There is little that is more essential for life than oxygen. Even a short-term lack of this gas can be life-threatening. But is there ever a point where it becomes dangerous? Is oxygen flammable, is it explosive, and, if so, how much should we worry about it catching alight in our homes?
Oxygen, by itself, is not flammable. It is an oxidizer and the presence of oxygen will aid in the flammability of other materials. However, because oxygen is an oxidizer, it is a fire hazard, and you should keep oxygen away from extreme heat.
When talking about the flammability of oxygen, we need to look at this gas in two different ways. First, I want to talk about the oxygen in our atmosphere. This is an important aspect of what we call the fire triangle, and I will explain how that works and its risks.
Then there is the factor of canisters of pure oxygen. This is where you have oxygen tanks for medical or life-preserving situations. While essential for life, they also pose a massive fire risk when they aren’t treated with respect. So, we need to look a why that is the case and how to avoid disaster.
The Fire Triangle
To understand the dangers of oxygen in a fire, we need to look at the fire triangle. Without these three elements, there is no way to create or sustain a fire.
Oxygen is one of those essential elements to oxidize the fire and keep it burning. But, that doesn’t mean that you can just ignite oxygen on its own. If we could, we’d light up the air around us every time we lit a candle or a cigarette.
Instead, we ignite a fuel source via a hot spark or another source of fire and the oxygen allows it to burn. For example, a lighter uses a spark of friction from the metal wheel and the oxygen in the air to create a flame.
Because we need these three separate elements to create and sustain a fire, this also means that we can extinguish a fire by removing one of them.
This is why fires will eventually burn themselves out. At some point, they will exhaust the available fuel supply.
For example, you may set up a fireplace with suitable firewood and then watch it die away once the combustible material is gone.
But, this isn’t a good strategy for fire fighting as you don’t want to put lives, property, or natural landscapes at risk this way.
An alternative option is to starve the fire of oxygen. With the right tools, this can be a fast and effective way to ensure that the fire goes out completely.
Smothering flames to block the air supply is a good starting point, while also reducing the heat to reduce the intensity of the blaze. This is why we use a range of fire extinguishing equipment and substances that cover the flames and provide that barrier.
Fire extinguishing foam, fire blankets, and water all help.
Are All Gases Flammable?
No, not all gases are flammable and some are incredibly safe to use in a range of seemingly dangerous applications. There are several gases in the periodic table called noble gases.
These are completely inert and non-reactive, allowing them to be used and manipulated in applications with high heat and the potential for sparks and ignition.
One of these is helium, which you can learn more about in my guide on the flammability of helium and the safety of helium blimps and balloons.
Can You Use Carbon Dioxide To Put Out A Fire?
There are other gases that are helpful in a fire but potentially dangerous in other situations. Carbon dioxide is a problematic gas when we don’t have the means to absorb it and allow for a cleaner atmosphere.
We also don’t want to breathe in too much or become exposed to the related carbon monoxide. Yet, we can make good use of it when fighting fires.
This gas displaces the oxygen around a flame, which removes that crucial part of the fire triangle. This is why we can blow out candles with our breath and use more substantial Co2 extinguishers on larger fires.
Oxygen And Dust Explosions
Another consideration when talking about oxygen and explosions is the risk of dust explosions. The physics behind these is similar to that of a fire, where you have three key components coming together to start a blaze.
In this case, you have the oxygen within the localized atmosphere, the fuel from the dust in the air, and the spark to ignite it all.
The reason that dust clouds and dust environments are so volatile is that there is such a high surface area for the fuel when ignited by an electrical spark or a flame.
This means there is more to burn at a more rapid rate. The oxygen in the air just makes it even easier for that fire to spread, leading to a big explosion and the chance of a major blaze.
Dust explosions like this can occur in a range of industrial settings, such as silos, breweries, and factories.
Once they start, they place the whole facility at risk because of the presence of other flammable materials.
Can Oxygen Tanks Explode?
The threat of dust explosions isn’t something we really need to worry about in our day-to-day lives if we don’t work in those environments.
A different threat, however, is that of tanks of pure oxygen exploding under the right conditions. You may have oxygen in your home to help with medical conditions, or while caring for loved ones with chronic health conditions.
The knowledge that oxygen can explode with the right heat and ignition is concerning. So, it is important to learn how to keep your oxygen tanks safe from harm, and in turn, protect your family and home.
Why Don’t Firefighter Air Tanks Explode?
You might wonder why firefighters go into fires with oxygen tanks if they are at risk of exploding.
These Self Contained Breathing Apparatuses (commonly known as SCBA) aren’t the same as medical oxygen tanks, because they use compressed air rather than pure oxygen.
They are also designed to prevent any sort of rupture from increased pressure. This means that firefighters can enter premises at high heat and deal with fires while breathing more easily – all without any additional risks.
How To Keep Oxygen Tanks Safe At Home.
The most important thing to do is to store the oxygen in a safe place when not in use – away from high heat and any fuel sources or open flames – and to be vigilant while they are in use.
This means making sure not to have any lit objects and open flames while the oxygen is on. This means no smoking, no using units the oxygen near a stove or fireplace, and being careful with candles.
You also want to make sure the oxygen is turned off after use to reduce the risk of leaks.
Then there is the risk of a fire starting from a spark, either from friction or from electrical equipment. It is best to remove all electrical equipment from the room while users are receiving oxygen, just to play it safe.
This also means removing any electric blankets, as these are far too close to the oxygen source and could cause serious injury to the recipient.
There are even warnings about toy cars that may spark from friction. It sounds like you are being overly cautious here, but better safe than sorry.
Finally, there is the issue of flammable products in and around the oxygen tank. These could make the tank an even bigger fire risk if a spark were to ignite the product and the gas.
One such example is the use of rubbing alcohol as a cleaner on parts of the machinery and mask. It is also advisable to use water-based lubricants around the mask for comfort, rather than anything with oil in it.
This means no Vaseline.
How Dangerous Is Oxygen?
To summarize, while oxygen is an essential component of fires, we don’t need to worry too much about it being flammable.
Oxygen is a key part of the fire triangle, but you aren’t going to see it ignite on its own. Instead, it will oxidize the reaction between the heat and fuel source and keep it burning.
Once we remove the oxygen supply, the fire goes out. This isn’t generally an issue when we practice good fire safety at home.
But, we do still need to be careful if we use oxygen tanks at home. So, as long as you take the right precautions and understand how to remove oxygen from a fire, you should be fine.