Carbon monoxide doesn’t announce itself. It has no color, smell, or taste. If you manage buildings with gas-fired equipment, you should take a look at three things before the heating season starts: your carbon monoxide alarms, combustion appliances, and venting.
Where Carbon Monoxide Comes From
Carbon monoxide is a byproduct of burning fuel. Any gas furnace, boiler, water heater, range, dryer, or fireplace can produce it. So can a vehicle running in an attached garage. That’s all normal. There’s only a problem when something in the chain breaks down. There are a few usual culprits:
- A cracked heat exchanger. The metal wall separating combustion gases from the air in your ducts. A crack can allow exhaust into the airstream.
- A blocked or disconnected flue. Bird nests, debris, rust, or a vent pipe that has separated at a joint.
- Backdrafting. Exhaust pulled back inside instead of up the vent, often because an exhaust fan is competing for air.
- Improvised heat sources. Unvented space heaters or a gas oven left open for warmth. Both can happen in rentals during cold snaps.
The CDC reports that more than 400 people die each year from unintentional, non-fire-related carbon monoxide poisoning, and more than 100,000 people visit an emergency department for it. Deaths are most common in the winter months when furnaces and boilers are working hard.
What New Mexico Code Requires
New Mexico adopts the International Residential Code as its state residential building code. Under Section R315, carbon monoxide alarms are required in dwellings containing a fuel-fired appliance or fireplace, or with an attached garage opening into the living space. Carbon monoxide alarms should go outside each sleeping area, near the bedrooms.
In existing buildings, the requirement is usually triggered by new building work, permitted additions or other alterations, a new fuel-fired appliance, or an additional sleeping room being added on. Commercial and larger multifamily properties fall under different code sections, and local jurisdictions can be stricter. Confirm your obligations with your building department or fire marshall. And keep in mind that the requirements are the floor, not the goal. The National Fire Protection Association recommends alarms outside each sleeping area and on each level. Follow the manufacturer’s instructions and use alarms with a recognized testing laboratory label.
Your Preseason Carbon Monoxide Checklist
- Check the date on every alarm. Carbon monoxide sensors wear out. Find the replacement date on the back and replace anything past it, even if the test button still works.
- Press the test button on each one monthly. This confirms that the horn and battery work, not that the sensor still detects carbon monoxide.
- Fill the gaps. Walk each level and sleeping area to ensure it has a functioning detector. Older buildings and converted space are places where they often get forgotten.
- Look at the venting. Flue pipes should be securely connected, sloped upward and free of rust or gaps. Check that exterior terminations aren’t blocked by nests or debris.
- Clear the mechanical room. Combustion appliances need air. Stored furniture and tenant belongings stacked against a furnace can choke off the supply.
- Schedule combustion testing. A technician can measure carbon monoxide in the flue, check draft and inspect the heat exchanger. These are things you can’t see on the outside.
- Tell tenants what to do. A short note explaining that a carbon monoxide alarm going off means you should get out and call 911, not open a window and wait. This can prevent confusion at 2 a.m.
Get Ahead of Heating Season
Carbon monoxide problems are almost always preventable, and almost always caught during routine service rather than an emergency. Schedule a heating system inspection with Aztec Mechanical, and we’ll verify your equipment is burning cleanly, venting properly and set up right.
Frequently Asked Questions
How often should carbon monoxide alarms be tested and replaced?
Test them monthly with the test button. Replacement follows the manufacturer’s instructions. Carbon monoxide sensors have a limited service life, and most units print a date on the housing. If you can’t confirm it, replace the unit.
Can a newer furnace still produce carbon monoxide?
Yes. A new furnace that wasn’t adjusted correctly, or one venting into a blocked flue, can produce carbon monoxide on day one. Installation quality and venting matter as much as equipment age.
Do carbon monoxide alarms replace a professional inspection?
No. An alarm tells you carbon monoxide is already in the building. An annual combustion inspection keeps it from getting there.
