Impact of a Leak (DX Cycle)
Refrigerants (CFC, HCFC, HFC, HC & HFO’s, natural or man-made) are controlled substances due to high pressures 100 - 450 psi, and extreme temperatures -50°C to 140°C, flammability & toxicity as classified by ISO817 & ASHRAE34. They must only be handled by qualified & certified engineers to C&G 2079-11 for (A1 class non-flammable), plus C&G 6187-21 for (A2/A2L/A3 class flammable/explosive). (about C&G)
Refrigerant circulates around (closed circuit) the DX cycle to perform energy transfer from inside to outside (cooling) or from outside to inside (Heating or Heat Pump). The refrigerant MUST NOT leak, as the system will shut down by built-in controls
If there is a refrigerant accidental leak or release, there are two issues must be considered, Saftey & Environmental effect (TEWI/GWP & ODP). These issues are described in two International Standards, which identifies the risks associated with refrigerant leaks or release. ISO817 & ASHRAE 34. These standards classifies refrigerants in terms of Flammability, Toxicity & GWP.
Flammibility is measured as, A1 class (non-flammable ), A2/A2L class (flammable 🔥) and A3 class (highly flammable & explosive 🔥💥). Toxicity is measured as, (B1 low, B2 medium, B3 high). GWP (Global Warming Potential)
- Safety (flammability & Toxicity) A of installers, service engineers, operators and USERS (accidental release)
- TEWI* (Total Environmental Warming Impact) B Includes energy consumption (operational & accidental release)
- ODP (Ozone Depletion Potential) C CFC & HCFC (accidental release)
A) Flammability being A1 Non-Flammable, A2/A2L Flammable or A3 Extremly Flammable & Explosive.
Toxicity (mainly displacement of Oxygen in an occupied space) being B1 Low, B2 Medium and B3 High.
B) *Total Environmental Warming Impact (TEWI) = Total greenhouse gas emissions (CO2) over a specific product life cycle, including:
1) the effects of refrigerant inadvertently released to the atmosphere from accidents, servicing, and leakage; 2) the efficiency of the equipment (due to CO2 emission from burning fuel to generate electricity to power the system). (read more)
C) Ozone Depletion Potential (ODP) in the event of release into the atmosphere. (applies to CFC, HCFC not HFC, HFO or HC)
UK Government Study in 2018 regarding flammable refrigerants
Gov Study: The impact of high GWP (above 750) A1 class non-flammables refrigerants (e.g. R410A) in Heat Pumps, concluded that the carbon benefit of displacing fossil fuels was around 17 times higher than the impact of refrigerant leaks. without the risks, cost and uncertainty of A2L class 🔥 flammable refrigerants future (e.g. R32)