One of the common concerns for homeowners that have a sprinkler system in compliance with NFPA 13D, Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, is the potential for frozen pipes. The Residential Sprinkler Systems Technical Committee, which is responsible for the development of NFPA 13D, has provided allowances to omit sprinklers in the parts of a home that are most susceptible to freeze protection concerns. This includes attic spaces, garages, and vestibules. These spaces are commonly left unheated to help keep costs down for the homeowner, and are therefore exposed to lower ambient temperatures.
The reason these spaces do not require sprinklers is not limited to freezing concerns; fires originating in these areas have not been known to lead to loss of life. As discussed in my previous blog post, one of the fundamental principles of NFPA 13D is that it is a life-safety system. Property protection is not the primary function of this system.
There are many methods that sprinkler designers and architects can employ to eliminate concerns over frozen pipes. The standard addresses the use of heat tracing, heating spaces, insulation, dry systems, and dry sprinklers as viable options.
While dry systems are not always a first choice for designers due to the additional maintenance commonly associated with drive valves, the use of dry heads is certainly something to consider. There are now dry residential heads on the market, and they have been effective in eliminating freeze protection concerns.
No matter what path is taken to provide freeze protection, should the homeowner have any concerns, it is important to discuss these issues with the system designer or service provider. Shutting off the system control valve over freezing fears is not the solution.
Matt Klaus is NFPA's principal fire protection engineer and staff liaison for NFPA 13D. Klaus is a regular contributor to this blog and discusses the technical components of home fire sprinklers.