# Carbon Monoxide Detector Placement

Reblogger Roy Kelley
Real Estate Agent with Realty Group Referrals 16766

"A carbon monoxide alarm or detector should be centrally located outside of each separated sleeping area in the immediate vicinity of the bedrooms. Where bedrooms are separated and the audibility of the alarm or detector to occupants within the bedroom area could be seriously impaired, more than one unit could be needed. Each alarm or detector should be located on the wall, ceiling, or other location as specified in the installation instructions that accompany the unit."

Original content by Jay Markanich 3380-000723

Carbon monoxide detector placement.

That title surrounds a question I get a lot during home inspections.  And this one -

Is carbon monoxide lighter or heavier than air?

Of course, any time you have gas appliances or a wood-burning fireplace, you should have at least one carbon monoxide (CO) detector in the home.

CO is odorless, tasteless and DOES NOT GIVE WARNING that it is being produced or building up.

And, is it lighter or heavier than air?  Which means, does it rise or fall when produced?

Since the molecular weights of gases differ, what makes them move is convection.  If a gas is released because of combustion, it would tend to rise due to its heat.

CARBON MONOXIDE HAS NEARLY THE DENSITY OF AIR.  CO is slightly lighter.   You can figure this out.  For example:

O=16   C=12   N=14   H=2

You would add things to get the pure density of gasses.

H2 = 1+1 = 2 (very light)
O2 = 16+16 = 32 (slightly heavy)
N2 = 14+14 = 28 (about neutral)
CO2 = 12+16+16 = 44 (heavy)
CO = 12+16 = 28 (about neutral)
H2O = 1+1+16 = 18 (light) - as in humidity or steam

So what is the density of air?  The air we breathe is composed of 80% Nitrogen, 19% Oxygen, .6% inert gases and .4% Carbon Dioxide.

N2 + O2 + CO2 = ?
.8(28) + .196(32) + .004(44) = 28.9 (by definition air is neutral)

So how does CO compare with air?  It is 3% lighter.  So it distributes very easily through a house.

But when CO is produced, it immediately begins mixing, and therefore diluting, with the air around it.  Therefore, it mixes with nitrogen, which doesn't burn, oxygen, which is burned creating the CO, H2O (humidity) and CO2 which are in the air.  So the CO produced is not in pure form in the air.  It is very diluted.  And as CO is produced, it is warmer than the air around it.

So what is the most advantageous place to put a CO detector?  CO moves with the air, so where the air is flowing it will go also.  It is very unpredictable where the air, and therefore CO, will move at any given time.  That is why the instructions with the unit you buy do not say to place it high or low on the wall.

Understanding all that, the National Fire Protection Association (NFPA) suggests in 720, 2-1.1.2* 1998 -

"A carbon monoxide alarm or detector should be centrally located outside of each separated sleeping area in the immediate vicinity of the bedrooms. Where bedrooms are separated and the audibility of the alarm or detector to occupants within the bedroom area could be seriously impaired, more than one unit could be needed. Each alarm or detector should be located on the wall, ceiling, or other location as specified in the installation instructions that accompany the unit."

The suggestion is one that is plugged in and preferably with a battery back up.  These detectors use electrochemical technology to detect CO gas.  Like smoke detectors, they are effective for 10 years.

A local Fire Marshall, my neighbor, told me that the plug-in detectors seem to have a better record for fewer false positives than do the battery-only detectors.  But that is his experience!

My recommendation:  buy a good plug-in detector!  If you want, get one with a battery back up.  Put it near any potential CO source and another near your bedroom(s).  Be sure everyone will hear it.

And you will be safe and feel safe.

Jay Markanich Real Estate Inspections, LLC

Based in Bristow, serving all of Northern Virginia.

Office (703) 330-6388   Cell (703) 585-7560

www.jaymarinspect.com

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Rainmaker
3,192,237
Sally K. & David L. Hanson
EXP Realty 414-525-0563 - Brookfield, WI
WI Realtors - Luxury - Divorce

Carbon monoxide detectors are now often combined in one device with smoke detectors and legally required on every floor in Wisconsin.

Dec 28, 2018 01:39 AM #1
Rainmaker
5,269,823
Roy Kelley
Realty Group Referrals - Gaithersburg, MD

Please be sure to leave comments at the original blog by Jay Markanich

Dec 28, 2018 04:00 AM #2
Rainmaker
3,126,268
Lawrence "Larry" & Sheila Agranoff. Cell: 631-805-4400
The Top Team @ Charles Rutenberg Realty 255 Executive Dr, Plainview NY 11803 - Plainview, NY
Long Island Home and Condo Specialists

Roy, This is such a good reminder by Jay, and reblog by you. We saw very small units at one of the home stores that work really well, and are 1/2 the cost of the larger units.

Dec 28, 2018 04:13 AM #3
Rainmaker
4,796,551
Gabe Sanders
Real Estate of Florida specializing in Martin County Residential Homes, Condos and Land Sales - Stuart, FL
Stuart Florida Real Estate

Thanks for the re-blog, Roy.  I learned something from this post.

Dec 28, 2018 05:29 AM #4
Rainmaker
1,515,862
Amanda S. Davidson
Amanda Davidson Real Estate Group Brokered By eXp Realty - Ashburn, VA
Alexandria Virginia Homes For Sale

Roy, this is such a great reminder. Jay did an excellent job on his post.

Dec 28, 2018 05:43 AM #5
Rainmaker
1,850,567
Grant Schneider
Performance Development Strategies - Armonk, NY
Your Coach Helping You Create Successful Outcomes

Good morning Roy - Jay's very informative post should be read by everyone.  This is an imporant issue.

Dec 28, 2018 07:01 AM #9
Rainmaker
4,023,957
Joan Cox
House to Home, Inc. - Denver Real Estate - 720-231-6373 - Denver, CO
Denver Real Estate - Selling One Home at a Time

Roy, great choice for a reblog, and it is important WHERE to place the CO detectors.

Dec 28, 2018 07:28 AM #10
3,192,569
Debe Maxwell, CRS
www.iCharlotteHomes.com | The Maxwell House Group | RE/MAX Executive | (704) 491-3310 - Charlotte, NC
Charlotte Homes for Sale - Charlotte Neighborhoods

I was messing with our gas log fireplace the other day having all kinds of trouble getting it lit. Suddenly my CO detectors started blaring because I was leaking too much gas. Took a while to clear the fumes but nice to know the detectors were working and properly placed.

Dec 28, 2018 01:55 PM #13
Rainmaker
1,835,479
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Thanks for the reblog Roy!  And be careful - many of the combined CO/smoke detectors have been recalled for causing fires!

Jan 21, 2019 10:11 AM #19
Rainmaker
5,269,823
Roy Kelley
Realty Group Referrals - Gaithersburg, MD

Thanks so much for stopping by. It is always good to hear from you.

Jan 21, 2019 11:58 AM #20
Rainmaker
5,269,823
Roy Kelley
Realty Group Referrals - Gaithersburg, MD

Make it a habit to post a reblog every day. It is an easy way to pay it forward.

Feb 12, 2019 12:21 PM #21
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Rainmaker
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