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I installed hard-wired and interconnected smoke alarms through the house. I wondered, though, if a fire spread through my attic I might not know about it until the ceiling or roof collapsed.
Should I install an interconnected alarm in the attic?
Is there some reason this isn't required/recommended?
FEMA writes:
Few, if any, smoke alarms are Underwriters Laboratories (UL)-listed for use in the temperature extremes an attic can experience. Few, if any, codes require alarms in one- and two- family residential attics where nearly all (90 percent) of attic fires occur.
— “Attic Fires in Residential Buildings”, Topical Fire Report Series 11(6), January 2011
As a firefighter that recently battled a large and rapidly moving fire that appears to have started in the attic, I found myself searching the topic of smoke alarms in attics. Though it is a low percentage of structure fires that begin in the attic, they are not isolated incidents.
Chimney fires can easily extend into attics as well as HVAC units can ignite unknown attic fires. Our recent fire seems to have occurred from a malfunction in exposed flue pipe (non-bricked/rocked) extending through the attic before exiting the roof. Attic spaces are generally open and vented allowing for rapid spread of the fire where as living space fires can be more compartmentalized slowing the spread of flames.
It is estimated that our recent fire burned for ten to fifteen minutes before the 911 call was made. At this point the fire had self vented through the exterior of the home and the 911 call was made by passing neighbors. Though we were on scene in 7 minutes from the time our alarm tones sounded, it was far too late to save this home. Fortunately, the two residents home at the time of the fire were able to escape with pets and records stored on their laptop computer. The house was a total loss; but I have to believe if a little investment had been made for a smoke detector that endures the attic temperatures, this home could have been saved with far less damage.
We specify a "heat detector" in the attic and crawl spaces of all our homes. A "smoke detector" will pick up a neighbor's burn barrel smoke (products of combustion) but a heat detector operates on the "rate-of-rise" principle. That is to say, when the attic gets hot quickly (not just from a hot summer day) then it will go into "alarm".
This is the same unit we use in commercial kitchens too.
If you sleep better at night with an attic smoke detector, they do make detectors for extreme temperatures. They go from -15 to + 200 degrees Fahrenheit.
The only problem with these is the dust in most unfinished attics. If you have a workman in they will stir up the insulation and create dust. Smokes are very sensitive to dust. But if there is some bad wiring smoldering in the insulation it can save your life. You will just need to vacuum it out say twice a year, and keep it close to the opening.
I service thousands of smoke detectors every year and they should NEVER be installed in an attic. There are reasons code does not require them in attics but code is a MINIMUM requirement. If you want to provide additional protection for attic exposure the proper device is a heat detector. Smoke detectors are not designed to function in the high temperatures found in attics. Smoke detectors are not designed to function in the low temperatures found in attics. Smoke detectors are not designed to function in the humidity found in attics. All of these environmental issues will lead to erratic operation and cause false alarms or non-alarms. False alarms will provoke the disconnection of the detector, then it is useless. A properly rated heat detector is the correct fire detector to use in attics. Yes, there are special smoke detectors that will survive and function in the attic environment but you better open up your wallet very wide, not just for the detector but for the related hardware required that goes with it.
Why smoke alarms are not mandatory in attics is beyond me. Ask any firefighter if they have one in their attic and the answer is yes We found out the necessity for attic smoke alarms the hard way, when our brand new, completely built to code, fully inspected home had an electrical fire in the attic, RIGHT ABOVE AN INTERIOR SMOKE ALARM.
I awoke to use the bathroom, upon returning to the bedroom I heard a strange noise, sounded like rain on the bathroom vent, or on a tin roof, but far, far away. Hmm, odd, I thought, didn't hear that in the bathroom, must have just started raining, and went back to the bathroom to check.
That moment of "hmmmm, this is strange" saved our lives...when I returned to the bathroom there was no noise. In my half awake state my brain decided there must have been a storm the night before...branch must have put a hole in the roof... the noise must be rain on the ceiling...noise is right where the fuse panel is... This odd, disjointed ramble of thoughts had me immediately pull the kill switch on the entire fuse panel. I was still NOT thinking fire, never occurred to me the sounds I was hearing were fire.
Knowing water and electricity do not mix I mentally debated whether I should call the fire department - I didn't want to be one of "those" people who waste emergency services due to panic. I wasted critical, valuable minutes before calling the fire department, ...I almost opened the attic hatch to look (this could have literally been fatal), all because I could not grasp WHY the smoke alarms had not gone off, IF there was, actually, a fire. Finally, thankfully, I called the fire department, evacuated all humans, 11 dogs and sundry other pets, and only once I exited the house did I become aware of the massive amounts of smoke coming out the eaves and roof vents.
We had smoke alarms directly below the fire, in our master bedroom; in the hallway outside of our master bedroom; and across the hall in the spare bedroom. These were all useless in our case, as smoke RISES and the fire was in the attic. Had I not woken, had I not heard the odd noise, had I not investigated the odd noise...well, to be frank, we would have slept until the burning roof collapsed on top of us.
I'm an electrician so I wanted to chime in and maybe clear up some of the confusion.
The reason we don't install smoke alarms in attics is because attics are rarely insulated the way the rest of a house is. There is a constant rising and lowering of the temperature (very hot in summer, very cold in winter) which messes with the circuitry inside leading to false alarms and no alarms. Attics also tend to be very dusty and smoke alarms often mistake excessive dust particles for smoke particles which, once again, leads to a false alarm.
Maybe down the line, someone will invent one that is impervious to these conditions but for now, we install HEAT DETECTORS in attics instead. They are programmed to go off should the temperature reach a certain degree (usually around 135 F). Someone pointed out that heat and fire rises so by placing these heat detectors ABOVE the rest of the house, they work very efficiently as the attic is one of the first places to heat up before a fire spreads.
Now Smoke & Heat Detector is used for fire alarm.
NFPA 72, 2010 Edition, Chapter 29, Section 29.5.1 Required Detection, states the following:
29.5.1.1 Where required by other governing laws, codes, or standards for a specific type of occupancy, approved single and multiple-station smoke alarms shall be installed as follows:
(1) In all sleeping rooms and guest rooms
(2) Outside of each separate dwelling unit sleeping area, within 6.4 m (21 ft) of any door to a sleeping room, the distance measured along a path of travel
(3) On every level of a dwelling unit, including basements
(4) On every level of a residential board and care occupancy (small facility), including basements and excluding crawl spaces and unfinished attics
(5) In the living area(s) of a guest suite
(6) In the living area(s) of a residential board and care occupancy (small facility)
I am baffled that smoke detectors in attics aren't more common. We suffered a catastrophic fire in our 3-week old home when the house next door, under construction, went up in flames and our roof caught. We were outside the home at the time but were shocked to discover that it took 20 minutes after the roof first caught fire for our smoke detector to go off. Because of the location of the fire the top of our staircase did burn, so I shudder to think what would have occured if this had happened in the middle of the night. When we rebuilt we added detectors in the attic, as well as ladders built below window frames in our kids' rooms... just wouldn't be able to sleep otherwise. I can't understand why smoke detectors are not standard.... the only other person I know who had a house fire had it start becuase of lightning, also on the roof.
