Firex combo smoke and carbon mon. detectors

[goldstar]

Here in NJ we are now required to have carbon monoxide detectors in hallways outside bedrooms. I've been using the Firex combination smoke and carbon monoxide detector for 2 reasons :1) they're interconnected with all other devices on the circuit and 2) you don't have to put a second device on the ceiling or plugged into a receptacle in the hallway.

So far, I've had 7 of these malfunction (3 of which were replaced twice and in the same residence) and trigger for no apparent reason. Now, I'm not knocking Firex, but has anyone else been having problems with these and if so, what was the solution ? Firex's solution was to replace the combo units with std. smoke detectors and sent separate plug-in units for the hallway.

Also, it is my understanding that carbon monoxide travels lower to the floor level rather than at the ceiling. If that theory is correct why would manufacturers make combination detectors ?

 

[earlydean]

Re: Firex combo smoke and carbon mon. detectors

When the CO gets all the way up to the ceiling, then it would alarm. Maybe the neighbors would hear it and call the morgue.

[ November 19, 2003, 02:16 PM: Message edited by: earlydean ]

 

[spsnyder]

Re: Firex combo smoke and carbon mon. detectors

Carbon Monoxide is lighter than air (~3%). See http://encarta.msn.com/encyclopedia_761551907/Carbon_Monoxide.html. It's not much lighter and would be more subject to therms, but it is a little lighter.

 

[spsnyder]

Re: Firex combo smoke and carbon mon. detectors

To answer your question... The gases from a burning object are hot and contain CO, and therefore would rise. The fact that the CO is 3% lighter than air wouldn't be as large of a bouency force as the fact that the fumes are hotter than air...I would think.

Regards

 

[Guest]

Re: Firex combo smoke and carbon mon. detectors

As for gases settling to the floor you may be thinking of natural gas or propane which are heavier than air and do settle to the floor. That's why gas fired water heaters & furnaces are required to be on an 18" high platform in a garage. The raised platform puts the burner above the flammable gas (if it leaks).

 

[eprice]

Re: Firex combo smoke and carbon mon. detectors

Actually, I believe propane is heavier than air, but natural gas is lighter than air. Note that NEC 511.3(B)(2) classifies the space within 18" of the ceiling in garages where CNG vehicles are repaired or stored. The reason for the 18" elevation of sources of ignition in garages is because of possible fuel leaks from vehicles, not from gas leaking from the water heater or furnace, otherwise the 18" elevation would be required everywhere these gas appliances are installed.

 

[tmarshall]

Re: Firex combo smoke and carbon mon. detectors

In my girlfriend's house they have Firex photoelectric smoke detectors. The one by her door started beeping randomly along with one on the first floor. I ended up replacing the one by her door and the one on the first floor stopped beeping. She is saying now that the one on the first floor is beeping every once in a while now. These units were only about 2 years old and had fresh batteries. It is a good thing I bought the twin pack of detectors cause it looks like I'll be replacing the other one. It looks like the Firex line is just not very good.