What can be used to verify the pressure of an SCBA?

Using a pressure gauge to verify the pressure of a Self-Contained Breathing Apparatus (SCBA) is essential because it provides a direct measurement of the air pressure within the cylinder. Pressure gauges are designed specifically for this purpose and are calibrated to give accurate readings, which are critical for ensuring that the SCBA is functioning properly during firefighting or rescue operations. This verification allows the user to assess if there is enough air supply for the upcoming tasks and is vital for safety, as underestimating the amount of breathable air can lead to life-threatening situations.

The other devices mentioned do not serve the same specific role in verifying SCBA pressure. For instance, a hydrogram tester is generally used for testing the integrity of the SCBA cylinder and may not provide the immediate pressure reading needed. A thermometer measures temperature, which is not relevant to quantifying pressure. Lastly, a pressure relief valve is a safety feature designed to release excess pressure but does not measure or indicate the actual pressure in an SCBA cylinder. Thus, the pressure gauge is the correct tool for this specific need.