Common Misconceptions About Gases and Oxygen Removal
Don’t have the cubic feet but have cubic meters?
Add your cubic meters here to convert to cubic feet:
Add your cubic feet here to convert to cubic meters:
How to Use the Oxygen Concentration Calculator
Oxygen Percentage (O₂):
What is this? This is the amount of oxygen in the air, which is usually around 20.9% in normal atmospheric conditions.
Why do you need this? The calculator uses this to understand the starting amount of oxygen in the space you’re calculating for.
Initial Volume:
What is this? This is the total volume of the space you are calculating for (in cubic feet).
Why do you need this? The volume helps us understand how much air is in the space to begin with. A larger space will have more oxygen, so it needs more gas to reduce the oxygen level.
Add Nitrogen (or other gas):
What is this? This is the amount of gas (usually nitrogen) you plan to add to the space. Nitrogen is used to displace oxygen in order to reduce the oxygen percentage.
Why do you need this? By adding nitrogen, the oxygen percentage will drop. The calculator will figure out the new oxygen level after you add the nitrogen.
Result: Remaining Oxygen Percentage:
After you enter your values and click Calculate, the calculator will tell you the new oxygen percentage in the space. This is the amount of oxygen left after you’ve added the gas.
What to Expect from the Results:
Above 19.5%: Normal oxygen level.
12% – 16%: Low oxygen level that can impair judgment and coordination. Fires can still burn.
Below 12%: Fire will struggle to burn, and humans might start experiencing distress.
Below 7%: People will feel severe symptoms like dizziness or unconsciousness.
Below 5%: Very dangerous. Survival becomes impossible due to lack of oxygen.
Converting Units:
- If you need to convert between cubic meters and cubic feet, you can use the input fields provided:
- Cubic meters to cubic feet: Enter your value in cubic meters, and it will automatically convert to cubic feet.
- Cubic feet to cubic meters: Enter your value in cubic feet, and it will convert to cubic meters.
This helps you easily convert your measurements, depending on the units you’re using.
Example:
- Let’s say you have a room with 100 cubic feet of air, and the oxygen level is 20.9%.
- If you add 50 cubic feet of nitrogen, the oxygen percentage will drop.
- The calculator will show you the new oxygen percentage, which in this case would be 13.9%.
This is a safer oxygen level for fire suppression but could cause discomfort or distress for humans if the levels drop further.
How do gas-based fire suppression systems affect oxygen levels?
Oxygen depletion is one of the most misunderstood concepts in fire safety and gas-based fire suppression systems. Many people believe that gases like FM-200, Novec 1230, and Inergen “kill” oxygen, but that’s not the case. These systems are designed to reduce oxygen levels just enough to suppress the fire, without reaching levels that would harm people.
We’ll help you understand these misconceptions to avoid dangerous situations, whether at home, at school, at the office, or in any confined space.
Misconception #1: Oxygen Depletion Is the Same as Oxygen Displacement
While oxygen depletion and oxygen displacement are related, they aren’t the same:
- Oxygen depletion: This happens when oxygen is displaced or consumed to a point where a fire can’t burn or you can’t breathe safely.
- Oxygen displacement: This occurs when inert gases like nitrogen or argon are introduced into a space, pushing oxygen out of the way and reducing its concentration.
Misconception #2: Fire Suppression Gases ‘Kill’ Oxygen
Fire suppression gases displace oxygen, not destroy it. Gases like FM-200, Novec 1230, and Inergen reduce oxygen concentration levels in the air, making it harder for fires to continue burning. Rather than chemically reacting with or “killing” oxygen, they take up space, lowering its percentage in the environment.
Misconception #3: Only Chemical Reactions Can Deplete Oxygen
Chemical reactions and physical displacement can both cause oxygen depletion, but they work differently.
With physical displacement, inert gases like nitrogen or argon from a fire suppression system simply push oxygen aside, reducing its concentration without any chemical reaction. On the other hand, chemical processes like burning fuels consume oxygen by combining it with other elements, such as carbon or hydrogen.
Misconception #4: Oxygen Depletion Is Always Obvious
Oxygen depletion can be silent and undetectable. If you lack proper monitoring systems, you may not notice the presence of inert gases like nitrogen or argon until it’s too late.
Since they’re odorless and colorless, you can suddenly experience symptoms of oxygen depletion, such as dizziness or confusion, without any warning. That’s why it’s important to install proper safety and monitoring solutions if you’re using gas-based fire suppression systems.
Misconception #5: Carbon Dioxide (CO₂) Is Only Harmful at Extremely High Levels
CO₂ can be dangerous even at moderate levels. CO₂ is commonly used in fire suppression systems because it displaces oxygen and cools flames. Nevertheless, it can lead to:
- Concentrations above 5%: Headaches, dizziness, confusion, and shortness of breath
- Concentrations above 10%: Unconsciousness or even death
Since CO₂ stimulates breathing, it can be harder to detect oxygen depletion until it’s too late.
Misconception #6: All Gases Displace Oxygen Equally
Gases have different properties and effects on oxygen displacement:
- Nitrogen (N2): Lighter than air, nonreactive, and mixes well throughout a space. It’s ideal for general fire suppression.
- Argon (Ar): Heavier than nitrogen and ideal for localized suppression in low-lying spaces.
- CO₂: Heavier than air and an effective fire suppressor, but with a higher risk to human health and safety.
- FM-200 and Novec 1230: Clean agents that absorb heat and slightly reduce oxygen levels. They’re ideal for occupied spaces.
The Risks of Oxygen Depletion
The air we breathe contains about 21% oxygen. Gases like CO₂ and nitrogen can lower this concentration, and depending on the oxygen levels in the space, you might experience:
- 12%-16%: Impaired coordination and judgment, but fires can still burn
- Below 12%: Fire struggles to sustain combustion, but breathing becomes difficult
- 7%-10%: Severe physical distress and likely loss of consciousness
- Below 5%: Fatal oxygen deprivation
Trust the Experts at Kord Fire Protection
It’s important to understand the difference between oxygen depletion and oxygen displacement. While no gases “kill” oxygen, they can displace or reduce it, creating a potentially hazardous environment.
That’s why at Kord Fire Protection, we design and install NFPA-compliant fire suppression systems for any confined or industrial setting. These systems keep oxygen levels low enough to prevent combustion but high enough to avoid difficulty breathing.
Ready to protect what matters most? Contact us today for a consultation or quote.
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