CSA/ANSI NGV 2:23
Compressed natural gas vehicle fuel containers
This Standard concerns high-pressure containers for the on-board storage of natural gas as a fuel for automotive vehicles.
This Standard contains requirements for the material, design, manufacture, and testing of serially produced, refillable Type NGV 2 containers intended for the storage of compressed natural gas (CNG) for vehicle operation. These containers are to be permanently attached to the vehicle. This Standard applies to containers up to and including 1000 L (35.4 ft3) water capacity.
Note: In Canada, the use of gas containers is governed by the Act. In the United States, the use of gas containers is governed by the U.S. Department of Transportation
1.2 Container types
1.2.1 Cylindrical containers
Type NGV 2 containers are designated as follows:
Type 1: metal;
Type 2: hoop-wrapped container with resin-impregnated continuous filaments and a metal liner with a minimum burst pressure of 125% of service pressure;
Type 3: fully wrapped container with resin-impregnated continuous filaments and with a metal liner; and
Type 4: fully wrapped container with resin-impregnated continuous filaments and with a nonmetallic liner.
1.2.2 Conformable containers
Conformable container types are designated as follows:
CT1: container or assembly of a non-cylindrical or non-spherical (i.e., irregular) shape without a protective shell (i.e., outside wall containing gas pressure);
CT2: container or assembly of possibly irregular shape within a conformable protective shell that is acting as a shield and not directly assisting the inner container with containing gas pressure; and
CT3: container or assembly of possibly irregular shape within a conformable protective shell that is acting as a shield and directly assisting the inner container with containing gas pressure.
The conformable container types are an additional identifier that is used in combination with the container type. A conformable container is designated based on the design as a Type 1 (metal) to Type 4 (resin-impregnated continuous filament with a nonmetallic liner) with the additional conformable type identifier. For example, a Type 4 CT2 container would be required to meet the criteria for a Type 4 container as well as the criteria specified for a CT2 container.
1.3 Welded containers
This Standard does not cover welded metal containers or liners.
1.4 Precedence of requirements
Where a clause in this Standard conflicts with codes or standards referenced in this Standard, the requirements of this Standard take precedence.
1.5 Requalification of containers
Type 1 steel containers may be requalified for further service in accordance with the procedure described in Annex E.
1.6 Canadian specific requirements
Annex Acontains requirements that are applicable only to Canada.
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.
1.8 Units of measure
The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only.
See also Annex D.