On 25^th May 2022, the official website of the International Electrotechnical Commission (IEC) released the IEC60335-2-40 ED7 standard: Household and Similar Electrical Appliances – Safety – Particular Requirements for Heat Pumps, Air-conditioners and Dehumidifiers.

The Edition 7 standard provides a more scientific and rational way to use the higher charge limits for a wide range of flammable refrigerants – A3 (higher flammability), A2 (flammable) and A2L (lower flammability) – in products, and the industry has waited seven years for this result. This will help accelerate the industry's shift from high-GWP HFC refrigerants to natural refrigerants, notably R290.

In the Edition 7 standard, safely determining refrigerant charge levels becomes the form of a "list" of choices: 1) There is no room size requirement if the amount of flammable refrigerant charged is less than 150g; 2) Conventional products need to follow the existing refrigerant charge calculation formula; 3) As for the products with the function of increasing ventilation quantity, the new formula in the standard can be used for calculation; 4) As for the products with enhanced tightness, the new formula in the standard can be used for calculation; 5) As for the products with both enhanced tightness and enhanced ventilation quantity, the new formula in the standard can be used for calculation; and 6) The products can limit the amount of refrigerant leaked through additional safety measures.

In this way, the Edition 7 standard will provide not only more reasonable and scientific provisions on the use of flammable refrigerants, but also a technical way to use hydrocarbon refrigerants under the premise of safety. Under the previous iteration of IEC 60335-2-40 ED6, a 20m² room with a 2.2m ceiling height could use a wall-mounted AC split system with a maximum allowable R290 charge of 334g. In the Edition 7 standard, with enhanced tightness in the air conditioning product design, the system can use 585 grams of R290 refrigerant; and with enhanced circulation airflow design, the system can use 836g of R290 refrigerant.

Enhanced tightness is closely related to the whole manufacturing process of air-conditioning products. Only when the whole manufacturing is upgraded, can higher charges and lower airflow requirements be met. In addition, with the proper circulation airflow, a leaked refrigerant from an air-conditioner won’t be able to fall to the floor and accumulate to ignition levels but will be distributed throughout the room. Theoretically, air-conditioners upgraded with these technologies can use more flammable refrigerants, and air-conditioning equipment does not take a lot of airflow to disperse the leaked refrigerant.

China's safety standard for room air conditioner products (GB4706.32), which equivalently adopts the IEC60335-2-40 standard, has been revised accordingly in recent years. It is believed that with the release of the Edition 7 standard, relevant countries including China will gradually carry out the domestic transformation of the standard, thus providing a basis and guidance for the more scientific and safe application of hydrocarbon and other environmentally friendly refrigerants, and promoting the implementation of the Montreal Protocol and the Kigali Amendment.

(Written by Dou Yanwei, China Household Electrical Appliances Association)