Which valves should not be used for primary shutoff in CNG systems?

Choosing valves for primary shutoff in CNG systems is critical for safety and reliability. Valves of cast iron that do not conform to specific standards are not suitable for primary shutoff because they may not provide the necessary strength and integrity required to handle high-pressure applications. Using standardized materials and products ensures that the valves can withstand the pressures and conditions specific to compressed natural gas systems, minimizing the risk of leaks or failures that could lead to hazardous situations.

Valves compliant with ASTM standards are tested for safety and performance, which makes them a reliable choice. Valves made from aluminum can offer weight-saving benefits and corrosion resistance, making them suitable for certain applications. Valves that can be easily disassembled may have uses in maintenance scenarios, but they need to be designed properly to maintain integrity under pressure. However, if they are not standardized for shutoff capabilities, it poses a risk. Thus, the correct identification of unsuitable valves helps maintain system safety, particularly when dealing with highly pressurized gases.