Cold Weather Preventative Maintenance for Fire Sprinklers

Posted February 24, 2017 by Koorsen Fire & Security

Cold Weather Preventative Maintenance for Fire Sprinklers


As the temperatures drop below freezing throughout much of the country, the risk of freezing water pipes is on many peoples’ minds. We’ve all heard the risks and seen the damage of a frozen water pipe bursting, but what about the pipes in a fire sprinkler system? Can they freeze and can they be “winterized”?

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If you work with a reputable fire sprinkler company, like Koorsen Fire & Security, then your fire sprinklers should be prepared for any harsh elements during their annual scheduled maintenance and inspections. Don’t be fooled by companies offering “winterization” for your fire sprinklers as cold weather preparation should already be part of regular maintenance, if required.

If the temperature in the area where your fire sprinkler system is located doesn’t get below 50 degrees Fahrenheit, then there is no need to worry about the sprinkler pipes freezing. If the sprinkler system is in an area that may experience freezing temperatures, then there are steps that should be taken to reduce the risk of the sprinkler system freezing. The steps to take depend on the type of fire sprinkler system you have installed.


Reducing the risk of your fire sprinkler system freezing depends on the type of fire sprinkler system installed. The type that is found inside many businesses is a wet system. In a wet system, the pipes of the sprinkler system are full of water. Once a sprinkler head is activated by the heat of a fire, the water sprays out, similar to what would happen when turning on a faucet.

The second type of sprinkler system is a dry system, which can typically be found in parking garages and warehouses where the temperatures can drop below freezing. In a dry system, the pipes are pressurized with air that holds the water back from the main water line. When a sprinkler is activated, the air is released, which allows the water to flow through the pipes and out the sprinkler head.

While dry systems are less susceptible to freezing compared to wet systems in cold weather conditions, they are still capable of freezing. This is due to the fact that the air in the pipes contains moisture, which can condense in the low points of the pipes and freeze. Due to the differences in the systems, they each require their own unique steps to reduce the risk of freezing.


While most wet fire sprinkler systems are installed in buildings where the temperature won’t drop below 50 degrees, there are certain applications where they may be susceptible to freezing, like when part of the wet system is run out to an unheated garage or area that is exposed to the elements.

To keep the water inside the pipes of a wet fire sprinkler system from freezing in areas where the temperature may drop below 50 degrees, an antifreeze loop is added. By adding antifreeze to the water in the fire sprinkler pipes, the freezing point is much lower, reducing the risk of the pipes freezing.

During the annual inspection, the fire sprinkler professional will take test samples from the fire sprinkler system to ensure the proper concentration of antifreeze is in the water. If the proper concentration of antifreeze is not sustained, it could lead to a frozen or burst fire sprinkler pipe.


A dry fire sprinkler system’s pipes aren’t full of water, like in a wet system, which means there’s no need for antifreeze. The dry system is full of air that contains moisture and can condense in the low points of the system, which can freeze and burst the pipes.

To prepare for the colder temperatures in the winter, a fire sprinkler professional will check and drain the low points of the system where drains are located to dispose of the condensation. The fire sprinkler technician will also check the pitch or angle of the pipes to the drains to make sure that the condensation flows properly to the low point drains. If the pitch isn’t correct, the condensation can collect elsewhere in the pipes where it could be at risk of freezing in the winter.

During the warmer months, the fire sprinkler professional will perform an annual inspection which may include flushing the fire sprinkler system. After flushing the system with water to ensure the system is operating properly, the pipes are then blown out with air to dry them. Once all the pipes have been dried out, they are sealed and pressurized with air. A professional will usually recommend that the low points are checked and drained every few days after flushing, due to the increased moisture in the newly pressurized lines.


While there isn’t much else that is needed beyond regular draining and inspections of dry systems, there are additional steps that one can take to prevent a wet system from freezing and bursting.

The one and only danger to a wet fire sprinkler system (without an antifreeze loop) freezing, is the temperature. The temperature where the wet fire sprinkler system is installed should not drop below 50 degrees Fahrenheit. You need to ensure the building heat is working in all areas where the fire sprinkler system is located. One of the most common causes of a wet fire sprinkler system freezing is that the heat in a building is accidentally turned off or loses power.

If there are vents that are blocked or shut off, open them to allow the heat to disperse and warm the room or area where the fire sprinkler system is located. Areas that pose the greatest risk for freezing are attics, stairwells, skylights, entryways, and under floors. If you can’t control the temperatures in these areas or seal off the cold air leaks, you should insulate the pipes.

While the fire sprinkler professional should inspect every part of the fire sprinkler system for potential exposure to freezing temperatures and address those issues, it’s still a good idea to regularly inspect the areas where the system is installed for cold temperatures. Broken windows, loose siding, damaged roofs, and other changes in a building’s exterior can quickly result in a big drop in temperature around the pipes of a fire sprinkler system.

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If you haven’t had your fire sprinkler system serviced and inspected within the past year, you should call a Koorsen technician to ensure your sprinkler system is working properly and is not at risk of freezing. Regular inspections and maintenance are always the cheapest and easiest way to avoid damage from the winter cold. Contact a Koorsen Fire & Security associate today to schedule an inspection of your fire protection system.

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Disclaimer: The information in this article is for informational purposes only. It is believed to be reliable, but Koorsen Fire & Security assumes no responsibility or liability for any errors or omissions in the content of this article. It does not constitute professional advice. The user of this article or the product(s) is responsible for verifying the information's accuracy from all available sources, including the product manufacturer. The authority having jurisdiction should be contacted for code interpretations.