Where Should Carbon Monoxide Detectors Be Installed in a Fire Alarm System?

Carbon monoxide (CO) is a serious safety concern in buildings where fuel-burning equipment is present. The gas is colorless and odorless, so people might not know it is present without a working CO detector. Proper placement helps CO detectors detect the gas and alert occupants when needed. This article explains where CO detectors should be installed, where they should not be placed, and how to maintain them.

Why Carbon Monoxide Detection Matters 

Carbon monoxide (CO) is a poisonous gas produced when fuels do not burn completely. It is colorless and odorless, so people cannot see or smell it. Furnaces, water heaters, generators, fireplaces, and other fuel-burning equipment are potential sources of CO.

CO exposure can cause headaches, dizziness, weakness, nausea, vomiting, chest pain, and confusion. Severe exposure can lead to loss of consciousness and death. 

A carbon monoxide detector provides an early warning when it detects CO under its specified alarm conditions. This gives occupants time to move to fresh air and seek help. Proper installation and regular maintenance help keep the detector working properly.

Where Should I Place a Carbon Monoxide Detector?

The right location for a CO detector depends on the building, its layout, and possible sources of CO. Detectors should be installed according to the manufacturer’s instructions and requirements for the building. The alarm should be easy for occupants to hear, and the detector should be easy to access for inspection and maintenance.

• Near sleeping areas

In homes, CPSC recommends installing CO alarms on every level and outside sleeping areas. NFPA 72 also has requirements for CO detection near sleeping areas in certain buildings. For other buildings, the required locations depend on the applicable codes and standards. The building layout and how each space is used should also be considered.

• In other occupied areas

CO detectors should be placed in areas where people could be exposed to carbon monoxide. Potential sources include fuel-burning equipment, vehicles, generators, and exhaust systems. The location of these sources and the way CO could move through the building help determine where additional detectors are needed. NFPA 72 also considers factors such as different building levels, HVAC zones, and areas separated by closed doors and walls. Local codes or standards may require that detectors be installed in other locations.

• Consider the building layout

The building’s ventilation and airflow patterns matter when deciding where CO detectors should go. HVAC systems can move, mix, or dilute carbon monoxide. Exhaust ducts, openings, shafts, and other pathways can also affect how CO moves through a building. Detector locations should account for these conditions rather than using the same approach for every building. Detectors should also remain easy to access for testing, inspection, and maintenance.

• Proper coverage and system integration

A CO detection system should provide the coverage needed for the building and its potential CO sources. Detector locations should also account for environmental conditions and airflow. When CO detectors form part of a fire alarm system, they should be installed according to the applicable codes, standards, and manufacturer’s instructions. The detectors should work properly with the rest of the fire alarm system.

Where Should Carbon Monoxide Detectors Not Be Installed?

Some locations are not suitable for CO detectors because heat, moisture, dust, fumes, or airflow could affect how they work. Always follow the manufacturer’s instructions and applicable codes and standards.

• Near sources of excessive heat and moisture

High temperatures, steam, and excessive moisture could affect detector performance if the device is not designed for these conditions. CO detectors should be installed within environmental limits specified by the manufacturer. 

• Areas with heavy dust or dirt

Heavy dust and dirt could affect a detector’s operation. Avoid placing detectors in areas with high levels of dust or other airborne contaminants unless the device is designed for these conditions. Keep detectors accessible for inspection, testing, and maintenance.

• Near fuel-burning equipment

CO detectors should not be placed near fuel-burning equipment without considering the conditions around the equipment. NFPA 72 includes requirements for CO detectors in rooms with permanently installed fuel-burning equipment. Placement should also consider ventilation, contamination, and possible nuisance alarms.

• Poorly accessible locations

CO detectors should be easy to access for testing, inspection, maintenance, and replacement. A difficult to reach detector can make routine maintenance harder.

• Locations with obstructed airflow

Airflow affects how CO reaches a detector. HVAC systems, vents, exhaust openings, and other pathways can change how CO moves through a building. Keep detectors unobstructed and follow the manufacturer’s placement instructions.

How Do CO Alarms Differ From Smoke Alarms?

CO alarms and smoke alarms detect different hazards. CO alarms detect carbon monoxide, while smoke alarms detect smoke produced by a fire. Their sensing methods and placement also differ.

	CO Alarms	Smoke Alarms
What they detect	Detect carbon monoxide, a poisonous gas produced when fuels do not burn completely.	Detect smoke particles produced by a fire.
How they work	Use sensors designed to detect carbon monoxide and sound an alarm when the device reaches its specified alarm conditions.	Use sensors to detect smoke particles and sound an alarm when the device reaches its specified alarm conditions.
Where they are used	Placement depends on the building, occupancy, potential CO sources, and applicable requirements. In homes, CPSC recommends CO alarms on every level and outside sleeping areas.	Placement depends on the building, occupancy, and applicable requirements. In homes, CPSC recommends smoke alarms on every level, outside sleeping areas, and inside each bedroom.
Why they are important	Provide an early warning of carbon monoxide, which people cannot see or smell.	Provide an early warning of smoke from a potential fire.
Can one replace the other?	No. A CO alarm does not replace a smoke alarm.	No. A smoke alarm does not replace a CO alarm.

 

Why regular CO detector testing matters

Common Carbon Monoxide Detection Problems

Several issues can affect how well a carbon monoxide detection system works. These include incorrect placement, detector failure, battery problems, nuisance alarms, and missed testing or maintenance.

Incorrect placement: A detector in the wrong location might not work as intended. Heat, moisture, dust, fumes, and airflow should all be considered when choosing a location.

Detector failure: A damaged or faulty detector might not respond when CO is present. Regular inspection and testing help identify these problems.

Battery problems: Battery-powered CO alarms need working batteries to operate. CPSC recommends testing household CO alarms monthly and replacing batteries according to the manufacturer’s instructions.

Nuisance alarms: Environmental conditions and other factors could cause nuisance alarms. Proper detector selection and placement help reduce them.

Lack of testing or maintenance: A detector could develop a fault without an obvious warning. Regular inspection, testing, and maintenance help identify problems and keep the system operating properly. TAS Fire also provides inspection and maintenance services for smoke and CO detection systems.

How Do I Take Care of My CO Alarm?

Regular maintenance helps keep a CO alarm working properly. Follow the manufacturer’s instructions for testing, cleaning, battery replacement, and alarm replacement.

Test the CO alarm regularly

Test household CO alarms monthly using the test button to confirm they work properly. For CO detectors connected to a fire alarm system, follow the required testing schedule and the manufacturer’s instructions.

Keep the alarm clean

Keep dust, dirt, and other contaminants away from the alarm. Clean it according to the manufacturer’s instructions. Do not cover or block the alarm, as this could affect its operation.

Replace batteries when needed

For battery-powered CO alarms, check the battery condition and replace batteries according to the manufacturer’s instructions. CPSC recommends replacing batteries at least once a year for alarms with replaceable batteries

Check for warning signals

Pay attention to low battery warnings, fault indicators, and end-of-life signals. Follow the manufacturer’s instructions when a warning appears. If the alarm sounds because it detects carbon monoxide, do not ignore it. Move to fresh air and follow your building’s emergency procedures.

 

Need professional support? Explore TAS Fire’s Fire Alarm System Services and Smoke and CO Detection Services.

Frequently Asked Questions

 

Where should carbon monoxide detectors be installed?

CO detectors should be installed where they can detect CO and alert people in the building. The right location depends on the building, its layout, and possible sources of CO. In homes, CPSC recommends installing CO alarms on every level and outside sleeping areas. Always follow the manufacturer’s installation instructions.

How many carbon monoxide detectors does a building need?

There is no single number of CO detectors that applies to every building. The number depends on the building’s size, layout, occupancy, possible CO sources, and the requirements that apply to the property. A fire protection professional can determine the right number and locations for the building.

Can carbon monoxide detectors be connected to a fire alarm system?

Yes. Carbon monoxide detectors can be connected to a building’s fire alarm system. When a detector senses CO under its specified alarm conditions, it sends a signal to the fire alarm system. The system then processes the signal based on its design. The detector and the fire alarm system should be compatible and installed according to the manufacturer’s instructions and applicable requirements.

Should carbon monoxide detectors be installed near sleeping areas?

Sleeping areas are an important location for carbon monoxide detection. In homes, CPSC recommends placing CO alarms on every level and outside sleeping areas. NFPA 72 also includes requirements for CO detectors near sleeping areas in certain occupancies. The exact placement depends on the building and the requirements that apply to it.

Where should carbon monoxide detectors not be installed?

CO detectors should not be placed where heat, moisture, dust, or fumes could affect their operation. Their location should allow air to reach the detector and provide easy access for testing and maintenance. Always follow the manufacturer’s placement instructions.