If you are a building owner or facilities manager and you have a sprinkler system being supplied by a fire pump, it is your legal responsibility to maintain your equipment and keep it in proper working order. If you don’t have the expertise or time to do this, you need to hire someone qualified who can. But putting legal responsibility aside — it is a good thing to do anyway, considering the undeniable importance of the equipment. In the disastrous and unfortunate event of a fire, your sprinkler system can save property and lives — assuming, of course, that it is in working order!
In past articles we have discussed pump testing as far as flowing water is concerned — which is mainly done yearly, and involves measuring flow at specific points on a pump’s performance curve. This is intended to keep a check on the pump’s hydraulic performance, as well as the adequacy of the existing water supply feeding the pump. But you don’t need to always flow water to keep an eye on things.
In between yearly tests, your equipment sits in the ‘off’ position. Many problems are invisible when pumps and controllers are sitting in a mechanical room and not running. Through simply running your equipment as part of a weekly test, many of the potentially serious problems can be discovered and addressed immediately.
The specific testing requirements and frequencies are thoroughly covered in NFPA 25, and we will not go into detail of what is covered there, but we will discuss in general the reasons we recommend performing proper testing and maintenance on your equipment. As with the operation of any industrial equipment please follow all safety precautions, follow manufacturer operating instructions, and make sure you wear protective gear.
Most fire pumps are either electric motor-driven, or diesel engine-driven, and the type and frequency of testing will vary depending on what you have in your building. For electric motor-driven fire pumps, we recommend at least running your equipment once a week for at least ten (10) minutes for a visual inspection. You do not need to flow and measure water during this test — just witness the equipment running and have someone qualified present to address any problems that may arise. Some may point out that NFPA 25 allows for monthly testing in some circumstances, but we will always recommend a simple weekly test due to the importance of the equipment. When running your pump weekly, keep an eye out for the following:
- Make sure the fire pump starts automatically by simulating a pressure drop in the system. If your pressure switch or transducer is not working properly, now is the time to know about it.
- Keep the packing drip under control. While running, you can expect water flow through the packing boxes of the pump, but not a large splash of water. Control as necessary by adjusting the packing glands a quarter turn to keep the water flow low but constant. Once the equipment is stopped, packing leakage should be approximately one (1) drip per second. Do not tighten to the point of zero drip! Doing so will dry out the packing and make it less effective, which will then require more tightening, cause damage to the shaft sleeve and shorten packing life.
- Make sure the casing relief valve (also known as a circulation relief valve) is flowing enough water to keep the casing from overheating, and is shutting off when the pump is turned off. The water flow should be warm to the touch, but not too hot. Some adjustment may be necessary.
- Verify that the packing drip drains are working properly and are not clogged with sediment or debris.
- Record your test in a log as a record of your test. This will keep you on schedule and provide some very useful information for your insurance company if required.
For diesel-driven fire pumps (we are assuming standard water-cooled engines here), you are required to run the equipment weekly, mainly to keep the engine’s running more smoothly by heating up the engine block, and to use some of its fuel. Diesel fuel can begin to degrade over time, and it’s best to avoid the situation where your diesel-driven engine is being fed by old fuel. Ideally, you want to use the fuel before it reaches more than two years of age.
Like the electric pump, the above items need to be checked, but for #3 above, the casing relief valve on a diesel is replaced by a water cooling loop. It is important to make sure that water is passing through this loop, because not only is this water keeping the pump casing cool, but it is also keeping the internal engine cooling loop cool. Keep the flows within the range recommended by the engine and pump manufacturer. Here are some additional points to watch:
- With diesel fire pumps, you are required to run them for at least 30 minutes each week.
- Keep the strainers clean on the water cooling loop. After running the engine, visually inspect the strainer on the cooling loop and keep clean. A dirty strainer affects water flow!
- Make sure the engine exhaust and room ventilation are working properly.
- Verify that the batteries are working properly.
- Verify that an “engine running” signal is sent to a monitoring point if the fire pump is in a room that is not constantly attended. If the engine ever starts, you want someone to know about it immediately.
By running this equipment weekly and recording the results in a written log, you are preventing a hidden deficiency from becoming a tragic catastrophe. Most other machinery in our world is operated constantly, and any problems are noticed more quickly. With fire pumps, however, the equipment has the disadvantage of sitting alone in a distant room and being in the ‘off’ position. The only way to keep up on the condition of your fire pump equipment is by turning it on and witnessing its operation in a regularly scheduled timeframe. That is precisely the reasoning behind NFPA 25.
As always, if you’d like to learn more, or have additional questions, feel free to reply to this post, call us at the contact number below, or use our service or info request page.