Can a Shut-off Valve be installed Upstream of a Relief Valve to allow for the removal of the Relief Valve for servicing without having to empty the contents of a tank?

The correct answer is that a shut-off valve should not be installed upstream of a relief valve. A relief valve is a critical safety component that is designed to prevent pressure build-up in a system by allowing excess pressure to escape. Installing a shut-off valve upstream of a relief valve creates a situation where the relief valve can be isolated from the system. This isolation eliminates the valve's ability to function as intended, potentially leading to dangerous conditions where the pressure in the system could exceed safe operating limits.

For proper safety practices and compliance with standards, the relief valve needs to be directly connected to the system that it is designed to protect without being obstructed by any shut-off valves. Therefore, if you were to remove the relief valve for servicing, the entire system would need to be emptied to ensure safe conditions, rather than relying on a shut-off valve, which could compromise safety.

In essence, safety regulations and engineering principles dictate that relief valves must remain freely connected to their respective gas systems to effectively mitigate risks associated with overpressure situations.