Lighting systems can utilize a number of different lamp types. Incandescent, high intensity discharge and fluorescent lamps are most commonly used in residential, commercial and industrial facilities. Fluorescent lamps are nearly always used in cleanroom environments due to their energy efficiency, low maintenance and long life.
It's no mystery that cleanrooms present numerous challenges to designers who specify lighting systems. Cleanroom lighting will vary depending on the room's use, its classification and ceiling air supply configuration. In an ideal situation, lighting systems should provide good visibility and be designed with contamination control issues—electromagnetic field generation and cleanability—in mind. But before that can be achieved, a thorough examination of the basic fundamentals, illumination requirements, available styles and fixture construction must be undertaken.
We will look at several areas of concern to get a better idea of the overall picture of contamination control. These are the things that need to be considered when providing an effective contamination control program.
The cleanroom classification needed depends on specifications for operations to be conducted within. Research in your specific field will probably provide a specification or at least a general guideline.
Achieving a specific cleanroom class requires not only clean physical design (non-particulating materials, etc.) but also a flow of clean, filtered air sufficient to both dilute existing particulates and to drive “dirty” air out of the controlled space.
Hardwall cleanrooms provide a rigid wall structure and a completely enclosed cleanroom with air vents to exhaust air. These cleanrooms hold higher pressure differentials, which is important to provide differing cleanliness levels in different areas. Negative and positive/negative pressure cleanroom designs require hardwall cleanrooms, as do A/C and humidity control cleanrooms.
A cleanroom provides a controlled, isolated environment for handling contamination-sensitive substances or for protecting the exterior environment from dangerous substances in the controlled area. The density of sub-micron and larger airborne particle contamination inside a cleanroom is kept within tightly controlled limits by forcing clean, filtered air into the cleanroom.
Below is a list of general regulations recommended as a minimum for the successful operation of a cleanroom. All professional cleaning personnel should be aware and follow these regulations at all times.
Cleanrooms are classified according to the number and size of particles permitted per volume of air. Large numbers like "class 100" or "class 1000" refer to FED-STD-209E, and denote the number of particles of size 0.5 µm or larger permitted per cubic foot of air. The standard also allows interpolation, so it is possible to describe, for example, "class 2000".
Cleanrooms maintain particulate-free air through the use of either HEPA or ULPA filters employing laminar or turbulent air flow principles. Laminar, or unidirectional, air flow systems direct filtered air downward or in horizontal direction in a constant stream towards filters located on walls near the cleanroom floor or through raised perforated floor panels to be recirculated.
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