Fire sprinkler system
"The sprinkler system worked all too well, causing a flood that washed away all the food and a good part of the kitchen.
[4][full citation needed] The world's first modern recognizable sprinkler system was installed in the Theatre Royal, Drury Lane in the United Kingdom in 1812 by its architect, William Congreve, and was covered by patent No.
[citation needed] The apparatus consisted of a cylindrical airtight reservoir of 400 hogsheads (c. 95,000 litres) fed by a 10-inch (250 mm) water main which branched to all parts of the theatre.
[citation needed] Frederick Grinnell improved Henry S. Parmalee's design and in 1881 patented the automatic sprinkler that bears his name.
[7] Until the 1940s, sprinklers were installed almost exclusively for the protection of commercial buildings, whose owners were generally able to recoup their expenses with savings in insurance costs.
Sprinklers have been in use in the United States since 1874, and were installed in factory applications where fires at the turn of the century were often catastrophic in terms of both human and property losses.
Sprinklers may be required to be installed by building codes, or may be recommended by insurance companies to reduce potential property losses or business interruption.
US building codes for places of assembly (generally over 100 persons) and places with overnight sleeping accommodation such as hotels, nursing homes, dormitories, and hospitals, usually require sprinklers either under local building codes, as a condition of receiving State and Federal funding, or as a requirement to obtain certification (essential for institutions who wish to train medical staff).
[9] This law requires that any hotel, meeting hall, or similar institution that receives federal funds (i.e. for overnight stay, or a conference, etc.
As more and more hotels and other public accommodations upgraded their facilities to enable business with government visitors, this type of construction became the de facto industry norm – even when not directly mandated by any local building codes.
The law applies to newly built houses and blocks of flats, as well as care homes and university halls of residence.
[citation needed] A sprinkler activation will usually do less water damage than a fire department hose stream (which provide approximately 900 litres/min (250 US gallons/min).
However, a typical Early Suppression Fast Response (ESFR) sprinkler at a pressure of 50 psi (340 kPa) will discharge approximately 380 litres per minute (100 US gal/min).
[15] This regulatory action has greatly increased costs and reduced options for cold weather tolerant sprinkler systems.
In regions using NFPA regulations, wet pipe systems cannot be installed unless the range of ambient temperatures remains above 40 °F (4 °C).
The maximum time of water delivery may be required to be reduced, depending on the hazard classification of the area protected by the sprinkler system.
The intent is to reduce the undesirable time delay of water delivery to sprinklers that is inherent in dry systems.
In this case, the pre-action valve will not open due to loss of supervisory pressure, and water will not enter the piping.
Activation of either the fire detectors alone, or sprinklers alone, without the concurrent operation of the other will not allow water to enter the piping.
These systems are usually used with special hazards occupancies associated with high challenge fires, such as flammable liquids, such as in aircraft hangars.
Examples of hazards protected by water spray systems are electrical transformers containing oil for cooling or turbo-generator bearings.
Water spray systems can also be used externally on the surfaces of tanks containing flammable liquids or gases (such as hydrogen).
The fire suppression mechanisms provided by water mist systems include cooling, local flame oxygen reduction, and radiation blocking.
Residential sprinkler systems are designed to control a fire for a sufficient time to allow for the safe escape of the building occupants.
In residential structures, sprinklers are often omitted from closets, bathrooms, balconies, garages and attics because a fire in these areas would not usually impact the occupant's escape route.
In 2008, the installed costs of sprinkler systems ranged from US$0.31 – $3.66 per square foot, depending on type and location.
Residential systems, installed at the time of initial home construction and utilizing municipal water supplies, average about US$0.35/square foot.
Some communities have laws requiring residential sprinkler systems, especially where large municipal hydrant water supplies ("fire flows") are not available.
[citation needed] Residential sprinkler systems are inexpensive (about the same per square foot as carpeting or floor tiling), but require larger water supply piping than is normally installed in homes, so retrofitting is usually cost prohibitive.
"[23] Elsewhere it has stated, "NFPA has no record of a multiple fatality in a fully sprinklered building where the system operated.
