How many pressure gauges should be used when pressure testing?

• A. One
• B. Two
• C. Three
• D. Four

Answer: (B)

Two gauges are used because redundancy and cross-checking improve accuracy and safety during pressure testing. With one gauge you’re trusting a single instrument, which could be miscalibrated, stuck, or damaged. Having a second gauge provides a second reading to compare against. If both readings agree and remain steady, you can be confident the test pressure is correct. If they diverge or one drops while the other doesn’t, you can identify a potential gauge fault, leakage, or abnormal pressure change and take action before proceeding. This double-check helps prevent under- or over-pressurizing and makes the test results trustworthy.