Hydrostatic testing of all piping including foam concentrate lines and the system piping shall be conducted at which pressure levels?

• A. 200 psi or 50 psi in excess of the maximum static pressure where the minimum static pressure exceeds 150 psi
• B. 100 psi
• C. 300 psi
• D. 75 psi

Answer: (A)

Hydrostatic testing checks that all piping, including foam-concentrate lines, can handle system pressures without leaking. The pressure used for the test is selected to reveal weaknesses while staying within what the system and components can safely endure. If the system’s minimum static pressure is 150 psi or less, the test is conducted at 200 psi. If the minimum static pressure exceeds 150 psi, the test uses the maximum static pressure plus 50 psi. This ensures a sufficient testing head to expose leaks and weaknesses, even under higher service pressures typical of foam systems, without overstressing components. The approach protects the integrity of both the main piping and the foam-concentrate lines under realistic, worst‑case conditions.