Don’t be careless when it’s hot! The air conditioner should be ventilated regularly.

　　The weather is getting hotter and hotter, and the epidemic situation has not completely ended. What kind of air conditioners may have the risk of transmission, and what precautions should be taken when using air conditioners? Recently, National Health Commission issued the Guidelines for Operation, Management and Use of Air Conditioning in Summer (Revised Edition), which is applicable to centralized air conditioning ventilation systems (including all-air air conditioning systems, fan-coil systems with fresh air, fan-coil systems without fresh air, and multi-connected systems) and split air conditioners in summer.

　　Preparation before opening of all-air air conditioning system

　　Grasp the source of fresh air and the scope of air supply, and strengthen personnel training;

　　Check whether the filters, surface coolers, heaters (humidifiers) and other equipment are operating normally. Clean and disinfect the open cooling tower and air handling unit, and clean the air duct when possible. Professional institutions are preferred to clean and disinfect the air conditioning system. When conditions permit, the sanitary quality of air supply should be tested, and the test results should conform to the Hygienic Management Standard for Central Air Conditioning and Ventilation Systems in Public Places (WS 394— 2012) and other national standards and specifications;

　　Keep the fresh air outlet and its surrounding environment clean, and the fresh air will not be polluted;

　　Keep a certain distance between the fresh air inlet and the exhaust outlet to avoid short circuit.

　　Management and maintenance in operation

　　Return air should be closed in medium and high risk areas. If the high-efficiency and above filter device is used in the air return port (pipeline) or air conditioning box, or an effective disinfection device is installed, the return air can be turned down;

　　It is suggested that the indoor temperature adjustment should not be lower than 26 degrees Celsius. If it can meet the demand of indoor temperature regulation, it is suggested that the doors and windows should not be completely closed when the air conditioner is running;

　　When using air conditioning system in crowded places, to strengthen indoor air flow, priority can be given to opening windows, opening doors or turning on ventilation devices such as fans, or air conditioning must be ventilated for 20 to 30 minutes every 2 to 3 hours;

　　For shopping malls, office buildings, underground garages and other places with large personnel flow, ventilation should be strengthened, and the fresh air and exhaust system of air conditioning system should continue to operate for a period of time after the business is over every day;

　　Strengthen the sanitary management of condensate water such as air handling units and fan coils and cooling water of cooling towers;

　　Regular cleaning, disinfection or replacement of filters, tuyeres, air handling units, surface coolers, heaters (humidifiers), condensate pans and other equipment and components of the operating air conditioning system;

　　U-shaped pipes such as sewer pipe, water seal of air handling device, floor drain of toilet and condensate drain pipe of air conditioning unit should be inspected regularly, and water should be replenished in time when there is water shortage.

　　Shutdown of air conditioning system

　　When confirmed cases and suspected cases are found in COVID-19, the following measures should be taken:

　　Immediately shut down the central air conditioning and ventilation system corresponding to the confirmed cases and suspected cases;

　　Under the guidance of the local disease control department, the central air conditioning and ventilation system in the above areas shall be disinfected and cleaned immediately, and can be re-used only after passing the hygienic inspection and evaluation;

　　Cleaning and disinfection of central air-conditioning ventilation system shall conform to the Code for Cleaning and Disinfection of Central Air-conditioning Ventilation System in Public Places (WS 396— 2012) requirements. (Reporter Wang Jingyu)