Under what condition can a zone exceed the 20,000 sq ft or 300 ft requirement?

• A. When an automatic sprinkler system is installed throughout the area and installed in accordance with NFPA 101, the area of the zone can coincide with the allowable sprinkler zone.
• B. When the building has no sprinklers.
• C. When the area is under 5,000 sq ft regardless of sprinklers.
• D. Never; the zone size cannot exceed standard limits.

Answer: (C)

The key idea is how zone size is controlled in fire alarm design. Normally a zone is limited by either a maximum area (about 20,000 sq ft) or a maximum span (roughly 300 ft) to keep detection timely and manageable. There is an exception to this rule for small spaces: if the area is 5,000 sq ft or less, a single zone may cover it even if that would exceed the usual size limits. This exception does not depend on whether sprinklers are installed; it simply recognizes that very small spaces don’t need multiple zones to achieve effective coverage.

So, the reason this option is correct is that it identifies the only situation where you’re allowed to exceed the standard zone size: the area being under 5,000 sq ft. The other scenarios—having sprinklers or not, or never allowing any exceedance—do not create this exception.