What device is recommended to prevent over-pressurization when conducting a tank air test?

The recommended device to prevent over-pressurization during a tank air test is a pressure release device. This device serves a critical function by allowing excess pressure to escape, thereby maintaining the tank's integrity and safety during testing. When a tank is subjected to air pressure for testing purposes, there is always a risk that pressure could build up beyond safe levels due to either the expansion of air or an inability to adequately vent.

A pressure release device is specifically designed to open when a predetermined pressure threshold is reached, thereby preventing potential damage to the tank or related equipment and reducing the risk of accidental injuries or spills. This makes it an essential component for ensuring a safe testing environment.

In comparison, a vacuum gauge measures the pressure in a tank when it is under vacuum conditions, but it does not prevent over-pressurization. A flow meter is used to measure the flow of liquids or gases, but it does not regulate pressure. A temperature sensor provides information about the temperature inside the tank, which could influence gas pressure but does not directly prevent over-pressurization. Thus, the pressure release device is the specific equipment needed to ensure safety during tank air testing procedures.