April 23, 2021
NFPA 25, Standard for Testing & Maintenance for Water-Based Fire Protection Systems calls for an annual flow test by a qualified sprinkler contractor.
The test will provide a static and residual pressure reading. The test is conducted by opening the main drain for the sprinkler system to flow water. The static reading on the system pressure gauge is before the flow is started. The residual reading is while water is flowing. There will be a drop in pressure with water flowing.
It is a very important component for an effective fire sprinkler defense of the building. Without enough water available to suppress a fire that activates one or two sprinkler heads, the fire can expand and quickly overwhelm the sprinkler system resulting in a possible complete loss.