sprinklernotes
Sidewall Sprinklers on Opposing or Adjacent Walls
You asked the following questions: “There are two sidewall sprinklers in a single room on adjacent walls with a 6-in. deflector distance from the ceiling. The distance between the two sprinklers is 16-ft and the opposing wall is at 19 ft-4 1/2 in. The specifications for the sprinkler (in regards to maximum coverage area) range from 12 ft x 12 ft all the way up to 16 ft x 20 ft. The coverage area is 16 ft x 16 ft and the AHJ is saying that the sprinklers will cold solder at 16-ft apart. Do the sidewall sprinklers have to be spaced 20-ft apart because that is the maximum throw of the sprinkler at the highest psi per the data sheets?” We have reviewed NFPA 13, 2013 edition that you indicated as the applicable standard. Our informal interpretation is that a sprinkler shouldn’t be located within the maximum protection area of a sidewall sprinkler on the adjacent wall. There hasn’t been any testing regarding your application to determine sufficient distances when sprinklers are located on opposing or adjacent walls. The minimum spacing between sprinklers mounted on the same wall is 6-ft apart for standard spray sidewall sprinklers and 8-ft apart for extended coverage and residential sidewall sprinklers to prevent the wetting of the thermal element or cold soldering. Sidewall sprinklers located on opposing walls and adjacent walls could be prone to cold soldering, so they have to be handled differently. The conservative approach by the standard is to locate these sprinklers outside the maximum protection area to avoid cold soldering another sprinkler. This is addressed in Section 8.7.3.1.6 for standard sidewalls, 8.9.3.4 for extended coverage sidewalls, and 8.10.3.4 for residential sidewall sprinklers. Sidewall sprinklers should be located on the same wall for future designs or located to prevent cold soldering. An alternative since this is already installed is to ask the AHJ to look at the sprinkler’s spray pattern from the manufacture’s data sheets and to make a judgment call if the existing installation is acceptable.
