In accordance with 2014 NFPA 25: Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, diesel fire pumps must go through not only an annual flow test, but also a weekly churn test (sometimes called a no-flow test or an operating test).
The standard procedure for a weekly test on a diesel fire pump is as follows:
INSPECTION:
Before any testing, follow the attached checklist to ensure the conditions are correct and the pump is ready to be tested.
TESTING:
- Use a fire pump churn test log to verify steps completed (see link.)
- Notify your alarm company and facility representatives of the pending churn test.
- Review the fire pump assembly nameplates, noting the voltage rating, rated speed, and churn pressure for the unit.
- Record the suction and discharge pressures. Record the current pressure reading as well as the highest and lowest pressures indicated on the fire pump controller event log. If these values are outside of the expected range, a record of the entire event log must be made and further investigation must be conducted, with corrective action being taken.
- Check the area surrounding the relief valve or cooling water discharge outlets to ensure there are no apparent conditions that would stop water from being discharged safely or cause direct damage to the area. If the discharge area is subject to potential freezing conditions, the facility representative should be advised.
- To limit the exposure of the connected systems to the surge or pressure during the start-up of the pump, consider closing discharge control valve prior to conducting the test.
- Simulate an automatic start for the fire pump by creating a pressure drop in the sensing line to the fire pump controller. This can be accomplished by slowly opening the drain valve on the sensing line located near the fire pump controller until the fire pump starts automatically. Do not use the “start” button when simulating an automatic start. Note the start time of the fire pump to measure the run time and record the starting pressure.
For pressure-actuated fire pump controllers that use an automatic timer, an automatic opening of a solenoid valve in the sensing line to the controller might be used to simulate the automatic start of the fire pump. These systems must include a record of the pressure drop on the pressure recorder for the controller.
- Observe the amount of time required for the diesel engine to crank. Any delays in starting the engine should be investigated and corrective action should be taken. Typically, the controller will attempt three 15-second crank cycles before registering a failure-to-start trouble condition.
- Check the operating speed of the diesel engine and note the time needed to reach the rated (should be within 20 seconds). The measurement can be taken with a handheld tachometer. Note that the use of a strobe-type handheld tachometer requires advance preparation prior to the test for proper measurement, including the application of a reflective tape on the shaft and/or removal of protective covers that shield the rotating shaft.
- Observe the engine instrument panel to ensure that the engine oil pressure, operating speed, water and oil temperature, and charging rate are within the acceptable range. Check approximately every 5 minutes during the test.
- Check the fire pump packing gland for a slow drip of water, adjusting the packing gland nuts as needed to achieve about 1 drip/second. For safety, the adjustment should be made when the pump is not running. Exercise care to ensure the glands are not tightened to the point of breaking.
- Monitor the fire pump operation for any unusual vibration, noise, or other sign of malfunction.
- For radiator-cooled diesel fire pumps, verify that the operation of the circulation (casing) relief valve has a steady stream of water to ensure proper cooling of the pump case.
- For heat exchanger-cooled diesel fire pumps, verify that the heat exchanger has a proper flow of cooling water.
- If the fire pump is equipped with a main pressure relief valve, verify the operation of the valve such that outlet pressures do not exceed the pressure rating of the piping downstream of the fire pump. Usually, this rating is 175 psi (12.1 bar); however, some systems are designed for higher pressures.
- Record the suction and discharge pressures. Note that for vertical turbine pumps, only the discharge pressure is recorded.
- Record the pressure at the fire pump controller pressure switch or pressure transducer, and compare it with the discharge pressure recorded above.
- Check the packing gland box, shift bearings, and pump casing for overheating about every five minutes during testing. The packing gland box and shaft bearings may be warm to the touch, but the pump casing should remain cool.
- Allow the fire pump to continue operating for 10 minutes, checking for overheating periodically. Shut down manually after 10 minutes have elapsed. Some fire pump controllers might include automatic run timers that shut down the pump after a specific amount of time. For these controllers, check the run time for the fire pump to ensure the required 10 minutes has passed.
- Reopen the fire pump discharge control valve (if closed) and conduct a valve test downstream of the closed valve.
- Inspect and clean any installed intake screens.
- Where the fire pump controller is equipped, replace any pressure recorder charts and rewind as necessary.
- Restore the fire pump to automatic operating position.
- After completing all testing, notify the fire department and/or alarm monitoring company and the facility representative that testing is complete. Reset fire alarm system as necessary. A state certified professional should also be called to correct the deficiency.
Click the link below to download a printable fire pump testing checklist.
Weekly Fire Pump Inspection Checklist
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