8.1 Annual Partial Trip Test vs. Three-Year Full Flow Trip Test

Purpose and test selection

A dry-valve trip test demonstrates operation of the installed valve arrangement. It is not a substitute for a separate quick-opening-device test, an air-leakage test, or a full hydraulic demand test. NFPA 25 (2023), 13.4.5.2, requires annual trip testing in warm weather. A full-flow trip test is required at least every three years and when the applicable alteration provision requires it. In intervening years, the permitted partial-flow method limits the amount of water introduced. Follow the actual valve instructions; a universal number of handwheel turns is not an adequate procedure for every control valve.

Before either test, obtain the system records, identify the listed valve and accessories, review the original acceptance results, and coordinate the impairment. Confirm that the outlet, drainage, staffing, and weather allow safe completion and restoration. The temporary loss of protection must be managed even when the test is expected to take only a few minutes. Notify the owner, monitoring service, and other required parties through the agreed process. Prevent unwanted dispatch without disabling unrelated protection.

Partial-flow test

The partial-flow method checks that the valve will operate while limiting water entry into downstream dry piping. Establish the manufacturer's specified control-valve position and drain arrangement, record the initial air and water pressures, and initiate the prescribed trip. Observe the trip pressure and time, close the supply as instructed, and drain and reset the arrangement. Do not improvise by removing a cover under pressure, manually forcing a clapper, or using a QOD connection that is not intended for the selected test.

The operating pressure comes from the actual valve instructions and approved arrangement. An ideal pressure-area ratio can explain why a differential valve holds back water, but it does not establish a universal operating pressure of “trip pressure plus 15 to 20 psi.” Mechanical differential designs, low-pressure valves, and latching arrangements differ. Record the specified normal pressure and observed trip pressure rather than substituting a textbook ratio for the manufacturer's data.

Full-flow test

For the full-flow test, leave the system supply control valve fully open and use the appropriate inspector's test connection. Test the complete operating arrangement, including the QOD where installed, under the required procedure. Record initial water and gas pressures, valve trip pressure, trip time, and water delivery time. The timing origin is the full opening of the test connection, not the later instant when the valve trips. Identify the exact connection and test configuration so future results are comparable.

Trip time ends when the valve operates. Total water delivery time continues until water reaches the test outlet under the prescribed observation method. These measure different parts of the response. A valve that trips quickly can still have slow delivery because of excess air pressure, an inoperative QOD, restrictions, or changes in the piping arrangement. Record the actual events rather than labeling both values “trip time.”

Evaluate the result against the right basis

Do not apply a universal 60-second maximum to every existing dry system. Approved installation criteria, hazard, design method, test arrangement, and original acceptance data matter. Compare equivalent test conditions. An apparent increase can reflect a different starting gas pressure or a changed outlet as well as a real equipment problem. Investigate the reason; an inspector must not prescribe a new accelerator or divide a system solely from an unsupported time shortcut.

Chapter 14 adds a specific obstruction-investigation trigger: a 25% increase in total water delivery time, or five seconds for dwelling-unit portions, compared with the original acceptance result at normal system gas pressure. For example, an original 48-second result and a current 61-second result represent an increase of 13/48, or about 27.1%, which reaches that trigger. This is not the same as declaring 61 seconds an automatic installation-code failure for every system.

Reset and prove restoration

Drain the system and all applicable low points. Isolate and depressurize before opening the valve. Inspect and clean the actual parts as directed, replace damaged components, and use only manufacturer-approved cleaning materials and lubricants. Not every elastomer has identical compatibility, and not every valve uses the same latch or priming arrangement. Reassemble with the specified gasket and fastening procedure, establish required priming water and gas pressure, and restore the water supply slowly as directed.

Keep intermediate-chamber automatic drains functional; never plug a leaking drain to hide a seat problem. Check for leakage, return QOD isolation valves and the normal air-supply path to service, and secure the system control valve in its prescribed position. Verify the valve-status test, alarms, and monitoring restoration as applicable. Record remaining deficiencies and do not remove impairment controls until protection is restored. Continued auxiliary drainage may be needed after a full-flow test as residual water reaches low points.

Source checked October 19, 2026: NFPA 25 (2023), 13.4.5.2, Chapter 14, and Chapter 15; use the installed valve manufacturer's procedure.