Research Facilities and Infrastructures
A clean room is an environment, typically used in manufacturing or scientific research that has a low level of environmental pollutants, such as dust airborne microbes aerosol particles, and chemical vapors. More accurately a clean room has a controlled level of contamination & cross-contamination that is specifying by the number of particles per M3 at a specified particle size. According to an observation as per ISO-9 clean room, the ambient air outside in a typical urban environment, contains, 35, 000, 00 particles per M 3, of 0.5 μm and large in diameter.
Clean room is an environment in which the air quality, temperature and humidity in order to safe guard against dust and bacteriological contaminated particles, which exist naturally in the atmosphere. As per ISO-14644. It is a room in which the concentration of Air bone Particles, is controlled and which is constructed and used in a manner to minimize the introduction, generation and retention of particles inside the room and in which other relevant parameters, e.g. Temperature, Rlative Humidity, Air Pressure are controlled as necessary.
Therefore the processes have to be carried out in the clean room such that air borne particles are limited, the air flow pattern is regulated, and the number of changes of air per hour of the clean room is controlled. In addition, the temperature & humidity should be regulated as per requirement. The room is also relatively pressurized by air w.r.t. adjusted zone, so that no outside Air can in filter into the space. The special materials of construction are used so as to eliminate generation of any particulate matter within the conditioned space.
HEPA (High Efficiency Particulate Air Filter) – These filters are extremely important for maintaining contamination control. They filter particles as small as 0.3 microns with a 99.97% minimum particle-collective efficiency.
CLEANROOM ARCHITECTURE – Clean rooms are designed to achieve and maintain a airflow in which essentially the entire body of air within a confined area moves with uniform velocity along parallel flow lines. This air flow in called laminar flow. The more restriction of airflow the more turbulence. Turbulence can cause particle movement.
FILTRATION – In addition to the HEPA filters commonly used in clean rooms, there are a number of other filtration mechanisms used to remove particles from gases and liquids. These filters are essential for providing effective contamination control.
Laminar flow, also known as streamline flow, which are a family of curves that are instantaneously tangent to the velocity vector of the flow, occurs when a fluid or gas or Air flows in parallel layers with absolutely non divergence from either layer. Laminar air flow workstations will have laminar Air flow, which would be the opposite of turbulent air flow. Both the pattern of air flow is shown below.
Air flow pattern for ‘Turbulence - Air flow pattern for Laminar Air Flow
To maintain clean room, particulate for air through, the use of HEPA & ULPA filters employing laminar or Turbulent air flow principles. Laminar, or unidirectional, air flow systems direct filtered air down word in a constant stream towards filters located on walls near the clean room floor or through raised perforated floor panels to be recirculated.
Preparation of Clean room:
Inside the clean zone area, surrounding the breaks wall, 2.5 to 3 mm thick, double skin pup insulated laminated FRP/Glass Fiver sheet wall to be erected, by maintaining the minimum gap of 25mm in between the bricks wall and insulated wall,( the thickness of the pup insulated sheet wall to be at least 25 mm), to protect the clean zone from Leakage and decapitation of temperature. All partition wall of the Clean Room to be prepared by above mentioned double skin pup insulated sheet walls, thickness 25 mm. Where applicable ,above the 39 inches height from the floor of the partition wall,8mm thick vacuumed, Toughened glass of 2ft X 2ft block to be used to continuing the partition wall up to 7 ft. height of the Partition wall, and the rest of the above wall i.e. up to 8 ft. again to be cover up by insulated wall. All surface of the walls as well as the partition walls to be finished properly, without any cracks, fleece, etc. All the joints to be properly fill up by using appropriate resign or so. All corners are to be making up properly by “Coving” of appropriate radios for protecting the clean zone from deposition.