Cleanroom lights are typically installed in cleanroom t-grid ceilings along with HEPA fan filter units. Normal troffer lights have knockouts and openings that would allow contamination to enter the cleanroom thru the lighting fixture. Cleanroom lighting fixtures are designed to have no openings.
Around 2014, cleanroom fixtures started shifting from fluorescent tubes to LED tubes. This had the advantage of eliminating ballasts which were a cause of failures in the fixtures. Around 2017, flat panel LED light prices dropped low enough that they started replacing specialized cleanroom fluorescent/LED tube troffer light fixtures. Common sizes of cleanroom lights are 1’x4’, 2’x4’ and 2’x2’.
Teardrop cleanroom lights that mount on a ceiling grid are used for cleanrooms with 100% ceiling HEPA coverage. In addition to not taking up ceiling grid space, the tear drop design minimizes the disruption of HEPA air flow. The CON’s of using teardrop cleanroom lights is the high cost of both the light and special ceiling grid.
Cleanroom lights sometimes appear amber colored. This is due to light filters that are designed to block certain wavelengths of light in semiconductor photolithography rooms. Red cleanroom lights (like old photo developing room lights) restrict even more wavelengths of lights. They are commonly used in laser cleanrooms.
Explosion proof lights are sometimes used in chemical processing cleanrooms. These are extremely expensive and are chemical, gas and heat resistant. They are typically surface mounted in the cleanroom.
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