February 14, 2018

Anti-Freeze & Methods for Reducing Sprinkler Pipe Freezing

What you need to know about anti-freeze and keeping fire sprinkler systems from freezing.

The National Fire Protection Agency (NFPA) has developed a series of guidelines and processes that regulate the use of anti-freeze in fire sprinkler systems. These rules are critical to ensure the safety of the people who use fire sprinkler systems to help save lives and protect property.

Why regulate anti-freeze?  This issue became a top priority several years ago, after two tragic incidents occurred. 

  • In 2001, an overhead heater on the outside deck of the Windandsea restaurant in New Jersey, became so hot that it triggered the sprinkler system. Fire experts believe that when the anti-freeze mixture was released from the sprinkler and hit the heater, it resulted in a flash fire. Nineteen people were injured.
  • In 2009, when water was put on a flaming pan in a home kitchen in California, the sprinkler activated and fire experts believe that when the anti-freeze made contact with the fire it resulted in an explosion. A young mother died and her husband and children were badly burned.

Safety is, and always will be, our number one priority. This article is a compilation of resources to help you find answers to your questions about the use of anti-freeze and how to safely keep fire sprinkler pipes from freezing during the winter.

Did you know that special regulations exist to determine when anti-freeze can and can’t be used? 

These rules can vary by jurisdiction depending on whether they follow the 2007 or earlier editions of NFPA 13. Make sure to check with your local code enforcement officer, NFPA or NFSA to find out what rules may apply to older sprinkler systems, retrofitted systems and new systems. 

To learn more visit the NFPA website:

Click here for special NFSA TechNotes article on anti-freeze and sprinklers 

Did you know that anti-freeze solutions can be flammable?

Many of the chemicals used to create antifreeze, such as propylene glycol and glycerin are flammable. In an effort to reduce the risk of combustion when these chemicals are released as a sprinkler is activated, the NFPA has established specific guidelines that determine the percentage and concentration allowed for these chemicals to be used. 

Click here for a summary of current NFPA requirements for sprinkler systems containing anti-freeze.

What alternatives to anti-freeze are available to keep pipes from freezing?

There are several ways to reduce the risk of freezing sprinkler pipes without using anti-freeze. The easiest and most economical method is to insulate the unheated space (attic/basement/crawlspace/utility closet) where the pipes are exposed. Another involves wrapping batt insulation around the actual pipes, also known as “tenting”.

Click here to read more about “Antifreeze Alternatives: Tenting of Insulation.”

What is a Dry-Pipe Sprinkler System?

A dry sprinkler system is another alternative to help protect systems from freezing.  Dry-pipe systems can be used in residential and commercial applications.  A dry pipe sprinkler system is designed so that the piping itself is filled with pressurized air instead of water, and doesn’t fill with water until a fire is detected.

Click here to learn more about dry-pipe systems and read the article,  “Don’t forget the Dry System.”

Click here to read the article “Dry Sprinkler Installation.”

Click here for a link to a article about dry-pipe sprinklers.   

What types of testing needs to be done for sprinklers that use anti-freeze?

All sprinklers should be tested annually in the fall before the cold weather season. It is even more important for testing to be conducted on fire suppression systems that use anti-freeze.  

NFPA recommends the following:

For existing systems that contain anti-freeze:

  • A qualified professional should test and examine the anti-freeze solution to make sure that it meets with NFPA standards for the specific type of sprinkler.
  • If it doesn’t meet the standards, the system will need to be drained and replaced with an acceptable solution.

For new sprinkler systems that contain antifreeze:

  • Systems must be tested to examine the solution annually for compliance with NFPA standards.
  • Systems can only use factory premixed solutions.
  • The solutions must have a certificate indicating the type of antifreeze, the concentration and freezing point.

To learn more visit the NFPA website:

For a list of all NFPA codes and standards visit this link:

Some related articles and resources: blog “Anti-freeze in fire sprinklers: What you need to know.”

NFPA 25 – Antifreeze Sprinkler Systems Video – NFMT Conference Session (2014)

Literature Review and Research Plan: Antifreeze Solutions in Home Fire Sprinkler Systems

NFSA TechNotes: Jan. 3, 2018/Issue #389/ Special Winter Edition (Anti-Freeze, Regulations, Testing)  

NFSA TechNotes: Nov. 28, 2017/Issue #387/Maintenance Considerations for Dry Sprinkler Systems 


February 14, 2018

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