Which NFPA standard governs water supplies for aircraft hangars in foam-water systems?

• A. NFPA 409
• B. NFPA 13
• C. NFPA 25
• D. NFPA 30

Answer: (A)

The key idea is identifying which NFPA document specifically addresses water supplies for foam-water systems installed in aircraft hangars. NFPA 409 is dedicated to aircraft hangars and includes the fire protection provisions for those facilities, including the requirements for foam-water sprinkler systems and the water supply needed to ensure adequate performance. It covers how much water is required, storage considerations, and coordination with foam concentrates to reliably protect large hangar spaces.

The other standards serve different purposes: NFPA 13 is a general sprinkler installation standard and doesn’t tailor to hangar foam systems; NFPA 25 focuses on inspection and maintenance; NFPA 30 deals with flammable liquids code. Therefore, when the question asks about the water supply requirements for foam-water systems in aircraft hangars, the standard that applies is NFPA 409.