NFPA 13D has developed guidelines to prevent fire sprinkler pipes from freezing.
The standard does not require sprinklers in certain areas of a home that might be prone to freezing pipes, since fires in those areas statistically do not lead to a large number of deaths or injuries. See a list of sprinkler omissions by visiting our fire sprinkler omissions page.
A wet pipe system is permitted where all piping is installed in areas maintained above 40 degrees Fahrenheit, including areas properly insulated to maintain 40 degrees Fahrenheit. In areas of the home equipped with water-filled sprinkler piping (wet pipe systems), NFPA 13D prohibits the use of traditional antifreeze solutions consisting of propylene glycol and glycerine in favor of a listed solution that does not ignite. This shift in antifreeze guidelines and the fact that no listed antifreeze solutions currently exist in the market place have prompted designers and other stakeholders to use other methods of freeze protection outlined in 13D.
Where system piping is located in areas not maintained above 40 degrees Fahrenheit, the pipe shall be protected against freezing by use of one of the following methods:
(1) Dry pipe system and preaction systems in accordance with NFPA 13D
(2) Antifreeze system in accordance with provisions in NFPA 13D
(3) Listed standard dry pendent or dry sidewall sprinklers extended from pipe in heated areas into unheated areas not intended for living purposes
(4) Listed heat tracing provided that it is installed and insulated in accordance with manufacturer’s instructions. Heat tracing is an electrical system used to maintain or raise the temperature of the sprinkler pipe so that the water in the pipe does not freeze.
(5) Listed residential dry pendent or dry sidewall sprinklers extended from pipe in heated areas into unheated areas
Consultation with the general contractor and/or owner is recommended to ensure proper methods and materials are used to make sure 40 degrees Fahrenheit will be maintained.
This information is for educational purposes only. Please reference NFPA 13D, Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, when installing home fire sprinklers.