At present, there is a lack of targeted professional design norms in China, and the understanding of design units around the negative pressure isolation ward clean engineering also needs to be improved. The clean equipment project of negative pressure isolation ward has its characteristics in the aspects of plane layout, people flow logistics, ventilation and air conditioning system, water supply and drainage system, etc. However, some design units lack basic knowledge of isolation theory, do not consider zoning (clean area, semi-polluted area and polluted area) in layout, do not consider unidirectional flow in airflow organization, unclear pressure gradient and other problems:

1. The content expression of ventilation and air conditioning construction design drawing is incomplete, lack of indoor parameter requirements of isolation ward and ordinary ward, lack of necessary profile or description, lack of necessary technical requirements and description of air conditioning units, high efficiency filters and other equipment.

2. High efficiency filter is not designed at the return air outlet (section) of isolation ward, and there is no spare fan for the system exhaust fan.