What do pressure test gauges measure in a gas system?

Pressure test gauges are specifically designed to measure the pressure of the gas within a system. This measurement is crucial for ensuring that the gas system operates within safe and efficient pressure levels, as both under-pressure and over-pressure situations can lead to system failures and potential hazards. Accurate pressure readings allow technicians to diagnose issues, perform maintenance, and make necessary adjustments to keep the system functioning correctly.

The other options—temperature, flow rate, and quality—are related to gas properties but do not pertain to the primary function of pressure test gauges. Temperature gauges are used to measure heat levels, flow meters assess the volume of gas flowing through the system, and quality measurements pertain to the composition or condition of the gas rather than its pressure. Therefore, the focus of pressure test gauges on measuring pressure makes the correct answer clear.