On July 6, 2010, the National Fire Protection Association (NFPA) issued a safety alert recommending that residential fire sprinkler systems containing antifreeze be drained and the antifreeze be replaced with water. While NFPA emphasized that residential sprinklers remain reliable and effective, a recent fire incident involving a sprinkler system containing a high concentration of antifreeze solution raised concerns surrounding the combustibility of antifreeze 
solutions in residential sprinkler systems. The subject incident involved a grease fire in a kitchen where a sprinkler system with a reported 71.2% concentration of antifreeze deployed. The fire resulted in a single fatality and serious injury to another individual.
Following this incident, NFPA initiated a research project in conjunction with the Fire Protection Research Foundation. The initial test results showed that antifreeze solutions consisting of 70/30% glycerin and 60/40% propylene glycol may provide an unacceptable risk of harm to occupants in certain types of fire scenarios, in particular kitchen grease fires. There were successful tests where kitchen grease fires were extinguished or contained with a 50/50% glycerin solution, but NFPA felt there should be additional testing to more fully understand if there is a risk associated with a 50/50% glycerin solution. Further testing on antifreeze is planned in the future.
Potential fire spread issues, such as the aforementioned, should always be considered when evaluating a case for subrogation potential.
