Pressure relief devices protect against equipment damage, loss of containment and ultimately fuel station shutdowns by prevention of overpressure in natural gas vehicle (NGV) fuel containers. ANSI/CSA PRD 1-2013 - Pressure Relief Devices for Natural Gas Vehicle (NGV) Fuel Containers provides guidelines for safe operation and substantial construction & performance testing for:
· Pressure relief devices (PRD)
· Natural gas vehicle (NGV) fuel containers
· On-board storage of compressed natural gas vehicle operations
Highlights of ANSI / CSA PRD 1-2013 Include:
ANSI/CSA PRD 1-2013 benefits these stakeholders:
· Compressed natural gas (CNG) tank manufacturers
· Pressure relief device manufacturers
· CNG station manufacturers
· Original equipment vehicle manufacturers
· Additional vehicle & station component manufacturers
· Vehicle mechanics and conversion shops
Major additions to this second-edition standard include:
· Pressure & temperature tolerances
· Resistance to automotive fluid exposure
· Ultraviolet resistance of external surfaces
· Impact due to drop test
· Ozone and oxygen aging
· Accelerated life test
· Accelerated cyclic corrosion test
· High pressure activation and flow rate
· Component literature
This publication represents a standard for safe operation, substantial and durable construction and performance testing of pressure relief devices (PRD) for natural gas vehicle (NGV) fuel containers, for the on-board storage of compressed natural gas for vehicle operation within limitations given below and in the scope of this standard.
This standard is based on proven engineering principles, research and the combined expertise of gas utilities, manufacturers, users, and others having specialized experience.
Nothing in this standard is to be considered in any way as indicating a measure of quality beyond compliance with the provisions it contains. It is designed to allow compliance of products which may exceed that specified in the provisions herein. In its preparation, full recognition has been given to possibilities of improvement through ingenuity of design. This standard is subject to revision as further experience and investigation may show it is necessary and desirable.
This standard does not apply to fuel system components that will be incorporated during original manufacture of motor vehicles which comply with Federal Motor Vehicle Safety Standards (FMVSS) or Canadian Motor Vehicle Safety Standards (CMVSS) for Natural Gas Powered Vehicles.
This standard establishes minimum requirements for pressure relief devices intended for use on fuel containers that comply with ANSI/CSA NGV2, Compressed Natural Gas Vehicle (NGV) Fuel Containers, FMVSS 304, Federal Motor Vehicle Safety Standards, 49 CFR Part 571.304, Compressed Natural Gas Fuel Container Integrity, CSA B51, Part 2, High Pressure Cylinders for On-Board Storage of Natural Gas as a Fuel for Automotive Vehicles and/or ISO 11439 Gas Cylinders - High Pressure Cylinders for the Onboard Storage of Natural Gas as a Fuel for Automotive Vehicles.
Pressure relief devices may be of any design or manufacturing method that meets the requirements of this standard.
The construction of pressure relief devices, whether specifically covered in this standard or not, shall be in accordance with reasonable concepts of safety, performance and durability.
This standard does not apply to reseating or resealing devices.
Pressure relief devices designed to comply with this standard are expected to be used with natural gas fuel containing no more than two percent hydrogen by volume.
Resistance to chloride stress corrosion cracking shall be taken under consideration if selecting stainless steel materials. Resistance to stress corrosion cracking and sustained load cracking shall be taken under consideration if selecting aluminum materials. Resistance to sulfide stress cracking shall be taken under consideration if selecting steel materials.