Saturday, February 4, 2023

How to design a clean room for pharmaceutical manufacturing

Design concepts of a clean room: 
Material Inflow and outflow: In the pharmaceutical manufacturing industry the clean room is designed to meet requirements of the process and quality of air required in the clean room. For example, if we have to design a clean room for injectable dosage form manufacturing, then one should first give importance for storage of the raw and primary and secondary packaging material, the movement of raw material should be unidirectional raw material and packing material movement should not cross each other’s path. Therefore, first design material flows it’s also important to give importance for designing the out flow of empty bags and containers and scraps etc., out of the respective area, it should be done though a dynamic pass box which will open to direction where the removal of these material out of the area will be easy. Design Material entry air locks and personal entry air locks by considering easy and unidirectional unhindered movements. 

For example, a dynamic pass box is provided in the manufacturing area for removal of used poly bags from the manufacturing area. A dynamic pass box other than one for entry of material provides a very perfect and useful facility. 
Clean room design

Area consideration for equipment: After designing the inflow and out flow of material, proper space for equipment is required to be considered including the height of equipment and space required for cleaning and maintenance activity. A better way is to draw actual lines on the flooring for equipment and their surrounding space, a drill of man movement should be done around the drawn lines considering as if there is equipment installed there. This will give a clear idea of a clean room. 

View panels: flushed glass view panels are required to be provided in a clean room to provide visual observation to avoid unnecessary entry inside the clean room. From all directions the inner view of a clean room should be observable without any hindrance. 

Washing and sanitizing PPE room: After assigning an area for clean room immediately an area for cleaning of utensils and accessories for floor cleaning and sanitization is required to be considered as per the grade of the clean room. The movement of unclean utensils from the area should be through a pass box designed especially for removal of such items from the area without hindrance. 

Air handling unit considerations: Most important factor to consider is now the supply lines of AHU ducts, and the supply points of the AHU. Terminally installed HEPA filters are advantageous. Space for placing the Air handling unit. An air handling unit should be installed near the clean room, in a closed area within the premises with proper ventilation, many people try to install AHU out of the factory in the open, it is incorrect. 

Level of cleanliness required in the room, refer clean room classification in pharmaceutical industry
Different class requirements of clean room with respect to dosage form is provided here.

Class 1 to 4 are required for handling of very potent chemicals like radiopharmaceuticals. 

ISO Class 1: Air changes per hour ACPH of 500-750, and the ceiling coverage should be 98–100%.
ISO Class 2: Air changes per hour ACPH of 450-760 and ceiling coverage should be 95-100% 
ISO Class 3: - Air changes per hour ACPH of 450-760, and ceiling coverage should be 70-100% 
ISO Class 4: Air changes per hour - ACPH of 350-760 and ceiling coverage should be 60-95% 
ISO Class 5: Air changes per hour ACPH of 230-680 and ceiling coverage should be 40-75% 
ISO Class 6: Air changes per hour ACPH of 150-230 and ceiling coverage should be 25-45% 
ISO Class 7: Air changes per hour ACPH of 60-140 and ceiling coverage should be 20-28% 
ISO Class 8: Air changes per hour ACPH of 6-50 and ceiling coverage should be 7-18% 

How to calculate CFM required for AHU? CFM is the velocity of air measured in cubic feet per minute, air supply speed is measured with an anemometer. 

Air changes per hour how to consider Air changes required for clean room: Once air change is the total amount of air present in a clean room, when it is filtered out completely from HEPA filters of AHU it is called as one air change. 

For making a clean room free from particles to the level of the clean rooms, rated class air in the room has to be filtered for a number of times depending on the particle count required. Less the particle count limit more will be the required air changes and vice versa. 
What is a soft wall clean room? A clean room designed with transparent soft and flexible sheets to contain the inner environment with support of metal framework, and metal panel sheets roof top up on which air filtration unit is directly installed and supply is provided from top panel supply ports with HEPA filters. This type of clean room is developed where there is higher particle count generated inside a clean room and to contain the workplace such clean rooms are made inside the clean room. 

What is a hard wall clean room? A conventional clean room with side walls are of puffed panel galvanized metal sheets coated with paint to provide a smooth surface. 

What is Ceiling coverage? The area of the ceiling which is used by HEPA filter ports to cover the entire area of a clean room is called ceiling coverage. More the ceiling coverage is the number of HEPA filter ports on ceiling and vice versa.

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