#117 - Winter Preparation for Fire Sprinkler Systems
by Will Strickler
It’s that time of year again, as winter preparation has started for those who maintain fire sprinkler systems exposed to winter’s cold temperatures. Even if you only see one day a year at or below 32 degrees Fahrenheit, winter preparation should be on your current to do list. There are crucial tasks that not only keep systems from having a freeze up, but also extend the life of the system. Therefore, it is important to be proactive for your company and /or customers, as they depend on the system to stay in working order and in good condition. The winter months can be some of the busiest times for a fire sprinkler contractor, so if we can take care of our customers properly, not only do we cut costs for them, but we have more free time to take on emergency calls and gain new customers.
As stated in NFPA 25, trip testing the deluge and dry pipe systems earlier in the season, when the weather is warmer, helps to ensure that we get all the excess water out of the piping. It is important to hit all the low points, after the trip test and several times thereafter, in order to get all remaining water out of the system. It can take several rounds of draining drum drips and low points before all the water is removed. While completing these tasks it is also a good idea to inspect the heating situation in the valve room with the onset of freezing temperatures.
Likewise, the following are standpipe systems to remember during winter prep: Dry, Semiautomatic Dry and Manual Dry Standpipes. These standpipes should be treated just like a dry system when preparing for the onset of colder temperatures. A dry standpipe is basically a dry system with hose valves instead of sprinkler heads. A semiautomatic dry standpipe is the same as a pre-action system with hose valves. Another standpipe that may not come to mind is the manual dry standpipe since there is no connection to a water source other than the fire department connection; however, if the fire department ever charges the system for use in firefighting operations, you have a chance for trapped water in low points and other drains that will need draining to prevent freezing. Standpipes need to be drained and prepared for the winter just like any other system, so let’s not forget them! Furthermore, make sure to check the hot boxes for back flows and heating systems in pump houses, as those should also be inspected before the winter months arrive. Often these fixtures will be noticed when inspecting and testing low temperature alarms, so be aware.
Winter maintenance on these systems can have a positive twofold outcome. Not only is it important to prepare the systems to keep them from freezing by removing any leftover water, but this practice also helps with preventing corrosion. Corrosion can be detrimental to the life and operation of a system. Changing sections of pipe every year due to pinhole leaks is not something you want to have to explain to your customer, as with proper maintenance the issue of corrosion can be avoided. I personally have seen two parking decks that need at least several full lengths of pipe replaced every year due to corrosion caused by lack of drainage. With precautionary upkeep this problem would be much less likely. Therefore, it is important to keep up with routine maintenance on these systems.
Remember, any time you can be proactive and prevent damage to a sprinkler system, do it! Setting up a good preventative maintenance program can be beneficial to you and your customer!
NFPA 25 2017
184.108.40.206.2* Auxiliary drains in dry pipe sprinkler systems shall be drained after each operation of the system, before the onset of freezing weather conditions, and thereafter as needed.
A.220.127.116.11.2 Removing water from a dry system is an essential part of a good maintenance program. Failure to keep the dry system free of water can result in damage and expensive repairs to both the system and building. A program for monitoring the condition of the system and the operation of the auxiliary drains should be instituted. Auxiliary drains should be operated daily after a dry sprinkler system operation until several days pass with no discharge of water from the drain valve. Thereafter, it might be possible to decrease the frequency to weekly or longer intervals depending on the volume of water discharged. Likewise, when preparing for cold weather, the auxiliary drains should be operated daily with the frequency of operation decreasing depending on the discharge of accumulated water. In many cases, the frequency of the operation can decrease significantly if a system is shown to be dry. A quick-opening device, if installed, should be removed temporarily from service prior to draining low points.