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Frequently Asked Question - Cleanroom Section
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 Air
Transfer with in the Cleanrooms
Within a cleanroom, many rules-of-conduct must be followed to ensure
that products are not contaminated. The management must produce
a set of written procedures suitable for their room. It may be useful
to have these 'does and don'ts' posted in the change or production
area. Commonly used procedures that may be adopted are given below.
These procedures do not consider the choice of cleanroom garments,
masks, gloves and similar clothing items.
Air Transfers with in the Cleanrooms
To ensure that air is not transferred from an area of high contamination
to one of lower contamination (e.g. the outside corridor to the
production room) the following disciplines should be adhered to:
- Personnel must always come in and out of the cleanroom through
change areas. The change area is used not only to change clothing,
but as a buffer zone between the outer dirty corridor and the
inner clean production area. Personnel should not use any entrance,
such as an emergency exit, which leads directly from the production
area to the corridor; this will allow contamination to enter directly
into the cleanroom, and their garments may also become contaminated.
- Doors should not be left open. If they are, air will be transferred
between the two adjoining areas because of general air turbulence
as well as air transfer caused by a temperature difference between
the two areas
- Doors should not be opened or closed quickly, or air will be
pumped from one area to the other.
- Doors usually open inwards into the production room and are
held shut by the higher pressure. However, to aid the movement
of personnel who are carrying materials, some doors open outwards.
Doors should then be fitted with door-closing devices to ensure
that the doors are kept closed, and shut slowly to reduce the
air transfer. Doors without handles will assist in preventing
contamination of gloves.
- When passing through the doors in an airlock, personnel should
ensure the first door is closed before going through the Next
one. Electrical interlocks between entry and exit doors achieve
this, but care must be taken to ensure that there is no danger
in the case of fire. Indicator lights, which show if the doors
are shut, are also used. Pass-through hatches should be used in
a similar way.
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