Many jurisdictions have adopted NFPA 25, Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, to help ensure that sprinkler systems are properly inspected and maintained. Many property insurance companies often require that this standard be used for sprinkler systems as well. However, this standard is not often fully understood. First of all, if an annual inspection of your sprinkler system is all that is required, then this standard is not fully being used. This standard requires many inspections and tests on a more frequent basis. In fact, a majority of sprinkler systems and private water supplies require more frequent tests. A very small sample of these tests is covered in this article. Additionally, it is often not known what should be recorded or how to tell when there is an issue. Items that are often missed during these tests and inspections along with how to tell when you have some common problems will be discussed in this article.
Fire pump churn tests – no flow tests – are often not fully understood. First of all, diesel driven pumps should be churn tested for at least 30 min. on a weekly basis. Electrically driven pumps should be churn tested for at least 10 min. However, the frequency for this pump type has been changed in recent editions of NFPA 25. Previous to the 2011 Edition, electric pumps needed to be churn tested weekly, the 2011 Edition relaxed this to a monthly basis. This frequency change was debated and testing frequencies were compared with failure rates. Thus, the 2014 Edition of NFPA 25 is modified to allow electric pumps to be churn tested monthly except in certain conditions – such as: in buildings that are taller than the pumping capacity of the fire department, vertical turbine pumps, pumps with limited service controllers, and pumps that take suction from a water supply that does not have sufficient pressure to be of material value without the pump.
These pumps should be started by flowing water – preferably opening a 2 in. main drain. This will test that pump will automatically start – pushing the start button does not test this aspect of the pump controls. Additionally, the start pressure along with the suction and discharge pressures should be documented. These pressures should be compared to previous test results and the performance curve for the pump. If the net pressure (discharge pressure minus the suction pressure) is more than 5% below the rated pressure (or 95% of the rated pressure), then there is likely an issue with the pump that needs to be investigated.
Additionally, pump bearings and packings should be checked to ensure that they are not overheating. The bearings can be lubricated and the packings can be loosened if they are too tight and overheating or they can be tightened if too much water is flowing past the packings such that a rooster tail of water is generated. A constant dripping of water should be coming from packings that are adjusted properly. Diesel fuel tanks should never be less than 2/3 full to ensure that the pump will run the expected duration of a fire.
Also, these pumps should be fully flow tested annually. This should include a churn test, flow at 100%, and flow at 150% of the rated flow. In locations that have limited water supplies or supplies that have diminished, then low city water pressures could be observed during the 150% flow. While NPFA allows for the suction pressure to drop to 0 psi, some jurisdictions limit the minimum suction pressures. The most common number used is 20 psi. If the 150% flow point cannot be achieved, then the pump(s) should have enough flow to provide for the most demanding sprinkler systems at your facility. If this cannot be achieved, then a secondary water supply may be necessary.
The 2 in. main drains should be flow tested annually or anytime after a fire protection control valve is closed and reopened. These pressures should also be documented. The pressures of each test should be compared to previous tests and the acceptance test. A reduction of more than 10% from previous tests should be investigated. Corrections may be necessary if the available water has dropped below that needed for the sprinkler systems at your facility.
The time that it takes to receive a sprinkler waterflow alarm should also be documented during quarterly and semi-annual tests. This too should be compared with previous tests to determine if there are any gross differences in the amount of time that it takes to receive an alarm. Slight changes are acceptable, but any large changes should be investigated.
Fire protection control valves should be readily accessible for normal inspection and testing as well as if they need to be accessed in the event of a fire or even a sprinkler system leak. A sprinkler system impairment notification system should be used any time a fire protection system is impaired. This includes, but is not limited to: taking proper precautions, notifying the proper authorities, and the use of impairment tags. Also, sprinkler system design placards should be provided for each sprinkler system that lists the design of the sprinkler system along with the water demands for these systems.
Records for inspection, maintenance, and testing should be kept on file by the building owner and/or tenant for no less than 1 yr. Again, this article covers a few items from NFPA 25 that often are not fully documented and some ways to help ensure that your system is operating properly. The intent of this article is not to cover all aspects of NFPA 25. If you have any questions about testing and inspecting your fire protection system, please contact Risk Logic.