A new study by refrigeration consulting firms Re-phridge and A/gent Consultancy compares annual indirect climate-related deaths from global warming attributable to HFC refrigerant emissions to direct deaths attributable to the ignition of hydrocarbon refrigerants in refrigeration, air-conditioning and heat pump (RACHP) equipment.
The study measures mortality until 2050 and operates under two assumptions for HFC emissions and hydrocarbon equipment in the marketplace:
- HFC emissions are estimated to be reduced in line with the Kigali Amendment and other national emissions-reduction legislation. This is referred to as the “current legislation with minimum effort (CLME)” scenario.
- All countries will switch to natural refrigerants in all RACHP applications by 2050. This is referred to as the “natural refrigerant maximum effort (NRME)” scenario.
- “2050 is taken as the reference year since most climate-related studies quantify mortality for 2050,” the study said. “Moreover, it is reasonable to assume that the RACHP industry can entirely transition to natural refrigerants over a period of 20-to-25 years.”
Daniel Colbourne, a Consultant at Re-phridge, highlighted the findings of the study in a presentation at the 1st IIR International Conference on Refrigeration Adapting to Rising Temperatures. The event was held August 10‒13 in Manchester, England.
“The mortality for the HFC-related impact is two to three orders of magnitude greater than hydrocarbon flammability,” Colbourne said. “The maximum use of hydrocarbons scenario results in approximately 150 fatalities annually by 2050, whereas the current minimum HFC effort could produce an annual mortality rate between 10,000 and 25,000.”
The analysis did not consider the industrial sector for the maximum use of natural refrigerants. It assumes that ammonia (R717) and CO2 (R744) would serve large-scale applications. To make the comparison as “bulletproof as possible,” Colbourne indicated that he took an optimistic approach for the HFC scenario and a pessimistic one for the hydrocarbons scenario.
Determining HFC impact: Colbourne adjusted figures in global warming studies to account for fatalities associated with the contribution of HFCs to the rising global temperatures determined by the Kigali Amendment (KA) 2022 scenario.
- Scientific studies attempting to quantify the mortality risks of global warming estimate 1 million fatalities per year for every 1.5°C (2.7°F) temperature rise and 8 million per year for a 4.5°C (8.1°F) rise due to extreme heat, drought, flooding, famine, disease, wildfires, infrastructure disruption and conflict.
- The range of 10,000 to 25,000 deaths annually comes from the analysis of five studies that estimated mortality related to climate change.
- The HFC scenario assumes compliance with the Kigali Amendment and selected national legislation, including EU, U.K. and U.S. f-gas regulations.
Determining hydrocarbon risks: Quantitative risk assessment studies in the RACHP sectors determined annual fatality figures for flammable refrigerants, with the numbers checked against anecdotal reports across the industry. Under this scenario there are no climate deaths related to refrigerant emissions due to the extremely low GWP of hydrocarbons.
- The assessments estimated the probability of ignition, explosion or secondary fire leading to fatality for different equipment types, including: domestic refrigeration, air-conditioning and heat pumps, mobile air-conditioning, transport refrigeration, plug-in retail refrigeration cabinets and commercial cold rooms, HVAC and heat pump applications.
- Industry incident reports considered by Colbourne included no fatalities or injuries in operating and serving over 1 million propane (R290) split AC units; some fires but no fatalities reported during servicing 1 million R290 heat pumps; tens of manufacturing incidents but no fatalities reported for over 1 billion domestic hydrocarbon refrigerators on the market, with occasional injuries but no fatalities during servicing; and no incidents with the operation of tens of millions of retrofitted hydrocarbon blend mobile HVAC systems, with tens of technician injuries reported in trade magazines.
- The analysis assumed that 75% of technicians servicing hydrocarbon equipment were “flammable competent.” The study also noted that the “risk of fatality for refrigerant handling activities” is around 10 times greater than for normal operation.
Regarding HFOs: The study’s authors chose not to make estimations for HFOs because of “a current lack of data.”
- “Considering the list of viable alternative refrigerants, this would mean that using almost any HFC would result in higher mortality than due to the HC flammability fatality risk,” the study said. “This may lead one to the conclusion that the most viable alternatives are therefore HFOs. However, concerns over the health and potential fatality impacts of decomposition products (e.g., TFA [trifluoroacetic acid]) are absent, and it would not be prudent to attempt to make such quantitative estimations.”
- In addition, the study said that some flammable HFOs can present a higher “flammability hazard” to technicians servicing equipment than hydrocarbons.
Quotable: “This preliminary study shows that the overall differences in mortality from HFC emissions compared to the potential flammability fatality risk from HC refrigerants are stark,” the study said. “Of course, due to the numerous assumptions for both aspects of the work, there are significant uncertainties, however, given the magnitude of differences between HFC mortality and HC flammability risk, there is strong confidence in the overall outcome.”
