What is a CO2 Gas Detector and How Does it Work?

Carbon Dioxide Safety Detector

A CO2 gas detector uses a built-in carbon dioxide sensor to measure CO2 levels in the air. It can display real-time CO2 levels and initiate audible and visual alarms if CO2 levels are too high.

CO2 gas detectors are at the heart of CO2 detection systems used by businesses and industrial processes that create, store, or use CO2. They are also used in homes, offices and classrooms to measure indoor air quality.

Common applications for CO2 gas detectors include monitoring IAQ, process control, indoor greenhouses, bars, restaurants, breweries, and landfills.

How does a CO2 gas detector measure CO2?

Most modern carbon dioxide detectors use a non-dispersive infrared (NDIR) sensor that measures infrared light in a sample of air. This technology is useful as the amount of light that passes through the air sample is inversely proportional to the number of carbon dioxide molecules in the air.

How is CO2 Actually Detected?

CO2 gas detectors use an NDIR CO2 sensors that detects the presence of CO2 molecules in the air based on the absorption of infrared light.

As IR light passes through a sample tube of air, the CO2 gas molecules absorb a single band of IR light while letting other wavelengths of light pass through. At the other end of the tube, the remaining light hits an optical filter that absorbs every wavelength of light except the wavelength absorbed by the CO2. The remaining CO2 molecules are counted by an infrared light detector which sends an analog voltage to the sensor's circuitry. In this way, a carbon dioxide sensor can be said to "count" the number of CO2 molecules in the air.

Learn more about how a CO2 sensor works here

Do I need a CO2 gas detector?

If you have stored CO2 tanks or cylinders you must use a CO2 gas detector.

For those that store, produce, or use carbon dioxide - exposure to high levels of CO2 in enclosed areas can lead to severe negative health effects like headaches, dizziness, fatigue, asphyxiation, and even fatality. Because of injuries in buildings that do not have proper monitoring in place, the Occupational Safety and Health Administration (OSHA) has established a permissible exposure limit (PEL) for CO2 of 5,000 ppm averaged over an 8-hour work day.

Overall, if you are using carbon dioxide and working in or around the gas, CO2 safety detectors should always be used in order to initiate an audible or visual alarm to alert individuals in the room where potential CO2 levels could be dangerous to their health.

See our CO2 gas detectors for safety.

If you are concerned about indoor air quality you should use a CO2 gas detector.

CO2 detectors are also used as a proxy measurement of indoor air quality. High levels of CO2 indicate poor air exchange. Poor air exchange is linked to room occupant discomfort as well as increased levels of mold, mildew, bacteria, particulate matter and viruses either floating in the air or carried on water droplets in the air. 

See our CO2 gas detectors that measure indoor air quality.

Is a CO2 Gas Detector the same as a Carbon Monoxide Detector?

No. While both carbon dioxide (CO2) and carbon monoxide (CO) detectors are important, they are very different. A CO2 detector will not detect CO, and vice versa. While both gases have some similarities they are very different.

One critical differentiator is that carbon dioxide is natural and non-flammable, while carbon monoxide is the product of incomplete combustion and flammable. While carbon dioxide can be naturally found in the earth's atmosphere, carbon monoxide is not.

Note that the density of both gases is also very different. CO2 is heavier than CO. For this reason, a CO2 detector should be near the floor while a CO detector should be placed near the ceiling to ensure proper detection.

Will a CO2 Gas Detector Detect Carbon Monoxide?

No. A CO2 gas detector cannot detect the presence of carbon monoxide gas. Conversely, a CO detector will not detect CO2.

A CO detector sounds an alarm if it senses elevated levels of carbon monoxide in the air near a furnace or gas burning appliances.

Learn more about the difference between carbon monoxide and carbon dioxide here.

What are Signs of High CO2 Levels Indoors?

While carbon dioxide is in the air naturally, in larger volumes (> 1,000 ppm) it can affect your health. For instance, excess CO2 can cause individuals to experience headaches, fatigue, nausea, asphyxiation, or convulsions. 

Fortunately, being aware of carbon dioxide concentrations indoors can help prevent negative health effects from occurring and create healthier lifestyles.

Here are 4 sources of carbon dioxide indoors, and how to lessen their impact:

  1. HVAC systems: HVAC systems are designed to control the atmosphere in a given environment by recycling air. But without proper ventilation, CO2 can build up. A CO2 sensor can warn against this.
  2. Fireplace: Carbon dioxide is one of several gases produced by combustion, which means indoor fireplaces can produce gas buildup if they are not ventilated properly. Installing CO2 monitors in your home and annual inspections can mitigate this.
  3. Crowds: Humans exhale approximately 1 liter of CO2 with each breath. More occupants in an enclosed area creates higher CO2 levels. This can be mitigated by opening windows to regulate ventilation and airflow, as well as have indoor air quality monitors in place to measure when CO2 levels exceed normal threshold.
  4. Smoking: CO2 levels in cigarette smoke are 200 times the levels in the atmosphere. Regular smoking indoors can also create consistent overexposure to carbon dioxide concentrations. By ensuring smoking is done outdoors you can be mitigate individual exposure.

Is there a way to check your CO2 levels at home?

CO2Meter Aranet4HOME Indoor Air Quality Monitor

By using a carbon dioxide detector or indoor air quality monitor like the Aranet4 HOME you can easily and affordably measure carbon dioxide levels.

These devices also use a quality NDIR sensor that gives the device the ability to quickly measure the amount of CO2 in the air in real-time.

Should levels exceed the normal threshold the device will show instant visual/audible indication so you are alerted to ventilate the space and mitigate from harmful CO2 exposure. When it comes to CO2 levels in a home, many individuals also look to ASHRAE which sets standards in place for recommended indoor air CO2 concentrations.

According to ASHRAE, the recommended CO2 level in buildings should be no more than 700 parts per million (ppm) above the levels in the outdoor air. Since outdoor air in most areas is approximately 400 ppm, indoor CO2 levels should be no more than approximately 1,100 ppm.

Here are 3 benefits to improving indoor air quality with CO2 monitoring:

  1. Occupant ComfortBy utilizing an indoor air quality monitor, you can eliminate potential contaminants that directly influence poor IAQ. This includes CO2, CO, and particulate matter (PM2.5/10).
  2. Increase in Productivity - Studies have shown, that with less CO2 buildup many people find that they gain back productivity, focus, and energy - three main areas where poor indoor air quality often influences.
  3. Energy Efficiency - Utilizing CO2 monitors or CO2 air quality sensors when occupying space can provide you with proper ventilation indicators, making energy costs significantly lower!

Where Should CO2 Detectors be Placed?

This depends on your application:

  • Safety - Carbon dioxide detectors should always be placed 12 inches (30cm) off the floor.
  • Indoor Air Quality - Placement is less important, but is typically placed at 36 - 60 inches ( 90-150cm) from the floor.

How Long Does a CO2 Detector Last?

The average lifespan of a CO2 detector can vary depending on factors such as quality of the device, its components, usage, and overall environmental conditions.

The most common carbon dioxide detectors typically use nondispersive infrared sensors at their core and last anywhere from 10-15 years with proper use. 

What Makes a Good CO2 Detector?

When it comes to purchasing or selecting your first C02 detector there are a few things to keep in mind to ensure the best quality product for your industry or application.

For starters, you want to have a detector that includes quality features and should look at CO2 detectors similar to purchasing a car. Not only do you want a quality product, you want an affordable cost, easy operation - and above all else the ability to ensure safety or air quality analysis.

Below are the top 5 features customers look for prior to purchasing any CO2 detector:

  1. Accuracy - including a high quality NDIR CO2 Sensor
  2. Audible/Visual Alarms - instant alarms that appear when CO2 levels exceed threshold
  3. Installation - easy operation and installation procedure with thorough documentation
  4. Meets Codes/Regulation - a detector that can meet code compliance around CO2 safety or meet specific ASHRAE IAQ standards
  5. Resolution - clear and easy visual display of CO2 concentrations from a large LCD screen

For more information on CO2 sensing technologies or to speak to a CO2Meter expert, contact us at Sales@CO2Meter.com or 877-678-4259


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