ANSI/IAS NGV 4.4/CSA 12.54-1999 (R2018)

1.1 SCOPE 1.1.1 This standard applies to newly produced compressed Natural Gas Vehicle (NGV) dispenser shear valves and fueling hose emergency breakaway shutoff devices, hereinafter referred to as devices. [It is not applicable to Vehicle Refueling Appliances.] 1.1.2 Devices covered by this standard are intended to: 1. (a) Minimize the escape of natural gas by automatically shutting off the flow of gas from the dispenser and control the depressurization of the hose, and; (b) Minimize damage to the vehicle and dispenser when a vehicle is driven off with the nozzle attached to the vehicle's fueling receptacle. 2. Automatically shut off the flow of gas in the event of a vehicular collision with a fuel dispenser that results in the displacement of the dispenser from its gas supply connection. 1.1.3 All dimensions used in this standard are in metric units [International System of Units (SI)], unless otherwise specified. If a value for a measurement, as given in this standard, is followed by an equivalent value in other units, the fi rst stated is to be regarded as the specification. 1.1.4 All references to pressure throughout this document are to be considered gauge pressures unless otherwise specified.