Why Would A Carbon Monoxide Alarm Go Off

A carbon monoxide (CO) alarm sounding can be a frightening experience. It's a warning sign that should never be ignored, as CO is a silent, odorless, and deadly gas. Understanding why your alarm might be going off is crucial for your safety and the safety of those around you. This guide will explore the common reasons for CO alarm activation, differentiating between genuine emergencies and nuisance alarms.

Understanding Carbon Monoxide

Carbon monoxide (CO) is produced by the incomplete burning of fuels such as natural gas, propane, oil, wood, and gasoline. Common sources in a home include:

Furnaces
Water heaters
Fireplaces (wood-burning and gas)
Gas stoves and ovens
Portable generators
Vehicles running in attached garages
Charcoal grills (never use indoors!)

When CO is inhaled, it prevents the blood from carrying oxygen, leading to serious health problems and even death. This is why CO detectors are vital safety devices. A working CO alarm is a critical component of a safe home.

Reasons for a Carbon Monoxide Alarm Activation

Let's explore the various reasons why your CO alarm might be sounding:

1. Genuine Carbon Monoxide Leak

This is the most serious reason and requires immediate attention. A genuine CO leak indicates that a source in your home is producing dangerous levels of the gas. The specific cause can vary.

Possible Causes:

Faulty Furnace: A malfunctioning furnace is a common culprit. Cracked heat exchangers, blocked vents, or improper combustion can all lead to CO buildup.
Blocked Chimney or Flue: If a chimney or flue is blocked by debris (birds' nests, leaves, etc.), exhaust gases, including CO, can back up into the home.
Improperly Vented Appliances: Gas water heaters, stoves, and dryers all require proper venting to the outside. If the venting is damaged or disconnected, CO can accumulate indoors.
Using a Generator Indoors or Too Close to a Home: Generators produce high levels of CO. Never operate a generator inside a home, garage, or shed, even if the doors and windows are open. Place it far away from the house and any windows or doors.
Vehicle Running in an Attached Garage: Exhaust fumes from vehicles contain high concentrations of CO. Never run a vehicle in an enclosed garage, even for a short period.
Cracked or Damaged Heat Exchanger: The heat exchanger is a critical component of your furnace. If it cracks, CO can leak into your home's air circulation system.

What to do:

Evacuate Immediately: Get everyone out of the house and into fresh air.
Call Emergency Services: Contact the fire department or your local emergency services from a safe location. Do not re-enter the home until authorized by emergency personnel.
Do Not Try to Find the Source Yourself: Leave that to the professionals. They have the proper equipment and training to locate and address the source of the CO leak safely.
Contact a Qualified Technician: Once the emergency responders have cleared the house, schedule an inspection of your fuel-burning appliances by a qualified HVAC technician.

2. Low Battery

Many CO alarms are battery-powered, either entirely or as a backup in case of a power outage. A low battery is a very common reason for an alarm to sound, especially in older alarms. The alarm will often emit a short chirp or beep intermittently, not the continuous alarm sound indicating a CO emergency.

What to do:

Replace the Battery: Follow the manufacturer's instructions for battery replacement.
Test the Alarm: After replacing the battery, press the test button to ensure the alarm is functioning correctly.
Consider Upgrading to a 10-Year Sealed Battery Alarm: These alarms eliminate the need for battery replacements for the lifespan of the alarm.

3. End of Life

CO alarms have a limited lifespan, typically 5-10 years. After this time, the sensor becomes less reliable and may trigger false alarms. Most alarms have an end-of-life warning signal, usually a specific type of chirp or flashing light.

What to do:

Check the Alarm's Manufacturing Date: Locate the manufacturing date on the alarm (usually on the back).
Replace the Alarm: If the alarm is beyond its recommended lifespan, replace it immediately with a new CO alarm.

4. Nuisance Alarms

Sometimes, a CO alarm might sound due to factors that don't involve a dangerous CO leak. These are often referred to as "nuisance alarms."

Possible Causes:

Temporary CO Exposure: Brief spikes in CO levels from sources like starting a car in an attached garage (even briefly) or using a gas stove for an extended period (especially if the kitchen is poorly ventilated) can trigger an alarm.
Humidity and Temperature Changes: Significant fluctuations in temperature and humidity can sometimes affect the sensor in the alarm.
Dust and Debris: Dust and debris accumulation on the sensor can interfere with its operation and trigger false alarms.
Chemical Interference: Certain household chemicals, such as cleaning products, paints, and aerosols, can release fumes that can trigger a false alarm.
Malfunctioning Alarm: In rare cases, the alarm itself may be malfunctioning and needs to be replaced.

What to do:

Ventilate the Area: Open windows and doors to increase ventilation.
Check for Obvious Sources: Make sure no appliances are running improperly and that no vehicles are running in attached garages.
Move the Alarm (If Possible): If the alarm is located near a potential source of interference (e.g., cleaning supplies), try moving it to a different location.
Clean the Alarm: Gently vacuum the outside of the alarm to remove dust and debris. Do not use water or cleaning solutions.
Reset the Alarm: Press the reset button on the alarm.
Monitor the Situation: If the alarm doesn't sound again after these steps, it was likely a nuisance alarm. However, if the alarm continues to sound, evacuate the house and call emergency services.

5. Improper Alarm Placement

The location of your CO alarm can significantly impact its effectiveness. If placed incorrectly, it may be more prone to nuisance alarms or fail to detect CO leaks promptly.

Recommended Placement:

On Each Level of Your Home: At least one CO alarm should be installed on every level of your home, including the basement.
Near Sleeping Areas: Place alarms in hallways outside of bedrooms so that you will be alerted while sleeping.
Away from Fuel-Burning Appliances: Avoid placing alarms directly next to furnaces, water heaters, or stoves, as temporary CO releases during startup can trigger nuisance alarms. Keep a distance of at least 10 feet.
Avoid Dusty or Humid Areas: Do not place alarms in areas prone to dust, dirt, or high humidity, such as garages, bathrooms, or laundry rooms.
At Head Height: CO is slightly lighter than air and tends to rise. Installing alarms at head height ensures optimal detection.

Troubleshooting Steps

When your CO alarm goes off, follow these troubleshooting steps to determine the cause and take appropriate action:

Stay Calm: Panic can lead to poor decision-making. Take a deep breath and assess the situation calmly.
Check for Symptoms: Are you or anyone else in the house experiencing symptoms of CO poisoning, such as headache, dizziness, nausea, vomiting, or confusion? If so, evacuate immediately and call emergency services.
Determine the Type of Alarm Sound: Is it a continuous alarm, a chirp, or a specific pattern? Consult the alarm's manual to understand what the sound indicates.
Ventilate the House: Open windows and doors to allow fresh air to circulate.
Check the Alarm's Display (If Applicable): Some CO alarms have a digital display that shows the CO level in parts per million (ppm). Note the reading.
Inspect Fuel-Burning Appliances: Visually inspect your furnace, water heater, and other appliances for signs of damage or malfunction.
Check the Chimney and Vents: Ensure that chimneys and vents are clear of obstructions.
Reset the Alarm: Press the reset button on the alarm.
Monitor the Situation: If the alarm doesn't sound again after these steps and you have no reason to suspect a CO leak, it was likely a nuisance alarm. However, if the alarm continues to sound, evacuate and call emergency services.

Prevention and Maintenance

Preventing CO leaks and ensuring your alarms are functioning properly is key to protecting your home and family.

Preventative Measures:

Annual Appliance Inspections: Have your furnace, water heater, and other fuel-burning appliances inspected and serviced annually by a qualified technician.
Chimney Cleaning: Have your chimney cleaned regularly to prevent blockages.
Proper Ventilation: Ensure proper ventilation when using gas stoves or ovens.
Never Use Grills or Generators Indoors: Never use charcoal grills, gas grills, or generators inside your home, garage, or shed.
Regular Alarm Testing: Test your CO alarms monthly by pressing the test button.
Replace Alarms as Needed: Replace CO alarms according to the manufacturer's instructions, typically every 5-10 years.

Maintenance Tips:

Dust Alarms Regularly: Gently vacuum the outside of your CO alarms to remove dust and debris.
Replace Batteries: Replace batteries in battery-powered alarms at least once a year, or more frequently if needed. Consider using long-life batteries.
Keep Alarms Clean: Avoid spraying cleaning products or aerosols near CO alarms.

Conclusion

A sounding carbon monoxide alarm is a serious matter. By understanding the potential causes, following proper troubleshooting steps, and implementing preventative measures, you can protect yourself and your loved ones from the dangers of CO poisoning. Remember to always err on the side of caution. If you are unsure about the cause of an alarm, evacuate the house and call emergency services.