Smoke/CO detector lifespan?

Hi,

One of the combo CO/smoke detectors here started acting up.

After consulting the 14 (!) different conditions that can be signaled by appropriate combinations of lights and horns, it seems this one boils down to: "System error. You're SOL" OK, fine. Buy a replacement (of course, this particular model is no longer sold so that means researching *current* offerings).

But, it begs the question: what *is* the useful life of such a device? IIRC, it was O(10) years -- so, this unit comes in at roughly that point (9 years to the day?).

Also, am I correct in noting that the ionization type detectors can't be "stock-piled"? I.e., buying extra for the future just means any *unused* units will be dying at the same time the *used* units crap out... (?)

However, that is *not* true of the photoelectric units?

Any similar consequences for the CO detection?

(of course, anything with a "built-in" battery is suspect... "freshness seal"?)

--don

Reply to
Don Y
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Many of the ionization detectors I've seen have an "expiration date" printed somewhere on the inside of the unit.

Reply to
bitrex

Probably the carbon monoxide section, which has a short useful life. However it might also be the ionization chamber that needs cleaning. If it's in the kitchen, clean the grease out with alcohol or solvent.

Any reason you didn't bother disclosing the maker and model so that I can determine which sensor it uses and which has failed?

Obsolescence is the price of technical progress.

Most web sites say 10 years. Americium 241 has a half life of 432 years, so it's unlikely to be caused by radioactive decay. If it's the smoke detector section that's failing, my guess(tm) is accumulate crud in the ionization chamber. Alcohol or solvent plus maybe some compressed air.

How to clean a photo-electric smoke alarm:

Nope. With a half life of 432 years, methinks stockpiling ionization detectors is quite practical. One of mine is about 30 years old, and still works fine.

The problem with photoelectric detectors is that they suck more power than an ionization detector. Most run on central power from an alarm panel. Ionization detectors will detect smaller particles, which means they'll detect a fire faster. Unfortunately, that also means it will detect my burning dinner or chemistry experiment gone awry, which was roughly what happened a few days ago.

Yep. There are 4 different types of sensors, each with their own issues. The lifetimes are limited. 5-10 year is typical. Wikipedia says the fuel cell variety is the most common in the USA. I've only seen a few with replaceable sensors.

This might help with your shopping spree:

These days, they put expiration dates on everything. [Insert conspiracy theory here].

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

It was located in the bedroom hallway.

(curiously, it's damn near impossible to get an *authoritative* answer regarding where detectors are allowed *and* prohibited!)

I'd have to fetch it out of the trash. It's a cheap enough item that I'm not going to try to pinch pennies to avoid replacing it!

But it doesn't do CO as well (?)

All of the detectors, here, are AC+DC backup. Local fire department had claimed photoelectric good for smokey fires (i.e., before visible flame) while ionization good for open flame. And, in the typical "never wanting to be pinned down" fashion, advocated using *both* technologies (even in the same detector!).

Yeah, my first glance at available devices told me this wasn't going to be a *quick* decision. :< *Talking* detectors? Ick! It's annoying enough listening to it chirp when the battery needs to be replaced; I think I'd beat it with a baseball bat if it started telling me "replace the battery; replace the battery; replace the battery..." :>

Of course, any expiration dates are carefully hidden in a place that can't be observed while the product is in its blisterpack!

The unit I discarded only had a manufactured date (I assume that is what it was as it said "SEP xx, 2004" -- hard to imagine it

*expired* 10 years ago as I distinctly recall installing it to replace one of the previous units -- and we've only been here ~20 years)

I should pull down the other units and see what they have by way of dates (replace everything at the same time as I probably

*installed* them all at roughly the same time!)
Reply to
Don Y

Well, the main thing about talking detectors is that I can hear the one I have in the hall. The other ones that just beep are almost out of my hearing range. I have very poor high frequency hearing now days, so the talking ones are useful.

Bill

Reply to
Bill Gill

What sound do they make? Coughing?

Cheers

--
Syd
Reply to
Syd Rumpo

...

....

CO detectors typically have a 5-7 year useful lifespan. Some older ones keep merrily pretending they work after that, but don't. False sense of security and all that.

Newer ones loudly proclaim that they are dead when the time is up (presumably a statistically secure period _before_ they actually stop working utterly.) Presumably someone got sued over the old version not admitting it was not longer functional.

Stockpiling is not a good plan, AFAIK.

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Cats, coffee, chocolate...vices to live by 
Please don't feed the trolls. Killfile and ignore them so they will go away.
Reply to
Ecnerwal

Oh, so it's not that the little crickets are too *far* to be heard but, rather, just operating in the wrong freq range? Do they talk *loud*? I.e., loud enough to awaken you from a sleep?

I figured there would be some value to "the battery is low" vs. "CO detected" vs. "false alarm" vs. "" instead of

2 blue flashes + 1 beep = fire; 3 yellow flashes + 2 beeps = CO; 1 red + 1 yellow + 1 blue = lunch is ready...

But, I hadn't considered the fact that the chirps might be hard to hear. I seem to be able to hear them through concrete walls!! :(

Reply to
Don Y

It's not a matter of "not wanting to be pinned down", it's a matter of detecting fires, and there is a significant difference in detection time WRT detector type and fire type. Unless you don't care about one type of fire, there is no "best" type of detector, other than both. On the third hand, for locations where you expect smoke without fire, a heat detector may be best. There's one about 3 feet from my stove, for instance. Directly over the oil-fired boiler, as well. Smoke detectors are a bit further away from those items, so there is less trouble with having your steak interrupted, or the oil-burner service guy setting off the smoke detector.

For photoelectric detectors, you would prefer one with good bug exclusion - bad ones are great for detecting spiders.

--
Cats, coffee, chocolate...vices to live by 
Please don't feed the trolls. Killfile and ignore them so they will go away.
Reply to
Ecnerwal

Don't cook in the hallway.

I am not an authority. The recommended location is in doorways, hallways, and along the natural escape route for hot air and smoke. For example: Since no two homes are identical, some guidelines are helpful.

CO has about the same density as air. Therefore, it can be located almost anywhere. Hot air and smoke rise, so it needs to be near the ceiling. Hot air increases the inside air temperature causing the smoke to try and escape via open windows and vents. If you start a fire in, for example, the bedroom, try to visualize where the smoke will accumulate and where it will travel if the windows and vents are open. Put the smoke detector in that path.

The usual screwup is to put the smoke detector too high, such as in a cathedral ceiling. If the windows are closed, the smoke will soon rise to the ceiling. However, if the windows are even slightly open, the smoke will prefer to exit out the window, and leave the ceiling area alone for a while. Eventually, it will get to the ceiling, but only after a delay.

If all else fails, ask your local fire department. Locally, they offer safe advice, such as more smoke detectors are better. Oh well.

Incidentally, don't put one near the house phone. I heard a story where someone was trying to phone 911 and the noisy buzzer prevented them from hearing the 911 operator.

Trash? Don't throw radioactive anything in the trash or landfill. It's considered hazardous waste. First Alert will allegedly accept them in the mail for disposal and recycling of the electronics.

True. I have a separate CO detector. At the time, the combo units were more expensive than just a CO detector. Since I already had an ionization smoke detector, I went for cheap. I later picked up an elaborate CO detector, with an LED indicator, at a thrift shop. It worked nicely for about a month before it died. That's when I discovered it has a finite lifetime.

As of 2011, Calif code requires AC powered smoke detectors on all residential transactions and new construction.

Ionization detectors are more sensitive to cooking type fires:

It's worse than that. Manufacturers of everything from wireless routers to automobiles retain the same outside and packaging appearance of their products, while drastically modifying the contents. Such changes can usually be identified only by a single digit change in the serial number, or something equally obscure. Lots of advantage based on the assumption that the buyer has no idea if it's the latest greatest version, or some antique that's been slowly depreciating on the shelf. The dealers love it because they're no longer stuck with obsolete inventory. The manufacturers love it because they can now tell the dealers that they don't need to return old stock every time a new product is released. I suspect that smoke alarms are much the same way. Same outsides, same package, different electronics.

I like the talking CO alarm. Add a "warranty timer" and it will loudly announce that it's time to buy a new alarm. Kinda reminds me of the talking seat belt alarms of the 1980's.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Not clear it makes much difference. I have multiple detectors replaced on a staggered schedule. You can check a smoke detector. Most of us don't have the tools to check a CO detector without hurting it. I asked myself...self...is it worth $20 every five years to not be dead? I'm really cheap, but the answer to that one doesn't take a genius.

Reply to
mike

My '83 280ZX had talking "reminders" which I thought were rather neat... instead of some buzzer noise and having to scan the dash for why, I'd hear, "passenger door is open", or "fuel is low".

My understanding is that voice alarms are common in aircraft... sexy voice always gets your attention >:-} ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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Reply to
Jim Thompson

We don't -- usually! :> It was the most convenient place to locate detectors without having to add wiring *in* each of the bedrooms.

There doesn't seem to be a concensus on many of the "problem areas"... places where a fire is actually *likely* to get started!

E.g., garage, laundry room, furnace room, water heater, kitchen, etc. Some places advise certain *types* of detectors in these locations (e.g., "heat" instead of "smoke" or "CO"). Other places (regs) prohibit them -- presumably because of false alarms or being replaced with the "wrong" type of detector for that particular locations.

:<

You have to avoid "corners" (including where ceiling meets wall). And, in direct airflows for vents, etc.

My issue was far more basic: do I put one in the kitchen or do I

*not*?

Most code regs intimidate even the "experts".

E.g., here, a vent is not required in the kitchen. OTOH, if one is

*installed*, then it must have a specified minimum flow rate. ("Huh? *0* is OK but nothing ELSE less than XXX CFM is??")

I tried that. "One for each bedroom". When pressed regarding the other likely places for fire/CO, they avoided answering.

Argh! I'll have to go fetch it out, then. I think this saturday is hazardous waste day so that will be good timing!

Yup. Got screwed buying a USB hub, recently, with "slightly different guts" -- causing it to work slightly different in the application! :<

As I am unable to evaluate the effectiveness of these devices (short of a real fire event!), cosmetics and serviceability are my main concerns. E.g., can I replace battery without having to take unit down? Can they be interconnected? How ghastly do they *look*? etc.

Reply to
Don Y

Ah, then the "alert" this one gave shouldn't be interpreted as "I'm broke" but, rather, "Time to replace me!"

Agreed. Though it means having to go through the selection exercise every "5-7 years".

Reply to
Don Y

In *their* case, I suspect it actually *was* "not wanting to be pinned down" -- see my other post regarding how noncomittal they were in indicating where detectors should, could and could NOT be located! (who am I supposed to ask, the dog catcher??)

I had considered a heat detector above the furnace. However, the "enclosure" (room?) for the furnace has particular fire ratings. Putting a hole in the ceiling for the wiring for the detector compromises that rating.

(things are never as obvious as they should be! :< )

Ha! I'd never have considered that!

Reply to
Don Y

I have to agree with this. Smoke detectors cost less then the batteries you install in them over a few years.

These all seem to take an obnoxious mix of batteries, like a 9 volt and some AAs for some lights, like an old ohmmeter.

Reply to
Cydrome Leader

Argh! That would drive me crazy! Do them all at the same time and forget about it. E.g., replace *all* the batteries on New Year's Day. Even if they aren't "bad". Batteries are cheap in the grand scheme of things. Ditto smoke/CO detectors! Buy a "set" and replace them all at the same time (instead of trying to remember which will need to be replaced next year, and the year after that, etc.)

[I do the same sort of thing with clothes: they all tend to see similar wear so as soon as one set of shoes/pants/shirts/socks starts to look ratty, toss them all and buy new! *One* shopping trip instead of *continual* shopping trips! :> ]

Well, it's more than $20 if you have more than one. But, I agree -- "cost of doing business" (where the "business" is

*living*! :> )
Reply to
Don Y

Oh? As I read it, the cited regulations (California Health and Safety Code, section 13114) do continue to allow battery-powered smoke alarms, as long as they "contain a nonreplaceable, nonremovable battery that is capable of powering the smoke alarm for a minimum of

10 years."

This would mean that a hefty lithium battery would likely be allowed.

It does seem to spell the end of smoke detectors which are powered by ordinary 9-volt alkaline batteries, which seem to have a nominal service life of a year or so in this application.

Reply to
David Platt

Find a store with a very liberal return or credit policy, such as Costco. Take it home, fire it up, see how it works, and then decide if you want to keep it.

Most such smoke detectors have some kind of seperate mounting clip or contrivance. A few degrees anti-clockwise rotation, and the whole unit comes down. That's somewhat better than climbing a ladder and working over my head (usually dropping the battery). Don't worry if it's good or bad. Y're suppose to replace the batteries at regular intervals no matter what condition.

Cosmetics? The uglier the product, the better it works.

Serviceability? If it's any good, it won't need repair. Beware of companies that have fabulous service departments.

Interconnected? What for? Do you want all the alarms to go off simultaneously, creating even more noise and confusion? I can just imagine all of them saying "Your house is on fire" without any synchronization. How will you know which one had detected a fire? How do you turn off ALL the alarms? With AC powered, there's usually an "alarm" output. Wire each to an alarm panel.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

I don't like abusing that sort of "generosity" on their part. :< I just need to do my research before making a purchase!

Yes, as do all of the units here. I just find it easier to open a "door" on the exposed surface and swap a battery out/in than having to remove the detector (for a battery compartment accessed from the rear)

Remind me not to ask what your *wife* looks like!!! ;-)

I don't want service. Or a warranty. I want to *know* it will work (for some period, "X"). I get annoyed with companies that provide liberal warranties... but you have to be hassled by returning a defective product (esp if more than once!).

We need a word beyond "warranty" and "guarantee" that means, "this REALLY *WILL* work for a period of X" (not "or we'll replace it free of charge")

Yes. I want to be sure there is no way in hell you could sleep through a fire!

*I* will wake up if I hear water running in the bathroom down the hall. OTOH, SWMBO won't wake up in the presence of police, fire and ambulance immediately outside bedroom window! (I have verified this :> )

For the "chirpers", this isn't a problem. Just one REALLY LOUD alarm!

The units we have currently will indicate which unit(s) is/are "signaling" the alarm and which are merely "repeating" it.

Only "output" is one intended for interconnect. With CYA warning that

*you* aren't supposed to connect anything to it (other than *certain* products made by the same manufacturer)

Press the "silence alarm" (aka "Test") button on any unit and only the "signaling" alarm(s) keep screaming (unless the unit whose button you pressed was the only signaling unit in which case it, too, is silenced -- temporarily). So, you can at least sort out *where* the condition is being sensed.

You can also use the "Test" button to test a single station (i.e., the station whose button you are pressing) *or* all stations that are interconnected with it. Gives you an idea of just how *loud* any such alarm will actually be!

We've actually been happy with the units we have. Annoying to know we now have to "roll the dice", again.

Reply to
Don Y

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