My experience with smoke detection setups for dwellings, specifically, one & two family, is that there are at least
three AHJs having authority per installation.
- Electrical Inspector for the wiring (if any).
- Building Inspector for the placement of the detectors per building code.
- Fire Marshall for the placement of the detectors per fire code.
Since the Fire Marshall and Building Inspector don't share each and every page of the same code one gets different requirements quoted as gospel, depending upon who's talking. I have learned that the first duty of the system is to increase the chance of survival of any occupant present at the time of a fire, and that all else is secondary. Because of the larger amount of time individual occupants spend sleeping, special attention is paid to placing the detectors and their alarms so as to wake the sleeper.
If the system also contacts a remote supervisory service, fine, but that is extra.
Here, the code(s) language(s) that is(are) enforced results in line powered interconnected battery backup smoke detectors with integral alarms being the least cost for new construction. Devices integrated with a central security package can not be substituted for this. I've seen interface relays used for the smokes to communicate with the security system, but, in my experience, supervised system installers don't want to support the interface. So, as a result, I've seen both systems installed side by side.
