HCFC

What are hydrochlorofluorocarbons (HCFCs)?

Hydrochlorofluorocarbons (HCFCs) are a type of gas composed of carbon, hydrogen, chlorine and fluorine atoms, and which have been introduced on an interim basis to replace CFCs. They are therefore considered to be second-generation refrigerant gases that were intended as cleaner alternatives to CFCs; however, they are also considered ozone-depleting gases.

Taking this point into account, it is safe to say that these gases have a lower ozone depletion potential than CFCs, but they should still be considered greenhouse gases.

What are HCFCs?

As already mentioned, HCFC is an abbreviation of hydrochlorofluorocarbon. These gases are composed of chlorine, carbon, fluorine and hydrogen. They are a type of gas that can be categorised as a transitional gas, as they are being used to replace CFCs as part of the plan to reduce the emission of ozone-depleting gases. HCFCs are gases used in the manufacture of other chemicals. Despite their lower ozone-depleting potential than CFCs, they have a high global warming potential. These are gases therefore that are to be gradually phased out. Their use is decreasing in developed countries, in particular, in line with the Montreal Protocol. This protocol aims to reduce the baseline to 90%.

HCFC applications

Some of the most important applications of HCFC gases are listed below. At this point it is time to talk about HCFC refrigerants. Indeed, both CFCs and HCFCs have often been used as thermal insulators as well as refrigerants. HCFC applications include fire extinguishers, as well their use as solvents or as aerosol propellants.

One of the most important factors that explains why CFCs have been gradually replaced by HCFCs is their durability in the atmosphere: after their emission, they can spend between 50 and 100 years in the atmosphere until their complete degradation, which occurs when they bind with the ozone present in the stratosphere.

HCFCs emerged as a type of fluorinated gas that does not damage the ozone layer, although they are greenhouse gases. These are very potent gases which, although less potent than CFCs, also contribute to global warming by contributing to the greenhouse effect. HCFC gases are used in air conditioning equipment and also in refrigeration equipment that is generally designed to use them. They are also used in processes related to the manufacture of foams.

Physical properties of HCFCs

To provide more information on HCFC refrigerant gases, we will mention some of their physical properties.

HCFC – 123

This is a liquid, non-flammable substance that is colourless and volatile. It is generally used as a substitute for CFCs, and has chemical properties very similar to CFCs. However, it is a gas that has better environmental qualities. It is in particular a gas with a low accumulation potential in the atmosphere.

HCFCs – 22

It is an odourless, non-flammable, colourless gas that is slightly soluble in water. It has a low octanol/water partition coefficient (in relative terms). This in turn indicates that it has a very low potential rate of accumulation, tending to be around zero, in fact. It is a gas used in refrigeration and air conditioning.

HCFCs – 141 b and 142 b

This is a colourless, flammable liquid, slightly soluble in water and volatile. Its octanol/water partition coefficient is low, so it also has a low accumulation potential. It is a substance that can, however, be toxic in marine environments. 142b has similar properties.

HCFCs – 124

It is a non-flammable and colourless gas.

Environmental impact of HCFCs

Having defined what HCFCs are and what their applications are, the environmental impact of these gases cannot be overlooked. As mentioned above, these gases are widely used in refrigeration and air conditioning equipment. Refrigeration systems can include temperature or energy control equipment, as well as air conditioning systems.

This is an important point, as consumption and use increases during certain seasons. Particularly in summer, when rising temperatures also increase the use of refrigeration and cooling equipment for products and environments. Efficiency and the proper use of equipment are particularly important when using HCFCs: if not used efficiently, they may generate more emissions or may not function properly, which makes them even more harmful.

HCFC gases contained in refrigeration and air conditioning equipment are dangerous if released into the atmosphere, as they cause ozone depletion. This situation, as will be seen below, can have  pernicious effects on human beings. Because they contain chlorine atoms, HCFC gases cause the ozone layer to weaken when they are released. This weakening occurs precisely as they degrade: when HCFC gases degrade, they combine with the ozone present in the stratosphere under certain light and temperature conditions. At that point, when the chemical degradation reaction takes place, the ozone is destroyed and the chlorine atoms are released into the atmosphere. It should be remembered that the degradation process for CFC gases can take between 50 and 100 years. This pernicious effect on the atmosphere also occurs in the case of HCFCs, although they are less harmful.

Measures against such gases

There are numerous conventions that have dealt with HCFC gases: the Vienna Convention and the Montreal Protocol of 2007, which is the most important in this field. All countries that have signed up to these protocols have committed themselves to the reduction and elimination of these gases. The process for the reduction of HCFC emissions specifically focused on projections for 2030: which aimed to reduce HCFC consumption by 97.5%, reserving the rest (2.5%) for refrigeration and air-conditioning systems (their main uses). This projection has been extended to 1 January 2040, when an absolute ban on these gases has been introduced.

Effects on human health

With regard to the harm that HCFC refrigerant gases can cause to human health, it is worth clarifying them because of the great confusion that exists. Firstly, large concentrations of this gas can cause asphyxiation and also unconsciousness. Redness also occurs, when in contact with the skin, and pain when in contact with the eyes. Therefore, although they have a lower rate of toxicity and bioaccumulation, these gases are still considered harmful to the ozone layer.