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Sometimes my hardwired smoke alarm goes off for a few seconds for no apparent reason. For example I am not cooking or burning any substance. It is 3 years old and has a new battery.

Other than smoke, are there unusual gases or particles that will activate it?

The ionization type detector in question is a BRK First Alert Model No. 9120B

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What type of smoke alarm do you have is a Photoelectric or Ionization as they both have different triggers. – iamchristos Jul 5 '13 at 9:51
@ChristosAmarandos it's look like it's a Ionization type detector. – aberration Jul 8 '13 at 16:57
up vote 2 down vote accepted

I've seen them triggered by steam, dust, and aerosols (hairspray).

Basically, they are succeptible to small, airborne particles. Most smoke detectors activate when the particles of smoke (or other substances) "block" the detector (which is usually either alpha radiation based or optical).

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I notice also that it's can be trigger by steam, for example when taking a shower. – aberration Jul 5 '13 at 15:18

I've mainly found that apart from smoke that drywall (Gyprock/Plasterboard) dust can set off smoke alarms in an instance.

Also, electric power tools (like drills) can cause a spark which produces a smoke like odor setting them off in an instance.

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An electrician added a ceiling fan to the same circuit of my wired smoke alarms and that would trigger the alarms for short periods of time when the fan was running, it was very intermittent and it could be days between alarms. See if there's anything "running" or being turned on and off at the time of your next alarm. You can also vacuum the detector to take care of any build up of dust, this is a good thing to do yearly anyways.

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I don't think that anything was running but I will look this next time it's happen. – aberration Jul 8 '13 at 16:54

My hard wired smoke alarms go off for no reason once in a while. I noticed it often happens during sudden weather changes so it might be humidity. I also wonder if small insects might get into the alarms and trigger them

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Most hard wired smoke detectors made within the past 5 years also detect Carbon Monoxide- which is a good reason to get everyone out of the house until you know what's causing the problem.

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Even if the landlord said me that it was doing CO alarm it is not written on it so I guess it's not detecting CO. I have a bunch of other device for detecting CO and so far it's didn't measure anything. – aberration Jul 5 '13 at 19:40

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