What Type of Sprinkler System Should You Use in Cold Rooms?

March 19, 2025

Introduction

The use of fire sprinkler systems can pose many challenges in freezer rooms, cold storage facilities, and cold weather areas. In wet systems, cold temperatures can cause water to freeze and rupture your piping. Meanwhile, in dry systems, you can experience corrosion and ice plug formation, blocking your pipes and making them prone to damage or rupture. However, standards like the NFPA 13 and NFPA 25 provide some great options for protecting fire sprinkler systems in cold weather. These methods may include air compressors, antifreeze solutions, trace heating elements, insulation, and more.

What Type of Sprinkler System Is Used in Areas Subject to Freezing?

The best sprinkler system for cold environments is dry or pre-action fire sprinkler systems. These systems are engineered for areas prone to freezing conditions. Instead of water, the pipes are filled with pressurized air or nitrogen, which keeps the control valve in place and mitigates corrosion. When a sprinkler activates, the pressure drastically lowers, causing water to be released. For freezer rooms or locations below 40° F, use a dry pipe system.

Learn More: Fire Protection in Cold Storage Facilities >>

How to Protect a Sprinkler System in Freezing Weather?

In some cold climate areas, you may need to ‘winterize’ your wet sprinkler system during the winter months. In other words, you may need additional methods to keep your pipes warm when the weather may dip below freezing temperatures. Besides dry pipe systems, there are several other methods listed in the NFPA standards for cold weather protection and other edge cases. This includes the following:

Antifreeze: Antifreeze can be mixed and added to a sprinkler system to prevent it from freezing. However, never mix these solutions yourself. Instead, opt for premixed, UL listed, noncombustible products, and have it installed by an expert technician.

Climate control: Maximizing the amount of piping that is in warmer areas in your home or business can help to prevent freezing pipes. Through means of convection, heat from the warmer areas of the pipe will flow to colder areas.

Heat tracing: Electric heat tracing, heat tape, or surface heating can be used to maintain or raise the temperature of your pipes. This involves an electrical heating element, which is used alongside insulation to retain heat around your piping. To find reliable heating products, take a look at UL Solution’s article on UL Certified Trace Heating Equipment.

Is Antifreeze Allowed in Fire Sprinkler Systems?

In 2013, the NFPA officially prohibited the use of antifreeze in new automatic residential sprinkler systems. When installing a new sprinkler system for a freezer room, you are required to use a dry pipe system over an antifreeze solution. The reason for this is because high ratios of glycerin and propylene glycol in antifreeze solutions were found to be flammable and make fire conditions worse. And so, If your system was installed before September 30, 2012 and relies on antifreeze, it may still be used as long as you flush your system and replace it with a noncombustible, UL listed antifreeze solution. However, continuing to use an antifreeze solution adds complexity to your maintenance routine. If the solution is mixed incorrectly or settles improperly, it can pose risks or a fire hazard. Thus, the system will require annual testing and sample analysis conducted by a professional.

Fire Sprinkler Antifreeze Requirements

If you do add antifreeze to your wet pipe system for protection against cold or freezing weather, there are several conditions that have been stipulated by the NFPA. Firstly, antifreeze systems must meet NFPA 25 design requirements. This includes expansion chambers that are sized according to their formulas in NFPA 13: A.7.6.3.2, and backflow preventers, which prevent antifreeze from leaking into your water supply. Second, you must present documentation to your local authority having jurisdiction (AHJ) to substantiate the use of the antifreeze solution. This is ensures that you are using an antifreeze solution only when it is necessary for your protection. Furthermore, all antifreeze solutions should be premixed and UL listed for safe use in fire sprinkler applications. Allowing building owners to mix these solutions themselves may put your building at risk, since incorrect mixture ratios can actually make a fire worse.

For antifreeze fire sprinkler solutions, maintenance requirements are also increased. These systems require annual testing to ensure that the active ingredients haven’t separated in the pipes over time. This is done by taking a sample of the solution and testing its specific gravity/concentration. According to the NFPA 25, if you own a particularly large sprinkler system, (>150 gal) you are required to test the solution at one additional point for every 100 gal. Due to the strict system design and maintenance requirements of antifreeze systems, it may be beneficial to transition to dry pipe systems, even in older installations.

Conclusion

Protecting your fire sprinkler system in cold environments requires careful consideration of methods to prevent freezing. Dry pipe systems with dry air generators are the most standard method to avoid freezing pipes, corrosion, and ice plugs. Additional measures like antifreeze, climate control, and heat tracing can provide extra protection for older systems, or systems that may experience extreme weather conditions. As always, it is crucial to follow NFPA guidelines and your local AHJ, especially when using antifreeze, to remain safe and compliant.

If you are looking forAt FireAlarm.com, our expert team is ready to assist you with system design, installation, inspection, and maintenance services tailored to your needs. Reach out to us today to discuss how we can get your business compliant with the codes.