Disinfection Method of Cleanroom

Medical industrial cleanrooms are different from other industrial cleanrooms, especially in aseptic production. It is necessary to control not only the general suspended aerosol particles in the air but also the number of living microorganisms, that is, to provide a so-called “sterile” environment. “Sterility” is relative, expressed by STA(Sterility Assurance Level). The methods of obtaining sterile air in the pharmaceutical industry can be roughly divided into two categories:

Sterilization:

The protein of bacteria in the air is denatured by heating (dry heat, damp heat), chemical reagents (such as formaldehyde and ethylene oxide), ozone, and rays (such as ultraviolet lamp irradiation) for sterilization.

Disinfection:

Use filter media (such as various air filters, high-efficiency filters, and other purification equipment) or electrostatic precipitator to capture and intercept dust and miscellaneous bacteria in the air.  

Industrial sterilization methods are often not single, but a combination of both. For flowing air (such as HVAC systems and compressed air), filter media is often used to sterilize, while for the air in a static environment, the sterilization method is often used to sterilize aseptic rooms, cultivation rooms, transfer windows, clothes, etc.

Although the air filtered by the high-efficiency filter in the HVAC system can control the number of living microorganisms in the room within the specified range. However, in actual production, dust particles will be produced on the surface of buildings due to the operation of machines and the action of people, which will breed bacteria and are easily blown off, especially the bacterial pollution caused by people. One person emits about 1,000 dead skin cells (equivalent to 20μm particles) per hour. Therefore, the indoor building materials of the aseptic room and the washing, drying, and packaging of clean clothing must also be carried out in a clean environment; Aseptic clothing should be sterilized at high temperature; Personnel, equipment, and instruments entering the aseptic room should undergo strict disinfection and sterilization (hands need to be disinfected or sprayed); Regularly carry out indoor disinfection and sterilization. GMP of various countries has strict regulations on airborne bacteria and surface bacteria in clean rooms. For example, USP recommends that the allowable values of bacteria in clean environments are shown in the following table.