Fire sprinkler advocates are likely familiar with the popular myths associated with home fire sprinklers. (No, smoke won't set off fire sprinklers.) Lesser-known myths pertain to requirements found in NFPA 13D, Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes. Setting the record straight is NFPA's Fire Sprinkler Initiative, which now includes a section on its site listing where fire sprinklers are and aren't required, per the standard. Take, for example, the following:
Sprinklers shall not be required in garages, open attached porches, carports, and similar structures.
Many are surprised to learn that NFPA 13D does not require sprinklers in garages. But, in fact, few deadly fires start in garages. A simple cost-benefit analysis can illustrate that the extra expense of placing sprinklers in garages does not provide an equal balance of protection due to the fact that most garages are not heated and the sprinkler system would need to be a dry system or an antifreeze system in many geographic regions. This cost-benefit analysis and the fact that most residential building codes require a one-hour fire resistance rating for the walls separating the garage and the remainder of the home led to this omission.
Keep in mind requirements for installations may vary from region to region. Check with your authority having jurisdiction for specifics.
For a list of fire sprinkler omissions in homes per NFPA 13D, visit NFPA's Fire Sprinkler Initiative site.