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GRANT LAIDLAW
Grant Laidlaw is currently the owner of the Air Conditioning and Refrigeration Academy( ACRA) in Edenvale. He holds a Bachelor of Business Administration and an associate degree in educational administration. He has a National Technical Diploma and completed an apprenticeship with Transnet. He has dual-trades status: refrigeration and electrical. He has been involved with SAIRAC for over two decades and served on the Johannesburg committee as chairman and was also president between 2015 and 2018. Currently he is the SAIRAC national treasurer.
WELCOME TO THE SOLUTIONS PAGE
By Grant Laidlaw
Many people ask for assistance in the understanding of theoretical and practical aspects of the industry. I will endeavour to enlighten. We are going back to basics as I have questions coming in that indicate that the basic understanding necessary to work in industry is not in place.
Stanley: Mr Laidlaw. Can you please explain the recovery of R290 and the venting please. Is venting allowed?
Hi Stanley. At the moment in South Africa the highest percentage of equipment using hydrocarbon refrigerants would be the domestic and light commercial sectors. However, the impact of the Montreal Protocol and in particular the Kigali Amendment will most certainly see an increase in the quantity and scope of equipment using hydrocarbon refrigerants. This is especially true of R290. In the overseas markets the use of R290 extends into and from the unitary air conditioning market right up to and including large capacity indirect industrial chillers.
Stanley, the release of natural refrigerants including R290 is virtually harmless to the environment, but we must consider all of our options. In addition, while venting is permissible, we have to consider the health and safety aspects. As you may be aware when dealing with hydrocarbons( R290, R66a) flammability and asphyxiation are hazards which must be considered.
All hydrocarbon refrigerants are highly flammable and even explosive when mixed with air. The flammability issue is manageable if certain measures are in place. Specifically for refrigerant removal, certain safety precautions have to be followed. Refrigerant must be recovered or vented from refrigeration or air conditioning systems prior to working on the refrigerant circuit. Please note that we are exclusively dealing with hydrocarbon refrigerants and not HCFC or HFC refrigerants.
It might also be necessary to remove refrigerant remains from cylinders. Recovered hydrocarbon refrigerant can be collected in a recovery cylinder, vented or burned in a controlled manner.
With regards to hydrocarbon refrigerant, venting should only be carried out as an alternative to recovery if the charge size is smaller than 500g. This is permissible due to the fact that HC refrigerants have no Ozone Depletion Potential and negligible Global Warming Potential. Larger quantities should be recovered.
Before venting a system, it is necessary to ensure that legislation addressing safety of hazardous substances is satisfied; therefore venting must be done in a safe manner.
Venting of hydrocarbon substances:
• A hose( vent Line) should be connected to a gauge manifold set and the point on the system from which the refrigerant will be vented
• The vent line must be of sufficient length and diameter such that it will extend to at least 3m beyond the outside of the building
• There should be no ignition sources within a minimum distance of 2.5m from the hose end
• The hose should be made of material that is compatible for use with HC refrigerants and oil
• The hose end should be raised approximately 1m above ground level and so that the discharge is pointed in an upwards direction to assist with dilution
• Should there be an emission of refrigerant oil, it should be collected and disposed of in the correct manner
• The hose should be checked to ensure that there are no holes or kinks
Precautions to be taken:
• Venting to the inside of a building is not permissible under any circumstances
• Venting must not be to a public area, or where people are unaware of the procedure taking place
• Venting should only take place if the refrigerant cannot get blown back into any adjacent buildings, and if it cannot migrate to a location below ground level( enter into drains etc)
• A flammable gas warning sign must be positioned close to the hose discharge
Tools:
• Manifold gauge set with calibration for the refrigerant in use
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RACA Journal I May 2025 www. refrigerationandaircon. co. za