In the clean room to build a very complete system, can fully guarantee the cleanliness of the production process. Any change in design standards, will produce special effects on the quality of clean room. The following fifteen factors will determine the cost of a clean room construction. The cost could range from $180 to $2.800 per square foot (depending on the cost of tools and assembly and process equipment).
Three, the success of the fifteen methods
Use the following fifteen factors cost variables, provide the design scheme of dynamic database available for clean room, the basic design and standards are improved, to meet the needs of the factory, by using these methods, we should be able to reduce the project cost. Architects and engineers using ATI these methods successfully clean room for bio pharmaceutical, microelectronics and food processing industry, design, and implementation of the construction project.
1 air change times. Cost factor variables: 0.08 to 0.19
Clean room air distribution equipment (usually a ceiling filter) is designed as a "spray type" to provide uniform, clean filtered air. The amount of air supplied to the room, reminiscent of the fire hydrant, which is opposite to the common shower nozzle. The United States federal standard 209E, Japanese standard JIS B9920 and ISO standard 14644-1 title is: clean outdoor and related control environment - Part 1: classification of clean air. These standards provide guidelines for clean room parameters, classification, and detection methods, but do not specify how economically and effectively to meet the requirements. This is because each production process is different from the requirements of the clean room, so that different recirculation air can be used to achieve the desired environmental requirements.
There are at least five different possible designs to achieve the desired results, but only one design is the best solution. Finding the best and most economical solution for the project is the most basic concept of the clean outdoor ventilation project.
The ratio of pollutants in the room and the production of the actual particles are the main factors affecting the air exchange rate in the clean room. In the production process, the removal of particles is very important in the absence of any other factors. Other factors that may affect the recirculation of air quantity is: structure, equipment room location, equipment surface temperature, air convection, air flow type (one-way through the sensitive area or by the whole space), operating space and regulations, the use of materials and chemicals etc..
Clean room may need to be identified under static, in the working conditions for identification, the production process to confirm or cGMP certification. Federal standard 209 (E), developed by the Department of integrated services management, is recommended for either 100 or 90fpm. However, it is possible to build a clean room with lower air flow rate, but higher than the 100 level of cleanliness. In fact, the air flow rate in the clean room is 45cfm/ square feet.
2 unidirectional, turbulent, vertical or horizontal flow. Cost factor: -0.073 to 0.18
In many cases, unidirectional airflow is only used in sensitive areas of small spaces and clean rooms, and the use of a micro environment. The source of contaminants may be present in the glove box, filter module, etc.. Most of the design for the whole unidirectional air flow of the cleaning chamber, only in these areas without exhaust device operators, production equipment and can achieve unidirectional airflow. The choice of vertical or horizontal air flow depends on the structure of the room and the location of the equipment.
The indoor floor of the clean room is used to cover the connection between the wire, the communication cable, the water and electricity, the pipeline. Later, in order to save costs, in the "bay-and-chase" type of clean room structure, these floors are used as the floor from the bay to the back of the corridor. In a clean room with a completely unidirectional airflow, particles are expected to flow from the work area to the floor with holes. We have successfully established 10 grade and 100 grade clean rooms, no overhead floor in these clean room, the wall lower return air system, and air clean room is designed to be turbulent.
Another way is to use a thin air jet device to isolate the ultra clean area, the air jet speed is 500 to 800 feet per minute. Its function is similar to the plastic curtain.
3 air filtration. Cost factor: -0.032 to 0.10
Using the HEPA filter to filter the air, the removal efficiency of 0.3 to 0.5 microns is 9g.gg%, and the removal efficiency of 0.12 micron is 99.999%. If the ULPA filter is used, the removal efficiency is about 0.12 micron. According to the use of clean room, you can also choose other equipment, for example, in the circulating air and fresh air treatment system towel, synthesis filter VOC processing using HEPA filters with similar functions or carbon adsorption, electrostatic filter box, etc..
In the clean room market, fan filter is no longer a new product, the proper use of it can provide a high level of clean room for many superior, economic solutions, especially in the ceiling height of the building is limited. It has been shown to reduce costs and reduce the pressure drop of the filter (the use of a low level filter in a clean room for a long period of time, the operation of a high pressure drop mode, the benefits are not very obvious).
4 air processor. Cost factor variable: -0.07-0.15
Fresh air conditioning box [Make-up AHUs]. Typical fresh air handling air conditioning unit (primary AHUs) provides the necessary fresh air for the air conditioning box (two AHUs). Fresh air by centrifugal fan, axial flow fan or plug plus filter, preheating and reheat coil, hot water for cooling and dehumidification using chilled water coil, steam and adiabatic humidifier etc.. The attachment and differences include electrostatic air mixers, steam preheating coil, the direct exchange of ultrasonic humidifier, saline, dehumidification using [Dx] or ethylene glycol cryogenic coil, VOC filter, noise attenuator, VFP (frequency) drive.
In the past 12 years,.M&I heat transfer products company has successfully developed and produced a very economical and reliable fan system. These systems work very quiet, and the energy consumption is very low, usually less than 20% of the centrifugal or plug fan system energy consumption. Fresh air air conditioning box channel is in the air into the collecting pipe, through the pipe system to provide fresh air circulating air box. Air measurements are carried out on the primary and two stage air ducts, and the blower, VFD or inlet air valve is adjusted to maintain a constant air volume. Magnahelic measure monitoring load installed in each box of HEPA air conditioning filter bag filter and pre filter. Under the circumstances of the ceiling fan filter, the air from the air conditioning box of the fresh air treatment enters the circulation air conditioning box and then sends out.
Circulating air conditioning box (Recirculation AHU s). Circulating air box by typical high efficiency centrifugal fan, filter and heat pipe cold (dry). Additional differences include the reheat coil, and for the local temperature control for steam or ultrasonic humidifier, air humidity control constant local control box. This way of using the Whisper-Air and Space Compac fan system provides a cost saving and full use of energy options.
Multiple circulating air duct through the box, and then through the ULPA filter or HEPA filter, the air into the clean room, clean in Grade 10 and 1 grade clean room ceiling, these filters usually cover 100%. Vertical unidirectional flow down through the clean room, through the overhead floor tile with holes in the floor below the air space, then return to vertical upward toward the ceiling plenum. Then the air enters the circulation air conditioning box again, and the air circulation is repeated again. If the ceiling fan filter is used, the ceiling space above the fan filter can be installed water or direct exchange cooling [DX-cooled] fan coil to achieve surface cooling.
5 air pressure difference. Cost factor: -0.041-0.08
Clean room pressurization is necessary, its role is to ensure that the clean room far away from its adjacent areas of pollution, control of harmful pollutants to prevent cross contamination between different areas, and help keep the temperature and humidity levels required.
The pressure difference between the clean room and other areas of the relevant corridors and facilities shall be maintained between 0.25 and o.005 inches of water column (in.w.g.). The pressure difference required by general pharmaceutical companies is higher than that in different regions, and the stack pressure difference is adopted to avoid cross contamination between different regions. Positive pressure cascade airlock door is installed in a series of different regions and allow rapid air diffusion, resulting in pressure difference. The design of microelectronic cleanroom good, usually in the entrance of clean room to install the 1.5 seal to keep pressure airlock between 0.02 and 0.005in.w.g. The locker room and the dressing room with mechanical air shower separation relative to the necessity of the entrance lock it, more is a matter of principle with industry culture and clean room.
A lot of microelectronics and photolithography clean rooms have been successfully operated with passive air pressure, and the air intake at the entrance is maintained at 50 to 100 feet per minute, with all the doors open. Some bio pharmaceutical enterprises requires active pressure control, with fresh air, the air leakage through the door automatically complement (when the door opened). Differential pressure sensors are used to accomplish this task, such as Henry G.Dietz's products. The monitor may be installed outside the clean room, and in the clean room there is a LED display, the display with a sound alarm device and two indicators, can indicate the normal or not. This equipment has biological restrictions within the region are usually used to measure the value of negative pressure in the bio pharmaceutical clean room, and in the electronic clean room, usually used to detect the value of negative pressure, and in the electronic clean room, usually used to detect the positive pressure. It comes with a digital differential pressure display, the display is 0.001m.w.c., the measured pressure value or vacuum range is 0.5 in.w.c. The pressure difference is represented by a flashing LED and an automatic alarm device. When the door is opened, the device is internally provided with an adjustable delay alarm time, which is used for avoiding the sound alarm device.
6 temperature control. Cost factor: -0.0321 to 0.15
The change of the temperature and humidity can cause the error of the production equipment, and thus affect the repeatability of the production process, and ultimately lead to the reduction of product qualification rate, increase waste. Therefore, it is obvious that the strict control of temperature in the clean room is necessary. Typically, requiring engineers to reduce construction cost in the design, at the same time required to accurately control the temperature in a large area, the temperature range allowed within 4 to 6 degrees (such as the use of shutter doors of warehouse). In the absence of hard wall and air brake device, it will be very demanding, and actually cannot control the humidity change. It is generally believed that the cleanliness, temperature, humidity, and air pressure of a clean room are very easy to achieve, and it is easy to maintain.
If the HVAC, power professional equipment and control system of clean room has strict requirements, such as clean room temperature control requirements for cost plus or minus 0.1 degrees Fahrenheit, may be higher than the reference point is 70 degrees, plus or minus 2 degrees (i.e. the standard 68 to 72 degrees Fahrenheit) above 20% to 50%. In each clean room area, there is a local thermostat to control the design temperature. It can drive the local installation on the wind pipe, or cold reheat pipe work, to meet the requirements of damp heat in the room. If you use the fan coil unit, local thermostat control the coil outlet air temperature.
7 temperature control. Cost factor: -0.034 to 0.19.
The relative humidity of each clean room is controlled by a local humidity regulator. If the relative humidity is higher in the cellar, humidistat by lowering the temperature of the air outflow refrigerating coil to strengthen dehumidification. At the same time, the reheat coil provides heat to keep the cellar temperature. Any relative humidity of clean room beyond the scope of design, local humidistat will start the installation on the wind pipe local humidity regulator. When must meet the precise humidity control, usually using the adiabatic air conditioning box in the air humidifying effect to achieve, and through the condensation point of the clean room to maintain. The local variation of humidity level can be controlled by the ultrasonic humidity regulator, which is located in the air duct static pressure box before the final filtration. Water is RO/DI, hydropower rate in 3 to 5 Yin Ding, GM. If the relative humidity is lower than the design range, humidistat humidity regulator will start to increase the amount of water in the air. If you want to high humidity, humidifier will reduce the fresh air control refrigerating coil outflow air dew point, so as to achieve the dehumidifying effect.
8 exhaust system. Cost factor: -0.031 to 0.16.
Typical process exhaust systems include: acids, solvents, and l VOC, toxic substances, heat and general room. If ammonia is present in the exhaust gas, a manufacturer may choose to use separate duct systems and processing systems. The most common method of acid elimination is horizontal or vertical gas scrubbing tower. The removal of solvents and VOC is usually performed in situ or on the spot. Need to carefully select the way the detachment and the detachment of the exhaust gas flow.
High quality air treatment equipment can reduce the exhaust gas to the lowest, so the implementation of the project can reduce the cost and energy waste. It is important to maintain the balance between the potential demand for air exhaust, the economic value of the production and installation of these spare parts. Under normal circumstances, taking into account the selling room for future expansion, when other power equipment and power system, HVAC professional (such as fresh air and cooling) can not meet this demand expansion, stainless steel lining or FRP expensive, large wind system has been established. It is also common to establish acid queuing systems that do not take into account future needs. Increase the supply of air and the new wind pipe branch, will make the wind pipe system in more than 4000 feet per minute. It is very difficult or impossible to keep the balance of the system, and the cost is expensive.
9 vibration and noise control. Cost factor: -0.027 to 0.10.
The size and weight of the equipment affect the propagation and control of vibration. Under the clean room floor below the "waffle", it is a good way to avoid the vibration of the equipment sent to other cattle production area or on the measurement tool. Even for the installation of pipelines in clean rooms and holes, Waffle concrete slab can still keep its wind. Because the strength of the floor lies in its grid system, and can be reorganized. Therefore, additional holes can be punched on the floor without any side effects on the vibration factors.
All HVAC, power professional equipment should be used spring, software and isolation installation, such as isolation of vibration, the vibration effect will be reduced to a minimum. Low noise fan and motor can be used to maintain clean room NC level. Experts in the field of vibration and noise should be the evaluation team members, their leader for experts in the field of vibration and noise should be the evaluation team members, they used to verify the mechanical and architectural principle in vibration and noise control. Reprocessing after completion can be very expensive. If the architects, HVAC, power professional engineers, owners and consultants from the design of the beginning to consider these factors, can be removed from a number of potentially expensive testing, or in a more economical way to replace.
10 magnetic flux and magnetic flux. Cost factor: 0.037 to 0.15.
Magnetic flux is considered to be the background of the ocean particles in the Milky way. The placement of the Milky way is also considered to be an electromagnetic cycle in nature. The word "flux" represents the flow, we can think of lines like a sort of liquid flow route that passes through a hypothetical surface. The size of the magnetic field represents the velocity of the flow, and its direction is the direction of flow. Magnetic flux is the capacity of the surface. In order to better understand, we can think of the number of magnetic flux is through the lines on the surface of the.
For a given velocity, when the particle moves in the direction perpendicular to the direction of the magnetic field, the magnetic force is the largest. At the most basic level, the interaction between the moving charges produces magnetic forces, as if the interaction between the electrostatic charge and the electric charge (whether or not they move) is produced by static electricity. Welcome to take pictures of planet research show that the metal core Earth placed and melt it makes it have a strong magnetic field. The density of the magnetic flux (instead of "Newton per ampere meter") has its own unit - tesla. The surface of the earth's magnetic field is approximately 1/2 feet worth of Gauss' man is about 200000 tesla. In areas open to the public, occupational safety and health requirements of magnetic field strength should not be greater than two Gauss 5.
The protection of the magnetic field in the clean room is very expensive. M15'clean room with 4 to 5 mm thick magnetic (iron silicon) plate (M15 type) as a shielding material can not meet the requirements. The strength of the current semiconductor, metrology, and communication laboratory areas is limited to O.05 Gauss or lower. There was once a very expensive clean room that was shut down shortly after it was built because of its high magnetic flux. Another clean room failed because of a high capacity high voltage cable that was buried a few feet on the floor of F. Again, it is possible to find solutions and save time and cost if the factors are evaluated at the beginning of the project. In fact, the cost of magnetic shielding should also be considered.
11 static charges on the surface of air and body. Cost factor variable 0.0327 to 0.1.
Static electricity is caused by the contact of two independent surfaces. The different surface charge, if not to speed fast enough to the ground, then they will gather and spread on the surface of the 1111 material which is "static" industrial area many residual static charge can be dangerous and cause problems. It can cause the combustion of combustible gas and the human body electric shock. It can make thin film and light fiber adhesion, adsorption of dust and debris in the air, damage to semiconductor equipment and interfere with the operation of microelectronic devices.
On the factors of inflammable and dangerous water vapor and dust and two aspects, one is the energy associated with the storage capacitor, relates to the minimum initiation energy; on the other hand is the destruction of voltage and the minimum spacing, which can cause fire. Typically, the minimum ignition energy of a general hydrocarbon gas or air mixture is 0.2 MJ and produces a breakdown voltage of at least several thousand volts. For dust, the minimum initiation energy is several joules. The shock caused by the electrostatic charge discharge can be distinguished at about 1 MJ, which is likely to cause discomfort when the vibration is in the range of 10 to 100 mj. More than 1 joules of energy will cause the contraction of the main muscles of the human body. When the electrostatic force is equal to the gravity or other binding force, it will result in the problem of mechanical operation. This is related to the gravity of the local electric field, so the insulator is related to the surface charge density.
In general, the electrostatic force is weak, but when the charge density is less than a few MJ 10-7/a, the dust will be adsorbed on its surface. People with normal activities will produce static electricity, such as walking, on the carpet, stood up from the chair rubbing the surface of the clothes etc.. In a low humidity environment and the widespread use of man-made fibers the environment produces higher static charge. Body voltage up to 15 thousand volts.
Electrostatic discharge can be carried out by means of live fabrics, charged bodies and metal objects. These electrostatic discharges may produce CMos) capable of passing through a few millimeters of voids within the outer package of the device into the internal circuit. Discharge can produce a few amperes of current, so that the frequency up to several hundred MHz - especially when the metal conductor as a power supply. The hazards of static electricity to semiconductor devices depend on the type and design of the equipment. Complementary metal oxide semiconductor (cMos) devices and fine geometry are particularly vulnerable. Although the damage is likely to be related to the discharge and voltage, the risk is expressed in relation to the discharge voltage of the human body model. Experience has shown that the damage is reduced by about 50 volts. Problems arising from the confusion of microelectronic systems. Have also been marked with human body model about fiao. The system must be able to withstand thousands of volts, because in normal working conditions, people walking on the floor and other activities are easy to easily generate high voltage. To avoid the most basic method of electrostatic discharge influence on microelectronic system. The equipment is placed in a good electrostatic and magnetic shielding in place, appropriate reduction in some input and output connection xin.
12 energy and production costs. Cost factor: -0.017 to 0.15.
The cost of recycling AHU fan and cooling air DX devices is the introduction of concern, is about the total HVAC production cost of 35%. The use of the latest design of the device can save production costs, such as fan filter VFD drive, high efficiency motor, cooling system with cooling tower, local hot water reheat cycle, adiabatic humidification. Cleanliness requirements for clean rooms are related to its inherent high production costs. However, if planned in advance, can greatly reduce costs:
1 define clean room level to meet process requirements.
2 accurate definition of clean room air temperature and humidity to meet the technical requirements.
3 clean outdoor exhaust air should meet the minimum requirements of the process, from the beginning of the exhaust management procedures. At the start of the project, to provide air flow and pressure difference in all the instructions of the instrument exhaust pipe and process equipment.
4 by determining the maximum and minimum wind speed of the device to reduce the pressure drop of the duct enamel pipeline, the implementation of these guidelines throughout the construction process
5 the use of micro environment, glove box, vacuum chamber and modular enclosure; reduce space requirements, so as to reduce the production cost.
6 use high efficiency motor with VFD (frequency conversion) drive.
7 use the supplemental cycle and exhaust system to reduce pressure drop and save space.
13 forms and functions. Cost factor: -0.0388 to 0.16.
In general, 20 to 30000 square feet of clean room area requires a building area of 60000 to 90000 square feet. In order to have a gap of about 100 feet in height, the height of the building must be about 21 to 26 feet. It should also be in a clean outdoor layer above or 1F surface and 12 to 16 feet for the installation of HVAC, power, professional equipment. In order to have the maximum flexibility, there should be no column in the clean room. The roof shall have a minimum depth of 100 to 200 pounds per square foot, in order to install water pipes, air ducts and air handling units suspended in the superstructure.
Typically, space is used as a plenum. Therefore, the construction of the building space and application of smoldering material. Gap space, that is, the space below the ceiling, there should be spray device. Strict implementation of the existing National Fire Protection Association (NFPA) regulations, together with local safety regulations. Obtaining construction permits (production licenses) may be long term, expensive, and will not be effective if all construction and fire safety regulations are not implemented.
14 particles. Cost factor: -0.040 to 0.15.
15 process piping systems. Cost factor: -0.021 to 0.20.
The impact of these factors (14 and 15) on costs should not be abolished. At the same time, because these variables are unique to each plant, it is best not to comment on it. However, they will be mentioned in the internal table. The design process of clean room facilities is dynamic and creative. Clean rooms may develop completely different clean rooms we know today. The micro environment, shielding technology, glove box and automatic control have changed the appearance and operation of clean room. However, with the clean room today in a few decades ago or unheard of, tomorrow the Holy Grail of technology production will undoubtedly show extraordinary mole to us and to our surprise, today all the challenge.