scope:

PREFACE

This standard is being developed for agencies in North America to use for examination, testing and certification of compressed Natural Gas Vehicle (NGV) fueling nozzles and receptacles only. As such, the scope refers to nozzles and receptacles used in the NGV fueling system and not to the system. The American Gas Association (A.G.A.) Requirements for Natural Gas Refueling Connection Devices (No. 1-90) and Canadian Gas Association Certification Requirement for NGV Nozzles and Receptacles (Draft CR 90-005) provided the basis for this standard.

A nozzle certified to this standard will be functionally compatible from a safety and performance perspective with all listed receptacles of Compatible profile and system pressure. Similarly, a receptacle certified to this standard will be functionally compatible from a safety and performance perspective with all listed nozzles of compatible profile and system pressure.

Whereas there may ultimately be a multitude of nozzles and receptacles by a host of manufacturers, all of which for safety reasons must be compatible with each other, a series of "standard" receptacle profiles have been specified. These standard profiles incorporate the mandated design specifications (mating materials, geometry and tolerances) which must be utilized in the certification of a submitted nozzle or receptacle. The design shall be unique and not currently in commercial use and shall only be used for compressed natural gas.

The construction and performance of nozzles and receptacles are based on the observation that three main parameters affect user safety and system compatibility.

1. Service Pressure. Currently, three vehicle system service pressures may be operated in North America; 16,500 kPa (2400 psi), 20,700 kPa (3000 psi) and 24,800 kPa (3600 psi). Consequently, the nozzle and receptacle must be designed in a manner which will prevent a vehicle from being fueled by a dispenser station with a service pressure higher than the vehicle. However, it is desirable that a vehicle can be fueled by a dispenser station with a service pressure lower than the vehicle. This issue is addressed in the geometry of the nozzle and receptacle. All nozzles and receptacles shall be designed to have a service pressure of either 16,500 kPa (2400 psi), 20,700 kPa (3000 psi) or 24,800 kPa (3600 psi), as applicable.

2. Disconnect Venting. Nozzles transferring fuel under high pressure must be fully and safely depressurized prior to being disconnected fiom the receptacle. This standard addresses three types of nozzles, described as follows:

Type 1 Nozzle - With a Type 1 Nozzle, the vent valve operating mechanism is integral to the nozzle. The term "integral" means that a single operation of a lever or operating mechanism first safely vents the gas trapped between the receptacle check valve and the nozzle inlet valve, and then safely disconnects the nozzle from the receptacle. This type node is primarily intended but not restricted to use at public fill stations.

Type 2 Nozzle - With a Type 2 Nozzle, the vent valve operating mechanism is external to the nozzle. Venting is required prior to disconnection of this type of nozzle. This type nozzle is primarily intended but not restricted to use in fleet vehicle applications.

Type 3 Nozzle - With a Type 3 Nozzle, the fueling hose is automatically depressurized [typically below 340 kPa (50 psi)] at dispenser shutdown. The nozzle may vent low pressure gas between the receptacle check valve and the nozzle inlet valve coincident with the disconnection of the nozzle. This type nozzle is primarily intended for residential and fleet applications.

3. Design Life. Frequency of use is the final parameter to be considered. Since frequency of use will differ with the nozzle/receptacle application (i.e., public sector, fleet employee and residential), all receptacles will be tested at 10,000 connect/disconnect cycles for compliance with this standard. In addition, all nozzles shall be tested according to the following frequency use classifications, as applicable:

Class A Nozzle - This class specifies high frequency use, with a cycle life of 100,000. This equates to approximately 100 fills per day for 3 years.

Class B Nozzle - This class specifies medium frequency use, with a cycle life of 20,000 cycles. This equates to approximately 10 fills per day for 5 years.