Cleanrooms
Cleanrooms were invented for aerospace and microtechnology in the early 1960's,
as the United States and other countries geared up for the "space race".
Rapid advancements were being made in the fields of technology and biochemistry
as scientists and researchers began working on smaller and smaller levels,
and as a result scientists and manufacturers required more and more rigidly
controlled working environments. These controlled work environments came to
be known as "clean rooms", rooms which are sealed off from any
air outside. Highly filtered air falls in what is usually a laminar
flow onto the working space below. All cleanroom
supplies, persons, and equipment coming in and out of the room are tightly
monitored and special clothing, mouth and head coverings are almost always
required.
The key to "clean room" cleanliness is the number of air pollutants,
or particles, in the air. Sterility is not usually a requirement, since the
real concern when working on microscopic and nearly microscopic scales is the
damage which can be done by particles such as dust, sand, or salt. Bacteria
are also a concern for pharmacists in regards to consumers, and for microelectronics
manufacturers because of the high ion content in bacteria which creates harmful
static electricity.
Clean room
design ranges in size, material and level of cleanliness based on their purpose
of use. Some cleanrooms used by manufacturers specializing in microelectronics,
pharmaceutical products, or circuitry are as large as warehouses (often called "ballrooms")
and may keep a high classification of cleanliness. Other cleanrooms used by manufacturers
such as special parts machinists, who only need cleanroom facilities for an occasional
specialized assembly, may have small portable
clean rooms the size of a large closet. Cleanrooms can have hard, usually glass
or clear plastic walls, or soft walls made of flexible acrylic or similar material.
There are two separate standards of cleanliness classification. The first is
FED standard 209, which classifies cleanroom air into four different classes.
The other recognized standard is the British Standard system which has four classifications
based on cubic meters instead of feet, and all four levels are slightly stricter
than the FED standards. Different levels are required by different industries
and various products. The major industries that use cleanroom facilities at varying
classifications are: chemical, printed circuit board, SMT, computer, silk screening,
biomedical, electronics, disc memory, small parts machining & assembly, packaging,
pharmaceutical, photographic, aerospace, nuclear, optical, hybrid, circuitry
and microelectronics.