NFPA 25 Inspection, Testing, and Maintenance
Frequencies
NFPA 25 is an ITM standard, not a design standard. Gauges are replaced every five years; main drains are flowed annually; waterflow alarms are tested quarterly; dry valves are trip-tested annually; fire pumps are flow-tested annually and run weekly (no-flow) where required; internal pipe inspections occur every five years. Sprinkler spare heads and wrenches are checked annually.
What to record
Record static and residual pressures, flow rates, valve positions, alarm times, pump suction and discharge pressures, and deficiencies with corrective actions. A main drain test compares static pressure before and residual during flow; a significant drop can indicate a main obstruction or a partially closed valve.
Worked example
A wet system has 70 psi static. The 2-in. main drain is opened and the residual reads 50 psi, with a full-flow sight glass. The 20-psi drop is compared with the original baseline. If the baseline was 12 psi, the larger drop suggests a supply restriction and requires investigation before the annual test is signed off.
Traps
Treating ITM as a one-time inspection; skipping the five-year internal; testing a dry valve without resetting it; and recording only “passed” without pressures and flows.