Flash-fires caused by antifreeze in sprinklers – latest news
Published: 15 September, 2010
The NFPA Standards Council has banned the use of antifreeze solution in residential fire sprinkler systems for new construction following an incident that showed that high levels of antifreeze solution in the sprinkler systems could actually cause flash fires.
The initial safety alert in July 2010 has now been followed up by updated guidance on the use of antifreeze in residential fire sprinkler systems, following new research.
NFPA Vice President & Chief Engineer Chris Dubay explained that in a specific incident a grease fire in a kitchen resulted in a fatality and a serious injury. In this case the sprinkler system had a reported concentration of 71.2% of antifreeze.
The NFPA carried out an initial research project with the Fire Protection Research Foundation to find out what is known about antifreeze solutions and fries.
At the same time (independently) the Underwriters Laboratory initiated some full-scale demonstration or a full scale minor test to look at the potential flammability of these solutions.
The initial research showed that there was potential for flash fires associated with various levels of antifreeze solution.
“Two things happened immediately. One, a phase two research project was initiated to do full scale fire testing to evaluate various concentrations of antifreeze solutions, as well as various arrangements of sprinklers. And NFPA issued its initial alert bulleting in July this year,” said Chris Dubay.
“First we learned that antifreeze solutions in concentrations of propylene glycol exceeding 40% and concentrations of glycerine exceeding 50% have the potential to ignite when discharged from automatic sprinklers.”
NFPA standards are installations standards and do not currently address the problem of antifreeze in existing sprinkler systems.
NFPA is providing guidance for currently installed automatic fire sprinkler systems using antifreeze solutions. “Where existing systems utilise antifreeze solutions, first and foremost, residential fire sprinkler systems are extremely effective fire protection devices and in no case should these systems be disconnected.
“Existing residential sprinklers systems whenever possible should not contain antifreeze solution. If you are responsible for one of these systems or have one of these systems, you should contact your sprinkler contractor and check if there is antifreeze in your system and if there is antifreeze determine if there are other means such as insulation that can be utilised to provide adequate freeze protection in lieu of utilising antifreeze solution.”
Where there’s no viable alternative to antifreeze solution, NFPA recommends you should only use propylene glycol or glycerine solution. Second, the solution should be the lowest possible concentration to reach the adequate antifreeze protection, and under no circumstances should the maximum concentration exceed 40 % propylene glycol or 50% glycerine: “And considerations should be given to reducing these concentrations by an additional safety factor.”
Third, the antifreeze solution should only be a factory premix solution. Use of factory premix solutions is essential to ensure the proper concentration level and for solution integrity. “And finally, any use of antifreeze solution should only be used with approval of your local authority having jurisdiction.”
The next steps for the NFPA include acting on the Standards Council’s recommendations. “In addition to issuing interim amendments the Standards Council provided feedback to the automatic fire sprinklers project and our maintenance project. Specifically two areas need to be addressed.
“One is, can technically substantiated safe use of antifreeze solutions be developed and documented with the NFPA codes and standards?
“And two, what should NFPA in our standards process do about our existing systems?”
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