Follow-Ups to Answer from Expert Joseph Retzer, C.E.T.

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ElegantFowl wrote at 2009-11-08 13:48:32
We built a four-bedroom house several years ago and installed the requisite 10 smoke detectors as required by code, powered by AC and wired together.  Supposedly good quality detectors, BRK 7010B, recommended by our electricians.



The system is a failure, with so many false alarms that our children are now habituated to sleep through them.



The manufacturer's "instructions" don't say anything except to clean the offending unit, which I do routinely with compressed air and vacuum.  Essentially that's the same advice you've offered, and it's not helpful.



As this the original questioner experienced, our alarms typically sound for 10-30 seconds, which is not long enough to sprint through the house at 3am to find the offending unit.  Sometimes I can find it, but the silence button on the 7010B doesn't work so I have to rip it out and disconnect it.



The fire codes seem to have been written by technical laymen who assume that the detector technology works as advertised.  Here in the real world, smoke detectors have a tough job maintaining calibration in unpredictable environments, and each of them have a certain probability of signalling false alarms.



When you connect 10 units, each of which signals one false alarm per month, you get a false alarm every 3 days.  When two of those units are misplaced (per code) outside bathrooms and laundry rooms, you get a false alarm every day.



By disconnecting the 3 most problematic of our units, and routinely cleaning the others, I've gotten our false alarm rate down to one a week or so, evenly distributed among all the detectors. Maybe that's acceptable, but I know one thing: when those alarms go off in the middle of the night, it absolutely never occurs to me that there might be a real fire.

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