What is explicitly prohibited for pressure relief valves used in CNG service?

Fitting pressure relief valves with lifting devices is explicitly prohibited for CNG service because it can compromise the function of the valve. Pressure relief valves are designed to automatically open and relieve pressure when it exceeds a certain limit, ensuring safety by preventing overpressure in gas storage and delivery systems.

Adding a lifting device could allow for manual intervention, thereby potentially overriding the automatic safety mechanism that is crucial for safe operation. This setup would increase the risk of pressure build-up and possible failure of the containment system, leading to hazardous situations.

In contrast, pressure regulation, multiple activation points, and connection to backup systems have valid applications within CNG systems, as they can enhance the overall functionality and safety when implemented correctly and within regulatory standards. These practices ensure proper pressure management and system reliability while maintaining appropriate safety protocols.