Hydraulic testing of a dry system _________

• A. requires the dry pipe valve clapper to be latch open or completely removed during test.
• B. requires the valve to remain closed during test
• C. requires the valve to be throttled manually
• D. requires the valve to be locked in place

Answer: (A)

During hydraulic testing of a dry system, the dry pipe valve clapper must be latch-open or removed so water can enter the dry piping and fill the system for the test. The clapper normally holds back water with air pressure, but for the test you need unobstructed water flow into the pipes to pressurize and inspect them for leaks. If the valve stayed closed, or was only throttled or locked in place, water wouldn’t fill the system properly, and the test wouldn’t accurately verify the system’s integrity.