I am pleased to introduce Matt Klaus, columnist for NFPA Journal and one of the newest contributors to this blog. As NFPA's principal fire protection engineer and staff liaison for NFPA 13D, Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, Klaus has extensive knowledge of the standard and will regularly discuss technical aspects of home fire sprinklers that will hopefully initiative some online discussions. (Click on the "comment" button below to offer your feedback or suggestions for future topics.) Here is his inaugural post. Check this blog often for additional insights from Matt.
One of the fundamental principles of an NFPA 13D sprinkler system is that it provides life safety to a dwelling's occupants. Unlike its big brother, NFPA 13, Installation of Sprinkler Systems, which applies to commercial structures and larger residential facilities, the concept of property protection is not written into the scope of 13D. This is not to say that an NFPA 13D system will not provide some level of property protection, but it's not the primary function of the system.
Two of the main differences between a life safety system and a system that provides both life safety and property protection are allowable omissions for sprinklers and the required water supply. There are several areas in the home--attics, small closets, bathrooms, and garages, for example--where sprinklers can be omitted since they have not historically been shown to lead to a loss of life. Adding sprinklers in these spaces would drive up the cost of the system without adding any inherent life safety benefit. Furthermore, there is a 10-minute water supply requirement for a 13D system (and as low as seven minutes for certain homes). Compared to a storage tank for a NFPA 13 system that might use 10 sprinklers for 30 or 60 minutes, there can be a significant difference in the amount of water needed.
For homeowners who are looking for not only the life safety aspects of the 13D system but also a higher level of property protection, they may want to speak to their system designer about enhancing the system by limiting the omissions and possibly increasing the water supply beyond the minimum requirements.