Objective To investigate the use situation and problems of relevant institutions in the implementation of the Hygienic Specification of Central Air Conditioning Ventilation System in Public Buildings (WS 394-2012), and to provide technical support for the revision of the specification.
Methods We conducted a questionnaire survey on the implementation of the specification among 84 institutions including central air conditioner users, testing agencies, and supervision and law enforcement agencies in 4 districts of Guangdong province and Jiangsu province and 3 districts of Chongqing municipality, China from October to December in 2019.
Results A total of 156 questionnaires were collected. All institutional users believed that the specification promoted the routine hygiene management of the central air conditioning ventilation system. Of the supervision and law enforcement personnel, 80.4% believed that there was a significant improvement in the hygiene of the central air conditioning ventilation system in local public buildings after the implementation of the specification. Of the institutional users, 79.2% could reach all the hygiene management requirements in the specification, and only 12.5% of the institutional users could reach the hygienic design requirements in the specification. The compliance rate was 50.0% for fresh air volume, 56.3% for the air purification and disinfection device, 60.4% for the insect vector control device for both the fresh air outlet and return air inlet, and 66.7% for the emergency shutdown device for both return air and fresh air. The compliance rate of fresh air volume of class 1 buildings was significantly lower than that of class 2 buildings (40.0% vs 76.9%, P < 0.05). The semi-central air conditioning system had significantly lower compliance rates than the central air conditioning system in equipping the air purification and disinfection device (44.8% vs 73.7%, P < 0.05) and the insect vector control device (48.3% vs 78.9%, P < 0.05). As for the testing agencies, 90.0% carried out hygienic testing of the central air conditioning ventilation system, but 65.0% had no capacity to test 10 items required in the specification, and 45.0% were not equipped with robots to take samples on the inner surface of central air conditioner ducts. The items that the testing agencies could not test mainly included Legionella pneumophila and β-hemolytic streptococci in air supply, fresh air volume, and Legionella pneumophila in cooling water and condensate. The main reasons included the difficulty in conducting testing and lack of testing personnel and facilities. The supervision and law enforcement agencies carried out hygiene supervision at least once a year, and 87.5% of the supervision and law enforcement personnel received publicity and implementation training on the specification, but 56.5% could not master the knowledge of hygiene management.
Conclusion The implementation of the specification promotes the improvement of the hygiene of the central air conditioning ventilation system in public buildings in China. However, there still exist some problems, such as unqualified hygienic design of institutional users, insufficient capacity of testing agencies, insufficient item knowledge of supervision and law enforcement personnel, and difficulty in the implementation of some items. It is recommended to strengthen the hygienic equipment of the central air conditioning ventilation system in institutional users, improve the capacity of testing agencies, strengthen the technical training for supervision and law enforcement agencies, and strengthen the development of testing method for the central air conditioning ventilation system, in order to provide a technical basis for future revision of the specification.
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