Closet volume of 350 ft³; how many sprinklers are required?

• A. A single sprinkler is sufficient.
• B. Zero sprinklers.
• C. Two sprinklers are required.
• D. Three sprinklers are required.

Answer: (A)

In NFPA 13R design for low-rise residences, storage closets can be protected with a single sprinkler as long as the closet volume stays under the permitted limit for that approach. A closet volume of 350 ft³ falls within that limit, so one sprinkler is sufficient to provide the needed protection for the closet contents. Additional heads would only be required if the volume exceeded the limit or if there were special design factors. Zero sprinklers would leave the space unprotected, and two or three would not be needed for this volume. Place the sprinkler close to the ceiling to maximize coverage of the closet space.