If you've seen a fire scene in a movie where a sprinkler soaks everything and everyone in its vicinity, you'll know how powerful a system it can be. Sprinklers are so powerful that most fires need only one or two of them to be put effectively extinguished. You may not know that it's not actually smoke, but heat that triggers a fire sprinkler.
The industry benchmark for the installation of automatic fire sprinkler systems is NFPA 13 Standard for the Installation of Sprinkler Systems. These guidelines contain fire sprinkler distance rules, which should be used by architects along with local codes.
Sprinkler Head Location
Fire sprinkler heads must be positioned within the hot-gas layer that forms near the ceiling during a fire. The sprinkler is activated when the head reaches a specific temperature. Sprinkler heads must also be positioned so that no water released by the system affects construction elements, such as beams and trusses. The distance between the deflector – the part that distributes water in a specified pattern – and the top of storage must be at least 18 inches, meaning all storage and items in the rooms must remain at least 18 inches below the sprinkler deflector.
Sprinkler Head Spacing
Sprinkler head spacing requirements depend on the project. For light hazard projects, such as an office, school, hospital, restaurant or theater, each sprinkler head requires 130 to 200 square feet, with a maximum space of 15 feet between sprinklers. For ordinary hazard projects, such as a mill, factory, repair garage, post office or bakery, each sprinkler head requires 130 square feet, with a maximum space of 15 feet between sprinklers. For extra hazard projects, like a plastic processing plant, chemical spraying factory or printing press, each sprinkler head requires 90 to 130 square feet, with a maximum space of 12 feet between sprinklers.
The minimum distance between sprinkler heads is typically 6 feet, and the maximum distance from the wall should be half of the maximum distance between sprinkler heads. An upright sprinkler head distance from the ceiling is a minimum of 1 inch and a maximum of 12 inches for unobstructed construction. However, concealed, recessed and flush sprinklers may be mounted less than 1 inch from the ceiling.
Extended Coverage Sprinkler Heads
Extended coverage sprinkler heads are installed to increase the spacing between heads, because in some circumstances, standard distribution sprinkler heads don't provide enough coverage. The extended coverage heads distribute water over a radius of more than 10 feet, so they can be spaced approximately 20 feet apart.
Sprinklers in Building Types
In some states, such as California and Texas, residential fire sprinklers are required in all new one- and two-family dwellings and in townhouse construction. Sprinklers are also required in all high-rise buildings in California, with a few exceptions, such as airport traffic control towers and open parking structures.