Abstract: The safety of flammable refrigerant air conditioners is a key concern in the industry, and one of the urgent issues to be solved for the safety of air conditioners using flammable refrigerants is how to design potential ignition sources as non-ignition sources to ensure that there is no risk of ignition in the event of flammable refrigerant leakage. IEC 60335-2-40:2022 provides the conditions for potential ignition sources in flammable refrigerant air conditioners to be considered as non-ignition sources by listing, summarizing, and analyze and interpret these conditions using methods such as analysis, and provide validation test methods to facilitate the industry to better understand and digest standards, and design flammable refrigerant air conditioning products that meet the requirements based on the standards

Key words: Air conditioner, Flammable refrigerants, Ignition source, IEC 60335-2-40, Safety