Draft Details

1.1 General
This Document contains recommendations for safely defueling, removing, or disposing of CNG containers for storing fuel used for vehicle propulsion and bulk transportationwhen the container
a) requires defueling for any reason, including but not limited to inspection, repair, or maintenance
b) has reached its end of life as indicated by the date on the container label;
c) has been condemned in accordance with visual inspection guidelines;
d) is no longer of value to an owner; or
e) has been deemed a public nuisance or imminent hazard by the local authority (abandoned, confiscated, or seized containers).
It is the owner’s responsibility to  confirm that the CNG containers on the vehicle are defueled or removed by qualified personnel whenever deemed required . Once the container has been removed, the custodian of the container is responsible to dispose of the container safely.
Note: Owners should obtain paperwork to document transfer of custody.

1.2 Exclusions
Recommendations for reusing or repurposing CNG fuel containers that are still within their manufacturer-designated service life are excluded from the scope of this specification. 
Additional associated exclusions include repurposed fuel container mounting arrangements, valve configurations, pressure relief device (PRD) venting systems, and fuel system plumbing. 
Refer to guidance from the fuel container manufacturer, the fuel system provider, and the authority having jurisdiction (AHJ) prior to reinstallation of any CNG fuel container.

1.3 Container type
Type NGV 2 containers are designated as follows:
a) Type 1: seamless metal container;
b) Type 2: hoop-wrapped container with resin - impregnated continuous filaments and a metal liner; 
c) Type 3: fully wrapped container with resin - impregnated continuous filaments and with a metal liner; and
d) Type 4: fully wrapped container with resin - impregnated continuous filaments and with a non-metallic liner.

1.4 Terminology
In this Document, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Document; “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 Document.
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.

1.5 Units of measurement
The values given in SI units are the units of record for the purposes of this Document. The values given in parentheses are for information and comparison only