Cleanroom: Making Way for Hygienic Food
Rooms free from any type of dust or contamination are essential for providing a secure environment for food handling and processing. Level of contamination in clean room are very specific to number of particle per cubic meter of specified Particle size. Controlled environment is achieved by permitting least amount of pollutants in the room by supplying control filtered air. Pollutants may vary from dust, airborne microbes, aerosol particles, and chemical vapours which differ highly in size making the environment highly complex.
Need for Cleanroom
Present day requirement for healthy foods had led to revolutionary change in food industries, bounding food Companies to manufacture products in utmost hygienic environment. Increase in customer awareness, have compelled food companies to process foods to hygienic standards to withstand the wide competition. Stringent laws and regulation set up by food authorities have also helped to achieve this goal. Even small amount of contamination can have detrimental effect on the quality of product which can lead to product rejection, loss in brand name and also legal issues. Cleanrooms are the most effective solution to overcome the above said issues.
FDA has certain norms starting with strict environmental control, determining classification, detailed planning & designing for clean room. It is always advisable to have written procedure for contamination prevention which can help in maintaining the cleanliness of room. Typically, organisation should be aware of their cleanroom requirement and the requirement should be set on the basis of customer, industry or government specifications.
Cleanrooms should be accessed only with specific dress suit. Dressing also varies with various class of cleanroom. Class 10,000 cleanrooms may use simple socks, head covers, and booties. For Class 10 cleanrooms, careful gown wearing procedures with a zipped cover all, boots, gloves and complete respirator enclosure are required. Hence it can be concluded that complexity of dress code depends on class of cleanliness.
Cleanrooms are classified on basis of purity of the air i.e., by the number and size of particles found in per volume of air. ISO 14644-1 states the specific standards for cleanroom operation. Standardly the cleanroom includes classes ISO 1, ISO 2, ISO 3, ISO 4, ISO 5, ISO 6, ISO 7, ISO 8 and ISO 9, with ISO 1 being the “cleanest” and ISO 9 the “dirtiest” class (but still cleaner than a regular room) and the most common classes being ISO 7 and ISO 8. In food industry most commonly used class is Class 10,000 which limits particles to 10,000. ISO 14644 standards require specific particle count measurements and calculations to classify the cleanliness level of a cleanroom or clean area. Widely accepted measurement being the number of particles equal to and greater than 0.5mm measured in one cubic foot of air.
Cleanroom Designing parameters
Cleanroom designing are very specific in respect to the product coming in contact with the room. Specific requirement of product like temperature, pressure & RH requirements. Temperature should be maintained within 22±2 deg. C and RH to be maintained within 50±5 % range. Most important factor is that all incoming air has to pass air filtration system before entering cleanroom. Air entering room passes through HEPA filters which has capacity of trapping and filtering particles of size that of 0.3 micron and larger.
1. Cleanroom Air Handlers:
Keeping pressure static in cleanroom is essential for avoiding the chances of infiltration into the room which can be achieved by maintaining balance between supply air and exhaust air. Air Pressurization maintains the overall clean environment in room. Maintaining a positive air space pressure, in relation to adjoining dirtier cleanliness classification spaces, is essential in preventing movement of contaminated air into cleanroom. Through many studies it has been concluded that a pressure differential of 74.65 to 124.42 Pa to be effective in reducing contaminant infiltration. It is also to be noted that maintaining such higher space pressure difference will be costly affair and will hinder with doors opening and closing. Hence it is recommended to keep the maximum pressure differential across a door to be 24.88 Pa.
To comply with GMP requirement cleanrooms should be supported by HVAC system.
- Fan filter unit should comprise of either HEPA filter or ULPA (Ultra Low Particulate) filter, depending on requirement of process.
- Particle trapping capacity should be 0.3 micron or above to trap bacterial particles as well.
- It is highly recommended to have variable speed controllers for controlled of air flow in cleanroom.
- Either the body should be of stainless steel or should be powder coated. Grills in room should be of Stainless Steel.
- Proper and scheduled cleaning helps in maintaining the quality of cleanroom and will increase the shelf life of filters as well.
- All duct works in cleanroom require to be fabricated so prevent gaps at corners or joints.
- Ducting should have flanges and gaskets can be used to prevent any sort of leakage of air to prevent cross contamination.
2. Cleanroom Walls: Cleanroom Surfaces are kept reflective, enamel like texture, making it easy for cleaning. Walls, ceilings and flooring are painted with light shade color or kept bright white to easily detect presence of dust.
3. Cleanroom Doors: If openings are not handled properly they possess threat to the cleanroom environment.
- Cleanroom doors should be void free and should have non Porous Construction and designed to meet GMP requirements.
- Doors should be durable and unaffected to different cleaning process like steam, water or chemicals.
- A pass through chamber, which are enclosed space, can be considered in place of doors for material transfer between cleanroom and other area which restricts man movement in the cleanroom.
4. Cleanroom Lighting: Sole criteria for designing cleanroom lighting should be for controlling of contamination. Most basic design for cleanroom that can be considered are teardrop, recessed, surface mount and integral ceiling grid and selection should be on the basis of cleanroom classification. As most of the space is basically used up by the supply air grids which basically leaves back only limited space for lighting. Hence to use up available space efficiently require proper designing and it should also not disturb the air flow movement in the room.
- It is recommended to use powder-coated steel, anodized aluminium or stainless steel fixtures in ISO Class 5 (Class 100) to ISO Class 3 (Class 1) cleanrooms.
- Electrical Outlet covers should be used inside the cleanroom to reduce the dirt build up.
- It should be flushed mounted in SS Wall Plates and wire should be conduited inside of walls.
- Lines for data & telephone should also be conduited and designed in a manner they are installed inside of the wall with pull string for field connection
5. Cleanroom Flooring: All particles entering room ends up on the floor making it prime site for contaminants.
- It is advisable to quickly fill or repair flooring of cleanrooms in case of cracks or gaps that can be area for dust accumulation.
- Apart from selecting floor which are easy to clean, it should also be durable enough to withstand pressure or else it will lead to cracks.
- Flooring solution for cleanroom ranges from tile to heat welded sheet flooring which totally depends on the operational need of particular cleanroom.
- For food industries it is best to go with epoxy flooring for normal food processing area or polyurethane flooring for highly hygienic area due to its antibacterial properties.
Cleanrooms are only efficient when properly designed with keeping all required parameters in mind or else they can be unreliable, leading to failure of cleanroom. It is always recommended to get your cleanroom designed and have construction under the supervision of experienced person. Cleanrooms presents numerous challenges to designing. Critical nature of cleanroom processes requires thorough analysis, specification and placement of the all parameter under one umbrella.