The National Fire Protection Association (NFPA) in 2010 issued a safety alert regarding fire sprinkler systems containing antifreeze.
Antifreeze is used in sprinkler systems that are subject to freezing. NFPA has removed its requirement that all antifreeze be removed from sprinkler systems. It does have specific requirements for NFPA 13D systems. 13R systems, typically installed in apartment buildings up to four stories in height, are required to comply with the antifreeze requirements contained in NFPA 13.
NFPA recommends considering alternatives to antifreeze, using the minimum necessary concentration of antifreeze and having the system tested by a qualified individual.