Gerbig Engineering uses commercially available light fixtures from a number of sources. The typical fixture is a three or four lamp fixture with universal electronic ballast, specifically designed for 1 ½” lay-in application. These fixtures are sealed against air leakage.
Yellow light rooms: Photolithography rooms require a yellow lamp with a wavelength cut-off of about 470 nanometers. We use standard florescent tubes and slip a yellow sleeve over the lamp. Presumably, the tube shortens the life of the lamp, but we have not found this to be true.
Plaster Frames: When using a gypsum board ceiling it is necessary to use a plaster frame for fixture mounting. These frames are available from the fixture manufacturer or may be made by the cleanroom contractor.
Overlapping Door Frame: This option is another type of fixture from most manufacturers. The door and lens seal against the grid. This type fixture is used for special cleaning.
Other Types of Cleanroom Fixtures
When the density of HEPA modules becomes too great, it is necessary to use flow through fixtures designed for top filter mounting. The lens used with this type fixture is
typically and plastic egg crate design. We have found some difficulty with the wire routing when several fixtures are mounted in a row.
Tear Drop Fixture
These 2” wide fixtures use a single four foot lamp and may be ganged in multiple units. They are found in pressure plenum systems. When used with pressurized plenums, care must be taken not to have the electrical conduit penetrate into the plenum.