www . refrigerationandaircon . co . za RACA Journal I May 2024 39
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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 . We are going back to basics as I have questions coming in that indicate that the basic understanding necessary to work in the industry is not in place .
Gareth sent in the following : Hi Grant . We have run into R-1234yf refrigerant which caused some debate , some making the comment that we can just use 134a on a system and that R-1234yf is flammable and poisonous . What do we do if exposed to a leak ? Could you help here please ? This seems dangerous .
R-1234yf is a hydrofluoroolefin refrigerant ( HFO ) with the chemical name Tetrafluoropropen . HFO refrigerants are composed of hydrogen , fluorine and carbon atoms , but contain at least one double bond between the carbon atoms . Due to its composition , R1234yf does not damage the ozone layer and has minimal global warming impact .
R-1234yf ( HFO-1234yf ) is the market replacement for R134a in automotive type applications . This substance is similar in cooling performance to R134a , while having a global warming potential ( GWP ) of 1 compared to R-134a ' s GWP of 1.430 . This refrigerant falls into the ASHRAE category A2L - mildly flammable . The temperature at which HFO-1234yf ignites is fairly low ( 405 º C ) and when it burns it produces hydrogen fluoride , which , when it comes into contact with water , is transformed into hydrofluoric acid , a highly toxic and corrosive substance .
As a result , some additional safety measures should be implemented when using this refrigerant .
Main characteristics of R-1234yf :
• Low toxicity
• Low GWP ; GWP = < 1
• Zero ozone-depleting potential
• Class A2L refrigerant - mildly flammable
• Low total contribution to climate change
WORKING ENVIRONMENT In general , all ignition sources including open flames , electric arcs formed by switch gear , single phase motors or any heat sources should be at least 2.5m away from the work area .
Work in a well-ventilated area with extract ventilation and a fan to dissipate any refrigerant leakage .
Note : currently it is difficult to get A2L compliant vacuum pumps . A typical vacuum pump used with fluorinated refrigerants can be used when evacuating a R-1234yf system by placing a service hose on the vacuum pump outlet and placing the hose outlet in a well-ventilated space – or preferably outdoors .
Switch pump on and off at the wall socket rather than the on / off switch on the pump itself .
EQUIPMENT NEEDED FOR R-1234YF The general requirement for R-1234yf tools is that they are ‘ ignition proof ’. Ignition proof tooling provides a spark free tool / work environment . This reference is relevant to any tool that has electrical requirements .
Images supplied by Grant Laidlaw
R-1234yf cylinder colour code ‘ white with red top / band ’ denoting flammability Comparative properties to R134a
www . refrigerationandaircon . co . za RACA Journal I May 2024 39