Dangers of Hydrocarbon

The chemical industry has made it a point to instill fear when it comes to natural refrigerants. The issue of natural gas being flammable has been harped on for many years. In developed countries the myth has been put to rest through rigorous testing. It is essential to understand from the get go that while natural gas is flammable by definition/classification, in terms of its application it is not, largely due to the area parameter restriction. Below is a clear description of that logic.

The Truth about Flammability

Hydrocarbon refrigerant will only ignite when its mixture with Oxygen is within the flammability window of 2% to 10% and in the presence of an ignition source (open flame).

                                                       Upper Flammability Level (UFL) 10% of HC:
                                                       UFL 175 grams HC/m3

Lower Flammability Level (LFL) 2% of HC :
LFL 35 grams HC/m3

At concentration above the 10% Upper Flammability Level (UFL), there is insufficient oxygen for combustion. Since the Hydrocarbon Refrigerant in the air conditioning system is always more than 10%, combustion can never occur inside the system as there is never enough oxygen.

At concentrations below the 2% Lower Flammability Level (LFL), there is not enough hydrocarbon refrigerant for combustion. This is the level below which we always operate (35 grams per cubic meter) to ensure total safety as explained in the table below:

Table 3: Cold 22 charge as per compressor size to room parameters.

*Assumption Room Height under ceiling is 2.5m

Size in HP

Charge of Cold
22 in gm(c)

Minimum Room
Volume in M3
based on 35gm/M3

Room size
in M2

1 405 12m3 5
2 540 15m3 6
3 810 23m3 9
4 1300 37m3 15
5 2040 58m3 23
6 3200 91m3 37
7 3500 100m3 40
8 3600 103 m3 41

Arena's Added Safety Features:

If necessary Arena installs an inexpensive electronic leak detection system which are sensitive at 0.4% mixture (20% of LFL or 8 grams per cubic meter) that shuts down the system and alerts the owner if a leak is detected.

To ensure proper training of engineers and contractors, Arena has entered into a smart partnership with University Tenaga National.

HFOS: The new HFCS

Given the number of applications using natural refrigerants around the world one

would expect the[3:16:37 PM IST] Anupam Singh: chemical companies who introduced F-gases to finally invest in these environmentally-friendly chemicals. However, the chemical industry has come out with yet another F-gas alternative – a new generation of HFCs called HFO's.

This time, it says that not only are they ozone-friendly, they also have a low impact on the climate. What the chemical industry has kept quiet though is how risky and toxic these new chemicals can be in other areas of the environment and human health. Until these risks are taken care of,

Greenpeace will oppose these chemicals, in line with the precautionary principle (see ‘The precautionary principle’ for definition). For the moment, they are only meant for car air-conditioning, but plans for other applications are in the pipeline even though HFC-free environmentally-friendly alternatives are already available. New chemicals will simply delay the deployment of the long term solutions - HFOs are wolves in sheep’s clothing. HFOs are only a short-term fix.

HFC black market

The chemical industry encourages the use of HFOs. However, because HFOs are much more expensive than any of the F-gases currently on the market, the door is left open to a black market in older, more environmentally harmful, but less expensive F-gases. This would prolong the use of more harmful F-gases, even after they are phased out (which happened with CFC and HCFCS when they were first regulated).

Looking backwards: soon to be phased-out HCFCs used to make HFOs

HCFCS, which destroy the ozone layer and have a high global warming potential are used to make HFO’s. This means that ozone depleting and global warming chemicals that are soon going to be banned under the Montreal Protocol are the source of the refrigerants of the future!

As opposed to natural refrigerant technology that is tried, tested and open for all to use and develop, the chemical details of HFOS are shrouded in secrecy. There are human health concerns for developmental toxicity and lethality of HFO when inhaled at high concentrations. Additionally, the substances that are released into the atmosphere as a result of its production are unknown.

HFOS- an unnecessary risk to the environment and human health Trifluoro acetic acid (TFA): a danger to aquatic ecosystems

When HFO breaks down in the atmosphere it produces a substance called trifluoro acetic acid (TFA). In high enough concentrations, TFA is toxic in aquatic ecosystems. While TFA is a common by-product when other HFCS breakdown, HFO produces 4 to 5 times as much TFA than the same amount of HFC 134a does. This means that if HFOS become the refrigerants of choice, the concentration of TFA in fresh water bodies around the world could increase dramatically, with unknown effects on ecosystems and human health, as TFA concentration approaching a milligram per liter may be toxic to some aquatic life forms.

HFO: a very toxic acid, fatal to humans