This what my searching turned up. Seems legit; comments welcome:
CARBON MONOXIDE DETECTORS PLACEMENT:
DO'S
In order to maximize the protection of your home from excess levels of carbon monoxide, place your detectors in all of the following places:
- On every level of your home. In order to ensure that your home has maximum protection, it's important to have a CO detector on every floor.
- Five feet from the ground. Carbon monoxide detectors can get the best reading of your home's air when they are placed five feet from the ground.
- Near every sleeping area. If your CO levels get too high during the nighttime, it's important that detectors can be heard by everyone sleeping in your home. Place your detectors close enough to every sleeping area so that they can awaken everyone in the case of an emergency.
- Near attached garages. Cars produce carbon monoxide any time they are running. If you have an attached garage, those gasses can quickly spread to the rest of your house. A CO detector near your attached garage will warn you if that becomes a problem.
- Where the manufacturer recommends. Every model of carbon monoxide detector is tested according to manufacturer specifications. It's important to take those specifications into account when you're deciding where to place your detectors.
CARBON MONOXIDE DETECTORS PLACEMENT:
DON'TS
The following locations can either create a false alarm or avoid your detector from properly identifying the CO levels in your home:
- In close proximity to any fuel-burning appliance.
- In excessively humid areas such as your bathroom.
- In direct sunlight.
- Near any sources of blowing air such as a fan, vent or open window.
--from
http://www.sterlinghomeinspections....bon-monoxide-detector-placement-dos-and-donts
Additional information, with some overlap, from the NFPA:
Although the popularity of carbon monoxide (CO) alarms has been growing in recent years, it cannot be assumed that everyone is familiar with the hazards of carbon monoxide poisoning in the home.
Often called the invisible killer, carbon monoxide is an odorless, colorless gas created when fuels (such as gasoline, wood, coal, natural gas, propane, oil, and methane) burn incompletely. In the home, heating and cooking equipment that burn fuel are potential sources of carbon monoxide. Vehicles or generators running in an attached garage can also produce dangerous levels of carbon monoxide.
- The dangers of CO exposure depend on a number of variables, including the victim's health and activity level. Infants, pregnant women, and people with physical conditions that limit their body's ability to use oxygen (i.e. emphysema, asthma, heart disease) can be more severely affected by lower concentrations of CO than healthy adults would be.
- A person can be poisoned by a small amount of CO over a longer period of time or by a large amount of CO over a shorter amount of time.
- In 2010, U.S. fire departments responded to an estimated 80,100 non-fire CO incidents in which carbon monoxide was found, or an average of nine such calls per hour. The number of incidents increased 96 % from 40,900 incidents reported in 2003. This increase is most likely due to the increased use of CO detectors, which alert people to the presence of CO.
Safety tips
- CO alarms should be installed in a central location outside each sleeping area and on every level of the home and in other locations where required by applicable laws, codes or standards. For the best protection, interconnect all CO alarms throughout the home. When one sounds, they all sound.
- Follow the manufacturer’s instructions for placement and mounting height.
- Choose a CO alarm that has the label of a recognized testing laboratory.
- Call your local fire department’s non-emergency number to find out what number to call if the CO alarm sounds.
- Test CO alarms at least once a month; replace them according to the manufacturer’s instructions.
- If the audible trouble signal sounds, check for low batteries. If the battery is low, replace it. If it still sounds, call the fire department.
- If the CO alarm sounds, immediately move to a fresh air location outdoors or by an open window or door. Make sure everyone inside the home is accounted for. Call for help from a fresh air location and stay there until emergency personnel.
- If you need to warm a vehicle, remove it from the garage immediately after starting it. Do not run a vehicle or other fueled engine or motor indoors, even if garage doors are open. Make sure the exhaust pipe of a running vehicle is not covered with snow.
- During and after a snowstorm, make sure vents for the dryer, furnace, stove, and fireplace are clear of snow build-up.
- A generator should be used in a well-ventilated location outdoors away from windows, doors and vent openings.
- Gas or charcoal grills can produce CO — only use outside.
Symptoms of CO poisoning
CO enters the body through breathing. CO poisoning can be confused with flu symptoms, food poisoning and other illnesses. Some symptoms include shortness of breath, nausea, dizziness, light headedness or headaches. High levels of CO can be fatal, causing death within minutes.
The concentration of CO, measured in parts per million (ppm) is a determining factor in the symptoms for an average, healthy adult.
- 50 ppm: No adverse effects with 8 hours of exposure.
- 200 ppm: Mild headache after 2-3 hours of exposure.
- 400 ppm: Headache and nausea after 1-2 hours of exposure.
- 800 ppm: Headache, nausea, and dizziness after 45 minutes; collapse and unconsciousness after 1 hour of exposure.
- 1,000 ppm: Loss of consciousness after 1 hour of exposure.
- 1,600 ppm: Headache, nausea, and dizziness after 20 minutes of exposure.
- 3,200 ppm: Headache, nausea, and dizziness after 5-10 minutes; collapse and unconsciousness after 30 minutes of exposure.
- 6,400 ppm: Headache and dizziness after 1-2 minutes; unconsciousness and danger of death after 10-15 minutes of exposure.
- 12,800 ppm: Immediate physiological effects, unconsciousness and danger of death after 1-3 minutes of exposure.
--from
http://www.nfpa.org/public-education/by-topic/fire-and-life-safety-equipment/carbon-monoxide
