FDNY Operating Engineer Practice Test 2026 – Complete Exam Preparation

To convert gauge pressure (PSIG) from absolute pressure (PSIA), it is essential to recognize that PSIA includes atmospheric pressure, whereas PSIG measures pressure relative to atmospheric pressure. Standard atmospheric pressure is approximately 14.7 PSI. Therefore, by subtracting the atmospheric pressure from the absolute pressure, we accurately determine the gauge pressure.

In this case, subtracting 14.7 from 26 PSIA gives us the PSIG value. The calculation goes as follows: 26 PSIA - 14.7 PSI equals 11.3 PSIG. This result indicates the pressure above atmospheric pressure, which is what PSIG represents. So, this option provides the correct method for converting PSIA to PSIG, demonstrating an understanding of the relationship between absolute and gauge pressure in a practical context.