What must shutoff valves be capable of withstanding?

Shutoff valves in CNG systems must be capable of withstanding a hydrostatic test of at least four times the rated service pressure. This requirement ensures that the valves can handle significant safety margins and potential overpressure situations without failing. Hydrostatic testing is essential for confirming the integrity and reliability of the valve, as this procedure helps to identify weak points or defects that could lead to leaks or catastrophic failures in real-world operations.

The specification of four times the rated service pressure provides assurance that under normal operating conditions, the valves will function safely and effectively without risk of failure. This is particularly important in high-pressure systems like those found in CNG applications, where maintaining system integrity is vital for safety and operational efficiency.

Other options focus on scenarios that are either less relevant to the structural integrity of the valves or do not reflect the industry standards for testing shutoff valves. For example, while operating temperatures and vacuum conditions are important considerations in the overall design and performance of valves, the specific requirement for hydrostatic pressure testing at four times the rated pressure is critical for ensuring safety in high-pressure systems.