How Many Lives Do Smoke Alarms Really Save?

Last year, we put out a podcast called “Death By Fire? Probably Not.” It was about the remarkable decline in fatal fires in the U.S. over the past century, and explored some of the contributing factors.

Joseph M. Fleming, a deputy fire chief with the Boston Fire Department, has now written in with a guest post that challenges what we think we know about smoke alarms. Fleming has more than 30 years of experience in the fire industry (in both firefighting and management), and suggests that people think a little harder about smoke alarms.

Do Smoke Alarms Really Save Lives?

By Joseph M. Fleming

As a deputy chief on a major municipal fire department, I have preached for years about the life-saving benefits of working smoke alarms.  I also trust the lives of my family to the eight smoke alarms installed in my house.  However, some of the available data regarding smoke alarms raise disturbing questions about the actual effectiveness of smoke alarms at reducing fire deaths in the U.S.

In the illustrated edition of SuperFreakonomics, the following chart appears. It shows a continuous downward trend in fire deaths for the last 90 years and particularly for the last 50 years. 

Now I would like to provide information on how smoke alarm usage has increased over time.  Most of these smoke alarms were single-station, battery-powered ionization alarms.

Keeping this chart in mind, consider the following statement from the U.S. National Institute of Standards and Technology:

According to estimates by the National Fire Protection Association and the U.S. Fire Administration, U.S. home usage of smoke alarms rose from less than 10% in 1975 to at least 95% in 2000, while the number of home fire deaths was cut nearly in half. Thus the home smoke alarm is credited as the greatest success story in fire safety in the last part of the 20th  century, because it alone represented a highly effective fire safety technology with leverage on most of the fire death problem that went from only token usage to nearly universal usage in a remarkably short time.

If the ionization smoke alarm was responsible for most of the decrease in fire deaths in the last part of the 20th century, shouldn’t the rate of decrease have been greatest over the time period that smoke alarm usage increased the fastest?   Yet over the time period of 1977–1987, when the use of smoke alarms skyrocketed, the trend line remained relatively constant.  The death rate was trending down before smoke alarms and continued to trend down after they saturated the market.  It does not appear that ionization smoke alarms affected the trend line. NIST inexplicably ignores the trends in better building codes, reduction in smoking, better firefighting equipment, and better emergency medical care as likely reasons for the reduction in fire deaths.

I would like to analyze another statistic often cited to support the effectiveness of smoke alarms: “The death rate in fires with working smoke alarms (0.52 per 100 fires) was less than half (56% lower) than the risk of death from fires that did not have working smoke alarms (1.18 deaths per 100 fires), either because no smoke alarm was present or an alarm was present but did not operate.”

However, these numbers are skewed by including “confined fires” — i.e., fires that are contained to the object of origin.  Over this time period (2005–2009), no one died in this type of fire if the fire was big enough to operate the alarm.  If, using the same report, we only analyze “non-confined” fires, we get the following death rate per 100 fires for homes.

  • Smoke alarm present and operated – 1.15 (980 deaths / 85,100 fires)
  • No smoke alarm or alarm did not operate – 1.64 (1,640 deaths / 99,800 fires)

This is only a 29 percent reduction in death rate (1.15 versus 1.64). Given that some of the reduction is probably due to socioeconomic factors that accompany smoke alarm ownership, the reduction in risk attributable to the alarm is less than this percentage.  The numbers for apartments are even more troubling.

  • Smoke alarm present and operated – 1.17 (220 deaths / 18,800 fires)
  • No smoke alarm or alarm did not operate – 1.43 (200 deaths / 14,000 fires)

In apartments, smoke alarms only reduce the risk of dying in a fire by 18 percent (1.17 versus 1.42). 

It is highly probable that the main reason for the lack of effectiveness of operating smoke alarms is that most smoke alarms utilize ionization technology (the less-expensive kind of alarm). This technology has been shown to operate only after dangerous conditions have developed during smoldering fires, and these types of fires are extremely common during the times when occupants are sleeping and relying on the alarm to alert them.  It is one of the reasons that some states — Massachusetts and Vermont, for example — as well as the International Association of Firefighters recommend the use of photoelectric smoke alarms. (The eight smoke alarms in my house are photoelectric alarms.)  Another reason is that photoelectric alarms are far less likely to sound nuisance alarms and, as a consequence, are less likely to be disabled.

More information on this topic can be obtained at the following links:

Smoke Detector Technology and the Investigation of Fatal Fires

Smoke Alarm Information from the International Association of Firefighters


Baltimark

This still doesn't seem to address the core concern of having a smoke detector, "does this save lives of someone sleeping in the house when a fire breaks out?"

Your denominators (I assume), still contain house fires, and apartment fires, that aren't contained but still break out when the occupant is out of the house, or is aware of the fire, and is able to get out of the house.

In all of those cases, I would expect similar rates from "no detector" and "detector". But, what about the number of cases where the fire broke out while the occupant was sleeping?

All of a sudden, we might see 980 deaths/5000 fires and 1640 deaths/5000 fires. . .no longer such a small difference.

frankenduf

um, getting an ion alarm for a couple o bucks in order to decrease death by fire by 18% is a no-brainer- notwithstanding the annoyance to neighbors every time i burn the damn toast...

Aaron Fuller

Is it possible that the impact of smoke alarms has been blunted by compensating risky behaviour by users? I believe there have been some studies shown that as car braking technology improves, people's average speed - even subconsciously - goes up. So if, for example, people with smoke alarms were less likely to have taken other fire safety precautions, the smoke alarms MAY be as effective as advertised, but that their use should be caveated with statements like 'Alarms can improve fire response time, but fires themselves may be more likely.'

All that said though, I'd still in favour of them being encouraged, as long as any compensating risky behavioiur is less effective in raising deaths than the alarms are in reducing them. I can't see any 'downside' in their introduction and use, only that the upside may not be as dramatic as they seem. If (as was covered in another Freakonomics podcast in the context of 'drunk walking' being more dangerous per mile than drunk driving), their installation made people behave so foolishly as the total number of fires went up, then that would be a case for not installing alarms. But if the net effect is what's causing even a relatively low proporion of the overall decrease, I'd say go for it.

Read more...

John

Most people don't even think about their smoke detectors when it is time to change the batteries, so I doubt they are increasing their risky behaviors due to them. Having been a firefighter for 20 years, I have found the lack of basic fire safety knowledge or common sense to be pervasive to the point of an epidemic. Unfortunately, we have lost so much funding we cannot maintain our inspection or public education programs. We have little time anymore to do anything but train for and respond to emergencies.

Dave

Know what else makes them less likely to be disabled? Allowing a temporary (say 8 hours) by-pass of the "low-batter warning."

I don't understand the logic of having the thing beep ever 5-10 minutes (the infrequency increases the time to locate which one's battery needs replaced) in the middle of the night. I wake up, find out which one it is (30 minutes later) only to realize I don't have any 9V batteries. I'll pick one up in the morning but why can't I hit a button to say, "I acknowledge the battery is low and needs replaced soon. I'll do so at my earliest convenience."

That feature would keep me from the only time I've disabled mine: I put the thing outside so I could sleep.

Jacquie

Ok, so given that fire alarms are a minor factor in reducing death, can you discuss some of the best precautions people can take to prevent fires in the first place? For example, making sure wiring is up to code, etc.

Joel Upchurch

If you look at the fire deaths, you will notice that most of decrease happened before smoke alarms were available. I suspect most of the decrease is from safer heating systems. A lot of the heating systems used open flames and exposed heating elements. I grew up in a house with a wood stove with no automatic controls and before that we had a open fire place. I had neighbors who burned down two houses because they left their oven open to heat the house in the winter.

I wonder how many of the houses that lack smoke detectors also have antiquated heating systems? When my house was built in 2003 it came with 7 smoke alarms without me asking.

Also there have been big improvements in emergency care. I suspect that many victims are resuscitated that would have died a few decades ago.

Becky

Everyone should consider a monitored or "supervised" smoke/heat detector. These are photoelectric detectors that are monitored along with your home security system. Your system does not have to armed for them to work, so no matter if you are away from the home or asleep, if the smoke detector goes off, the monitoring station will immediately dispatch the fire department. I have been 4000 miles away from home and received a call from my local fire department while they were at my home responding to an alert from my smoke detector -- that's peace of mind that is well worth the small monthly fee for a monitored smoke detector!! I'm convinced that hese types of detectors are the ones that save lives, pets, and property.

James

Guess this is evidence that some of us live in vastly different worlds. Home security system? Not unless you count a couple of dogs (who'd probably lick an intruder to death) and some friendly neighbors.

James

I suspect a lot of the decrease post 1965 or so is due to the decline in cigarette smoking. At least superficially, the declines seem to be similar: http://www.cdc.gov/tobacco/data_statistics/tables/trends/cig_smoking/index.htm There are probably a bunch of linked secondary effects, too. For instance, how many fires are attributed to kids playing with matches? If the parents don't smoke, they're far less likely to leave matches &c where the kids can easily get them.

Matt v

Even if it's based on a different statistic I feel safer that not only does my smoke detector sound but the siren on my security system does as well. Also while trying to get all four of my kids out of the house if there is a fire , the first thing on my mind won't be calling the fire department. In that event it's nice to know due to them being monitored it just might help save some of my cherished belongings. While we're running out the fire department will already be in route.i know the guys at select security have already been a life saver for me.

MeanOnSunday

If you look at the major causes of house fires you will see that the great majority of fires will occur when the house occupants are awake; the situation in which a smoke alarm is least effective. More than half of all fires start in the kitchen when someone is cooking. Probably the only common fire source that is just as likely to occur when occupants are asleep is the heating system. Heating system fires are about 5% of all house fires.

Smoke alarms may very well be like air bags; useful only in a small proportion of cases or as a backup for other much more effective safety measures (seat belts). Unfortunately research in these areas tends to be done by those who are pre-disposed to find what is expected; either manufacturers, or the government offices that mandated the devices. The few that use careful data analysis to challenge the official wisdom often walk into a political firestorm because everyone "knows" they must be wrong.

Read more...

ChrisV

As Mr. Fleming says the results probably aren't even as good as his adjusted numbers. I rent apartments and the city requires detectors in each BR and outside each BR, so I see a lotof smoke alarms. Guess which ones are disabled? the less educated / lower income (as mentioned) and also those who suffer lots of nuisance alarms. Who suffers nuisance alarms? Those who smoke cigarettes or pot. Smoking being of course a significant source of fires and one that I assume is somewhat likely to occur while sleeping and/or passed out.

Brian

It's not just bad behavior that is responsible for disabling smoke detectors.

I had to disable the smoke alarm at my apartment because it was installed in the kitchen and caused too many false alarms from normal cooking. I had one apartment where a hot shower could set it off. The hush button only last for 1 minute, which makes it a chore to silence.

The designers of smoke alarms focus everything on safety above everything else, without considering real world usage. It is no different than when car alarms first came out.

Rajat

This is the first I heard of the two different alarm types, and the issues with the ionization type rings true with my family. The fire alarm goes off practically every day whenever we cook (and no, we are not burning the food). There's been times it went off within minutes of turning on the oven. We keep the battery in now in the name of safety, but for most of my life it had been disabled due to the annoyance.

The problem now is that even though it is now kept working, our reaction to it has been dulled. Much like car alarms, when I hear a fire alarm, my first reaction is not that there is danger; more likely it's just another false alarm.

Sal's Dad

In my family, the first reaction to the alarm is "the chicken is done!"

Of course, this provides a regular test, and the kids know what the alarm means, should it ever go off in the middle of the night!

Klaus Esteran

Ok if we accept the statistics don't add up, there is still the question if smoke alarms help me individually

If they reduce the risk of dying in an apartment fire by 18% I know my answer. I'd like my death risk reduced by 18%. I really like the idea, and I of course wouldn't mind the rate being higher.

I once read some information that the average time a smoke alarm gains you is one minute. I can't find the reference at the moment. One minute isn't much additional time, but if that one minute, or one additional second, helps me to reach the door or window before the smoke gets me, I'd pretty please have that one minute.

So, my smoke alarms will stay, especially considering the cost.

Dean

Klaus, if you like your death risk reduced by 18%, wouldn't you really like your death risk reduced by 80-90%. The IAFF endorses photoelectric alarms for a reason and a number of states are now starting to mandate photoelectric alarms. Most security systems will not even install ionization alarms anymore. Why? Here is why; they get disabled nearly 5 times more than photoelectric alarms because of the nuisance alarms problems (they were originally designed to detect gases not larger particles such as smoke) and ionization alarms sound more than 30-60 minutes slower in smoldering fires than photoelectric alarms. The type of fire that kills you when you are sleeping and your senses aren't as keen. THIS is why more than 50% of all fire deaths occur during the sleeping hours. Ponder this information before you go to sleep.

Adrian Butler

The International Association of Fire Fighters (IAFF) is the largest fire fighter's union in the world with over 300,000 members throughout Canada and the USA.
The Australasian Fire & Emergency Service Authorities Council (AFAC) is the peak representative body of all Australian and New Zealand Fire Brigades.
The officially documented position on smoke alarms, of both the IAFF and AFAC is that:
"Ionization smoke alarms may not operate in time to alert occupants early enough to escape from smoldering fires."
The latest edition of 'The Volunteer Fire Fighter' magazine from here in Australia carries a very informative report (including information from Boston's Chief Jay Felming) about this issue titled, 'Ionization Smoke Alarms are DEADLY'.
Please take just a few minutes and check it out:
www.TheWFSF.org/vffa

Thank you.
Adrian Butler
Chairman
The World Fire Safety Foundation
Wooloweyah, NSW, Australia

Read more...

Jay Fleming

I would like to respond to some of the comments regarding my article.

1st - I greatly appreciate Freakonomics publishing this information. It is a breath of fresh air to have people who are willing to listen to opinions that challenge the majority. I would also like to thank everyone who took the time to read and comment on my article.

2nd - I am not trying to argue that smoke alarms, i.e. ionization smoke alarms, do not help reduce the risk of dying in a fire. I am trying to argue that they are not nearly as effective as people assume they are. So although it is definitely worth spending $7 - $10 for an ionization detectors that might provide an 18% reduction in risk, it is far more effective to spend $10-$12 for a photoelectric detector that could provide a 50% reduction in risk.

3rd - A good way to analyze the benefit of alarms while people are sleeping is to look at the statistics regarding fires started with smoking materials. The vast majority occur while people are sleeping. According to the NFPA the number of deaths per 100 fires (started by smoking materials) has increased since the introduction of ionization smoke alarms. This would appear to indicate that for the type of fire that occurs while people are sleeping, which should be the kind of fire where smoke alarms could provide the biggest benefit, it has not helped that much.

http://www.scribd.com/doc/13917324/Photoelectric-and-Ionization-Detectors-A-Review-of-the-Literature-Revisited

4th - It is important for people to maintain there smoke alarms but since my argument focused on operating alarms the battery maintenance issue is irrelevant to my argument.

5th –Several people mentioned other factors that might be responsible for the decrease. I mention several in the article. I discuss this possibility in much more detail in the link listed earlier.

6th – In addition to providing better protection from fires, photoelectric smoke alarms are also far less prone to nuisance alarms. Several studies have shown that they are disabled 4-5 times less often than ionization.

7th – The best thing that people can do to reduce their risk from fire is to install photoelectric smoke alarms. The vast majority of Americans have ionization.

Read more...

Gordon Simpkinson

As Fire Marshal for the City of Palo Alto in Silicon Valley, I was privileged to participate on the California State Fire Marshal's task force on smoke alarm technology and effectiveness. That panel found and published several shortcomings of ionization alarms, and has recommended that they be phased out in favor of technology better able to resist nuisance activation.

Chief Fleming's analysis is compelling and I agree with his conclusions. Other factors which I would like to emphasize are:

- One should have smoke alarms in all recommended locations (one on each floor level outside of sleeping rooms and one in each bedroom), and that for large homes these should be interconnected so they will all sound when one is activated. Many people are under the impression that a single alarm is sufficient to protect their families. All parties including NIST, IAFF, The International Association of Fire Chiefs, Underwriters' Laboratories, the National Fire Protection Association, the National Safwety Council and others agree that having working smoke alarms in all recommended locations is the minimum recommended level of protection.

- To avoid nuisance activation, whenever possible one should avoid locating a smoke alarm within 20 feet of a fire place or cooking appliance or within 5 feet of a doorway to a bathroom with a tub or shower. Photoelectric technology is most resistant to nuisance activations, but any technology can be susceptible if located to close to a source of misleading vapors or fumes.

- To assure reliability, smoke alarms should be replaced after 10 years. For all alarms manufactured within the last 10 years, a date marking can be found inside the battery compartment or on the back cover plate. If you can't find a marking, replace the alarm with a new photoelectric alarm.

There are currently on the market reasonably-priced photoelectric smoke alarms with wireless technology that create a secure network within your home, with optional units which detect carbon monoxide as well as smoke. This is what I selected for my family in our home, and we have had no nuisance activations even with toast burnings and cooking mishaps.

On a final note, one of the best ways to avoid having the annoying low battery warning in the middle of the night is by testing the alarms at least monthly and replacing the batteries every six months. I use New Year's eve and the Fourth of July as my reminders now that daylight savings time has been pushed around so much.

Read more...

Joseph Fleming

I would like to respond to some of the comments regarding my article.

1st - I greatly appreciate Freakonomics publishing this information. It is a breath of fresh air to have people who are willing to listen to opinions that challenge the majority. I would also like to thank everyone who took the time to read and comment on my article.

2nd - I am not trying to argue that smoke alarms, i.e. ionization smoke alarms, do not help reduce the risk of dying in a fire. I am trying to argue that they are not nearly as effective as people assume they are. So although it is definitely worth spending $7 - $10 for an ionization detectors that might provide an 18% reduction in risk, it is far more effective to spend $10-$12 for a photoelectric detector that could provide a 50% reduction in risk.

3rd - A good way to analyze the benefit of alarms while people are sleeping is to look at the statistics regarding fires started with smoking materials. The vast majority occur while people are sleeping. According to the NFPA the number of deaths per 100 fires (started by smoking materials) has increased since the introduction of ionization smoke alarms. This would appear to indicate that for the type of fire that occurs while people are sleeping, which should be the kind of fire where smoke alarms could provide the biggest benefit, it has not helped that much.

http://www.scribd.com/doc/13917324/Photoelectric-and-Ionization-Detectors-A-Review-of-the-Literature-Revisited

4th - It is important for people to maintain their smoke alarms but since my argument focused on operating alarms the battery maintenance issue is irrelevant to my argument.

5th –Several people mentioned other factors that might be responsible for the decrease. I mention several in the article. I discuss this possibility in much more detail in the link listed earlier.

6th – In addition to providing better protection from fires, photoelectric smoke alarms are also far less prone to nuisance alarms. Several studies have shown that they are disabled 4-5 times less often than ionization. Switching to photoelectric smoke alarms could save several hundred due to reduced disablements.

7th – The best thing that people can do to reduce their risk from fire is to install photoelectric smoke alarms. The vast majority of Americans have ionization.

Read more...

Joseph Clare

Fleming raises some important points with respect to smoke alarms and life safety. Fleming identifies that:
1. It is unclear exactly how many lives have been saved by smoke alarms.
2. The reduction in residential fires (and associated fatalities) that have been observed in recent decades is almost certainly a consequence of a range of improvements associated with building codes, smoking behavior, firefighting equipment/strategy, and emergency medical care.
3. Socioeconomic status of citizens does influence the likelihood of a dwelling possessing a smoke alarm.

However, perhaps as a consequence of the title, Fleming’s article gives the impression that the lack of effectiveness of operating alarms is the crux of the smoke alarm problem. Although there are definitely a large number of design issues that could be addressed to improve smoke alarm functionality (outlawing 9 volt battery powered alarms being just a jumping off point for this), vocally advocating this position at the present time clouds two other major issues of more pressing importance. First, not every dwelling has a smoke alarm, of any kind. Second, smoke alarms do not work forever, and a large number of citizens that currently think they are protected are actually relying on alarms that no longer function. These points are summarized in Ahrens’ (2011) report entitled, “Smoke alarms in US Home Fires”, cited by Fleming. In this report Ahrens states:

“Almost all households in the US have at least one smoke alarm, yet in 2005-2009, smoke alarms were present in less than three-quarters (72%) of all reported home fires and operated in half (51%) of the reported home fires. More than one-third (38%) of all home fire deaths resulted from fires in homes with no smoke alarms, while one-quarter (24%) resulted from fires in homes in which smoke alarms were present but did not operate.”

Combined, this means that almost two-thirds of home fire deaths Ahrens examined occurred in properties that did not have a working smoke alarm of any type. The major reasons for failure to operate when the alarms were present were due to missing, disconnected, or dead batteries. In some respects (and this may be the case for some ionization alarms) power may have been removed in response to excessive false alarms due to poor alarm placement. In others, the dead battery of non-functionality is a maintenance issue. Regardless of the reason, these percentages almost exactly mirror those from the recent review of 47,555 fires and 663 fatalities in Canada (Garis and Clare, 2012, “Smoke alarms work, but not forever”, released through the University of the Fraser Valley, http://www.ufv.ca/Assets/CCJR/Reports+and+Publications/Smoke_Alarms_Work$!2c_But_not_Forever.pdf).

Even from the data presented within Fleming’s article, it is clear that functioning smoke alarms do save lives when compared to situations where a fire occurs in the absence of a functioning smoke alarm. Fleming argues that confined fires inflate the life-protection benefits of functioning alarms and corrects these data to indicate that the death rate in the presence of a functioning alarm is actually 29% less than without one. Given the size of the samples involved this represents a highly significant difference (rate ratio z-test = ?8.81), which translates to an estimated saving approximately 490 of the 1,640 lives that were lost, had smoke alarms been present and operated in all cases. In the same manner, the difference in death rates for apartment buildings discussed by Fleming is also significant, Z = ?2.04, and it can be estimated that approximately 36 of the 200 deaths that occurred without functioning smoke alarms could have been prevented. (As a side note here, it is questionable as to whether confined fires should have been removed from these calculations, as data from Canada analyzed by Garis and Clare has demonstrated that fires that occur in the presence of a functioning smoke alarm are smaller and more contained (on average), presumably as a direct consequence of the alarm.)

However, rather than emphasizing these benefits, Fleming argues that, “It is highly probable that the main reason for the lack of effectiveness of operating smoke alarms is that most smoke alarms utilize ionization technology.” This redirects the focus of the argument away from the potential benefits that could be expected if all homes had functioning alarms of some type, and focuses instead on the difference between ionization and photoelectric alarms. With respect to this issue, Warda and Ballesteros (2007) in the, “Interventions to prevent residential fire injury” (Handbook of Injury and Violence Prevention, published by Springer) explain that:

“A recent National Institute of Standards and Technology (NIST) Fire Research Division study reports extensive testing of current residential smoke alarm technologies in a controlled laboratory setting and in a series of real-scale tests conducted in two residential structures. These studies affirmed that both ionization and photoelectric smoke alarms consistently provide time for occupants to escape from most residential fires. Consistent with prior findings, ionization-type alarms provided somewhat better responses to flaming fires than photoelectric alarms, and photoelectric alarms provided considerably faster response to smoldering fires than ionization type alarms.”

As such, best evidence currently supports the fact that having an alarm is better than not having one, regardless of alarm type. In addition to this, many smoke alarms available on the market now have combined photoelectric and ionization capabilities, which makes this distinction moot.

In campaigning to eradicate ionization smoke alarms in favor of photoelectric smoke alarms there is a risk that Fleming has presented an argument that can be interpreted to suggest the life-safety benefits of smoke alarms are in question. Even by the data that he presents, available information demonstrates that this just simply is not the case. This article makes no useful comment as to whether alarms actually save lives, particularly in the case when someone is in the house and either asleep or impaired. Furthermore, Fleming does not discuss the much more significant issues associated with smoke alarms: first, that they are not present and functioning in every home, and second, that they stop working over time. To this end, discussion of the reasons why alarms stop functioning, and posing any sort of challenges to industry to correct deficiencies associated with inadequate designs, would make a valuable contribution to a movement to maximize the protection the general public can have as a result of functioning smoke alarms. Fleming does not makes these points, however, and instead distracts people from this important messages associated with making sure all homes are protected by functioning smoke alarms.

Read more...

jay Fleming

I would like to respond to these comments. (I greatly appreciate the effort that was put into these concerns.)

Mr. Clare's Comment-

However, perhaps as a consequence of the title, Fleming’s article gives the impression that the lack of effectiveness of operating alarms is the crux of the smoke alarm problem. Although there are definitely a large number of design issues that could be addressed to improve smoke alarm functionality (outlawing 9 volt battery powered alarms being just a jumping off point for this), vocally advocating this position at the present time clouds two other major issues of more pressing importance.
First, not every dwelling has a smoke alarm, of any kind. Second, smoke alarms do not work forever, and a large number of citizens that currently think they are protected are actually relying on alarms that no longer function.

These points are summarized in Ahrens’ (2011) report entitled, “Smoke alarms in US Home Fires”, cited by Fleming. In this report Ahrens states:
“Almost all households in the US have at least one smoke alarm, yet in 2005-2009, smoke alarms were present in less than three-quarters (72%) of all reported home fires and operated in half (51%) of the reported home fires. More than one-third (38%) of all home fire deaths resulted from fires in homes with no smoke alarms, while one-quarter (24%) resulted from fires in homes in which smoke alarms were present but did not operate.”

Chief Fleming's Response -

1st - 38% of fire fatalities did have operating alarms and 24% had alarms that did not operate. So the problem of people dying with operating alarms, which is understated in my opinion, is at least as large as the problem of people dying with no smoke alarm at all. It is reasonable to assume that the use of photoelectric alarms might reduce the % of fatalities with operating alarms by 50% and reduce the number of fatalities with disabled alarms by at least 50%. This could reduce deaths in the US by 30% (almost 1,000 lives per year).

2nd – The main reason that smoke alarms are disabled is due to nuisance alarms. Most people do not realize that switching to photoelectric technology will in most cases solve the problem.

3rd – According to the NFPA, “Ninety-six percent of all homes have at least one smoke alarm, according to a 2010 telephone survey. Overall, three-quarters of all U.S. homes have at least one working smoke alarm.” Given this data shouldn’t we have seen an impact in the trend in fire deaths due to increase use of smoke alarms? It appears that we did not which raises the question that I ask, “Why not.”

Mr. Clare’s Comment –

Combined, this means that almost two-thirds of home fire deaths Ahrens examined occurred in properties that did not have a working smoke alarm of any type. The major reasons for failure to operate when the alarms were present were due to missing, disconnected, or dead batteries. In some respects (and this may be the case for some ionization alarms) power may have been removed in response to excessive false alarms due to poor alarm placement.

Chief Fleming’s response –

I find it fascinating that the problem of disabled detectors is blamed on “poor alarm placement” and the fact that “poor alarm selection,” i.e. selection of ionization for use within 20 feet of kitchen is ignored. Many manufactured homes and small apartments must put the smoke alarm within 20 feet of a kitchen appliance. Why isn’t the public being educated to use photoelectric technology in this situation? (Maine, Massachusetts, and Vermont all require photoelectric alarms within 20 feet of a kitchen appliance.)

Mr. Clare’s Comment –

Even from the data presented within Fleming’s article, it is clear that functioning smoke alarms do save lives when compared to situations where a fire occurs in the absence of a functioning smoke alarm. Fleming argues that confined fires inflate the life-protection benefits of functioning alarms and corrects these data to indicate that the death rate in the presence of a functioning alarm is actually 29% less than without one. Given the size of the samples involved this represents a highly significant difference (rate ratio z-test = ?8.81), which translates to an estimated saving approximately 490 of the 1,640 lives that were lost, had smoke alarms been present and operated in all cases. In the same manner, the difference in death rates for apartment buildings discussed by Fleming is also significant, Z = ?2.04, and it can be estimated that approximately 36 of the 200 deaths that occurred without functioning smoke alarms could have been prevented. (As a side note here, it is questionable as to whether confined fires should have been removed from these calculations, as data from Canada analyzed by Garis and Clare has demonstrated that fires that occur in the presence of a functioning smoke alarm are smaller and more contained (on average), presumably as a direct consequence of the alarm.)

Chief Fleming’s Response -

The point of the original article was not to claim that smoke alarms, i.e. ionization smoke alarms do not provide any benefit. The point of the article was to show that the benefit is not nearly as large as most people assume that it is and that we should be asking why it isn’t. In addition, the way the USFA defines a “confined fire” is a fire that does not escape the object that it begins in. (this is almost always a food on the stove situation.) So I am not discounting fires that are smaller than average, I am discounting fires that are so small that they seldom if any cause anyone any harm.

Mr. Clare’s’ Comment –

However, rather than emphasizing these benefits, Fleming argues that, “It is highly probable that the main reason for the lack of effectiveness of operating smoke alarms is that most smoke alarms utilize ionization technology.” This redirects the focus of the argument away from the potential benefits that could be expected if all homes had functioning alarms of some type, and focuses instead on the difference between ionization and photoelectric alarms. With respect to this issue, Warda and Ballesteros (2007) in the, “Interventions to prevent residential fire injury” (Handbook of Injury and Violence Prevention, published by Springer) explain that:
“A recent National Institute of Standards and Technology (NIST) Fire Research Division study reports extensive testing of current residential smoke alarm technologies in a controlled laboratory setting and in a series of real-scale tests conducted in two residential structures. These studies affirmed that both ionization and photoelectric smoke alarms consistently provide time for occupants to escape from most residential fires. Consistent with prior findings, ionization-type alarms provided somewhat better responses to flaming fires than photoelectric alarms, and photoelectric alarms provided considerably faster response to smoldering fires than ionization type alarms.” As such, best evidence currently supports the fact that having an alarm is better than not having one, regardless of alarm type. In addition to this, many smoke alarms available on the market now have combined photoelectric and ionization capabilities, which makes this distinction moot.”

Chief Fleming’s Response –

I agree that this is the way that NIST originally characterized their results but I would disagree that it is an accurate summary of their results. In response to a series of questions that I posed NIST clarified their results in a follow up document tilled, “Questions and Answers Clarifying Findings of NIST Home Smoke Alarm Study,” NIST documented that in a large percentage of the smoldering fires the ionization smoke alarm did not respond until it was to late to escape. The ionization was the only alarm that was providing negative available escape times.

http://www.nist.gov/el/fire_protection/buildings/upload/SmokeDetectors_Q-As_Feb2008.pdf

This was not the first study to document this finding. Researchers in Norway, using UL listed alarms, as well as California had previously studied smoke alarms and recommended the use of photoelectric smoke alarms due the fact that ionization smoke alarms operated too late in smoldering scenarios.

http://osfm.fire.ca.gov/firelifesafety/pdf/Smoke%20Alarm%20Task%20Force/R-27%20An%20Evaluation%20of%20Fire%20Detectors%20for%20Residential%20Placement.pdf

In addition in suggestion the use of combination smoke alarms Mr. Clare is ignoring the issue of nuisance alarms, which the combined ion/photo alarms will experience. In addition, since the manufacturers can reduce the sensitivity of each sensor type and still pass the UL Fire Tests there is no guarantee that a combined alarm will respond better than a stand alone alarm of either type. So the distinction is not moot at all.

Mr. Clare’s Comment –

In campaigning to eradicate ionization smoke alarms in favor of photoelectric smoke alarms there is a risk that Fleming has presented an argument that can be interpreted to suggest the life-safety benefits of smoke alarms are in question. Even by the data that he presents, available information demonstrates that this just simply is not the case. This article makes no useful comment as to whether alarms actually save lives, particularly in the case when someone is in the house and either asleep or impaired. Furthermore, Fleming does not discuss the much more significant issues associated with smoke alarms: first, that they are not present and functioning in every home, and second, that they stop working over time. To this end, discussion of the reasons why alarms stop functioning, and posing any sort of challenges to industry to correct deficiencies associated with inadequate designs, would make a valuable contribution to a movement to maximize the protection the general public can have as a result of functioning smoke alarms. Fleming does not makes these points, however, and instead distracts people from this important messages associated with making sure all homes are protected by functioning smoke alarms.

Chief Fleming’s Response –

Actually I do not want to run the risk that I might “suggest the life-safety benefits of (ionization) smoke alarms are in question.” I want to state it explicitly. If ionization smoke alarms reduced the risk of dying in a fire when people were sleeping, which I agree is when smoke alarms should provide the greatest benefit, then the # deaths per 100 fires, which is the methodology used by the NFPA and USFA to measure smoke alarm effectiveness, from smoking materials should have substantially decreased over the last 30 years. The truth is that it increased: from 1980 - 1984 it was 3.0 deaths per hundred fires, from 2004 - 2008 it was 3.5 deaths per hundred fires. Although I have always taken the public position that any smoke alarm is better than nothing, in my opinion, we should not be thankful that the glass is ¼ full; we should be asking why it is ¾ empty.

I think it is unfair to criticize my efforts in this area as “distracting.” In the space limited by the blog it is difficult to touch upon all of the issues surrounding smoke alarms. I have spent the last 25 years of my life advocating for stricter smoke alarm laws and am responsible for much of the language in the current Massachusetts fire and building codes that in many people’s opinions are the strictest in the United States. In addition, I have been a member of the UL (Underwriters' Laboratories) Committee that regulates smoke alarms for several years and have submitted many recommendations to the NFPA Fire Alarm Code that have been adopted. In fact, it was largely due my research in the mid 90’s that the NIST Study referenced by Mr. Clare was undertaken. (Here is an excerpt from a letter written by Jim Hoebel, the former Chief Engineer of the CPSC.

CPSC was also an advocate for the installation of working smoke alarms, having conducted a national survey that revealed the extent of the problem of non-working alarms. By establishing communications with the CPSC, Jay described his concern over the performance of ionization alarms and helped CPSC understand its importance. As a result, CPSC developed a major new fire test program to evaluate the ability of different types of alarms to detect different types of real fires. Jay Fleming was especially instrumental in helping justify this study. CPSC needed to solicit support and funding from other agencies and organizations since fire testing is expensive, and Jay’s knowledge was crucial to this effort. In addition, it was important to precisely plan the project so that the test results and analysis would accurately measure the alarm performance over a wide variety of situations. Jay Fleming was a participating contributor to this planning phase. The project is now under way at the National Institute of Standards and Technology. Jay continues to be an active contributor to the project’s oversight.

I agree that we have to increase the number of homes with working alarms. In fact, I am not aware of anything in the article that disagrees with this position. However the statistics and evidence would seem to indicate that we can achieve the greatest reduction in fire deaths by improving a smoke alarms response to all types of fires and reducing the potential for disablement, by the use of photoelectric technology. Neither of which is advocated by any major fire safety group in the US except for the International Association of Fire Fighters (IAFF). I do not advocate one option over the other. I am advocating that we pursue both options simultaneously. However the benefit of increasing the use of alarms will be minimized if the technology that is used is ionization

Read more...

Adrian Butler

Please examine the data from the Building Research Association of New Zealand's controlled scientific tests where all ionization smoke alarms had a 100% failure rate in real-world smoldering fires:
www.theWFSF.org/positions

If VALID scientific tests are conducted, on LEGITIMATE, real-world, slow smouldering fires, ionization smoke alarms will fail to sound a timely warning.

After examining Chief Fleming's (and other) research, the Australasian Fire & Emergency Service Authorities Council (AFAC) published their official 'Position on Smoke Alarms in Residential Accomodation' statement in June, 2006.

The International Association of Fire Fighters (IAFF) and AFAC's official positions state:
"Ionization smoke alarms may not operate in time to alert occupants early enough to escape from smouldering fires."

The IAFF and AFAC ONLY recommend photoelectric smoke alarms. They do NOT recommend combination ionization/photoelectric alarms.

People will continue to die needlessly in house fires 'protected' by ionization smoke alarms as long as those who are paid to protect us sit on the fence and misrepresent the facts (either wantonly or as victims of decades of misinformation) about ionization smoke alarms.

What's more important, 'Saving Face or Saving Lives'?

Please take just a few moments and check out these links.

Adrian Butler
Chairman, Co-Founder, Former Fire Fighter
THe World Fire Safety Foundation
NSW, AUSTRALIA

Read more...

Bruce

Great, and now that the market is saturated with the first product that was unnecessary, they have decided to tell us we wasted our money, and now need to increase the profits of the same companies that have ripped us off once.

You know, growing up, I didn't once wear a bike/skateboard helmet. Life is a risk, and you can't regulate the risk out of life. If we leave it to the so called experts, we'll all be sitting in a corner afraid to move because we might get a scrape unless we have on our PPE.

Sydney Electrical emergency

The importance of installing and maintaining smoke alarms in homes, as they literally save lives and alerting families to fires in their homes and allowing them to escape unharmed.

Christopher Garbacz

See my articles in Economics Letters (1989,2007). The effectiveness of smoke detectors (alarms) is in the 10 % range. Other factors are more important. Decline in cig smoking for example is quite powerful and other factors enter as well. As income/wealth increases we chose more safety. You can see this as you move thru time before smoke detectors appear. When you test the efficacy of a smoke alarm in the lab you get a higher impact than in the field. Not exactly surprising for the economist.

Reality

To claim smoke alarms don't or wont save many lives according to this data is utter nonsense.

Every one of us have had smoke alarms go off throughout our lives due to cooking fumes, bathroom steam, a BBQ too close to the home etc. In turn causing us to complain about how sensitive they can be.

I personally have been dealing with this since the early 80s (false alarms)

What you forgot to add was this:

How many people installed their smoke alarms improperly? In turn causing the alarm to miss a beat? For example installing one to high or too low on a wall, near a corner or above a beam etc.?

How many people died in the fire NOT because their smoke alarm didn't go off but because they were too drunk, too stoned or too high on a prescription drug to wake up and get out of the burning building in time?

How many were heavy sleepers and did not hear the alarm go off due to a sleep disorder or seizure condition etc. ?

How many were narcoleptic? I mean c'mon! you tend to lean toward the bizarre this is no different.

How many actually chose to die in the fire due to suicidal tendencies or severe depression? Despite the smoke alarm going off on time.

How many were disabled and couldn't make it out of bed?

I could go on all day like this! Shall we continue?

Your "freakonomics" needs to get a little more freaky (in a common sense fashion) before I'll buy into it 100% ...

Read more...