What should be done before disconnecting any gauges or test fittings on a tank?

Before disconnecting any gauges or test fittings on a tank, it is essential to release pressure in the tank. This step is crucial to ensure safety and to prevent any hazardous situations that could arise from sudden releases of pressure. When the pressure is not properly managed, disconnecting gauges or fittings may result in the sudden expulsion of fuel vapors or liquids, leading to potential injuries or accidents.

By releasing the pressure, you reduce the risk of explosive or dangerous reactions, as well as protect the integrity of both the tank and the equipment involved. This practice aligns with safety protocols and guidelines for working with tanks, ensuring that technicians can perform their tasks without unnecessary risks.