Frequently Asked Questions 1. How will the new F-gas regulation affect the choice of refrigerant for heat pump air conditioners? Heat pump air conditioning systems are impacted by the new F-gas regulation, the gradual phase down of HFC’s quantities on the market will push the industry to use lower GWP refrigerants. Since 2017 the price of HFC’s has started to rise significantly, especially for those gases with high Global Warming Potential (GWP). Note: In the new F-gas regulation, the use of HFC’s with GWP greater than 750 will be prohibited from 2025 for mono split-system room air conditioners containing less than 3 kg of refrigerant. 2. What is Toshiba’s refrigerant of choice as a replacement for R-410A heat pump air conditioners? R-410A alternatives must provide an acceptable compromise in terms of GWP, human safety, energy efficiency, and system cost. After several years of research and evaluation, Toshiba along with other air conditioner manufacturers are switching from R-410A to R-32 (Difluoromethane HFC32) refrigerant which has a lower Global Warming Potential (GWP), is better for the environment and delivers greater energy efficiency. However this gas is mildly flammable (A2L safety class) and does require some redesign change. These changes will be seen in our new range of R32 residential and light commercial heat pump air conditioning systems. The benefits of HFC R-32 are:- - Zero Ozone Depletion - 1/3 GWP of HFC 410A (GWP675 v GWP2088) - Superior energy efficiency - High refrigeration capacity and thermal conductivity - Low pressure drop - Single component refrigerant easy to handle and recover - Low toxicity - Readily available R32 is classified as A2L “lower flammability” according to the International Standard for Refrigerant Designation: - - Safety Classification: ISO 817:2014 - REACH Registration number: 01-2119471312-47 International Standard ISO 817:2014 segregates the flammability class of refrigerants into 4 categories: - - (Class 1) no flame propagation non flammable - (Class 2L) lower flammability mildly flammable - (Class 2) flammable (Class 2) flammable - (Class 3) higher flammability highly flammable Refrigerants are divided into two groups according to toxicity: - - (Class A) signifies refrigerants for which toxicity has not been identified at concentrations less than or equal to 400 ppm - (Class B) signifies refrigerants for which there is evidence of toxicity at concentrations below 400 ppm Air Conditioning offering total HVAC Solutions Frequently Asked Questions 3. How easy is R-32 to ignite? For a gas mixture to ignite, 3 specific conditions must be met simultaneously. 1) The concentration of the flammable gas must lie between the Lower and Upper Flammability Limit (LFL and UFL) for the particular gas. For R-32 this is between 14% volume and 29% volume (300 grams/m3 and 620 grams/m3 respectively). It should be noted that a 14% concentration of any foreign gas in air is the accepted oxygen deprivation safety limit. 2) The second requirement is that the flammable gas mixture must have a velocity lower than 3 to 4 times its laminar burning velocity for R-32 this is 6.7 cm/second. In the case of a wall mounted split system, because R-32 is heavier than air any leaked refrigerant leaving the unit will exceed 4 times its burning velocity due to gravity within 40 cm. Furthermore, measurements and computational fluid dynamic modelling has shown that even a rapid R-32 leak of 1000 grams in one minute will not present a flammable mixture outside of the wall unit due to dilution and the falling velocity of the refrigerant. 3) The third requirement for ignition to take place is an ignition source of sufficient energy. Unlike common flammable gases such as propane, R-32 cannot be ignited by the usual static electricity we experience. Tests by independent laboratories in Japan and America1 have demonstrated that sparks from light switches or contactors in residential appliances do not have sufficient energy to ignite R32. Therefore, the most likely source of ignition in a residential application is an open flame such as a candle, combustion heater or gas cook top. Therefore, if an accidental release of R32 refrigerant occurs from a cylinder or piping, the velocity will be too high to ignite near the release point and the concentration will be too low where the velocity becomes low enough. So, ignition of R-32 is difficult even if it is attempted intentionally. Even if all 3 criteria are met simultaneously, other characteristics such as quenching distance can limit propagation should ignition occur. For example, if ignition occurred inside a large commercial circuit breaker, the flame will not propagate outside the circuit breaker enclosure unless the enclosure has openings bigger that the quenching distance 5-6 mm for R-32. Flammability range LFL UFL by Volume % in air 0% 14% 29% 100% Lower Flammability Limit (LFL): the minimum concentration of the refrigerant that is Unsafe range capable of propagating a flame Upper Flammability Limit (UFL): the maximum concentration of the refrigerant that is capable of propagating a flame All flammable refrigerants must be handled with precautions and in accordance with local regulations, In accordance with operation and installation manuals and safety standards. Manufacturers’ refrigerant charge limits must always be complied with when installing and servicing equipment. Air Conditioning offering total HVAC Solutions Frequently Asked Questions 4. Are they specific safety requirements to install heat pump air conditioners with A2L refrigerants It is mandatory to comply with safety requirements from local building safety codes with regard to the installation and operation of heat pump air conditioning equipment containing A2L mildly flammable refrigerants for human comfort in buildings and design, installation and maintenance must comply with safety requirements from EN378: 2016. All refrigerant gasses classified in ISO 817 can initiate some form of adverse health effect if the concentration is high enough, therefore it is technically incorrect to claim any classified refrigerant as “non-toxic”. However, compared to all other common refrigerants, R-32 requires the highest concentration level to cause any adverse health effect. International Standard ISO 817 defines 2 toxicity classes for refrigerants:- - (Class A) Lower Chronic Toxicity - (Class B) Higher Chronic Toxicity R32 is categorized as Class A. Class A refrigerants are called non-toxic and Class B are called toxic. Compared to all other Class A (Lower Toxicity) refrigerants such as R-22, R-410A, R-134a, R-290 (Propane) and R-600a (Isobutane), R-32 has the highest (safest) Acute Toxicity Exposure Limit (ATEL) of 220,000 ppm. R-32 has the highest ATEL of the 99 refrigerants designated in Table 5 of ISO 817. 5. What is produced when R-32 decomposes? As is the case with all fluorinated refrigerants, R-32 will decompose and produce toxic by-products such as hydrogen fluoride and carbon dioxide when burnt. The likelihood of R-32 being present within its flammable range and then being ignited is extremely rare. The most probable (but still extremely unlikely) cause of R-32 thermal decomposition would be a leak into an enclosed space that has an open flame source such as an electric or gas heater close to floor level. In this scenario, with a wall mounted split system mounted directly above the heater, testing has demonstrated that production of hydrogen fluoride from leaked R-32 is no more than the hydrogen fluoride produced by non-flammable refrigerants such R410A. Further, laboratory measurements of decomposition products from contact with a hot surface rather than a high temperature flame demonstrated that a 5% R-32 in air mixture exposed to a red hot wire produced significantly less hydrogen fluoride (less than 5ppm) than an equivalent mixture of R-22 (more than 70ppm of hydrogen fluoride). Analysis of R-32 exposed to a variable temperature heater revealed that hydrogen fluoride started to be produced when the temperature was in the range of 570°C to 590°C. Note that R-410A, R-407C, R-404A, R-134A, R-22 and other commonly used non-flammable refrigerants also start to decompose at around the same temperature at which R-32 starts to decompose. Hydrogen fluoride has a very foul odour. It would be expected that if an R-32, R-22 or R-410A leak occurred in a room with a combustion source the smell would alert occupants to leave the room before they are exposed to dangerous levels of hydrogen fluoride. As HCFC and HFC refrigerants have been used in air conditioners for close to 50 years without major concern about the toxic by-products of combustion, any risk associated with the decomposition of R-32 can be managed in the same manner as existing fluorinated refrigerants. Air Conditioning offering total HVAC Solutions Frequently Asked Questions 6. Can we retrofit an R-410A heat pump air conditioners with a lower GWP refrigerant? No, for now, all R-410A alternatives are mildly flammable (A2L safety class) and cannot be used to retrofit existing equipment designed to operate with non-flammable R-410A refrigerant. Retrofitting R-410A systems with mildly flammable refrigerants should not be attempted to avoid damaged to equipment and potential damage to property and or possible injury to humans or animals. 7. Will it be possible to service heat pump air conditioners using R-410A in the future? In the new F-gas regulation there are no restrictions on the use of R-410A refrigerant for servicing refrigeration or air conditioning equipment. The new regulation introduces a gradual phase down of HFC’s quantities (in tons of C02 equivalent) with 21% of the reference level still available after 2030 to service equipment. Therefore, it should be possible to service heat pump air conditioners with R-410A for the foreseeable future.