Fire Pump Tests

Fire Pump Testing (NFPA25 and NFPA20)

NFPA 25 currently requires annual performance testing of fire pumps. In a performance test water is discharged and the net performance of the fire pump is analyzed through a minimum of three flow points. NFPA 25 also requires non-flow testing of fire pumps, were the fire pump is started and run for a time interval under churn conditions. Currently weekly non-flow tests are required for diesel fire pumps and monthly non-flow tests are required for electric fire pumps. The non-flow test frequency remains an item that is debated during every NFPA 25 code cycle. NFPA 25 contains the testing requirements after acceptance. Two different types of fire pump test are required: Performance Tests, and Non-flow tests. In the 2007 edition of NFPA 25 Non-flow fire pump tests were required weekly for both electric motor and diesel engine drive fire pumps. In the 2011 edition of NFPA 25, the required test frequency for electric motor drive fire pumps was reduced to monthly.  NFPA 20 contains the requirements for acceptance testing of fire pumps.

NON-FLOW TESTS

Although NFPA 25 requires qualified personnel present at all pump tests, non-flow test can be conducted automatically by new fire pump controllers. If the pump starts automatically from a pressure drop, and completes the required run cycle, it would pass, even if no one was there to observe the pump performance.

Non Flow tests are required primarily to verify if the pump will start and run without any apparent problems. Data for these tests can be on a paper check list and require visual observation but no analysis. The data collected could be limited to the date tested, or there might be a list of items that were visually inspected. In a non-flow test the pump operates at churn for a minimum time of 10 minutes for electric motor pumps and 30 minutes for diesel engine fire pumps.

The only water discharged is a small quantity through the circulation relief valve in order to keep the pump from overheating. NFPA 25 currently requires non-flow test to be conducted weekly for diesel engine fire pumps and monthly for electric motor fire pumps

PERFORMANCE TESTS

The annual fire pump performance test is also an opportunity to determine if there are any problems with the fire pump water supply, such as shut or partially shut valves or obstructions from the water supply to the pump. If the test is conducted with a flow meter, it usually will not be possible to identify problems with the fire pump water supply NFPA 20 requires a performance test before pump acceptance.

NFPA 25 requires a yearly performance test in which performance readings are recorded at Churn pressure - no flow, 100% of rated flow, and 150% of rated flow. Annual flow testing is typically performed by qualified personnel who have a better understanding of the fire pump operation.

Acceptable test results can be up to 5% below the above figures due to possible experimental error. Test results worse than 5% below the next figures (by NFPA20) should be investigated and corrected.

FIELD ACCEPTANCE TESTS PROCEDURE

This activity evaluates the pump performance over a range condition to ensure the pump will perform as needed during an any emergency.

First, make a visual check of the fire pump package. Verify the proper setting of pressure switches and circuit breakers.  Check for signs of overheating and excessive vibration. If hose and nozzles are used, ensure they are securely tied down. Ensure the hose valves are closed. If a flow meter is used, verify the valve on the discharge side of the meter is closed. Verify the pressure in the mains is normal (i.e., jockey pump pressure) to prevent water hammer.

After starting the pump, verify that the relief valve (if provided) is not flowing water, and then partially open one or two hose valves, or slightly open the meter discharge valve. Check the general operation of the pump and driver. Watch for vibration, leaks (oil or water), unusual noises, and general operation; confirm slight water flow from packing glands.

If a test valve header is used, regulate the discharge by means of the hose valves and selection of the nozzle tips. The play pipe has a removable 1 1⁄8-in. (28.6 mm) tip and, when the tip is removed, the play pipe has a 1 3⁄4-in. (44.4 mm) nozzle.  When a test meter is used, regulate the discharge valve to achieve various flow readings

Test the fire pump over its entire range of flow (0 to 150% of the rated capacity) by controlling the quantity of water discharged. Start at low flow and gradually increase it; starting the pump with hoses open can cause cavitation. Important test points are at churn (no flow), rated capacity, and 150% of rated capacity. Two intermediate points should be taken to help develop the performance curve.

Record the following data at each test point: (a) Pump rpm  (b) Suction pressure (c) Discharge pressure  (d)  Number and size of hose nozzles, pitot pressure for each nozzle, and total gpm (L/min). For flow meter, record gpm (L/min) (e) Amperes and volts (for electric motors drivers)

Analyze the data with the pump manufacturer submittal.

Throughout the course of testing, start the pump 6 times manually and 6 times automatically to verify prompt and smooth start-up at the required pressures or flow. For electric motors, allow at least 5 minutes at full speed after each start-up to allow motor windings to cool properly. For electric motors > 200hp (150kW), no more than 2 starts in 10 to 12 hours should be attempted, and a running interval of at least 15 minutes at full speed should be allowed.

For a diesel engine run the pump for at least 1 hour to verify smooth operation without coupling failure or overheating. Check this by discharging at the 150% point, allowing the engine temperature to stabilize, and then run the pump for an additional 15 minutes.

After the test, verify pressure in fire service mains is up to normal or up to jockey pump pressure before the pump is returned to automatic service to prevent water hammer. Verify all fire protection equipment is returned to the automatic mode and fire protection control valves fully open. Only the valve to the test header should remain closed