During pressure testing, which pressure value should be used from the listed options?

• A. Highest
• B. Lowest
• C. Average
• D. Median

Answer: (B)

When performing a pressure test, the reference pressure you use is the lowest permissible test pressure. Starting at the lowest level provides a conservative baseline to confirm the joint or weld seals properly without risking damage from higher stresses. If no leaks are found at that initial, lower pressure, you typically step up to the higher levels per the procedure, but you always begin with the lowest value to verify integrity safely. Using the highest pressure would introduce unnecessary risk, and average or median values do not define the actual test condition or safety limit—they’re statistical summaries, not the pressure used to validate the joint.