What is the usual proof-test pressure relative to operating pressure for a flexible hose assembly?

• A. About one times operating pressure.
• B. About two times operating pressure.
• C. About three times the operating pressure.
• D. About half the operating pressure.

Answer: (B)

Proof-test pressure is chosen to push a hose assembly beyond normal use without risking damage, so it’s raised above the service pressure to reveal hidden defects. Using about twice the operating pressure provides a safe, practical margin: it’s high enough to expose leaks, cracks, or weak fittings that wouldn’t show up at normal pressure, but not so high that the hose or its fittings are likely to fail during the test. Testing at the operating pressure wouldn’t stress potential defects enough to reveal problems, and testing at a much higher level could cause damage or rupture. Half the operating pressure wouldn’t challenge the assembly enough to ensure reliability.