Sprinkler spacing is the distance between sprinklers, typically 130 ft2 per unit.

• A. 130 ft2 (12 m2) per unit
• B. 100 ft2 (9 m2) per unit
• C. 150 ft2 (14 m2) per unit
• D. 90 ft2 (8 m2) per unit

Answer: (A)

The main thing this question tests is how much floor area one sprinkler head is expected to protect in a low-rise residential system. In NFPA 13R design, the spacing guideline is based on a coverage area per sprinkler, not a fixed physical distance. For typical residential head types and ordinary hazards, about 130 square feet (roughly 12 square meters) of floor area is intended to be covered by each sprinkler.

So the best choice is the one that matches that standard coverage: 130 ft2 per unit. This aligns with the idea that each sprinkler should control about 130 ft2 of space, which helps ensure adequate heat release, proper water distribution, and reliable activation in a typical home setting. The other options would correspond to smaller or larger per-head coverage than what NFPA 13R commonly uses, leading to more sprinklers (higher cost) or less protection (larger area per head) than the standard design.

As a quick mental check, a 130 ft2 area translates to an approximate square of about 11 by 11 feet, so sprinklers spaced roughly in that neighborhood would achieve the intended coverage.