Posted: 8/13/2014 8:25:31 AM EDT
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During thunder storms, just prior to lightening, my smoke detectors go off. They are hardwired, battery back up and new batteries. They have done this since the house was built. Finished building 4-5 years ago. Random survey at work and with friends say this does not happened to them. Any suggestions?
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No clue. When we first got our house (125 year old house), one night the smoke detector in the stairway started going off. We have ALL BATTERY alarms, keep in mind. No smoke, nothing we could find that should set it off. Removed the detector from the area and it stopped. Brought it back to the stairway and it started again. Grabbed a couple alarms from around the house and they ALL went off in the stairway. Called the local fire chief, asking what else could set off the detector. He said nothing else should, especially 3 different alarms. He actually came out to our place at 11pm (volunteer, he had a job so thanks again!) to check it out. He found nothing. Never did it again.
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Quoted: During thunder storms, just prior to lightening, my smoke detectors go off. They are hardwired, battery back up and new batteries. They have done this since the house was built. Finished building 4-5 years ago. Random survey at work and with friends say this does not happened to them. Any suggestions? EMP from lightning is inducing current in the unshielded DC wiring, setting off the detectors. Remove from DC wiring, alarms should stop. ETA: Sounds like I'm dead wrong. See next post. |
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Bet you a dollar that you have ionization detectors:
http://electronics.stackexchange.com/questions/15597/why-do-smoke-detectors-go-off-when-lightning-strikes also, see http://www.nfpa.org/safety-information/for-consumers/fire-and-safety-equipment/smoke-alarms/ionization-vs-photoelectric Basically, the lighting is near enough to your house that your detectors are effected. If it is enough of an issue for you, you might consider swapping them out for photoelectric ones. You may also try getting some compressed air and blowing them out, you may have cobwebs and dust in there that are effecting them and making them overly sensitive. Detectors generally only have a 10 year life span, so check one and see if the builder had old stock laying around that he installed. There should be a 'born on' date either printed, stamped or molded on your detector. |
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Bet you a dollar that you have ionization detectors... I own a small alarm company and this is spot on. The cheap detectors you get at home depot, walmart, etc, are almost all ionization type. Those have a couple of advantages; they're cheaper, and they're faster to respond in certain types of fires (smoldering vs. blazing). The 120-volt hardwired with battery backup are almost all ionization type, and the cheap 9-volt battery type are almost all ionization type as well. So even getting away from the hardwired aspect of it, if you replace the hardwired detectors with the 9-volt battery ones, you'll probably still have the same issue since most of those are ionization style. Photoelectric are absolutely the way to go in 90%+ of installations; the exceptions being primarily clean-electronic areas like computer rooms, telephone-switching rooms, etc. Most people don't have issues with ionization detectors and can get by fine with them, but for those that do have problems, the only real fix is a photoelectric type. Fwiw, the photo type is what we install more than 99% of the time; homes, churches, schools, theaters, whatever, we use photo almost exclusively. Photo's are most often false-triggered by ingress of bugs, steam and dust. Ion's can more easily be false-triggered by dust, atmospheric/electrical influences such as lightning, and even oddball things like pollen. Photoelectric style can theoretically be made to last a lot longer than ionization as well, since you can clean it to pretty much like-new status with some care & compressed air. Ionization smoke detectors are a lot like CO detectors in that they have a degrading/deteriorating element or isotope in them, and that degrading process simply can't be stopped. Like tritium sights - no matter how well or often you clean them, they're going to get perpetually dimmer and there's just nothing that can be done about it. |
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they're faster to respond in certain types of fires (smoldering vs. blazing). To clarify what quake said, ionization detectors tend to alarm more quickly to fast-burning flaming fires which can produce very minimal smoke initially, while photoelectric detectors respond more quickly to smoldering fires, which tend to put off heavier, sooty smoke. Anything sold in the US should meet UL standards, so the practical effective difference in performance should be minimal. (In the true ARFCOM spirit of "get both", I have dual sensor alarms in my house  ).
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Quoted:
To clarify what quake said, ionization detectors tend to alarm more quickly to fast-burning flaming fires which can produce very minimal smoke initially, while photoelectric detectors respond more quickly to smoldering fires, which tend to put off heavier, sooty smoke. Anything sold in the US should meet UL standards, so the practical effective difference in performance should be minimal. (In the true ARFCOM spirit of "get both", I have dual sensor alarms in my house ).
Quoted:
Quoted:
they're faster to respond in certain types of fires (smoldering vs. blazing). To clarify what quake said, ionization detectors tend to alarm more quickly to fast-burning flaming fires which can produce very minimal smoke initially, while photoelectric detectors respond more quickly to smoldering fires, which tend to put off heavier, sooty smoke. Anything sold in the US should meet UL standards, so the practical effective difference in performance should be minimal. (In the true ARFCOM spirit of "get both", I have dual sensor alarms in my house ).
The dual style are best. Depending on the type of fire, there can be a huge difference in when the detector activates. http://www.newsnet5.com/money/consumer/consumer-specialist/results-of-smoke-alarm-test-have-some-experts-sounding-an-alarm-but-not-ohio-fire-marshal |
I can't help responding to this thread. 
Some time ago my Team and I developed a lightning tracking device for certain applications and I spent more hours observing lightning strike properties on very fast Agilent equipment -than maybe I should have. Hundreds upon hundreds of hours. Some of the characteristics I observed were the common polarity reversals, and the uncommon strikes to 60 Hz power lines when to my amazement, the waveform of the strike was nicely modulated with 60 Hz! A couple folks here will appreciate this observation. 
Another interesting phenomena when looking at nearby storms using a short vertical antenna [like a broadband VHF antenna] and feeding the signals thru a low frequency preamp in the 100's of kHz to a logarithmic amplifier... ...then into an audio amplifier. Was a sound starting from a low audio frequency, increasing in pitch over maybe 15 seconds, to a high note and then BOOM, a nearby lightning strike. [This has nothing to do with high atmospheric 'Spheric' events taking place over half the earth and being detected. I'm talking abt a local event and this can be easily reproduced by anyone sufficiently motivated, at nominal cost nowadays, ask] At the barn, I have an IC7000R monitoring a VHF freq all the time and a few times a year when there I'll observe a similar phenomena, the squelch will break, the noise will increase, and after maybe 20 seconds or so, there will be a lightning strike nearby. If I had an audio amplifier and log amp connected to the antenna, the same aforementioned increasing audio note would be heard. This is probably the same sort of static dishcharge in a sort of relaxation oscillator that folks talk abt making their hair stand on end before a strike. 
Re the smoke detectors, the Ionization type are internally VERY well shielded from RFI or... EMP
Take one apart and look... The OP's issue I would bet a donut to $5, is incorrect wiring, [grounds to the control panel, etc.] in his installation. OP, why not get the manual for your system, and look at the wiring and see if any short-cuts were taken? Or the equipment may just be a bad design. |
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It is a good thing to change out your detectors every few years. Mine would go off if I cooked bacon without my exhaust vent on. They didn't go off when my fireplace lost its draft and the house filled with pretty dense smoke.
I was very lucky. You can buy smoke detectors that you can link together with a traveler wire so that if one zone triggers, they all go off. |
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Quoted:...You can buy smoke detectors that you can link together with a traveler wire so that if one zone triggers, they all go off. Building code for new construction (at least in Arkansas and I suspect most US states) require that if any detector in a dwelling sound, they all sound. (The exception is if the dwelling has a genuine detection system, with sounders separate from the detector heads themselves. The tandem-wire approach is how that "all must sound" requirement is usually handled if an electrician supplies & installs the detectors during house construction; he simply runs one extra conductor between all the 120-volt smoke detectors (ie, the tandem wire), and when one detector goes off, they all go off sympathetically. Not a bad approach, but can be nearly impossible to do after the fact if not done during construction. |