Hydrocarbons like all Liquid Petroleum Gases (LPG), it is flammable when handled incorrectly. Have you ever given a thought about the 9 kilogram LPG cylinder that you use for cooking or the 60 litre tank of LPG in the back of a Taxi? Probably not, because we assume that it is safe to use with all the safeguards provided with the LPG cylinders.
All over the world Hydrocarbons are currently being used in things such as cooking, heating, fridges, powering vehicles, as aerosol propellants for hairsprays, deodorants, whipped cream, cooking sprays etc… If you add this up, all together there are currently millions of tons of Hydrocarbons being used safely all over the world in our everyday activities.
Bosch, Electrolux, Miele, Whirlpool, Delonghi and AEG are just a few of the manufacturers who have already turned to using Hydrocarbons throughout their product range. There are currently over 400 million hydrocarbon, or Greenfreeze, refrigerators in the world today!
In refrigeration and air conditioning systems which currently use chemical refrigerants, oil is used to mix with the refrigerant and travel around the system. Therefore all of these chemical refrigerants also become flammable due to the oil vapour content of the gases when being discharged from the systems.
Most chemical refrigerants also produce toxic by-products and poisonous gases following accidental release in the presence of an adequate heat source. Apparently R410a may turn into “Mustard Gas” when leaked into an Oxygen rich environment!
All over the world procedures and standards have been developed and adopted to ensure the safe use of Hydrocarbon Refrigerants.
What conditions are needed for combustion?
Hydrocarbon refrigerants do not spontaneously combust on contact with air! There are 3 elements that all need to coincide at the same time:
- Hydrocarbons will need to be released.
- The correct proportion of air needs to mix with the Hydrocarbon, the range of flammability generally being 1.9% to 8.5%. Combustion can not occur outside these limits!
- There needs to be some type of ignition source, which exceeds 598°C. Some blends of Hydrocarbon may have a slightly lower or higher temperature.
If any 1 of these 3 elements isn’t present, then the combustion can not occur!
Generally if there is a leak in a system, only a small percentage of refrigerant will leak out, not the whole amount. Then due to the Hydrocarbon being able to dissipate so quickly, it would be extremely difficult to meet the range of flammability.
In commercial applications where a large volume of refrigerant is present, it is vital all safety precautions are made. This may include sensors, extraction vents and fans etc… The area around the unit or plant should also be well signed.
Each country should have a set of standards that need to be met in regards to the Lower Explosive Limit (LEL) for Hydrocarbons. In the Australian Standards AS/NZ 1677 part 1, it covers the lower explosive limit (LEL) which is 35 g/m3 for the hydrocarbon – R290(propane).
|Refrigerant Name||R12||R134a||R22||R410a||Oz-Chill 22a||Any Brand|
|Flammability window(Percentage)||Nil||Nil||Nil||Nil||1.9 to 8.5||Wide band|
As long as your refrigeration mechanic has been trained in the safe use of Hydrocarbons, and has used all the safety precautions possible, you do not have to worry about the flammability issue with regards to hydrocarbon refrigerants.
If there is ever an inkling of doubt that the application may be a potential fire hazard, the conversion should not be undertaken.
Hydrocarbon safety needs to be taken serious by everyone.