We have designed three dry systems for an nursing home in Tenn.. The building is divided into (3) riser systems. Each Riser covers Attic Area and Living Area in it section. Upon plan review, the State Health Building Inspector quoted
NFPA 13--18.104.22.168.3 - (For Dry Pipe Systems protecting dwelling unit portions of any occupancy, the sprinklers in the dwelling unit shall have a maximum water delivery time of 15 seconds to the single most remote sprinkler).
My question is this considered only for a residential 13R & 13D systems, or is it for Standard 13 Commercial Systems. I find it hard to believe you can get water in 15 seconds to any Dry System of normal size in this amount of time. NFPA states Ordinary Hazard with a Dry System is 60 seconds. I haven't come across anyone concerned about this particular code on any other projects.