1. Definitions and Standards
Class D clean area refers to the production or experimental area where the air cleanliness reaches a certain standard. In the pharmaceutical industry, a Class D clean area is usually equivalent to a class 100,000 clean area, and its standards mainly include limits on the number of airborne particles and the control of microorganisms. Specifically, a Class D clean zone requires that the number of solid particles with a diameter greater than 5 microns in each cubic meter of air must not exceed 350,000, and the number of particles with a diameter between 5 microns and 1 microns must not exceed 3,500. In addition, Class D clean areas also require strict control of microorganisms to ensure the hygiene and quality of the production environment.
2. Environmental parameters
In addition to the control of particulates and microorganisms, a Class D clean area also needs to meet the requirements of a series of environmental parameters to ensure the stability of the production process and the safety of the product. These parameters include:
Air temperature: usually should be controlled between 18 ℃ and 26℃ to provide a suitable production environment.
Air relative humidity: It should be maintained in the range of 45%-60% to prevent excessive humidity from causing microbial growth or low humidity from affecting product quality.
Room ventilation times: should reach or exceed 15 times/hour to ensure air circulation and timely removal of pollutants.
Pressure difference: A certain pressure difference should be maintained between the Class D clean area and the adjacent area to prevent the diffusion of pollutants from the low cleanliness area to the high cleanliness area.
Illumination: should be greater than 300lx and less than 600lx, in order to provide sufficient light conditions, convenient for production operation and monitoring.
Noise: should be controlled below 75dB (dynamic test) to reduce interference and fatigue to production personnel.
