the Federal Motor Vehicle Safety Standards (FMVSS) for Compressed Natural Gas Fueled Vehicles and the Canadian Motor Vehicle Safety Standard (CMVSS);

b) fuel containers;

c) stationary gas engines;

d) container mounting hardware;

e) electronic fuel management;

f) fueling receptacles; or

g) three way valves.

In the case of conflict between this Standard and Federal, Provincial, State or local requirements, the government requirements are to take precedence.

All references to "psi" throughout this Standard are to be considered gauge pressures, unless otherwise specified.

This Standard contains SI (metric) units corresponding to the yard/pound quantities, the purpose being to allow the Standard to be used in SI (metric) units. IEEE/ASTM SI I0, American National Standard for Metric Practice, or ISO 80000-1:2009 Quantities and units - Part 1: General, 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 stated, the first stated value is to be regarded as the requirement. The given corresponding value may be approximate. 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.

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.

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