A 33-Year Journey to Dwelling sprinklers
NFPA Journal®, September/October 2008
The September 21, 2008, vote to change the International Residential Code (IRC) to require fire sprinklers in all new single-family dwellings represents the culmination of a 33-year journey begun by the NFPA Committee on Automatic Sprinklers in 1975. That was the year the first edition was published of NFPA 13D, Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, then titled Sprinklers in Dwellings and Mobile Homes. This journey is one in which the technical committees responsible for the document have continually sought to balance the effectiveness of fire sprinkler protection against the needs of economical system installation. Without that proper balance, sprinklers in single-family homes would never have become a reality.
The 1975 edition of NFPA 13D sought to use existing sprinkler technology with a 25-gallon-per-minute (95-liter-per-minute) water supply. However, subsequent testing showed that it fell short in the area of effectiveness. The level of sprinkler thermal sensitivity available with traditional sprinklers could not address the impact of fast-developing fires in small residential compartments, a deficiency that led the U.S. Fire Administration to fund research aimed at developing a new sprinkler specifically for residential applications.
The residential sprinkler was the first of the fast-response sprinklers, using smaller solder links or thinner liquid-filled bulbs to more rapidly assimilate the temperature of the fire environment. Fast response has two big advantages for dwelling sprinklers: It not only allows them to address fires in small compartments before they become deadly, but it also allows the use of modest domestic water supplies while they can still be effective due to the small size of the fire. The new residential sprinklers also had a special distribution pattern that directed more spray to the perimeter of its coverage area, where residential fuels are often located.
The first residential sprinklers were listed for a coverage area of 12 by 12 feet (3.7 by 3.7 meters), with a minimum flow rate of 18 gallons (69 liters) per minute for the first sprinkler operating and 13 gallons (49 liters) per minute each for the full two-sprinkler design area. This represented an average minimum density of 0.09 gpm/ft2 (4 mm/min) over the design area.
The NFPA Sprinkler Committee left the door open to encourage improved technology, and the sprinkler manufacturers responded with a competitive battle for expanded coverage areas and lower flow rates. By the 2002 edition, the listing laboratories and sprinkler manufacturers had cooperated in the development of more consistent fire test requirements and reasonable baselines, such that today’s residential sprinklers are permitted a maximum protection area of 400 square feet (37 square meters) and minimum application rates of 0.05 gpm/ft2 (2 mm/min) for both sprinklers in the two-sprinkler NFPA 13D design area.
The historic September 21 vote was carried by a 73 percent majority among the voting representatives, substantially more than the two-thirds needed to overturn a recommended rejection by an IRC committee heavy with homebuilders. Although the mandate for sprinklers in one- and two-family dwellings will carry an effective date of January 1, 2011, a companion change that calls for sprinklers in all new single-family townhouses or adjacent dwellings becomes effective with the adoption of the forthcoming 2009 edition of the IRC.
With the housing industry in a slump, some may believe that this is an ill-timed burden on housing costs. But when we step back and look at the big picture, we should realize that this is probably the best time to implement a new requirement. As the demand for sprinklers in commercial construction slows a bit with the economy, experienced fire sprinkler contractors will have more time to devote to the needs of the residential sector. A slower market means that the number of new homes being built will be more manageable than in past years. While quantity may be down, quality, especially in terms of fire protection, will be substantially higher.
NFPA has played key roles throughout this journey, from the first concepts advanced by its technical committee to its leadership in the Home Fire Sprinkler Coalition to the mandate for sprinklers in dwellings in the 2006 edition of NFPA 1, Uniform Fire CodeTM; NFPA 101®, Life Safety Code®; and NFPA 5000®, Building Construction and Safety Code® . There is much work ahead, but congratulations should be extended to everyone who has assisted in this major advance in home fire safety.
Russ Fleming, P.E., is the executive vice-president of the National Fire Sprinkler Association and a member of the NFPA Technical Correlating Committee on Automatic Sprinklers.