Universal Lighting Technologies

Appendix G: Noise


Care must be taken to select a ballast with the sound rating for a particular lighting installation. All electrical equipment produces some noise. This is also true of fluorescent lamp ballasts. It is the degree of noise or hum which determines the existence of a problem. Ballast sound will be noticeable only when it exceeds the ambient sound level. It is obvious that a ballast made primarily for use in a factory location would not be suitable in a library.

  • The presence of objectionable ballast hum depends upon various factors:
  • The ambient sound level of the area to be lighted
  • The selection of properly sound-rated ballasts
  • Fixture design and construction
  • Method of mounting ballast to fixture
  • Type and purpose of room
  • Acoustics of room
  • Number of ballasts in a given area
  • Excessive ballast operating temperatures

Careful analysis of all influences bearing on sound within an area to be lighted will enable you to select the proper ballast to eliminate objectionable ballast noise. Just as Universal Lighting Technologies ballasts are produced to meet various electrical requirements, so are they made to fit particular sound needs (see “Sound Rating” chart below).

In situations where required light output necessitates using a ballast with a sound rating not normally acceptable, the ballast should be remotely located.


A- For installations such as private offices, recording studios, study halls, libraries, etc. (where the ambient sound level is 20 to 24 decibels)

B- For offices, residential use, etc. (where the ambient sound level is 25 to 30 decibels)

C- For large office areas, commercial use, stores, etc. (where the ambient sound level is31 to 36 decibels)

D- For manufacturing facilities, large stores, offices with much equipment in use (where the ambient sound level is 37 to 42 decibels)