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CONSTRUCTION WORLD
MAY
2017
The two ozone treaties have been ratified by 197 parties, which
includes 196 states and the European Union, making them the first
universally ratified treaties in United Nations history. The Protocol
is structured around several groups of Ozone Depleting (ODS) and
Global Warming Potential (GWP) 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 for HCFC’s was gazetted in South Africa
in 2014 when all the country had to phase out R22 (HCFCs). By 2030
use must be down to 2,5% of the 2013 baseline
The change in the refrigerants are placing a great burden of
responsibility on the refrigeration practitioners as the mechanics
have to change to the new refrigerants not being as easy to use
as the older 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
phase-out of HFC refrigerants, e.g. R134a and R410a impact on the
equipment currently being installed will be next on the plan being
proposed by the Department of Environmental Affairs.
Natural refrigerants are coming into favour like Carbon
Dioxide known as R744 is being used in supermarkets.
Some systems use CO
2
as a secondary refrigerant in a 2 stage
cascade system. Ammonia R717 is sometimes used as the primary
refrigerant. Some people consider that these systems are easier
to use, but new skills are needed for
installation and maintenance.
Hydro carbons (R600) and (R290) are being looked at for small
refrigeration units. These refrigerants are highly flammable and
need special handling skills.
Methylene Fluoride (R32) is being considered for use in room and
packaged air conditioners. It is classified mildly flammable.
HFO 1234yf and it family of refrigerants are used in car air
conditioning and Chillers but it is mildly flammable but has energy
efficiency advantages. With packaged air conditioning units the
refrigerant charge with HC and HFO may be too large.
CO
2
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 a phase
out for HFC refrigerants as is being done in first world countries.
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
refrigeration 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.
PHASING OUT
Hydro chlorofluorocarbon
The Montreal Protocol of 1987 and its amend-
ments on Substances that Deplete the Ozone
Layer (a protocol to the Vienna Convention for the
Protection of the Ozone Layer) is an international
treaty designed to protect the ozone layer by
phasing out the production of numerous substances
that are responsible for ozone depletion.