The Montreal Protocol of 1987 is the phase out plan of (HCFCs) to save the ozone layer of Earth. The Protocol is structured around several groups of ozone depleting substances that are classified according to chemical families. For each group there is a timetable for the phasing out of the production and consumption of the substances with the aim to eliminate them completely
The phasing out process was gazetted only in 2014 when all the countries had to phase out all R12 refrigerants and now the R22 (HCFCs) by 2026.It must be down to 2.5% of the baseline
The change in the refrigerants are placing a great burden of responsibilities on the refrigeration practitioners as the mechanics have to change due to the new refrigerants not being as easy to use as the R12 and R22. The skills of the installing mechanics will have to be improved in order to handle the new gasses as not everyone knows how the gasses will react in the long run How will the R134a and R410a impact on the equipment being installed?.
Natural refrigerants are more in favour like Carbon Dioxide known as R744 and classified asA1 is used in supermarkets. Some systems use CO2 as a secondary refrigerant in a 2 stage cascade system using HFC’s as the main refrigerant. Ammonia R717 is sometimes used as the main refrigerant. Some people feel that these systems are easier to use, but new skills are needed to set them up.
Hydro carbons (R600) and (R290) are being looked at for small refrigeration units. These refrigerants are highly flammable and need special handling skills (A3) Methylene Fluoride (R32) is used in Japanese designed and made room and packaged air conditioners. It is classified A2L
Technicians are worried that some of the safe gasses can become flammable with high humidity.
HFO1234 is used in car air conditioning but its flammability is known to increase under these conditions. With packaged air conditioning units the refrigerant charge with HC and HFO may be too large. The safe air conditioning units do not connect to duct work.
CO2 systems will become more common for supermarket and cold room refrigeration, but R410a and R417 will be in use for some time until the Department of Environmental Affairs starts to organize a phase out for HFC refrigerants like some parts of the world.
Refrigerants are classified on the basis of ASHRAE standard 34. Refrigerants are the gasses that are the compounds that make the refrigeration work. They are classified by reference numbers, safety classes and limits on concentration in parts per million for permissible exposure levels or occupation exposure levels. The process provides the motion of the gas from a low temperature and pressure to a high temperature and pressure and condensation to a liquid in the condenser.
Refrigerants get an identification prefix e.g. C for carbon, F if there is Florine and a 2nd C for chlorine –CFC-12. Where there is an H it’s for hydrogen-HFC-410a.
Their safety group classification is an A or B depending on toxicity. Numeral class 1, 2, or 3 denotes the flammability. Refrigerants classified under this system is according to the danger in their use. A1 refrigerants- least danger, B3 highest hazard.