What is the minimum hydrostatic test pressure specified for these systems?

• A. 150 PSI
• B. 250 PSI
• C. 200 PSI
• D. 300 PSI

Answer: (C)

When sprinkler piping is installed, a hydrostatic test is performed to prove the system can hold pressure without leaks or failures. Water is pumped into the piping and the pressure is raised above the normal operating level so joints, fittings, and walls are stressed enough to reveal weaknesses. The minimum hydrostatic test pressure specified for these systems is 200 psi because it provides a solid margin over typical design working pressures (which are usually around 150–180 psi). This ensures leaks or deficiencies show up during testing. Higher pressures, like 250 or 300 psi, may be required for certain high-pressure designs, but they aren’t the minimum. A test pressure of 150 psi would generally be too low to reliably detect issues in many systems.