By Barney Richardson
I have previously written about the training providers setting themselves up for training in the hydrocarbon (HC) refrigerants. This is mainly for R290, which is a propane gas, but also for R600a which is an Isobutane.
Both gases are very similar and require special care when working with these flammable refrigerants. Both these refrigerants are classified by ASHRAE as A3 with high flammability and low toxicity.
Class A signifies a refrigerant where toxicity concentration is less than 400 ppm.
Class 3 indicates refrigerants that are highly flammable as defined by a lower flammability limit (LFL) of less than or equal to 0.10 kg/m3 at 21°C and 101kPa or a heat of combustion greater than or equal to 19kJ/kg.
R600a is used and has been used in domestic and small refrigeration units for a number of years. But now R290 is becoming more attractive in refrigeration systems and is found in a variety of applications including commercial refrigeration and water chillers. Soon we will see this refrigerant in room air conditioners
The International Electrotechnical Commission in June 2019 published IEC 60335-2-89, edition 3.0; this raised the charge limit for A3 flammable refrigerants in self-contained units to 13 times the lower flammability limit for R290 refrigerant. This therefore allows the refrigerant charge to increase from 150g to 500g.
The low flammable refrigerants classed as A2 and A2L such as R32 will also see an increase in the charge limit from 150g to 1 200g.
The IEC working group has also proposed an update to standard EC 60335-2-40 for room air-conditioning units and systems.
What does this mean for us herein South Africa?
As mentioned before, the Western Cape Provincial Government has an initiative to concentrate on R290 as a refrigerant in conjunction with German support via the Bavarian State Government. An RAC Project is being put together and is in the planning stage for skills training in hydrocarbon refrigerants use.
An Authorised Refrigerant Gas Practitioner registered with SAQCC Gas has a specific category designated category A2 for practitioners who are semi-skilled for refrigeration work. These category A2 Authorised Refrigeration Gas Practitioners are assessed in their particular skill for domestic refrigerators charged with R600a.
Practitioners are trained in particular on the safety aspects of a flammable gas and to ensure procedures are followed in particular on domestic refrigerators. For this equipment, spark proof switches must be used particularly when original components are replaced in a repair.
As the use of hydrocarbon gases becomes more common and used in different applications, the skills requirement will be more important particularly when considered with the greater charge limit proposed above.
As mentioned above, the International Electrotechnical Commission has released a proposal to update the safety standard for room air-conditioning units and systems including heat pumps using flammable refrigerant. This proposal will allow for larger charges of flammable hydrocarbon refrigerants like R290 in these applications. This means that Installers will soon have to acquire the skills for safety standards required when working with hydrocarbon refrigerants like R290.