Smoke detectors

[ArkTinkerer]

Was reminded of a task we did last year that most people don't think about. Most of us know to change our smoke detector batteries about every six months or at least every year. New models are out that last years with a permanent battery.

One thing many of us are old enough to have, without being aware of it, is outdated smoke detectors. A smoke detector life, depending on model, is about 10 years and some only 7. So, even if you replace the battery, the detector itself may no longer function. We swapped all of ours this year to the type with the permanent battery. Some of our detectors were over 15 years old.

Just a small PSA.

 

[braumeister]

I had never heard that before.
Looking at the NFPA website, they say you only need to replace ones with non-replaceable 10-year batteries.

The kind most of us have, with replaceable batteries (usually 9-volt), shouldn't need replacement (except the battery every year).

Installing and maintaining smoke alarms - NFPA

 

[samclem]

The kind most of us have, with replaceable batteries (usually 9-volt), shouldn't need replacement (except the battery every year).

Installing and maintaining smoke alarms - NFPA

No, they say every 10 years. From a text box at the site you linked to:

Replace all smoke alarms when they are 10 years old. To determine the age of your smoke alarm, look at the back where you will find the date of manufacture. Smoke alarms should be replaced 10 years from the date of manufacture.

It's cheap insurance.

 

[ArkTinkerer]

When purchasing rental property we have found smoke detectors with the radioactive emitters. Those were phased out in the '80s I think. Don't know if the half life of the emitters would be the limiting factor in those?

Most other electronics the limiting factor is often the electrolytic caps. They do dry out over time. I'm sure they could make ones without that issue now but it would cost a few cents more so I suspect they will do it as cheap as possible even if it limits the life of the product.

 

[braumeister]

No, they say every 10 years. From a text box at the site you linked to:

Thanks! I completely missed that.

 

[Walt34]

All of ours were "smoked" by a near-miss lightning strike last spring so I replaced them then. They were due anyway.

When we repainted FIL's house a few years ago we found that his was over 25 years old! I doubt it would have gone off if we'd put it in a fire.

 

[Car-Guy]

For me, I test mine before and after I replace the batteries (twice a year) I use the test button and the smoke from a candle. I'm not sure that's a "bullet proof" test but if they don't pass, then I replace them immediately. And I've found a few that failed the test after a few years in service. If I ever stay in the same house for ten years, I guess I'll need to think about replacing them all.

 

[samclem]

When purchasing rental property we have found smoke detectors with the radioactive emitters. Those were phased out in the '80s I think. Don't know if the half life of the emitters would be the limiting factor in those?

They contain americium, I think the isotope responsible for making smoke detectors work has a half-life of over 400 years. So, it was probably the capacitors that cause those detectors to crump out, too.
I hadn't heard that they were no longer available. Last advice I heard was that these "ionization" detectors were useful in some places where the "photocell" ones weren't.

 

[martyp]

I tested mine last week while cooking.

 

[45th Birthday]

I tested mine last week while cooking.

Yes, when my wife cooks we rely on them to tell when dinner is ready.

Another thing while we are on the topic is that carbon monoxide detectors also have a finite working life and you should determine when that is. Ours are centrally wired and beep when they die. Not sure if they all do, but worth a look.

 

[pb4uski]

We recently had all of our replaced under warranty so we're good to go for another 10 years.

 

[ERD50]

The OP makes a good point, and it isn't mentioned very often (I think I only know because I read and research this stuff and might actually read the manual). Journalists should bring this up when they mention battery replacement with the time change - check the age also. But then...

I tested mine last week while cooking.

Yep.

I've only recently replaced the original AC powered alarms in our house (I also have a battery type in each bedroom, and the basement. So they were ~ 28 years old, and they still seemed to work fine up to that point (the one near the kitchen would alarm with high temp oven settings or aggressive frying). I replaced the one near the kitchen with one with a silence button, and replaced the other while I was at it.

I've had a couple CO ( not CO2 ) detectors as well. They say those are good for something like 7 years. One was ancient, but still alarmed with the prescribed smoke test. The other is ~ 8 years old, I think I'll replace that soon. When I replaced the ancient one with the same model as my ~ 7 year old one, I found they updated it to actually display a message that it is non-functional after ~ 7 years. Pre-programmed obsolescence, but I guess it makes sense.

-ERD50

 

[Hermit]

I just bought a CO and Propane detector for my motor home. It is to be replaced at 5 years from the date of manufacture. It will start going off at that time.

 

[rbmrtn]

T
I hadn't heard that they were no longer available. Last advice I heard was that these "ionization" detectors were useful in some places where the "photocell" ones weren't.

Still in use, Smoke Detectors and Americium

Remember the eagle scout using smoke detectors for a badge...

Nuke Kid On The Block - Nu Energy ™ Research Archive

 

[Goonie]

I replaced all of our smoke and CO detectors last year. I change out the batteries twice a year, whether they need it or not. I figure a new battery is the cheapest insurance I can buy.

 

[travelover]

I had some mice in the refrigerator compartment of my camper. I stuck my weed eater exhaust into the vent to smoke them out and / or kill them. I was amazed that the smoke alarm went off inside the camper before the CO detector.

 

[jazz4cash]

I replaced the hard wired smoke detectors the builder installed when they were ~12 yrs old. I was pleased to find a combination model (smoke and CO) that was plug n play. I was surprised to find the builder had installed the wiring to activate all alarms when any unit is triggered. The old alarms did not use this feature. The new ones yell "FIRE!" or "CO!" throughout the house when any unit is tested or triggered.

 

[Corporateburnout]

I replaced the hard wired smoke detectors the builder installed when they were ~12 yrs old. I was pleased to find a combination model (smoke and CO) that was plug n play. I was surprised to find the builder had installed the wiring to activate all alarms when any unit is triggered. The old alarms did not use this feature. The new ones yell "FIRE!" or "CO!" throughout the house when any unit is tested or triggered.

We have a total of 8 talking hard wired detectors, 9 including a heat sensor in the garage in our (4year old) townhome, 5 of those are CO/smoke while the others are smoke only. They are all connected so when one goes off they all do. I replace the batteries every Fall and I test them every two months or so. I was having problems with annoying false alarms and when I called the manufacturer First Alert they said that combination alarms should be replaced every 5 years and smoke only detectors every 10 years from date of manufacture. Apparently the builders had them in stock for a couple of years before installation so I plan to replace the combination alarms in the spring or after the next false alarm whichever comes first.

 

[jazz4cash]

We have a total of 8 talking hard wired detectors 9 including a heat sensor in the garage in our (4year old) townhome, 5 of those are CO/smoke while the others are smoke only. They are all connected so when one goes off they all do. I replace the batteries every fall and I test them every two months or so. I was having problems with annoying false alarms and when I called the manufacturer First Alert they said that combination alarms should be replaced every 5 years and smoke only detectors every 10 years from date of manufacture. Apparently the builders had them in stock for a couple of years before installation so I plan to replace the combination alarms in the spring or at the next false alarm whichever comes first.

Our units are made by Kidde and they recommend replacement at 7yrs. They also have an audible end of life alert. I replace the batteries when the unit detects a low battery condition. In the past when I have replaced batteries, they still have decent voltage for use in other non-critical applications.

 

[zinger1457]

Thanks for the heads up, looks like I'm long overdue in replacing the 16 year old smoke detectors in my house.

 

[foxfirev5]

Last summer we bought a dozen from Home Depot in bulk to replace our 11 and 18 year old models. I have all of them changed out in both houses with about 1 1/2 hours labor. Cheap insurance.

 

[ArkTinkerer]

We actually have a very old one we left up in our personal home--Its not really a smoke detector, its a fire alarm. Has a wound up spring that releases a hammer mechanism when a bit of metal with a low melting point lets go.

 

[GalaxyBoy]

As a fire protection engineer I'm quite embarrassed I was unaware of the recommendation to replace smoke alarms after ten years. Oh well, I don't do residential work anyway and rarely, if ever, encounter smoke alarms (vs. smoke "detectors," which are by definition connected to a fire alarm control panel as part of a fire detection/alarm system).

And ionization-type smoke alarms containing a very small amount of radioactive material are very much still in production. Most of the smoke alarms installed over the years are of this type simply because they are cheaper than photoelectric.

I'm off to the big box home improvement store AFTER Black Friday to buy replacements. When you design fire protection systems for a living, it would be damn embarrassing to have your house burn down around you while you sleep because twenty bucks worth of equipment had outlived its useful life.

 

[samclem]

We actually have a very old one we left up in our personal home--Its not really a smoke detector, its a fire alarm. Has a wound up spring that releases a hammer mechanism when a bit of metal with a low melting point lets go.

Pretty neat, I've never seen one of those. Probably not very sensitive, but nothing to go out of date (unless the spring takes a "set" and loses it's "umph").

The modern smoke detectors are really a marvel of technology/low cost. In the "life-years saved per dollar" department, they've got to be near the top.

 

[BrianB]

Our HOA did repairs to several units due to ice dam damage. Part of the work required removing / reinstalling water heaters. This required pulling permits and an inspection when the work was done to get a final sign-off.

Even though the permit had nothing to do with smoke / CO detectors, the inspector verified they were present in the required locations (near bedrooms, every level of home, etc.), and even pushed the test button to confirm they worked.

I feel better knowing that everyone has working detectors - a surprising number of our neighbors had just pulled them down when the low battery "beep" started!