4. Determinants of clean room prices

4.1 air change rate

The ratio of pollutants and the actual particle production are the main factors affecting the number of air changes in the clean room. In the production process, without any influence on other factors, the speed of removal of particles is very important. Other factors that may affect the amount of recirculated air are: modular clean room structure, equipment location, equipment surface temperature, air convection, air flow type, operating space and regulations, materials and chemicals used, etc.

4.2 unidirectional, turbulent, vertical or horizontal flow of air

In many cases, one-way airflow is only used in sensitive areas of small spaces and small portable clean room, and micro-environments are used. The source of contaminants may be in the glove box, filter module, etc. Most solutions are designed to clean the outdoor area with an overall unidirectional air flow, which can only be achieved if there are no operators, production equipment and exhaust units in these areas. The choice of vertical or horizontal air flow depends on the structure of the room and the location of the equipment, and the turbulence can carry away pollutants.

4.3 air purification

Fresh air treatment air conditioning box provides the necessary fresh air for the clean room. The multi-cycle air conditioning box feeds air through the air supply pipe, and the ULPA filter or HEPA filter，then get into the clean room, which is usually 100% covered on the ceiling of the clean room in the cleanliness class 10 and Class 1. The vertical unidirectional air flow passes down through the clean room, passes through the overhead floor tile with holes into the return air space under the floor, and then goes up through the vertical return air tunnel into the suspended ceiling return air plenum. Then, the air enters the circulating air conditioning box again, and the above air circulation is repeated again.

Clean room pressurization is necessary to ensure that the clean room is free from contamination in its immediate area, control the flow of harmful pollutants, prevent cross-contamination between different areas, and help maintain the required temperature and humidity levels. The pressure difference between clean rooms and associated corridors and other areas within the facility should be maintained between 0.25 and 0.005 inches of water column (in.w.g.). General pharmaceutical companies require a higher differential pressure value than this, and use laminated differential pressure between different areas to avoid cross-contamination. A series of stacked airlocks and positive pressure gates are installed between the different zones to allow rapid diffusion of air, thereby creating differential pressure.

4.5 temperature control

Changes in temperature and humidity can cause errors in production equipment, which affects the repeatability of the production process, and ultimately leads to a reduction in product qualification and an increase in waste. Therefore, the requirement for strict temperature control in clean rooms is obvious, and this cost is necessary. Under normal circumstances, engineers are required to reduce construction costs at the time of design, and precise temperature control is required in a large area. If there are strict requirements for HVAC, power professional devices and control systems in the clean room, there are local automatic temperature controllers to control the design temperature in each clean room area. It can drive the local reheat or recold coil installed on the air duct to meet the requirements of humidity and heat in the room.

4.6 humidity control

The relative humidity of each clean room is controlled by a local humidity regulator. When precise humidity control must be achieved, it is usually achieved using the adiabatic humidification effect of the fresh air in the air conditioning box. Local changes in the humidity level can be controlled by an ultrasonic humidity regulator located in the air duct plenum before final filtration.

4.7 exhaust system

Quality air treatment equipment minimizes the amount of exhaust gas, thus reducing engineering costs and energy waste during implementation. It is important to maintain a balance between the potential demand for increased exhaust volume, the expansion of production and the economic value required to install these spares.

4.8 anti-static factor

Residual electrostatic charges in many areas of the industrial scale can pose a danger and cause problems. It can cause the combustion of flammable gases and human electrocution. It can make thin films and light fibers stick, absorb dust and debris in the air, damage semiconductor devices and interfere with the operation of microelectronic devices. The most basic way to avoid the impact of electrostatic discharge on microelectronic systems is to place the device in a good electrostatic and magnetic field shielding place, and appropriately reduce all input and output connections.

4.9 Form and function

• Planning in advance can greatly reduce costs：

• Precisely define the level of clean room to meet the process requirements.

• Precisely define clean room air temperature and humidity to meet process requirements.

• The exhaust volume of clean outdoor air should meet the minimum requirements of the process, and the exhaust management procedure should be carried out at the beginning.

•  Reduce the pressure drop of air ducts and pipes by determining the maximum and minimum wind speed of the equipment, and implement these guidelines throughout the construction process.

To be continued...

Suzhou Pharma Machinery Co.,Ltd.

2023/10/23

Tia