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Clean Room-57

The document discusses clean room classifications and design. It describes how clean rooms are segregated by class levels and use vertical unidirectional airflow. It also discusses filter coverage, pressurization, individual fan powered filter modules, and air return methods.

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71 views1 page

Clean Room-57

The document discusses clean room classifications and design. It describes how clean rooms are segregated by class levels and use vertical unidirectional airflow. It also discusses filter coverage, pressurization, individual fan powered filter modules, and air return methods.

Uploaded by

CIVIL
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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www.PDHcenter.com PDH Course M143 www.PDHonline.

org

1) The facility is segregated to various class levels according to requisite needs. For

example, the uncrating of incoming items may be Class 100,000, the next stage of setup

and inspection is Class 10,000 area and the final stage before entering the main area is

Class 1000.

2) Semiconductor clean rooms generally use vertical unidirectional airflow with raised floor

return. The particles are swept from personnel and equipment with contaminated air

leaving at floor level. This results in clean air for all space above the work surface.

3) The ceiling area is 85 to 95% covered with HEPA filters set in a T-bar grid with gasketed

or caulked seals for Class 100 rooms.

4) Class 1 and 10 rooms use 100% filter coverage with ceiling grid using special gels to seal

the filters into a channel shaped grid.

5) The space pressurization is key to resistance to infiltration of external sources of

contaminants. Semiconductor clean spaces usually have plenum systems that are

designed to ensure even pressurization to keep uniform airflow through each filter.

Ducted filters where employed typically have higher static pressure losses from the ducts

and balancing dampers, and have a higher maintenance cost due to the balancing

needed.

6) Individual fan-powered filter modules are often provided which use fractional horsepower

motors and usually forward curved fans to flow air through one filter assembly. This

allows airflow to be varied and takes less space for mechanical components. The

disadvantages are the large number of fans involved, low operating efficiency, potentially

higher noises, and higher operating and maintenance costs.

7) Air is normally returned through perforated raised floor panels or floor grates. There may

be vibration problems if the panels are not very rigid. Insufficient raised floor height may

cause turbulence, raising particles up, and increase system static pressure. Basement

return is often used as it provides a more uniform return and can more effectively handle

chemical spills.

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