Gas Fitter Practice Test

A pressure reading of 14.7 psia is equivalent to?

1. 2.35 in w.c.

2. 14 in w.c.

3. 0 psig (gauge '0' is calibrated to atmosphere)

4. 10 psig

The correct answer is: 0 psig (gauge '0' is calibrated to atmosphere)

A pressure reading of 14.7 psia indicates a pressure of 14.7 pounds per square inch absolute. This is the standard atmospheric pressure at sea level. When discussing gauge pressure, which measures pressure relative to atmospheric pressure, a reading of 0 psig means that the pressure inside the system is the same as atmospheric pressure. In other words, if the gauge is calibrated to read zero at atmospheric pressure, then 14.7 psia would correspond to 0 psig since there is no additional pressure above atmospheric level. This means that at 14.7 psia, the pressure being measured is equivalent to atmospheric pressure, which is the reference point for gauge pressure measurements. The alternative options relate to other specific measurements but do not correctly represent the relationship between absolute pressure and gauge pressure at standard atmospheric conditions. Hence, the interpretation of 14.7 psia as 0 psig is accurate and aligns with the principles of pressure measurement in gas fitting practices.