Are refrigerants flammable? What is the safest refrigerant?

From air conditioners to your refrigerators, it is used everywhere. It would not be possible to keep things cool these days without it!

What am I talking about? Refrigerants. One of the most crucial components needed for modern-day refrigeration. We are surrounded by devices like refrigerators, water coolers, air conditioners. So, we know that these refrigerants are all around us.

As such, you may be curious to know more about it. This may lead you to ask- are refrigerants flammable?

The answer depends on what exact refrigerants you are using. It can be totally non-combustible or highly flammable. Read this article to find out more about refrigerants.

Also Read: Check out our other article about Is Freon Flammable Or Explosive?

What type of refrigerant is flammable?

Are Refrigerants Flammable 3

Over the decades, many chemicals and fluids were tested and used as a refrigerant. Of course, these chemicals and fluids have different properties than one another but one widespread property that can be found among them is that they are flammable.

To distinguish between these refrigerants, “Refrigerant flammability classes” were introduced. According to that, all the refrigerants are divided into three groups. They are:

Flammability class 1:

Examples of fluids in this class are; Helium (He), Nitrogen (N), Neon (Ne), Carbon dioxide (CO2), Sulfur dioxide (SO2), water, air etc.

Flammability class 2:  

Examples of fluids in this class are; Ammonia (NH3), Propane (C3H8), Methyl Chloride (CH3CL), Ethane (C2H6), iso-butane (iC4H10).

Flammability class 3:

Examples of fluids in this class are; Methane (Ch4), trifluromethane (CHF3), pentafluroethane (C2HF5), difluoroethane (CHF2CH3).

The flammability of class 1 substances is the least and the flammability of class 3 substances are the most, while the flammability of class 2 substances is average.

Is flammable refrigerant dangerous?

Many risks are associated with the use of refrigerants. Among many hazards, flammability is a commonly well-known property of refrigerants.

Historically almost all refrigerants were flammable. Whenever these gases accidentally leaked due to equipment failure, poor maintenance, or human error, it always results in big accidents like a huge fire or an explosion.

The refrigerants are flammable for two big reasons: flashpoint and the vapor pressure of the fluid. The flashpoint of these refrigerants is the lowest temperature at which it can mix with air to form an ignitable mixture and the vapor pressure of the refrigerants indicates the evaporation rate of the fluid.

Normally in devices like the refrigerator or air conditioner, these gases are kept under very high pressures to ensure quality and efficiency. However, higher vapor pressures result in lower flash points and hence, higher flammability.

Also Read: Does It Insulation Catch Fire?

Is R134a refrigerant flammable?

R134a is one of many common refrigerants that were used in the last decade. It is also known as Tetrafluoroethene (CF3CH2F), and it belongs in the family of HFC refrigerants. Under normal instances, R134a refrigerant is a non-flammable, non-toxic, and non-corrosive substance. I

t was developed to replace the CFCs and HCFCs refrigerants as these caused damages to the Ozone layer of the Earth’s atmosphere.

It was widely used in air conditioning systems and automotive vehicles. But recently, it was questioned that R134a also contributes to global warming, causing it to be banned in many countries.

Which refrigerant blend is highly flammable?

R290 (propane) and R600A (Iso-butane) are two refrigerants blends that are considered highly flammable. However, both are famous and getting more popular as they are efficient and have low global warming potential.

R290 is used in newer refrigeration and air conditioning systems. It is used in commercial and industrial refrigeration, Commercial and industrial air conditioning, and even domestic air conditioning. It has excellent thermodynamic properties, which results in high energy efficiency.

R600A is becoming a refrigerant of choice due to its low global warming potential. It is used mostly in domestic and commercial refrigeration. As a vast amount of people are using refrigeration devices, a low environment-affecting refrigerant like R600A is being promoted for use.

What is the safest refrigerant?

There are many safe refrigerants out there, so singling one outcome down to personal preference. However, here are some of the safest refrigerants and their properties:


R-134A is one of the rare refrigerants which is not blended and is made up of a single component. Which makes it a lot easier to work with. It has thermodynamic properties and is also known as Norflurane. Many experts believe using R-134A is better for the environment as it has an insignificant effect on the ozone layer.

However, some countries are still skeptical of this chemical and are phasing it out. Besides environmental safety, R-134A is safer to use in the workplace. According to “Refrigerant safety group classification,” R-134A has low toxicity and does not propagate flames.


R-407C is a mixture of hydrocarbons which includes a blend of pentafluoroethane, difluoromethane, and 1,1,1,2-tetrafluoroethane.

This is a widely accepted alternative refrigerant to packaged air conditioners, ductless split systems, and water chillers. It is also a common choice to use in newly manufactured appliances.

This refrigerant is considered safe as it is believed that it does no significant harm to our Ozone layer. According to “Refrigerant safety group classification”, R-407C has low toxicity and does not propagate flames.


Similar to R-134A and R-407C, R-404A is considered safe for the environment as it does not affect the Earth’s ozone layer. Industrial transport industries commonly use this refrigerant. It does not react rapidly with air and water and is also non-flammable, odorless.

Are Refrigerants Flammable 2

How are flammable refrigerants identified?

There are 3 classes of flammability. Class 1 refrigerants are those which does not show flame propagation at 60 degrees Celsius. Class 2 refrigerants show flame propagation at 60 degrees Celsius and have a low heat of combustion. Finally, class 3 refrigerants show flame propagation at 60 degrees Celsius and have a high heat of combustion.

Refrigerants in class 3 are considered highly flammable, while refrigerants in class 2 are considered less flammable. These classifications are used as guidelines for determining how much refrigerant can be used in a closed space.

What happens when refrigerants are exposed to high temperatures?

Normally when refrigerants are exposed to high temperature, it decomposes and emits toxic and decomposing fumes. Depending on the flammability of the refrigerant burnt, there may also be a fire or an explosion if the amount burnt is high. Increasing pressure affects this and makes the refrigerants more flammable and explosive.

The toxic fumes that are emitted are hydrogen and fluorine chloride.


As safer and more compliant refrigerants are being made, it is essential to know the properties of different refrigerants to make the right choice of Air conditioners and Refrigerators while purchasing. Some choose the environment-friendly one, while many choose the less flammable one.

We hope the information provided in this article helped you know whether refrigerants are flammable.



Leave a Comment