If you own a propane space heater, a vent-free heater or a vent-free fireplace, chances are it has an oxygen depletion sensor (ODS). These sensors are designed to shut the fuel off if the oxygen level in the air gets too low.
On the surface, this makes sense. A lack of oxygen sounds like a bad thing. But in order for oxygen levels to get too low, some other gas has to take its place. The “other gas” can be carbon dioxide - which is bad – or carbon monoxide – which can kill.
So when customers ask if an oxygen depletion sensor will protect them around gas space heaters, in virtually every case our answer is that
“it isn’t the lack of oxygen that kills. It is the carbon monoxide."
What is an Oxygen Depletion Sensor (ODS)?
An Oxygen Depletion Sensor (ODS) is a safety device designed to detect when oxygen levels in an environment drop below a critical threshold, typically around 19.5%.
These sensors are commonly used in confined spaces or areas where oxygen displacement by gases like nitrogen, argon, or carbon dioxide can pose a serious risk to human health. When the oxygen level falls too low, the ODS triggers an alarm, ensuring that occupants can evacuate or take corrective action before the situation becomes dangerous. This type of sensor is essential in industries such as laboratories, breweries, and other environments where gases that can displace oxygen are frequently used.
The primary purpose of an ODS is to prevent oxygen deficiency, which can lead to symptoms such as dizziness, confusion, and in severe cases, unconsciousness or fatality.
Unlike other gas detectors, ODS devices are specifically focused on monitoring oxygen levels, ensuring that environments remain safe for workers and occupants. By continuously measuring the concentration of oxygen in the air, an ODS provides real-time protection, making it an indispensable tool for industries that deal with inert gases or operate in confined spaces.
Where are Oxygen Depletion Sensors used?
Oxygen depletion sensors (ODS) are used on virtually all modern vent-free heaters and fireplaces. The sensor is designed to shut off the fuel if the oxygen level in the room drops from 21% (normal air) to 18.5% oxygen by volume or below. The reduction in oxygen triggers a thermocouple which closes the gas valve. As a result, the heater is starved of gas and will shut off automatically.
Beginning in 1980, all ANSI certified vent-free units require an ODS. Gas and vent-free heater and fireplace manufacturers are proud of their record of no recorded deaths attributed to lack of oxygen when their heaters were used.
Do Oxygen Depletion Sensors really protect you?
No. While the idea of an oxygen depletion sensor is good, in reality it will not protect you from the deadly gases carbon dioxide or carbon monoxide.
The problem with this is one of logic. For room oxygen levels to drop from 21% to 18.5% by volume, 2.5% of another gas has to take its place. Most of this will be carbon dioxide, which is bad for your health above 3%.
Carbon monoxide is even more deadly. Breathing air with CO levels above 400ppm is deadly in hours and above 1,600ppm is fatal within minutes.
So while oxygen depletion sensors might make you feel safe when you read about them in your heater’s manual, they are not a complete answer. That’s why carbon monoxide detectors are more important.
How Does a Carbon Monoxide Detector Work?
A carbon monoxide detector works by continuously monitoring the air for the presence of carbon monoxide (CO), a colorless, odorless, and highly toxic gas. The most common type of CO detector uses electrochemical sensors, which contain electrodes in a chemical solution that react when carbon monoxide is present.
As CO molecules enter the sensor, they trigger a chemical reaction that generates a small electrical current. The detector then measures the strength of this current to determine the concentration of carbon monoxide in the air. If CO levels reach a dangerous threshold, typically around 50 parts per million (ppm), the detector sounds an alarm, alerting occupants to evacuate or ventilate the area.
Carbon monoxide detectors are essential in homes, offices, and industrial settings where fuel-burning appliances such as furnaces, gas stoves, and generators are used. These devices provide early warning of CO buildup, which is crucial since carbon monoxide poisoning can occur quickly and without warning.
By detecting carbon monoxide before it reaches harmful levels, CO detectors help prevent serious health risks such as headaches, dizziness, and even death, ensuring the safety of those in both residential and commercial spaces.
Carbon Monoxide Detectors are more Important
Carbon monoxide poisoning (CO) is the second most common cause of non-medicinal poisonings death in the US and the most common cause of poisoning worldwide. According to the CDC, over 10,000 are poisoned by CO each year and more than 438 people in the U.S. die annually from CO poisoning. That’s why the majority of states in the US now require CO detectors in homes.
Because CO detectors are relatively cheap and easy to install, most heaters and furnaces don’t have separate CO sensors. Instead, home owners are strongly encouraged – and in some states legally required - to place a CO detector in every bedroom and near the home’s furnace.
Even if you are using a heating device with an oxygen depletion sensor, you should always have a carbon monoxide detector nearby.
Key Differences Between Oxygen Depletion Sensors and Carbon Monoxide Detectors
The key differences between oxygen depletion sensors (ODS) and carbon monoxide detectors lie in the specific gases they monitor and their applications.
Oxygen depletion sensors are designed to detect when oxygen levels in an environment drop below safe thresholds, typically due to the displacement of oxygen by inert gases such as nitrogen or argon. These sensors are commonly used in industrial settings like laboratories, confined spaces, and gas storage areas where oxygen depletion can pose a significant health risk.
In contrast, carbon monoxide detectors are focused on identifying the presence of carbon monoxide (CO), a colorless and odorless gas that results from the incomplete combustion of fuels like gas, oil, and wood. CO detectors are crucial in environments where fuel-burning appliances are used, such as homes, garages, and industrial facilities.
Another significant difference is how these devices protect individuals. Oxygen depletion sensors ensure that sufficient oxygen levels are maintained, as low oxygen concentrations can lead to symptoms like dizziness, fatigue, and even unconsciousness.
On the other hand, carbon monoxide detectors are designed to alert occupants to the presence of toxic carbon monoxide gas, which can cause poisoning even in small amounts. Both devices are essential for safety, but they serve different purposes and are used in different environments depending on the specific gas-related hazards present.
Applications of Oxygen Depletion Sensors in Industrial and Commercial Settings
Oxygen depletion sensors (ODS) are crucial safety devices in a wide range of industrial and commercial settings where inert gases, such as nitrogen, argon, or carbon dioxide, are used and can potentially displace oxygen in the air.
In industries such as chemical manufacturing, welding, and laboratories, ODS devices are often installed to ensure that oxygen levels remain safe for workers. For example, in confined spaces where gases are stored or processed, an ODS can prevent dangerous situations caused by oxygen displacement, ensuring compliance with health and safety regulations while protecting workers from asphyxiation risks.
In commercial settings, oxygen depletion sensors are commonly used in cold storage facilities, breweries, and areas where cryogenic gases are handled. These sensors monitor oxygen levels in environments where gas leaks or spills could quickly lead to oxygen depletion, creating hazardous conditions.
By continuously measuring oxygen concentrations, ODS devices provide real-time alerts and automatic shutdowns, offering an essential layer of protection for both employees and equipment. This proactive approach to safety minimizes risks and ensures that oxygen levels remain within safe ranges, making ODS devices indispensable in a variety of industrial and commercial applications.
Safety Regulations and Standards for Oxygen Depletion Sensors and Carbon Monoxide Detectors
Safety regulations and standards for oxygen depletion sensors (ODS) and carbon monoxide detectors are critical to ensuring the protection of workers and the public in environments where gas hazards exist.
For oxygen depletion sensors, organizations like OSHA (Occupational Safety and Health Administration) and ANSI (American National Standards Institute) set guidelines for safe oxygen levels, typically requiring that oxygen concentrations remain above 19.5% in most industrial settings.
Compliance with these standards often necessitates the use of ODS devices in areas where gases such as nitrogen, argon, or carbon dioxide are present, ensuring that oxygen levels do not fall to dangerous levels. These sensors are essential in industries such as chemical manufacturing, laboratories, and gas storage facilities, where strict adherence to safety regulations is required to prevent life-threatening conditions.
Similarly, carbon monoxide detectors must meet specific safety standards established by regulatory bodies such as UL (Underwriters Laboratories) and NFPA (National Fire Protection Association).
These standards require that carbon monoxide detectors alert occupants when CO levels exceed safe limits, generally around 50 parts per million (ppm) over a prolonged period. In residential and commercial settings, compliance with CO detector standards is essential to avoid carbon monoxide poisoning, which can lead to serious health risks or death.
Both ODS and CO detectors must meet these regulations to ensure proper functionality, providing reliable safety for workers and the public in environments where gas exposure could become hazardous.
Benefits of Using Both ODS and Carbon Monoxide Detectors for Comprehensive Safety
Using both oxygen depletion sensors (ODS) and carbon monoxide detectors together offers comprehensive safety coverage in environments where various gas-related hazards may exist.
While an ODS is designed to monitor oxygen levels and prevent oxygen depletion, a carbon monoxide detector focuses on detecting toxic carbon monoxide (CO) buildup, which can occur in spaces with fuel-burning appliances.
By integrating both types of sensors, industries and commercial settings can safeguard against two of the most common and potentially deadly gas hazards: oxygen deficiency and carbon monoxide poisoning. This dual approach ensures that workers and occupants are protected from the risks of asphyxiation due to low oxygen levels and exposure to harmful CO gas.
The combination of ODS and CO detectors is particularly important in industries like manufacturing, laboratories, and confined spaces, where both oxygen displacement by inert gases and carbon monoxide emissions may occur.
By using both detectors, facilities can achieve compliance with strict safety standards and regulations while ensuring that all gas-related risks are properly monitored. This comprehensive safety system minimizes the chances of workplace accidents, reduces liability, and enhances overall safety protocols, offering peace of mind in environments where gas hazards are a constant concern.
For more information on multi-gas safety systems, click here.
How to Choose Between an Oxygen Depletion Sensor and a Carbon Monoxide Detector
Choosing between an oxygen depletion sensor (ODS) and a carbon monoxide (CO) detector depends on the specific gas hazards present in your environment. If your facility involves the use of inert gases like nitrogen, argon, or carbon dioxide, which can displace oxygen and create a risk of oxygen deficiency, an oxygen depletion sensor is the right choice.
These sensors are crucial in industries such as manufacturing, gas storage, and laboratories, where maintaining safe oxygen levels is essential for worker safety. An ODS will continuously monitor oxygen concentrations and alert you when levels drop below the safe threshold, ensuring that corrective actions can be taken before oxygen depletion becomes dangerous.
On the other hand, if your environment contains fuel-burning appliances, such as furnaces, heaters, or gas stoves, or exhaust in automotive applications - a carbon monoxide detector is necessary to detect the presence of toxic CO gas.
When choosing between the two, consider the specific gas risks in your environment, and in some cases, using both devices may provide the most comprehensive safety solution.
If you need further assistance or advice on what gas solution is the best for your gas detection needs, environment, or safety requirements - contact us today.