As summer approaches, more and more air conditioning and ventilation systems will be put into operation. Experts on building air conditioning technology from the China Academy of Building Sciences suggest that in order to effectively prevent and control the spread of the SARS virus through the air conditioning and ventilation systems and prevent cross-infection, emergency treatment should be carried out for the central air conditioning and ventilation systems of key buildings and large buildings to ensure that the buildings safety of personnel inside.
According to the spread of the epidemic, air conditioning and ventilation systems should be divided into three categories, and different prevention and control strategies should be adopted.
The first category is the centralized air-conditioning and ventilation systems of buildings without SARS cases. The guiding ideology of prevention first must be implemented, natural ventilation should be utilized to the maximum extent, and mandatory measures should be taken during operation. Regular cleaning and disinfection measures.
The second category is the centralized air-conditioning and ventilation systems of buildings where SARS cases have occurred. They must be comprehensively, strictly and thoroughly disinfected, and can only be put back into use after being inspected and approved by the disease prevention and control department. . Mandatory regular cleaning and disinfection measures should be taken during operation.
The third category is the air-conditioning and ventilation system in the hospital. Strict and reliable measures must be taken to avoid cross-infection and prevent the spread of pathogenic microorganisms. Otherwise, their use is prohibited.
The specific operation methods are as follows:
(1) The air-conditioning system must be thoroughly cleaned and disinfected before operation. The key parts are the primary and medium-efficiency filters, water storage parts, The surface of the heat exchanger and the indoor air supply and return vents.
1． It is necessary to ensure that the air inlet and outlet of the air conditioning ventilation system inhales fresh and clean outdoor air.
2. The air-conditioned and ventilated machine room must be kept clean and dry, and stacking of irrelevant items is strictly prohibited.
3． The filters and inlet and return air filters in the air conditioning unit must be cleaned and replaced regularly: during the epidemic period, they should be cleaned (or replaced) at least once a week, and after the epidemic, they should be cleaned (or replaced) at least once a month.
4. The heating coils and cooling coils in the air conditioning unit must be flushed regularly: during the epidemic period, they should be flushed at least once a week, and after the epidemic, they should be flushed at least once a month.
5. For the condensate pan, spray room sink, and box bottom with accumulated water in the air conditioning unit: flush at least once a day during the epidemic period, and at least once a week after the epidemic.
6. Spray and disinfect fan coil units at least once a week during the epidemic period, and at least once a month after the epidemic.
(2) Disinfection and sterilization of the air conditioning and ventilation system must be carried out with the fresh air vents and exhaust vents closed for at least 6 hours, then open the fresh air vents and exhaust vents, and then run for at least 6 hours .
1． During the epidemic, the centralized all-air system must operate at the maximum fresh air volume.
2. Air-conditioning systems without fresh air must strengthen natural ventilation to ensure indoor fresh air volume, otherwise the air-conditioning system should be deactivated.
3． Air-conditioned rooms can use shielded ultraviolet circulating air sterilizers, electrostatic air self-purifiers and other measures for auxiliary disinfection.
(3) Stricter measures should be taken for the ventilation and air-conditioning system in the hospital:
1. In hospitals that treat SARS patients, all air-conditioning and ventilation systems with return air or adiabatic humidification devices should be suspended from use.
2. The isolation ward area (including temporary isolation area) shall not share the same air conditioning and ventilation system with the general ward area.
3． The air conditioning and ventilation system (including filters, surface coolers, condensate pans, etc.) should be disinfected regularly.
4. Air filters that may be contaminated by pathogenic microorganisms must be disinfected before cleaning and discarding.
(4) During the epidemic period, buildings using open cooling towers should improve the water quality and bacterial content of the cooling water system by increasing the amount of sewage discharge and increasing the amount of water replenishment.
(5) If the new exhaust device of the building’s air conditioning and ventilation system has unreasonable settings, the fresh air volume does not meet the hygienic requirements, there is no air filter device, and there are dead zones in the indoor air conditioning and ventilation airflow organization, etc. Air conditioning and ventilation systems must not be used during the epidemic.
(6) The fresh air volume and dust content of important buildings should be implemented in accordance with the "Indoor Air Quality Standard" GB/T18881-2002. The air conditioning and ventilation systems must be professionally inspected and measured; the disinfection effect Must be tested by the Department of Disease Control and Prevention.