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Residential Fire Sprinklers and Quick Response Sprinklers

There is a new technology in fire sprinklers - fast response. It is attracting a lot of interest, but raising a number of questions as well.

This pamphlet is being distributed by the National Fire Sprinkler Association to help answer those questions. The National Fire Sprinkler Association is a non-profit trade association which promotes the fire sprinkler concept. It is supported by its member sprinkler manufacturers, installing contractors, and suppliers and manufacturers of related equipment and services. Subscribing memberships are also available to Authorities Having Jurisdiction (fire, building code, and insurance officials), who need to keep ahead of the changing technology to properly regulate the use of fire sprinklers in their critical role of saving lives and property.


• What is a "fast response sprinkler"as opposed to a "residential" or a "quick response sprinkler"?

"Fast response sprinkler" refers to the general type of fire sprinkler which exhibits a level of thermal sensitivity greater than that of the standard sprinkler which has been used successfully for more than a hundred years. There are no specific requirements of a fast response sprinkler; it is merely an all-inclusive term covering listed residential sprinklers, listed quick response sprinklers, ESFR (Early Suppression Fast Response) sprinklers for high challenge industrial applications, and any other sprinkler a manufacturer might want to market on the basis of its speed of operation.


• What is a "listed" sprinkler?

All fire sprinklers installed in conformance with National Fire Protection Association (NFPA) standards must be listed. A listing basically means that the manufacturer has successfully submitted the product to an independent laboratory for testing against an established standard of quality. Both Underwriters Laboratories and Factory Mutual Research have established special listing categories for fire sprinklers.


• What is a residential sprinkler?

The residential fire sprinkler was the first sprinkler to incorporate the new fast response technology. It was developed in the late 1970s in conjunction with federally funded research into a low-cost residential sprinkler system. Research showed that in order to make relatively small domestic water supplies effective for sprinkler protection, and to control a residential fire before small rooms could fill up with toxic smoke, a sprinkler needed to be considerably more sensitive to heat than the standard sprinklers. The needed residential sprinklers were developed by sprinkler manufacturers while appropriate product testing criteria were being developed by Underwriters Laboratories and appropriate installation rules were being developed by the NFPA Committee on Automatic Sprinklers. The result is that there are now listed residential sprinklers which can be installed in conformance with NFPA 13D and, in some cases, NFPA 13. The listed residential sprinklers are tested not only for fast response, but also for special distribution and cooling abilities.


• What is a quick response sprinkler?

Quick response sprinklers are those which are tested under the same product testing criteria as standard sprinklers, but also exhibit the fast response characteristics of listed residential sprinklers. Some manufacturers developed these sprinklers by inserting the residential sprinkler operating mechanism into a standard sprinkler frame. Other manufacturers successfully submitted residential sprinklers to the laboratory for testing under the criteria for standard sprinklers. In both cases, Underwriters Laboratories designated these special sprinklers as quick response sprinklers. By establishing a separate listing category, UL has identified listed quick response sprinklers as being different from both standard and residential sprinklers. Unlike the residential sprinklers, quick response sprinklers are not required to have special cooling and distribution abilities.


• How can listed quick response sprinklers be used?

Full scale fire tests conducted by the NFSA at Factory Mutual Research in 1988 demonstrated that quick response sprinklers could be effectively used with the light hazard and ordinary hazard area/density curves of NFPA 13. Prior to the NFSA testing, there was concern that an excessive number of quick response sprinklers might operate in a fire which was controlled but not suppressed. The NFSA tests showed that quick response sprinklers perform as well or better than standard response sprinklers even under conditions where the fire is not readily suppressed. Therefore, except in extra hazard occupancies, quick response sprinklers may be used under the same design rules as standard response sprinklers. However, all sprinklers within a compartment should be of the same manufacturer's brand and temperature rating, to ensure consistent response characteristics.


• How can residential sprinklers be used in NFPA 13 and NFPA 13D?

Both NFPA 13 and 13D are national consensus standards containing guidance for proper installation of sprinkler systems. NFPA 13 contains rules for the installation of sprinkler systems in most types of occupancies while NFPA 13D was specifically written to cover the installation of listed residential sprinklers in one and two-family dwellings and mobile homes. To make sprinkler systems economically practical for dwellings, NFPA 13D permits omission of sprinklers from certain building areas where NFPA 13 would require sprinklers. NFPA 13D also permits a 2-sprinkler design area so as to accommodate limited domestic water supplies. This means that the water supply only needs to be able to handle two sprinklers flowing simultaneously among the total number of sprinklers in the building. This is less than for standard sprinkler systems, but has been verified by tests demonstrating the effectiveness of residential sprinklers in dwellings. Both NFPA 13 and NFPA 13D are available from the National Fire Protection Association, Batterymarch Park, Quincy, MA 02269.

Beginning with the 1983 edition of NFPA 13, listed residential sprinklers were permitted to be used in residential portions of all types of occupancies, provided they were installed in accordance with the provisions of their listings. Today, residential sprinklers can be used within the dwelling units and their adjacent corridors in hotels, nursing homes, dormitories, and similar occupancies listed within the scope of NFPA 13.


• What is the advantage of using residential sprinklers in these areas?

Aside from the fact that the residential sprinklers were specifically tested for their ability to improve the chances for life safety from fires in the types of fires typical to these dwelling areas, NFPA 13 offers an incentive in the form of a 4-sprinkler design area. While slightly more conservative than the NFPA 13D design, this still can reduce total water supply requirements, creating an economical system installation.


• What is a 13R system?

NFPA 13R is a new standard, first available in 1989. Intended to bridge the gap between NFPA 13 and 13D systems, it provides life safety oriented economical sprinkler protection for low-rise (up to 4 stories) residential occupancies, including:

Apartments Lodging and Rooming Houses Hotels and Motels Board and Care Facilities (Slow evacuation capability up to 16 residents and fast evacuation capability)

NFPA 13R is an optional alternative to NFPA 13 for protection of these occupancies. It is based primarily on the use of residential sprinklers within dwelling units with a 4-sprinkler design area, but permits other types of sprinklers under specific circumstances. NFPA 13 protection is required in nonresidential areas, but some key exceptions are provided in an attempt to permit the use of economical water supplies.


• How much does a 13D system cost?

While prices can be expected to vary with a geographical area, it is generally found that a fire sprinkler system for a typical single-family home with a good municipal water supply costs between $1500 and $2500. In a 1987 study, the National Association of home Builders determined that the average cost of a residential sprinkler system was $1.31 per square foot.


• What if no public water supply is available?

If it becomes necessary to provide a stored water supply, the system cost will increase by about $2500. Several companies market "packaged" pump and tank systems specifically for NFPA 13D use.


• Are insurance savings available?

A 1980 study by the Ad Hoe Insurance Committee on Residential Sprinklers concluded that residential sprinklers could reduce claim payments in single family homes by up to 80 percent. Although fire is only a portion of typical homeowners insurance, a number of insurance companies are offering discounts. The discount recommended by the Insurance Services Office in most states is 13 percent for a 13D system covering all building areas, 15 percent if smoke detectors are also provided.

Larger insurance reductions are generally available for sprinkler systems in multi-family residential occupancies.


• Can a dry sprinkler system be installed in accordance with NFPA 13D in cold climates?

No. Since the 2-sprinkler design of a 13D system is based on rapid sprinkler response, the delay inherent in dry systems must be considered. NFPA 13D only permits dry systems if the residential sprinkler is specifically listed for such use. To date there are no such sprinklers. Until such time as dry systems are available, some authorities Having Jurisdiction are permitting antifreeze systems, while others are exempting unheated areas such as attics from the requirements for sprinkler protection. This is permitted by 13D provided the attic is not used for occupancy or storage.


• How can you protect pipe against freezing if it is located in a ceiling below an unheated attic space?

A leading fiberglass insulation manufacturing company has advised that insulation with an R-19 rating, carefully placed above sprinkler piping so as to seal off both sides of a joist space, can prevent a freeze-up for outdoor temperatures as low as 20°F provided the piping is directly above gypsum sheathing and the space immediately below is maintained at 40°F or above. It is important that insulation not be placed between the heated area and the sprinkler piping.


• How large an area can each residential sprinkler cover?

The original listed residential fire sprinklers were pendents which protected a maximum area of 12 feet by 12 feet. Today, however, there are at least a dozen different listed residential sprinklers, including flush, recessed, and sidewall styles. All of these sprinklers are covered by special listings, recognized within NFPA 13D, which permit their use at larger spacings if specified minimum flows and pressures are provided. Currently available are pendent sprinklers with coverage areas of up to 20 by 20 feet, and sidewall sprinklers with coverage areas of up to 16 feet wide by 20 feet long.


• How can I keep up with the new listings and technology?

The National Fire Sprinkler Association helps its members stay abreast of the changes in products and standards. If you are part of the sprinkler industry, join the Association. If you are a building, fire, or insurance authority, consider becoming a subscriber member. In addition to the NFSA quarterly magazine and other periodicals, you will receive the bi-monthly technical newsletter Sprinkler TechNotes, and be eligible for other NFSA services at member rates. For Membership Information, Call or Write: Director of Marketing National Fire Sprinkler Association, Inc. Robin Hill Corporate Park - Route 22 P.O. Box 1000 Patterson, NY 12563 914/878-4200

Visit the IPS site for more information.