Building a new house in Palo Alto

Building a new house in Palo Alto

Saturday, April 5, 2014

Smoke Detectors, Nuisance Alarms, Fire Safety & Why I'd Still Buy a Nest Protect

The Nest the hottest must-have toy that you won't be able to buy.

Just my luck, on the day I was going post my review of the Nest Protect Smoke and Carbon Monoxide detector, the company yanks them off the shelf. Apparently their gimmicky wave feature doesn't work right so they're halting new sales and deactivating the feature on already installed units through a wifi software update. Safety is so annoying. [Update, July 2014: Woohoo! They're back on the shelves and $20 cheaper! You can order one with free shipping from Amazon: Nest Protect.  If you purchased the Nest Protect for $129, you are eligible for a credit of $33 per device. You can get your Nest Protect rebate here].

I decided to research the Nest Protect because I wasn't satisfied with the darling reviews from the technorati. Instead of examining practical safety aspects (i.e. whether it uses an ionization or photoelectric sensor), they declared it a thing of beauty and fawned over superfluous extras like the night light (David Pogue's favorite feature). C'mon night lights are a dime a dozen and if my goal was beauty, I'd hang an Arctic Pear chandelier or the Boffi Air ceiling fan, not a hipster smoke detector that looks like a giant Square credit card dongle.

For the record, I was going to recommend including the Nest Protect as part of your home's protection system but advise against replacing all your detectors with them (we put one on each floor). I found the wave feature to be useless and unnecessary, so no big deal that it's not enabled on our detectors anymore. In my opinion Nest Protect's killer app is it's ability to communicate — it tells you when the battery is low, if the alarm isn't working, and if the smoke detector is going off while you're out to dinner and the baby is home with the sitter. This kind of peace of mind is priceless.

It's a shame that the company advertised the Wave feature so heavily that now they have to spend months finding a way to fix it. I still think they have a great product (which currently sells on eBay for an even larger premium). Their main tagline is "Safety doesn't have to be annoying." Nest, you had me at Safety. You had me at Safety.

To me, the biggest tragedy of the Nest Protect marketing campaign is that they had opportunity to educate consumers about how smoke detectors work and how to be safe without sacrificing your sanity. It has nothing to do with being able to silence your detector with a wave. You don't have to swing a towel at the Nest Protect because it uses a photoelectric sensor, which makes it less prone to nuisance activations and much safer.

The first question you should ask when evaluating a smoke detector is: "What kind of sensor does it use? Here's why:

Most nuisance alarms are caused by Ionization sensors
There are two types of smoke detectors—Ionization and Photoelectric. About 90% of homes have ionization sensor detectors, they are cheaper and better at sensing hot flaming/fast-moving fires (i.e. cooking fires and fires fueled by paper or flammable liquids). About 5% of homes have photoelectric sensor alarms, which are faster at detecting slow smoldering fires (i.e. smoking, electrical or heater-related fires). If you need help determining what type of detector you have, this post has a great explanation: IONIZATION VS. PHOTOELECTRIC SMOKE ALARMS.

The trouble with ionization sensors is they often get triggered when you cook, burn toast or shower. After one or two unwanted alarms, they invariably wind up in the junk drawer, making them the least safe kind of detector that you can have. According to the National Fire Protection Agency nearly two-thirds of US home fire deaths happen in homes without a working smoke alarm—usually because the batteries are dead or they've been deliberately disabled. One Alaskan Public Housing study found that ionization detectors have 8 times more false alarms and 19% of them are disabled within 6 months of installation. 

Combo/Dual Sensor alarms are also prone to nuisance tripping
Because you cannot predict the type of fire you may have, fire officials recommend that you have both ionization and photoelectric technologies in your home. Combination or "dual sensor" alarms which include both ionization and photoelectric technologies in one device are often touted as the best way to protect your home, however they get mixed reviews from people in the field.

Electricians, home inspectors, as well as our city's fire marshal told me that combo alarms (which were required by the California Fire Code when we built our house) are prone to nuisance alarms. Some say they're too sensitive to moving air or dust. Others say they have a high failure rate because they are cheaply manufactured in order to be cost competitive with single unit devices. Some experts also argue that they are unreliable because there's no industry or UL standard for dual/multi sensor alarms. Regardless of the reason, the experts I spoke to all recommended replacing dual unit devices with single detector ones if they are causing nuisance alarms. So far all of our false alarms have been caused by the Kidde combo photoelectric/carbon monoxide alarms, so we can't blame an ionization sensor.

Before going Office Space on your detectors, try these tips...
Tips for preventing nuisance alarms

1. Switch to a photoelectric only smoke detector. Photoelectric alarms are much less susceptible to nuisance alarms. If your main concern is preventing false alarms, there's no need wait for the Nest Protect to come back on the market, there are plenty of other capable photoelectric smoke detectors.

2. Locate smoke detectors at least 20 feet from the sources of combustion particles (cooking appliances, furnace, water heater, space heater). Avoid placing alarms in air streams near kitchens since currents can draw cooking smoke into a detector's sensing chamber. Within 20 feet of a kitchen, use photoelectric only alarms. 

3. Avoid placing detectors in damp, humid or steamy areas e.g. directly near bathrooms with showers. Make sure smoke detectors are mounted on a surface that does not get cold in winter. Warm balmy nights without good air circulation can also trigger them. Avoid exterior walls if possible and do not mount on cathedral ceilings if there is a wall location available.

4. Do not place a smoke detector in garages, furnace rooms, crawl spaces and poorly ventilated areas.

5. Use a vacuum cleaner to clean out dust every three months. Avoid insect infested areas, bugs can trigger smoke detectors.

6. Keep detectors at lease 12 inches away from fluorescent lights since electrical "noise" can interfere with the sensor.

7. Install alarms with a hush feature that can be temporarily silenced. And learn how to use it! If an alarm is sounding too frequently, the problem could be solved by moving it. If all else fails, replace the alarm, you may have gotten a lemon.

Note: If your smoke detectors are interconnected, there should be a flashing red light on the device that was  originally triggered. If you can't identify which unit is setting off the alarms, you may need to disconnect them from each other and wait for the next false alarm to troubleshoot.

Why every home should have a photoelectric smoke detector
Nuisance alarms are not the only reason to install a photoelectric alarm. The number one reason to have a photoelectric smoke detector is safety. Smoldering fires, like those started from overloaded power strips, can fill a home with toxic gases for minutes, or even hours before there are enough flames to trigger an ionization alarm. Friends of mine were recently in trapped by a fire on the 20th floor of their apartment building when a smoldering fire broke out two doors down. Their ionization smoke detectors never sounded despite the fact that hot, black smoke filled the upper half of the 42-story complex, killing one and seriously injuring another.

You can not predict what type of fire you may have but smoldering ones are the deadliest. Fast flaming fires account for a larger percentage of fires (mostly started in the kitchen when occupants are awake), however smoldering fires (often occurring at night) are the leading cause of home fire deaths. Within the industry there's a movement to replace ionization detectors with photoelectric ones however the awareness by the general public is still quite low. 

I'm hoping that Nest gives up on finding a way to make their Wave feature work and instead focuses on educating consumers on photoelectric technology and their product's real benefits. After researching the differences, I'm convinced: if you only have one kind of smoke detector in your home, make it a photoelectricThis mama bear has both types in her home, just to be safe.

For maximum protection, install smoke alarms inside every bedroom, outside each sleeping area and on every level of the home, including the basement (replace units every 10 years). Carbon monoxide detectors should be installed in a central location outside each sleeping area and on every level of the home (replace units every 7 years). Most fire experts recommend having a completely interconnected system, however we decided for our house we’d rather be covered by the benefits of multiple technologies.

We installed a Nest Protect, which includes a carbon monoxide detector, on each floor. They interconnect wirelessly to each other but they can’t talk to our other ionization and photoelectric detectors. I didn’t feel like it was worth $129 to replace every alarm in the house, nor would I want to rely entirely on a new-to-market, largely untested device. I did however, feel it was worth adding to the mix for the remote alerts (in case we're not home when an alarm goes off) and because the Nests perform self-checks (since we never do the recommended monthly tests with our other detectors). This way, we have the security of knowing that at least one detector on each floor is working at all times. 

Here's more reading on the subject:

Ionization versus Photoelectric Smoke Alarms: In Real-World Fires The Differences Are Deadly

Deadly Differences, Ionization vs Photoelectric Smoke Alarms (data-filled presentation with links)

Organizations that advocate replacing all ionization alarms with photoelectric alarms:
International Association of Firefighters (a labor union representing firefighters in US & Canada)

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