Clean Rooms Design

Aug 22, 2020
Aspects of Pharma Clean Room design:

Pharma Clean room is an area specially design to meet requirements of quality of working area and its air quality, with respect to particle and microbial count to at most minimal level, so that handling of sterile material can be done without any risk of contamination of particulate matter or microorganism.

Air can be made almost particle free with help of HEPA filters, air being circulated in clean room is filtered through heap filters, heap filters can remove almost 99.99 percent of microbial and particulate contamination from air, thus filtered air is kept in continuous circulation cycle to achieve clean environment, such environments are very useful for handling and manufacturing of sterile pharmaceuticals.

1) Equipments in clean room should be placed such that it can be operated with most possible minimal movements of operators.

3) Persons working in clean room should be maintained to a possible minimum number so that it do not create contaminations due to personal movements.

4) Personnel movements should be kept minimum

5) Transfers of materials inside clean room or isolators should be kept minimum.

6) Reporting of problems in clean room, problems arising while working should be reported immediately so that a corrective and preventive action can be placed, it can prevent major failures.

Also see Clean Room Classification

7) How much room air changes are required?
It depends up on the area of clean room and the class of clean room but twenty room air changes are found optimal.

8) What should be the area of clean room?
Area of a clean room depends up on the nature of activity which will be carried out, area of clean depends on maximum number of persons working in the clean room, and larger clean rooms are preferred as local air disturbance produced by individual is less.

9) Why positive air pressure is maintained in clean room:
Clean room air pressure is always kept at positive pressure than that of surrounding area , so that contaminated air from surrounding air’s don not enter inside clean room , that is even when clean room door is open its air flows from clean room to out side from the door.

Air pressure inside a critical clean room is around 45 Pascal , and a difference of 15 Pascal is kept between adjacent less critical areas.

10 ) What should be the direction of Air flow in clean room?
Direction of clean air should be from clean rooms to surrounding area, that means from clean to non clean environment.

Clean up time: It is a time required for a clean room to attain desired level of cleanness after circulation of clean filtered air from HEPA filters is started , it is normally range from 30 minutes to one hour, ideally it is one hour.
Type of air circulation patterns in clean room:
There are two types of clean air circulation patterns
1) Unidirectional air flow pattern
2) Non unidirectional air flow pattern.
In case of unidirectional air flow, air filtered through HEPA filter is showered in the clean room from top from ceiling and it is collected back from recirculation points at bottom of side walls and flour.
Air flow pattern in unidirectional clean room are vertical from ceiling to towards flour also it can be horizontal , from one side wall towards other , with air recirculation points at other side for collecting back air thrown from other wall.
In case non unidirectional air flow pattern clean rooms, clean air is showered from all directions vertical as well as horizontal , keeping air collection points for recirculation at opposite direction to each inlet point.

What should not be in clean room?
There should not be window ledges, shelves and frames of door which might facilitate accumulation of dust. There should not be ducting or piping inside the clean room .There should not be sinks and drains in clean room, also there should not be a source of water inside a clean room, which may facilitate microbial growth and contamination.

Doors of a clean room:
Doors should be provided with air loc systems, which will ensure that air, do not flow directly from clean room to other area. Door of an air lock and main door of clean room should not be kept open at a time, rather one door is opened other should be closed.

Benches used in clean room:
Benches which are required for keeping and handling sterile articles, utensils and product being manufactured should be made of stainless steel, benches can be wall mounted to reduce dust setting at points of contact of bench and flour, also it is easy to clean.

Cupboards used in clean room:
Cupboards in clean rooms should be made up of stainless steels and should be easy to clean and disinfect, corners should be rounded and surface should be accessible for cleaning and disinfection, should be detachable should be movable from one point to other for purpose of disinfection and cleaning and replacements.

Chairs and trolley used in clean room should be made of stainless steel, should be easily movable and should allow easy cleaning and disinfection it should be made of material which is nonreactive, corners and joints should be rounded and smooth so that dirt do not accumulate over them and it is easily dislodged during cleaning.

Switches and electric sockets used in clean room should be of flush fitting type so as to facilitate cleaning and disinfection.

Equipments : We require many equipments inside a clean room just to facilitate processing of sterile pharmaceutical and biopharmaceuticals , these equipments should not hinder clean air flowing from heap filters neither it should hinder returning air enter in to return points, therefore placing equipments is very important aspect of clean room design, otherwise it may lead to failure of clean room .

Hand washing facilities and clean room:
Hand washing facilities should not be provided directly inside the clean room rather those should be provided on the way of entry point just prior to sterile gowning.
Soap dispenser should be provided such that it is easy to operate, with very easy and just simple push it should be able to dispense aliquot of soap for hand washing.
An electric hot air shower hand dryer should be provided at this point so that after washing hand should be dried with hot air which will ensure that hand do not soil again with particles shed from towels during if used after hand washing.

Flooring of a clean room should facilitate easy cleaning , sanitization and disinfection, it can be coated with epoxy material which will give a continuous and smooth surface, which can be cleaned easily , flooring should not develop minute cracks and corners should be rounded so that dust is not accumulated owing to gravity.

How material is transferred in to clean rooms:
An supportive area should be provided just adjacent to clean room, where activities like sterilization, cleaning disinfection, and autoclaving is performed autoclaved material can be transferred in to clean room from this supportive area which itself too is highly controlled with respect to its cleanness , particle count and microbiological load by providing HEPA filtered air and adapting cleaning and sanitization procedures to keep it clean.
Small hatches should be provided to transfer sterile material from supportive area in to clean room. Hatches should be operated such that at any given point both hatch both outer and inner door of hatch should not be kept open, rather an electronic system should be adapted to ensure this, also UV lamps can be fitted which are kept irradiating area inside hatch. Surfaces inside hatch should be easily cleaned and disinfected, and corners should be rounded should not have any point where dirt may accumulate by gravity.

Alarms and alerts systems:
A suitable alarm and alert systems should be in place which should detect failure of air supply or air pressure, when an alarm is set work in a clean room should be stopped with duly covering all critical material and equipment with sterile coverings or closing lids of Isolator.

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