The 10-year life of home smoke & CO detectors - Page 1
Forum section: electronics / beginners

author: Peabody
author_rank: Super Contributor
timestamp: May 17, 2024, 03:22:14 am
content: I thought it was because of Americium decay. But Americium's half-life is 432 years. And of course the newer photoelectric detectors don't even use Americium. But it's still 10 years, and some detectors beep at you for replacement after 10 years of use. Apparently it's just because the cheap electronic parts used in detectors are subject to failure. But I have mixed feelings about that. Maybe a detector that has functioned for 10 years is a better bet than a random new one.And it's also so Kidde and other manufacturers can have automatic repeat sales.

author: ataradov
author_rank: Super Contributor
timestamp: May 17, 2024, 04:10:43 am
content: Many of them don't have a replaceable battery, so 10 year life is due to the battery. Plus CO detectors use chemical sensors, which are consumable and degrade over time.And the parts are cheap to match that life time set by the battery. Those things are pretty well optimized for their expected lifespan.

author: jwet
author_rank: Frequent Contributor
timestamp: May 17, 2024, 04:17:54 am
content: Don't get conspiratorial- this is just very conservative and smart and if you think about it, why would you quibble about a $20 investment every ten years. Yes, the Americium half life is not an issue but other things might be. Electrolytic caps have lives in the 2000 hour range of continuous maximum use. LED's have output loss over time that would be significant over 10 years. Resistors have defined aging characteristics- 10 years is a long time. Even semiconductors like voltage references change over time. This assumes everything is perfect. If you live in salt air, things deteriorate faster, inexpensive IC's used in consumer goods themselves might have possibilities of contamination internally and less than infiinite lifetimes. You don't have to pitch everything but pitching safety systems makes a lot of sense especially after a decade. I have fire extinguishers in my house that I've never used thankfully. When they get to 5 years, my son and I will go out in the woods and have a great time emptying them. Did they function- of course. Should they have been pitched- of course.

author: bdunham7
author_rank: Super Contributor
timestamp: May 17, 2024, 04:30:38 am
content: Quote from: Peabody on May 17, 2024, 03:22:14 amHaving the product 'expire' also reduces legal liability. If you didn't do that, then how long would the manufacturer remain on the hook if the product failed?

author: richnormand
author_rank: Unknown
timestamp: May 17, 2024, 09:35:14 pm
content: The CO monitors I have are hard coded to give you a warming after a set time from activation.As previously mentioned the detectors will lose sensitivity after time and might depend on previous exposures as far as I know.Mine were very sensitive to hydrogen too (car battery charging for example) in the garage.For the fire detectors I replace the 10 year rated ones as the lithium primary batteries fail.Once I get the replacement I keep the older unit, replace the three lithium batteries with a simple 9V one.It is then used in other places like my home office, 3D printer, electronics bench, etc... so I end up with multiple unit on each floor.Each one get a yearly (to do list on my birthday along with checking fire extinguishers) smoke test with a partially wet paper to generate smoke.Over the years I only found one that did not respond to smoke, all the other failure were draining the battery too fast from electrolytic caps current leakage.So instead of throwing them away I "check and verify" the old ones and renew to new ones in the main areas.

author: Haenk
author_rank: Super Contributor
timestamp: May 18, 2024, 11:44:58 am
content: I think the optics just gets too dirty over a longer period - even in smoke-free homes. Even with auto-adjusting this might reduce sensitivity by a lot.Btw. these are not flawless lifesavers. The house next to my brothers house burnt down with the fire spreading inside the ceiling, so the detectors had no chance to react. They only noticed the fire because the ceiling light went off.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: May 18, 2024, 12:00:08 pm
content: Quote from: richnormand on May 17, 2024, 09:35:14 pmYes. As ataradov said, CO sensors work via chemical reaction, so the more CO they are exposed to, the faster they wear out.

author: tszaboo
author_rank: Super Contributor
timestamp: May 18, 2024, 02:02:20 pm
content: Quote from: bdunham7 on May 17, 2024, 04:30:38 amMine also tells me to "Test weekly".I don't think anyone ever did that.

author: Kleinstein
author_rank: Super Contributor
timestamp: May 18, 2024, 05:13:16 pm
content: At least in Germany also the smoke detectors with a battery for 1 year nominal as supposed to be used for a maximum of 10 years.It is likely dirt accumulation that is the issue, but it is also difficult to predict reliably how the parts age. Ideally most parts should last longer, but there are things like wisker growth and corrosion when used in a more humid environment.I think that can already be an issue earlier is insects (or spiders) finding a nice hiding place, possibly plugging the inlet paths.

author: aliarifat794
author_rank: Regular Contributor
timestamp: May 19, 2024, 08:25:44 am
content: Manufacturers like Kidde recommend a 10-year replacement period to ensure the detector's performance remains at an optimal level. While it might seem like a push for repeat sales, this recommendation is grounded in ensuring safety.The electronic components inside smoke detectors degrade over time due to environmental conditions like dust, humidity, and temperature fluctuations. These conditions can affect the sensitivity and reliability of the detector.

author: perieanuo
author_rank: Frequent Contributor
timestamp: May 20, 2024, 12:18:10 pm
content: Quote from: tszaboo on May 18, 2024, 02:02:20 pmit must be the same idiots saying the differential disjunctors need to be tested once a month.yep, I will cut the power in all my house monthly on purpose