Clean room is described as “a individually constructed room where the supply and distribution of air, presence of dust and airborne particle, room temperature, pressure and humidity are environmentally controlled to meet appropriate cleanliness.” In more precise terms, a clean room has a controlled level of contamination that is specified by the number of particles per cubic meter at a specified particle size. To give perspective, the air outside in a general urban environment contains 33,000,000 particles per cubic meter, 0.5 μm and larger in diameter, corresponding to an ISO 9 clean room. Clean rooms can vary in their sizes and are extensively used in biotechnology, life sciences, research and development, laboratories and other areas that are sensitive to environmental contamination.
Clean rooms are commonly used in high technological industries such as electronics, semiconductor manufacturing, optical and biological industries where the production quality is extremely sensitive to the presence of airborne particles or dust. Commonly used air filters such as HVAC system are inefficient in collecting these particles and other factors also need to be taken into account to control the temperature, pressure, humidity and others factors to make the room suitable for production. Computer hard disk, microprocessor, semiconductors, medicine and pharmaceuticals, food processing, life-sciences research and development are some of the key areas where there is a need to control the micro-organism presence to maintain the quality and this is where clean rooms find their usage.
Human body is one of the biggest sources of particles generation, the quantity generally differs depending upon the person, children, their movement, kind of garment and other factors. For example, human body generates 100,000 particles per minute when sitting of standing without movement while walking quickly will generate 10,000,000 particles per minute. With such high volumes of particles generated every minute there is a clear need to control these micro pollutants to maintain hygiene. Clean rooms are an effective way of controlling these micro pollutants.
A micron, which is also the short form for micrometer, is a unit of measurement equal to one millionth of a meter. A micron is actually 0.000039 of an inch.
In several ways. Clean room technicians wear special clothing that’s designed not to shed or let particles escape. Often before entering the clean room, personnel will walk through an air shower which blows off any particles using high velocity air. And, in the clean room, places where dust could settle like ledges and moldings are minimized. We also create an airflow pattern called laminar flow that constantly cleans the air by directing and re-circulating it through special filters.
The naked eye can see particles as small as 40-150 microns.
The other contaminants in a clean room besides people are:
- Raw Materials
- Chemical and Gases
- Machinery and Equipment
- All personnel / visitors must wear Clean Room garments while entering Clean room
- Clean Room Garments are to be stored properly in a laminar air flow storage cabinet- Personnel should not carry any personnel items such as pencils, pens, hand kerchiefs etc. into the Clean Room
- Persons with skin ailments or coughing etc should not be allowed
- Avoid talking inside the Clean room- For cleaning the Clean room it is always better to use liquid detergents and the cleaning process should be slow and the cleaning personnel should also wear Clean room garments- Do not use any blowing equipment inside or nearby a Clean room, instead, it is always recommended to use a vacuuming equipment for cleaning- Movement of materials from and to the Clean room must be as minimum as possible- Avoid touching by hand the material inside the Clean room, instead use forceps wherever possible- A sitting person sheds over 100000 particles, a moving person emits over one million particles and walking person emits 5 million particles of 0.5 micron size
Air Showers have always been questioned for their role in contamination control process. We at M/s. Clean Air Systems, Chennai – India, believes that the effectiveness of Air Shower Entry System is directly proportional to its design and use. Our supremely built air shower systems are incorporated within the design of an engineered clean room “entry system”. Our Air Shower Entry Systems show efficiency of 90% particle removal on particles 5-20 micron, 60-65% on loose lead oxides, and that the use of a two air shower particle removal system, one prior to the change room and one prior to the clean room is considerably more effective than one. Clean Air System’s Air Showers serve to guard your clean room environment from redundant contamination. Our Air showers to a great extent improve your Clean room’s performance by removing surface contamination from clothing and clean room garments. Gowning/changing room areas are the common platform between a polluted environment and a clean room environment. Unfortunately, the changing or gowning process itself releases contaminants from outside world that can settle onto the “clean” garments. Air showers blow off and remove much of this contamination preventing it from entering the clean space.
Air shower systems have long been criticized for is the time delay that is caused due to the shift changes and to get personnel through the shower and working. The delay, however, far overshadows the damage that many people entering a Clean room simultaneously could have on particle counts. Spread out breaks and shift hours have been used over time as part of clean room operating parameters to minimize square footage allotted to gown rooms. Tunnel Technology helps reduce these delays. In State of the art clean room design, multiple person air showers are being widely used to shower personnel while walking. When designing multiple person air showers, a minimum of four feet in length should be designed for each person targeted to utilize the shower, per cycle. In a walk through tunnel design, optimum length for effectiveness is 32 feet to achieve acceptable contamination removal. Dimensions less than the above stated criteria will reduce air shower effectiveness and should be evaluated for cost benefit.
Air Changes per hour= Average airflow velocity* x room area x 60 min/hr.
Following garments are recommended for Aseptic Clean rooms as per IEST RP CC-003.2 Standards:
- Hair Cover
- Facial Cover
- Barrier Gloves
Extra care and precaution must be taken while working in laboratories where one can come in contact with chemicals and reagents. Clean Air Systems recommends use of rubber aprons, asbestos gloves, safety glasses, full face shields and approval respirators to protect personnel from spills, burns, spattering chemicals, flying fragments, and irritating fumes. In addition, the laminated safety glass doors on chemical fume hoods protect personnel from mishaps in the hood.
ISO 14644 Standards were first formed from the US Federal Standard 209E Airborne Particulate Cleanliness Classes in Clean rooms and Clean Zones. The need for a single standard for clean room classification and testing was long felt. After ANSI and IEST petitioned to ISO for new standards, the first document of ISO 14644 was published in 1999.
Food, beverages, cigarettes, pipes, and cigars should not be permitted in the chemical laboratory under any circumstances. Chemical glassware should never be used to hold food. Laboratory technicians must never pipette toxic, corrosive, or radioactive chemicals by mouth; instead they should always use a rubber bulb or syringe.
It’s when all of the air in a clean room is forced to move in the same direction and speed to a filter. One common example of laminar flow is when the air moves from the ceiling through the floor, is forced up through the walls to be filtered above the ceiling and then re-enters the room and continues the cycle.
High Efficiency Particulate Air. These replaceable filters will catch almost 100% of particles as small as .3 microns.
Ultra Low Penetration Air. These filters can remove almost 100% of particles as small as .1 micron from circulating air.
It’s a hallway or room leading to the entrance of the clean room. Often there is an air shower between the dressing room or gowning area and the main entrance to the clean room. In the air shower, high velocity air blows off debris that could contaminate the clean room environment. Sometimes de-ionizers are used to remove static thereby increasing the effectiveness of removing hair and lint.
A pass-through (pass-thru) is a chamber that allows items to be moved between clean rooms or between clean room and non-clean room areas. Less traffic in and out of the clean room means fewer chances for contaminants to enter. Pass-throughs can also be designed so that only one door will open at a time. This, in conjunction with higher air pressure inside the clean room, forces particles out when the inner door opens. Pass-box in one of the pass-through.
A micron is a millionth of a meter. Invisible to the naked eye, just for comparison, a human hair is about 100 microns thick.
Absolute minimum of material necessary to conduct any procedure in the fume hood. This completely guarantees that the fume hood can effectively capture and exhaust chemical fumes generated in the fume hood. The overall idea is to not use a fume hood for chemical storage and remove excess equipment while it is being used.
The hood design and the amount of exhausted air determine the efficiency of the Fume Hood. A fume hood should be designed to exhaust air at rates ample for complete removal of all contaminants. Below is a description of hood face velocity and conditions under which these are ideal.
|Condition||Hood face velocity|
|Very low toxic level materials; noxious odors, nuisance dusts, fumes||80 FPM|
|General lab use. Corrosive materials, moderate toxicity level materials tracer quantities of radioisotopes. TLV of 10=1000 PPM||100 FPM|
|Higher toxic level materials. TLV less than 10 PPM||125 to 150 FPM|
|Pathogenic micro organisms, very high toxic materials. TLV less than 0.01 PPM||Enclosed GLOVE BOX should be used|
Fume Hoods are generally made up of wood, sheet metal, fibre glass, stainless steel, polyvinyl chloride and polypropylene. Generally, wood is considered to have poor chemical resistance, and poor light reflectivity that makes the interiors of the room darker. On the same lines, polyvinyl chloride and polypropylene are mostly preferred for their excellent chemical resistance, fire-retardant properties, and are well suited to acid digestion application
Clean rooms are classified according to the number and size of particles permitted per volume of air. Large numbers like “class 100” or “class 1000” refer to FED-STD-209E, and denote the number of particles of size 0.5 µm or larger permitted per cubic foot of air. The standard also allows interpolation, so it is possible to describe e.g. “class 2000”. Small numbers refer to ISO 14644-1 standards, which specify the decimal logarithm of the number of particles 0.1 µm or larger permitted per cubic meter of air. So, for example, an ISO class 5 clean room has at most 105 = 100,000 particles per m³. Both FS 209E and ISO 14644-1 assume log-log relationships between particle size and particle concentration. For that reason, there is no such thing as zero particle concentration. The table locations without entries are non-applicable combinations of particle sizes and cleanliness classes, and should not be read as zero. Because 1 m³ is approximately 35 ft³, the two standards are mostly equivalent when measuring 0.5 µm particles, although the testing standards differ. Ordinary room air is approximately class 1,000,000 or ISO 9.
Laminar Air flow works on the principle of circulating filtered air in parallel-flowing planes in hospitals or other health care facilities. The system diminishes the risk of airborne contamination and exposure to chemical pollutants in surgical theaters, food preparation areas, hospital pharmacies, and laboratories. Constructed from all white seamless polypropylene, Clean Air System’s laminar air clean benches are the supreme answer for Class 100 (ISO 5) applications. The equipment comes in three different types namely, Horizontal, Vertical and Ceiling Laminar Air Flows. Standard on all horizontal laminar airflow workbenches, the controller constantly monitors filter conditions, alerting the operator of insufficient airflow
A micron is a millionth of a meter. Invisible to the naked eye, just for comparison, a human hair is about 100 microns thick.
- Process description and process flow diagrams
- cGMP floor plan and general equipment arrangement
- Sized major process equipment list with utilities requirements/consumption
- Sized process support services utilities list (e.g., WFI, etc.)
- Functionality flow diagrams (process, people, product, material, components, waste, directionality of air flows)
- HVAC zoning and room classifications, including MICROBIAL limits
- Budget quality cost screening estimate
- Scope of Work matrix (design/specify/furnish/install/inspect/test/balance/certify/guaranty/challenge/qualify -i.e. identify explicity WHO is responsible for every element of the HVAC, envelope, and process)
- Realistic project schedule from kick-off through validation
- A listing of the appropriate/applicable regulatory authorities and jurisdictional venues for which the facility will have to be validated.