CO and Smoke Detectors

Chemist1961

I have a gas water heater and furnace in the basement but am considerring replacing a 30 year old smoke detector wired into the 2nd level hallway. My battery /plug in CO detectors and battery operated smoke detectors are on all levels of the house.
I am concerned about a plug in unit getting knocked loose or being unplugged. What is the best location for a CO detector and will it function properly mounted on an upstairs ceiling or is a low level wall mounted plug with battery back up better.

handy man88

Most CO detectors today have battery backup, and will alarm if AC power is lost. Low level is better as CO is heavier than air.

chris75

The specific gavity of oxygen is 1.000, and the specfic gravity of CO is 0.9667, pretty damn close if you ask me.

yuri

There is no definitive answer to where to place CO and smoke detectors. The electrical code varies from state to state/province to province. First Alert has a good website:http://www.firstalert.com/co_legislation.php
With some good recommendations. The main point being from what I have heard is that they should be replaced every 3-5 yrs as the internal sensors can wear out from age/dust etc. My local fire dept I believe recommends that. I would not trust an aging CO detector with my safety and would replace it after 3-4 yrs. They do not cost much and that is not an area to try an save $$ on. I would phone or visit your local fire dept for free info. UL Underwriters Laboratories has a good site:http://www.ul.com/
Use the search box and type in "smoke detector location" etc for good info

Chemist1961

My impression was that CO is heavier and therefore by the time it got to the ceiling it may be well over my head while I'm sleeping.
Since the death of a family of 4 near here in December, CO detectors are very scarce in some stores.
I am debating, installing a hardwired combo where my original 30 year old built in smoke detector is upstairs. Either way I have battery operated of both types on all 3 levels.

Yuri stay warm, just 4 more months, then the mosquitoes arrive

dac122

yuri is correct. The only other thing I can add is be sure to read the manual as they have specific dos and don'ts and recommendations on where to not place it. I just bought an extra CO monitor for upstairs where we heat with a wood stove and the manual had more info in it about placement than I expected.

yuri

10 months of hockey and 2 months of bad sledding. The mosquito is our provincial bird, big as crows ours are.LOL

sgthvac

My company had a Bachrach rep. come in and give a class on CO. He said teh best place for co detector is a room or area of the house that doesn't have a lot of traffic ie.. people coming in and out or near an outside entrance. Most CO detctors don't give an alarm until it's been exposed to 70ppm for 8hrs. He suggested placing one in a guest bedroom. He didn't mention low to the floor or near the ceiling. Of course part of his presentation was to talk about Bachrach's combustion analizer, but it was a good class.

beenthere

Co in the air stream of a furnace, will rise(be at ceiling level) in a room, its warmer then the air in that room.

Chemist1961

Hi BT, Excellent point. So if a plug in unit were mounted on the wall positioning closer to a heat vent than cold return would make better sense correct? So Master Bedroom versus hall with no heat vents, MB is best?
Could there be an incident of back flow if the fan were off, allowing it to climb back through the cold return or does it need forced air to travel and would it travel forward through the heat vents first?

yuri

Most CO lethal poisoning events are caused by blocked/collapsed chimneys and or smoke spilling out the front of the furnace. This can be caused by a negative pressure/downdraft in the chimney as well. In your house you have natural air circulation currents/hot air rises and cold air settles. The stairwell to the upstairs works like a chimney so I would put a CO detector there as it will likely get a high concentration of it. When the furnace runs the hot air duct is under high pressure so CO won't easily go upstairs. If the heat exchanger is cracked the high pressure air goes thru the crack and forces the smoke out the front of the furnace and into the furnace room. Hence a CO detector in the furnace room is a good idea. I feel horrible, what happened to that poor family? did they say what caused the problem.

handy man88

Strange. I think most instructions on placement of CO detectors say at least 8 ft. away from the combustion source.

Chemist1961

Yuri the family from Woodstock, ON seems to have died due to backup and blockage from a basement fireplace just before Christmas. From what I've read it appears the father and two teenage kids died first,the mom a police officer likely came home from work and was overtaken by fumes upstairs. The son had failed to deliver papers on Thursday, Friday, Sat . Mom was not discoverred until Sunday or Monday, likely very grave but had some oxygen. She died a week later in hospital. Terrible lesson for the general public. Apparently the family had had some symptoms for several days and had not caught on. Hopefully the loss will trigger more public awareness. Very, very tragic mistake.
CO detectors sold out at various local HD's, etc within a week and are still in short supply. I hate to even talk about this but we all need to be more cautious and if the discussion triggers someone else to react it's worthwhile.

handy man88

What kind of symptoms were noted?

Leah Frances

HMMM? I always walk past the CO detectors, maybe I should get one. I've got the smokes.

BTW - according to the manufacturer of my smoke detector (Kiddie) there is no good place in my kitchen to put it I've got four doors and four windows around the perimeter of the room. My solution: put it up somewhere it wouldn't go off every time I made stir-fry.

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