This article will answer the following question: “Is CFC gas Flammable?”. We will also demonstrate their relation to the ozone layer and how could CFCs burn.
Is cfc gas flammable?
Chlorofluorocarbons are nonflammable substances. There’s no fire hazard in dealing with CFCs in their pure form. In a mixture, other compounds such as organic solvents could make the entire product very flammable (the CFC constituents, although, wouldn’t burn).
What is CFC gas?
Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are organic volatile compounds that started being used during the 70s.
The compounds are full or partially halogenated hydrocarbons, derived from simpler volatile organic compounds.
CFCs were widely used as refrigerants and propellant gases, especially thanks to their higher boiling point and inert properties.
The gases suddenly gained across-the-board industrial applications and were used in aerosol spray cans, insulating foam, industrial solvents, and cleaning agents.
But there was a problem. Scientists discovered that CFCs gases could creep into higher places in our atmosphere, destroying the ozone layer at a very fast pace, and allowing dangerous radiation to freely reach the surface of our planet.
Some industries still use hazardous CFCs in well-controlled environments, but only as a precursor for other compounds, like Teflon. All these CFCs are consumed in the process.
There are also a few CFC compounds that have insignificant ozone depletion potential. The most common is 1,1,1,2-Tetrafluoroethane (also known as CF3-CH2F, norflurane, INN, HFC-134a, and R-134a), which is mainly used as a refrigerant gas.
What is the problem with CFC gas?
CFC gas is pretty much inert. After being released in the air, it can spend years simply flying around according to the breeze, barely interested in reacting with any living or inanimate thing.
If so, why did it affects the ozone layer so much?
Well, a common molecule of CFC or HCFC is composed of one or a few more carbons, hydrogen, chlorine, and fluorine.The molecules are very concise, they can’t react directly with compounds, but they can break in contact with radiation.
What happens is that CFCs can hold on to chloride atoms very firmly (not by simply carrying them away, but as a part of the CFC molecule), maintaining them until reaching the top of the atmosphere, where the ozone layer is.
The UV (ultraviolet and near-violet) radiation tears the CFCs molecules, which liberates reactive chloride species. Unfortunately, these reactive compounds can help break down the ozone molecules. We will see more about that.
The ozone layer
Have you ever felt an odd smell in the air around an electrical spark? That’s the smell of ozone.
Ozone is an oxygen molecule. The oxygen we breathe is not an oxygen atom (O), but a molecule made of two oxygen atoms (O2).
When there’s a spark, an oxygen gas molecule breaks apart, producing reactive oxygen species that react with other oxygen molecules, yielding O3.
In our homes, these few ozone molecules quickly react with other things and vanish but, up in our stratosphere, they remain in a thin layer. Its thickness can vary depending on the season and geographic location.
So ozone is just a layer made with unusual oxygen molecules. It may not seem exciting but it is the shield that protects life, including ourselves, from the dangers of cosmic radiation.
Ozone can absorb the radiation itself instead of leaving it to our skin. This is a very interesting deal for us: we leave ozone alone, and it prevents us from getting skin cancer.
What do CFCs do to the ozone layer?
CFCs themselves don’t do much to it, but a byproduct of the photolysis (a chemical reaction that requires a source of radiation like the Sun) of CFCs is what does the damage. We are talking about chloride.
Chloride is a catalyst in the reaction of breaking down ozone molecules back into the form of oxygen gas. In chemistry, catalysts are like GPS devices.
You can travel from one point to another by car if you don’t know the path very well, but you can do it much easier and quicker if you have a GPS. To do so, the device is not consumed (unlike your gasoline), and you can use it again on your next trip.
Likewise, chlorine atoms are not consumed during ozone destruction. One single chlorine atom can be the catalyst for tearing apart 100.000 ozone molecules. That’s why CFCs stopped being used in the 80s.
As Carl Sagan, perhaps the most influent and popular scientist and science communicator that ever lived, said in his book “Billions and Billions”:
“We are not always smart or wise enough to foresee all the consequences of our actions. The invention of CFCs was a brilliant achievement. But as smart as those chemists were, they weren’t smart enough. Precisely because CFCs are so inert, they survived long enough to reach the ozone layer.
The world is complicated. The air is thin. Nature is subtle. Our capacity to cause harm is great. We must be much more careful and much less forgiving about polluting our fragile atmosphere.”
CFCs and HCFs are non-flammable, colorless, volatile, non-toxic liquids and gases.
No flammability is attributed to pure CFC gases in any of the sources consulted to write this blog. This is because even if the compounds were tossed into a fire, the combustion would not liberate energy.
Whenever we burn a source of fuel like the gasoline in a car engine, the wood in a fireplace, or the kitchen gas, our main goal is to produce energy.
A good source of fuel is something that can liberate a lot of energy after we give initial energy to it. One main reason we still use fossil fuels is that the energy we retrieve from burning them is thousands of times bigger than the spark required to first ignite’em.
This is why burning CFCs is not hazardous. Even if we could apply enough temperature to it, the “combustion reaction” (if we can call it that) wouldn’t generate heat or light. In fact, it would absorb some energy from the surroundings, cooling itself a little.
Although, we found one aerosol spray used for cleaning electronic components of precision equipment in which the CFC was a just part of the formula. The rest was made with highly flammable organic solvents.
The product’s name is LPS® CFC Free Nu.
Here you can find some Safety Data Sheets for other CFC products.
- CFC®, from Chemetall US, Inc.
- CFC-13, by Honeywell Company.
- Halocarbon R-12 (Dichlorodifluoromethane), by Airgas.
- Freon 113, by Fisher Scientific.
Chlorofluorocarbons are not flammable. No fire could rise from their burnings because the chemical reaction doesn’t liberate energy. Although, CFCs can still liberate harmful vapors in a fire, due to thermal deterioration.
Frequently Asked Questions (FAQS): Is cfc gas flammable?
Are cfc greenhouse gases?
Yes. Greenhouse gases are gases that can increase the average temperature on our planet. CFC compounds are usually capable of damaging the ozone layer, which can lead to more radiation on the surface of our planet.
While this event alone can already increase temperatures, CFCs can also trigger other events that lead to much more catastrophic occurrences. Polar holes in the ozone layer, for example, can lead to the melting of polar ice caps.
is cfc gas still used?
Yes, but not the harmful CFC gases. There are CFC compounds with low and very low ozone depletion potential that can still be used in many countries. These are considered practically not harmful to the environment.
is cfc gas harmful to humans?
CFC gas is not clearly related to any acute health hazard. There is some evidence that points that CFCs can impair the human immune system.
The biggest problem CFCs can bring to humans is the damage to the ozone layer, which can lead to many harmful health conditions like skin cancer and eye damage.
Sagan, Carl. Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium. Ballantine books, 1998.