I convinced my wife that we really needed to get ventless logs for the fireplace rather than monkey around with wood, so I just bought a couple combo detecters as well, though mine are not networked in any way. I also did some research into the relative weights, and the only thing I found that is different from what Dan has so well explained is that apparently mixing can be affected by air temperature. I suspect though that it would have to be pretty cold in a house before this would be a factor. Apparently, at least according to the manual, mine are also supposed to scream at you when the batteries are low, so we'll see.
Bill Stephan Kansas Citty MO Email: [email protected] Phone: (816)803-2469 ----- Original Message ----- From: Dan Rossi <[email protected]> Date: Wednesday, January 13, 2010 8:37 pm Subject: [BlindHandyMan] wireless bad thing detectors. > So, I just got some battery operated, wirelessly inter connected, > voice announcing, smoke or smoke and Carbon Monoxide detectors. > > I got one combination smoke and C O detector, and two smoke > detectors. > The combo unit will go in the basement, and then one smoke > detector on the > main floor, and one in the hallway on the second floor. > > You program each one for the location it is in, and then if any > one of > them go off, all of them go off and tell you what the danger is, > and where > it is. IE, if the unit in the basement activates because of a > carbon > monoxide issue,, and it is late at night and we are snug in our > beds on > the second floor, all of the units, will alarm, then say, > "EVACUATE! > CARBON MONOXIDE IN THE BASEMENT!" > > Since these are battery operated, and wireless, there are no wires > to > run. Makes it quite easy to install. Just hang them on the > ceiling and > you are good to go. > > Before anyone starts raising your hand and saying that Carbon > Monoxide is > heavier than air and thus the detectors should be near the floor, > you are > mistaken. I've done a lot of research on this. There are many > web sites > that make this invalid claim. But the real science is more > convincing. > Air is made of Nitrogen, N2, with an molecular mass of 28. And > Oxygen, > O2, with an molecular mass of 32. Carbon Monoxide is made of a > Carbon > atom, atomic mass 12, and one Oxygen, atomic mass 16, giving it an > molecular mass of 28, equal to N2, and lighter than Oxygen. Add > to that, > the fact that C O is going to be a product of combustion, IE, it > will be > warm and thus convect upward, and you get quite a good mix of the > air and C O. > > Some manufacturers say to put the Co detector on the wall at eye > level, > but that is more for the fact that many CO detectors have visual > displays > showing the Parts Per Million of CO in the air, and thus it makes > more > sense to put it somewhere where it is more easily seen on a > regular basis. > > I thought these were worth mentioning. They're not that cheap, > the combo > unit was 70 bucks, and the two pack of smoke detectors was 90 I > think. I > got the combo direct from amazon, but the smoke detector twin pack > came > from EAccess via amazon. > > -- > Blue skies. > Dan Rossi > Carnegie Mellon University. > E-Mail: [email protected] > Tel: (412) 268-9081 >
