Are Ionization Smoke Alarms Really Junk?

Without getting too deep in fire science. Let me be very clear. Different materials give off different particle sizes and gases when they burn. (ie. when you burn alcohol it doesn't give off many large/visible particles or visible flame, but it's giving off smaller invisible particles and when you burn a tire you'll see huge particulate) There are many different materials in a home and those materials have changed in the past few decades. NO single smoke detector technology will detect ALL types of fires, but ALL of the technologies have improved. Smoke detector manufacturers weren't cutting corners, stuffing their wallets with profits, or shaving manufacturing costs on ionization detectors. They have their place. 20 years ago photoelectric technology was hit-or-miss you wouldn't have dreamed of having them in your home. Ionization technology has been stable and has been successfully protecting lives and property for a long long time. I've seen both technologies work extremely well, and I've seen both fail to detect some fires, and I've seen both false alarm. If I had to choose only one technology to put in my house, I'd pick a well made photoelectric. But, I have both in my house both tied together and tied to a security system with a dialer to a central station / local fire department. I also have a third technology that I have yet to install (high sensitivity laser-based aspirating smoke detection) (they're a few thousand $'s per detector).

I'm not sure how the new construction materials burn (artificial fibers in modern carpet and upholstery). However, some materials will smolder while others will quickly ignite with active flame. Both technologies have there place.

But here are a few certainties, Ionization detectors false alarm like crazy or don't work in high air flow, Photoelectric detectors don't work well in high airflow but probably won't false alarm. NO detector should be very close to air supply registers and ceiling fans... (this is covered in NFPA 72) .... Smoke generally rises and may be subject to stratification. New construction styles with high ceilings, vaulted and cathedral ceilings, passageway arches etc, adversely effect smoke transport and detection. Smoke detector quantity and location in those environments are VERY important. Many home inspectors don't know what they should look for in the pass/fail analysis. My last house was new construction and I'll tell you that the detectors were in the wrong places and would have not performed well in a fire. I suspect many houses across the US are the same. Most home fire deaths I hear about don't have smoke detectors or the batteries have been removed.

RE: CO detector placement... see my comments in a previous thread www.hearth.com/econtent/index.php/forums/viewthread/30951/ ...
You can put smoke and CO detectors right beside each other, just make sure that the smoke detector is clear so that air can travel in and out of all sides (though the sensor chamber).
If you would like to see some of the data from NFPA 72 RE spacing let me know. Can't send the whole code...it's huge.

Detector$ said:

Without getting too deep in fire science. Let me be very clear. Different materials give off different particle sizes and gases when they burn. (ie. when you burn alcohol it doesn't give off many large/visible particles or visible flame, but it's giving off smaller invisible particles and when you burn a tire you'll see huge particulate) There are many different materials in a home and those materials have changed in the past few decades. NO single smoke detector technology will detect ALL types of fires, but ALL of the technologies have improved. Smoke detector manufacturers weren't cutting corners, stuffing their wallets with profits, or shaving manufacturing costs on ionization detectors. They have their place. 20 years ago photoelectric technology was hit-or-miss you wouldn't have dreamed of having them in your home. Ionization technology has been stable and has been successfully protecting lives and property for a long long time. I've seen both technologies work extremely well, and I've seen both fail to detect some fires, and I've seen both false alarm. If I had to choose only one technology to put in my house, I'd pick a well made photoelectric. But, I have both in my house both tied together and tied to a security system with a dialer to a central station / local fire department. I also have a third technology that I have yet to install (high sensitivity laser-based aspirating smoke detection) (they're a few thousand $'s per detector).

I'm not sure how the new construction materials burn (artificial fibers in modern carpet and upholstery). However, some materials will smolder while others will quickly ignite with active flame. Both technologies have there place.

But here are a few certainties, Ionization detectors false alarm like crazy or don't work in high air flow, Photoelectric detectors don't work well in high airflow but probably won't false alarm. NO detector should be very close to air supply registers and ceiling fans... (this is covered in NFPA 72) .... Smoke generally rises and may be subject to stratification. New construction styles with high ceilings, vaulted and cathedral ceilings, passageway arches etc, adversely effect smoke transport and detection. Smoke detector quantity and location in those environments are VERY important. Many home inspectors don't know what they should look for in the pass/fail analysis. My last house was new construction and I'll tell you that the detectors were in the wrong places and would have not performed well in a fire. I suspect many houses across the US are the same. Most home fire deaths I hear about don't have smoke detectors or the batteries have been removed.

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+1 . . . again

A few comments on the highlighted points.

No single smoke detector is good for every type of fire . . . I agree . . . which is why I have in my own home dual ion/photo-electric and why I encourage folks to purchase dual units or some of each type for maximum fire safety. As Detectors mentioned . . . what catches on fire can really make a difference in how fast the detector activates -- whether it be smoldering smoke from plastic sheathing or wood from an electrical wiring malfunction or a flaming type of smoke caused by someone who left the frying pan with the hamburgers (and grease) on the stove top and forgot to turn it off.

The PE detectors were not seen very often initially . . . as Detectors stated they were not all that reliable and were quite honestly rather expensive compared to the ion detectors. Today, that has changed.

Placement and numbers . . . I tell folks that for the best protection they should have both types, but at the very least they should make sure they have smoke detectors (regardless of the type) in their home AND that they have enough of them and have them placed in the right places. I've been on the job for 20 years now and I've seen a number of fatalities (both during body recovery and in follow up investigations) . . . and as Detectors said the two most common factors I keep seeing over and over and over again is not so much that folks have the wrong type of detector and that it didn't activate soon enough, but rather I see #1) Folks just don't have any detectors in their home or #2 (even more common) They have detectors but they are not working since they have pulled out the battery due to false alarms, didn't replace the dead battery in the detector, etc.

velvetfoot said:

I just thought I'd update this thread.
We've had 5 false alarms (with absolutely nothing going on) so far with the BRK photo/ion combos.
They go off for a short while and then stop.
There's no way to tell which one was the offender after the alarm goes off (no memory).
The BRK troubleshooting guide mentions possible loose connection, but even when I throw the breaker, the smokes make no noise, so I don't think that's the problem.
I read this morning that the Kiddes have an alarm memory function so you know which one initiated the alarm.
I also will say the BRKs seem to be an old design, with not much consideration for air sealing (energy efficiency) or annual battery replacement.
I'm going to try to give BRK a call, but I do believe Kidde is in my future.
I believe the photo/ion hardwired Kiddes are back on the shelves after the recall.
Thing is, the 3 CO detectors will probably also have to be replaced since they won't 'match' anymore.

If I get no satisfaction from BRK, (hard to think I would since it's an intermittant failure from an undetermined detector), I'll see if I can drop a line to Consumer Reports and call it a day.

I'm a little wound up because the last false alarm was 12:30 AM this morning.

Oh well.

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How is the power supply in your area . . . I have a combo unit, but it is powered by a battery and there have been zero false alarms. A lot of times we hear of false alarms or blips when the power goes off briefly, in brown-outs, etc.

If nothing else, definitely check in with BRK . . . false alarms should not be tolerated since I am of the firm belief that you really shouldn't have smoke detectors going off unless there is a real reason for them to alarm . . . otherwise we tend to get complacent and just think of every alarm as a false alarm.

velvetfoot said:

Power supply is pretty good. The alarms aren't designed to make noise when the breaker is tripped and reset, which I verified.

I talked to BRK. They suggest to disconnect from power and run on battery only to ID the culprit.
I'm not sure how long they can run on battery only and there is still only 15-20 seconds to find the bad actor.
I'm now thinking of putting them all in one place to quicker find the bad one.
Fantastic.

BRK did say they have a 10 year warranty.
It'd just be nice that on this model it'd be easier to see which one initiated the alarm.

Also, the Kidde PI2000 model (on recall) won't hit the shelves til the end of February now.

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D'oh . . . I never thought of the other obvious problem . . . a faulty detector causing the inter-connected detectors to all go off. D'oh. D'oh. D'oh.

Here's another possible smoke detector if the BRKs don't work out . . .

Ah, wasabi . . .

http://www.reuters.com/article/idUST29421020080318

I have a individual combo on the ceiling in the kitchen.
Bathroom off to one side. Laundry off to the other.

Taking a shower in August/July humid weather will set it off as will boiling pasta water. My ceiling is low enough I can reach up and twist it off and put it outside for about 5 minutes.

Most people would probably never put it back, in part because they have normal heightceilings and would be up on a chair.
I'd rather have the false alarms and play the move it game.
(If I had high ceilings now I'd build a shelf to put it on)

I don't have a lot of faith in 'recent study(ies)'.

There's a few kids in the world that might not have measles and other maladies if they didn't put faith in 'recent studies'.

billb3 said:

I have a individual combo on the ceiling in the kitchen.
Bathroom off to one side. Laundry off to the other.

Taking a shower in August/July humid weather will set it off as will boiling pasta water. My ceiling is low enough I can reach up and twist it off and put it outside for about 5 minutes.

Most people would probably never put it back, in part because they have normal heightceilings and would be up on a chair.
I'd rather have the false alarms and play the move it game.
(If I had high ceilings now I'd build a shelf to put it on)

I don't have a lot of faith in 'recent study(ies)'.

There's a few kids in the world that might not have measles and other maladies if they didn't put faith in 'recent studies'.

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Most folks do not recommend smoke detectors in the kitchen and/or near an area like a bathroom or laundry room due to the possibility of false alarms . . . that said, if someone was insisting on sticking a smoke detector in these areas I would tend to recommend a photo-electric detector in these areas to lessen the possibility of a false alarm . . . especially one with a hush feature so it could be easily silenced for those false alarms without having to risk someone pulling it down and forgetting to put it back up.

velvetfoot said:

Just as an update, I threw those six combo detectors away - too many false alarms out of the blue.
BRK is coming out with a new combo model, but althought the website catalog says August, the customer service people (who spoke with an engineer) says more like December.
I wound up getting 6 BRK photo alarms, the 7010. It has latching, which means you know which one set off the alarm even though it might have stopped alarming. If you want this feature, you can't get a unit with an old mfg. date - key is that it has an Itek certification on it rather than UL - that's how you can tell. Mine were in the June 2010 timeframe.

In 'testing' that latching feature on the photoelectric alarm with some 'punks', (not the kind that hang around on the corner), I was surprised at the amount of smoke that was required to set it off.
I wound up ordering 6 more ionization models, model 9120, which also latch. I installed one so far (have to drill holes in the ceiling, etc), and it reacts a lot quicker.

All of these are AC only - I have the wireless interconnected ones I can re-deploy (from the garage and breezway) in the event of a long-term power outage, plus the CO detectors have batteries.

One question though, the literature that came with the detectors say that there can be 12 interconnected detectors with a total of 18 devices. I'll probably wind up with 13 smoke detectors and 3 CO detectors. What exactly will happen when the maximum is exceeded?

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The system shorts out and causes a fire? Sorry, couldn't help myself . . . on a serious note . . . I'm not sure.

I saw earlier in the tread that CO detectors go bad, do smoke detectors ever go bad. Bought my house last year and several of the detectors in the house are from '02 and '05. CO detector is brand new.

I must not have seen this thread the first time through. We have BRK ionization units wired together in our MI house (not my choice, came with the house). Nothing but trouble, constant false alarms, especially when the humidity is high, and the alarm seems capable of causing serious ear damage from the close distances needed to unplug and remove the battery. No latching, so it took a long time to hunt down the one that was causing the false alarms (but did eventually). I see that latching replacements are available, which I'll get. I think connected systems should have to have a master "silence" button, otherwise it's like a bad horror movie when your house is sonically attacking you at 2 AM.

ChoppingAccountant said:

I saw earlier in the tread that CO detectors go bad, do smoke detectors ever go bad. Bought my house last year and several of the detectors in the house are from '02 and '05. CO detector is brand new.

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Most experts suggest replacing smoke detectors every 10 years . . . CO detectors should be replaced 4-7 years (depending on the manufacturer and their recommendations.)

The reasoning behind replacing the smoke detectors at the 10-year interval is based on studies which found that most did well up to 10 years and then slowly after that point the sensing unit (not the power source or audible alarm . . . which is what you are testing when you hit the test button on the detector) becomes less reliable.

I suppose if my house was over 1200 sq ft, ............say 4,000 sq ft or more............I might want a smoke and CO detector "in every room." But otherwise........isn't that overkill???????

We've always maintained one each, on each staircase landing ceiling. (Sometimes one will go off when the wife has the stove cranked.........lol).


-Soupy1957

soupy1957 said:

I suppose if my house was over 1200 sq ft, ............say 4,000 sq ft or more............I might want a smoke and CO detector "in every room." But otherwise........isn't that overkill???????

We've always maintained one each, on each staircase landing ceiling. (Sometimes one will go off when the wife has the stove cranked.........lol).


-Soupy1957

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It's all in how much you protection you want. Most experts (myself included . . . although I would not consider myself an expert . . . maybe a semi-vert ) suggest smoke detectors be placed on every level of the home, outside bedrooms in the hall and in bedrooms at a minimum. That said, it doesn't hurt to have more . . . especially since the more you have, typically the greater the chances of survival.

That said, you can go overboard and place them in areas where they may be susceptible to frequent false alarms . . . boiler/furnace rooms, near a woodstove/pelletstoe, kitchen, bathroom, laundry room, etc. . . . although it should be noted that it is also possible to have a smoke detector in one of these areas and not have a problem -- for example I have one in my laundryroom/boiler room and have few false alarms.

In my own home I have a smoke detector in the hallway (or rather I will when I'm done renovating that section), master bedroom and the aforementioned laundry room/boiler room on the first floor . . . and detectors in the two upstairs bedrooms and the hallway.

As for CO detectors . . . most experts suggest buying at least one and installing it in the hallway outside the bedroom . . . if you buy a second unit it's a good idea to place that close (but not too close -- I think it was 10-15 feet away) from your most likely source of CO . . . which could be the heating system, oven, etc.

In my own home I have a CO detector in the kitchen and one in the boiler room . . . although technically I should have one near the master bedroom the one in the kitchen is close to most, if not all, the most likely sources of CO in the house.