Where should ASME connections for pressure relief valves be installed?

The correct choice indicates that ASME connections for pressure relief valves should be installed with direct communication with the vapor space. This is crucial for the effective operation of pressure relief devices. In the event of an increase in pressure, the relief valve needs to access the vapor space to function properly.

When installed this way, the pressure relief valve can quickly respond to any build-up of pressure within the system, allowing gases to vent safely and preventing dangerous overpressure conditions. If the relief valve were not in direct communication with the vapor space, it could fail to relieve pressure effectively, potentially leading to catastrophic failure or explosion in the system.

The choice to place the connection away from the vapor space would inhibit the valve's ability to monitor and respond to pressure changes effectively, while positioning it only above the liquid level could lead to a risk of liquid backup, which would hinder the valve's functionality. Similarly, placing it in a hidden location could obstruct proper maintenance and inspection, which are vital for safety in propane gas systems.