CSA/ANSI NGV 4.4:21

1 Scope 1.1 Inclusions This Standard applies to newly produced compressed natural gas vehicle (NGV) dispenser fuelling hose emergency main line breakaway devices and vent line breakaway devices, herein to be referred to as devices. 1.2 Main line breakaway inclusions Main line breakaway devices covered by this Standard are intended to a) minimize the escape of natural gas by automatically shutting off the flow of gas from the dispenser and control the depressurization of the downstream hose; and b) separate the fuelling hoses attached to the vehicle from the dispenser during an unintended drive- off event. 1.3 Vent line breakaway inclusions Vent line breakaway devices covered by this Standard are intended to separate the vent line hose attached to the vehicle from the dispenser during an unintended drive-off event. 1.4 Exclusions The Standard is not applicable to home or private use vehicle refuelling appliances. 1.5 Pressure references All references to pressure throughout this Standard are to be considered gauge pressures unless otherwise specified. 1.6 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. 1.7 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.