Customer Reviews: Read 5 more reviews...
 Kidde KN-COB-B Basic Carbon Monoxide Alarm November 30, 2008
Seller was terrific. Low price, fast delivery and reasonable shipping.
Product is easy to install.
 Better Safe Than Sorry September 17, 2008
I've used several carbon monoxide alarms from First Alert for the past couple of years. Sadly, I was very dissapointed with the fact that they've shorted out after only a few months. For Kidde, they've made high quality carbon monoxide alarms, but also a very convient prices. The Kidde KN-COBB Basic Carbin Monoxide Alarm is a very simple and easy to setup alarm. This alrm is very affordable, and you can easily hang it up, without any problems. It is also easy to install the batteries, unlike those that require a 9 Volt batteries. Here, all it takes is a trio of AA batteries, and it works better, even during a power outage. Kidde does show it, and I really suggest you have one for your everyday houselhold.
Price: B 1/2+
Setup: B+
Convience: B
Overall: B
why everyone should have this February 13, 2008
12 out of 13 found this review helpful
This was fowarded to me.I reviewed it. Then i changed all my dedectors.
I feel this is the best bang for your buck.
On Dec. 17, 2005, my department in Barre City , VT , responded to the worst fatal fire in our history. At a few minutes before 6 a.m., we were dispatched to a fire in a two-story wood-frame apartment building. The initial report was that there were people still in the building. The on-duty crew was met with heavy fire blowing from the second floor windows on side A and heavy smoke pushing through out. Additionally, the initial crew was advised, by bystanders, the apartment had two adults and four children still inside. The officer in charge quickly upgraded to a second alarm.
Before the arrival of the fire department, two Barre City police officers arrived on scene and attempted to enter the fire apartment, but were unsuccessful. They did make entry to the downstairs apartment and they reported a considerable amount of smoke inside. They stayed in the downstairs apartment, trying to listen for activity above them, but the smoke forced them out. These officers reported that they heard no smoke detectors coming from the second floor apartment, and incredibly, no smoke detectors sounding in the down stairs apartment. The detectors in the downstairs apartment were later tested and found to be operational.
Because of a water supply problem, initial crews conducted their searches without the protection of a hoseline. The fire conditions forced these crews out of the apartment two times before finally making it in through a bedroom window on the C side. In this room, an adult male was found and was extricated out the same window and down a ladder. At about this time, water had been established and the fire was effectively knocked down.
Crews next located three young girls together in one bedroom. Two were extricated down ladders and the third down an interior stairway. The next to be found was a young boy in another bedroom, who was extricated down an interior stairway. The final occupant to be found, an adult female, was found in the living room in the area of fire origin and was not extricated, for obvious reasons. In the end, a mother, three little girls and the little boy died. The father was airlifted to the nearest trauma center and has since recovered. A seventh occupant escaped on his own prior to our arrival and is also doing fine.
To add insult to injury, a few minutes after the last victim was transported to the hospital, we all learned that this family was related to our fire chief. All of a sudden, it wasn't someone else's tragedy anymore.
The area of origin was a living room couch. The exact cause has not been determined, but has been narrowed down to a cigarette, candle or Christmas lights. Based on the investigation, it is believed this began as a smoldering fire and eventually became a flaming fire. The time it remained a smoldering fire is unknown.
Smoke Detectors Did Not Activate
The apartment had three hardwired smoke detectors - one in the family room, one in the master bedroom and one in the girls bedroom. There is a report that early on a bystander may have heard a smoke detector. As stated earlier, the police officers, who were on scene very quickly, did not hear any coming from either apartment. No one from the fire service heard any operating smoke alarms.
There are many other details and events of this fire that I could share with you. Acts of heroism, compassion and desperation and more played out. I suspect I would be preaching to the choir, however. On some level, we all have been there. But for the purpose of telling this story, enough has been said.
For the next few months, this fire was all we talked about. Some had opinions and all had questions. We just couldn't figure out how so many people could get caught in a fire, still in their bedrooms, with working smoke detectors. In the early spring of 2006, we learned why, and have been doing our best to keep it from happening ever again. What I tell you next is all we didn't know.
My Chief, Peter John, attended a conference in a neighboring town presented by Deputy Chief Joe Fleming of the Boston Fire Department. During this conference, Chief Fleming discussed the differences between ionization and photoelectric smoke detector technology, among other issues related to this topic. When Chief John returned from this conference, he handed me a large stack of information he picked up, and told me the detectors in the apartment didn't activate.
The Fish Tank Test
I had never heard of such a thing before, and spent most of that night researching on the Internet to find out what I could. It didn't take me long to come upon some disturbing information. The most interesting site was from a group out of Australia . Their site, [...], shows a fish tank full of smoke and an ionization smoke detector inside that didn't make a sound. When a photoelectric smoke alarm was introduced to the smoke, it sounded almost immediately. That was to hard to believe. So we decided to try it ourselves.
Two days later, we had our own fish tank and created our own smoke outside the firehouse and we video taped it (see videos below). What happened was almost beyond words. We created thick, yellow/brown smoke that hurt to breath and placed an ionization smoke detector in it. It did not activate. Yet a photoelectric smoke detector activated after five seconds when exposed to the same smoke. The ionization smoke alarm did finally activate, but only after it was almost completely obscured by the smoke.
All of a sudden, the idea that a smoke detector was just a smoke detector was as foolish as saying a fire is just a fire. They are not the same. They are very different. And knowing the differences can save your life. Since this first test, we have conducted several tests in an abandoned house, testing both ionization and photoelectric smoke alarms in different types of smoke.
Ionization Smoke Alarms
An ionization smoke alarm has two plates that have a small voltage going across them. Added into this mix is a small amount of radioactive material called AMERICIUM-241. This material ionizes the oxygen and nitrogen in the air. Basically what this means is that an electron is taken off from each atom. These electrons are now considered free and have a negative charge to them. The atoms, on the other hand, now have a positive charge. The electrons, with the negative charge, are attracted to the positively charged plate. The atoms, with the positive charge, are attracted to the negatively charged plate. The amount of electrical current traveling between the two plates is monitored by the detector.
As small particles enter the chamber, they interrupt the electrical current between the plates causing the electrical current to drop. This is what causes the horn to activate.
Photoelectric Smoke Alarms
A photoelectric smoke alarm works all together different. A beam of light is projected inside the chamber so that it does not come in contact with a sensor called a photo-detector. When smoke enters the chamber, it scatters the light so that it reaches the sensor. The light reaching the sensor is what causes the horn to activate.
Just like a smoke detector is not just a smoke detector, smoke is not just smoke. Different stages of fire create different types of smoke. A flaming fire creates smoke particles that are 0.01 - 3 microns in size. Smoldering fires create smoke particles that are 0.3 - 10 microns in size. Smoke from a smoldering fire is referred to as "Cold Smoke". A flaming fire produces a large volume of smoke with particles that are 0.01 - 3 microns in size. These small particles fill an ionization chamber with sufficient quantity to disrupt the current between the metal plates. This disruption then causes the horn to activate. These small particles will also scatter the light in a photoelectric smoke alarm, causing this horn to activate as well. Generally, however, the photoelectric is slightly slower to activate. The difference in activation time during a flaming fire is measured in seconds.
A smoldering fire produces a large volume of smoke with particles that are 0.3 - 10 microns in size. These larger particles still enter the ionization chamber. However, because of the larger size, not enough can fit into the chamber to disrupt the current. The current is able to, essentially, filter between the particles without enough of a disruption to sound the horn. Because of this, the ionization alarm can be in an environment full of this cold smoke and yet it may not activate. The photoelectric alarm is much better at detecting this smoke. As the smoke enters the alarm, the smoke scatters the light causing the alarm to activate. In almost every test we have done, the photoelectric alarms have sounded before we could see any smoke in the room.
What Are the Differences?
In order to illustrate this better, think of smoke in terms of water. Ask yourself this question - What is the difference between water from the tap and the steam coming out of your shower? The answer is temperature. It is still water, but because the water coming from your shower is hotter, it is in the form of steam. The particle sizes are smaller. Smoke acts the same way, the hotter the smoke, the smaller the particles. The colder the smoke, the larger the particles.
Taking this a step further, what happens to the steam as it travels away from the shower? It cools down. As it cools, the particles combine with other particles eventually creating water droplets that you can see on the walls and windows. Again, the same is true of smoke. As the smaller, hot particles travel away from the heat source, the individual particles cool and combine with other particles. This is a process called agglomeration. The cooler they get, the larger the particles become. If this hot smoke has to travel a distance to reach an ionization smoke alarm, it may have cooled sufficiently to essentially create cold smoke. This cold smoke with larger particle sizes may not activate the ionization alarm. However, regardless of the distance traveled, this same smoke will activate the photoelectric alarms simply because of how the alarms operate.
So what do we do now? Education and legislation - we need to make sure that the differences between these types of detectors are known by everyone. If the public really understood the differences and how unprotected they are without both types, most folks would take care of themselves. Additionally, we need to push law makers to force home builders and manufactures to include both technologies in the homes they build.
Here in Barre City , we are advocating duel sensor smoke alarms, those with both ionization and photoelectric sensors built in. There is no way to tell where a fire will start, or what type of fire you will have. A dual sensor smoke alarm will protect against both types. Existing homes can either replace the ionization alarms with dual sensor alarms, or supplement them with photoelectric alarms. In kitchens, where the ionization alarms are routinely activated by cooking which then causes the occupants to remove the batteries, we are advocating stand alone photoelectric alarms. This will cut down on these nuisance alarms and the likelihood that the batteries will be removed causing the alarm to be ineffective.
Carbon Monoxide vs. Smoke Alarms
When you add carbon monoxide (CO) alarms to the mix, you are now talking about three technologies. We are advocating a stand alone CO alarm. There are two reasons for this. First, CO alarms need to be replaced every five years where smoke alarms need to be replaced every 10 years. When you combine a CO and smoke sensor in one detector, that detector is only as good as its weakest link and in this case, the CO sensor, is just five years. The other reason is how CO travels in the spaces. Because it is essentially the same weight as air, CO travels with the normal air currents. We advocate placing CO alarms at the same level of the heads of the sleeping occupants on the floor they sleep on. If there is a second CO alarm, we advocate that one to be placed closer to the ceiling, again, on the floor they sleep on. It goes without saying, however, that each floor should be protected with alarms.
Cost is a huge factor for everyone. Dual sensor alarms cost more than a stand alone photoelectric or ionization alarm. The dual sensor alarms in my home cost about $23.00 each, where a stand alone photoelectric costs around $12.00. For folks that are not able to afford the dual sensor alarms, we tell them to use a stand alone photoelectric alarms. Even though it is slightly slower than the ionization alarm at detecting a flaming fire (30 seconds or less on the average), it is considerably faster at detecting a smoldering fire (30 - 40 minutes on the average). It is these smoldering fires at night that are the most deadly.
As a fire service, we tell people to protect themselves with smoke alarms. Although we have not been wrong, we have not been completely right either. We still have a huge problem in this country of homes without any smoke alarms, and any smoke alarm is better than no smoke alarm. But we need to tell the public to have both types of technology in their homes. It is their families at stake. It is your families at stake. The only hope we have to get out of a burning building at night is for our smoke alarms to sound early. If they don't, the occupants will die. We know. We saw it.
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The Barre City Fire Department is a career department located in Central Vermont . The staff consists of 17 full-time staff and an equal number of call force members, with an average call volume around 2,500 fire and EMS calls per year. Working out of one station, they shift strength is three to four. At the time of this fire, there were three firefighters on duty.
Related Videos:
Full Scale Smoke Detector Demonstration
Full Scale Open Flame Detector Demonstration
Smoke Detector Aquarium Test
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Russel Ashe, a deputy chief with Barre City, VT, Fire Department, began his career with the Williamstown Volunteer Fire Department in 1991. He appointed to the City of Barre Fire Department in September 2000 by then Chief Doug Brent. In 2005, he was promoted to lieutenant, and in May of 2007, was promoted again to Deputy Chief of Fire Operations. While with the City of Barre Fire Department , he has helped to secure over $800,000.00 for the department through several state and federal grants. In 2004, he started a very successful Cadet Program which continues today.
Matthew Cetin is a career firefighter/EMT-I with the Barre City Fire Department. A five-year career firefighter, he served the first two with the Burlington Fire Department. Prior to his becoming a career firefighter, Matthew served seven years active duty in the United States Coast Guard with his last duty station being the U.S. Coast Guard Station in Marblehead, OH. While serving with the Coast Guard, Matthew had the opportunity to volunteer with theMarblehead Fire Department and the Ballville Fire Department.
 Put it up somewhere away from people! June 12, 2007
2 out of 12 found this review helpful
I guess this item is good for the price that you pay for it.Ive had 2 of these and twice had a careless person knock it down, once off the countertop minutes after purchasing it and once off the top of the fridge (that was partially my fault for never putting that one up) But what Im trying to say is if you purchase this item NEVER let it fall on the floor after it hits the floor its no more good the alarm keeps going off even after moving it outside to fresh air. Dont even think you can call the PROFESSIONALS at Kidde and expect them to help because the RUDE customer service agent is just going to cut you off in the middle of you explaining the problen and tell you to go buy a new one!
False Alarm? May 1, 2007
7 out of 10 found this review helpful
I have had one of these alarms for a month or so, and last night it started going off while I was making dinner. I took the alarm outside and it stopped beeping, so I decided it was probably real and called 911. They came over and their detectors read absolutely nothing. So while I think a CO detector is an important item in every home, I worry about the accuracy of this one.
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