CI-81-12-4 -- Sound Pressure Level Prediction in Computer and Office Equipment Rooms

Computers and business equipment are common sources of noise in commercial and industrial establishments. Interest in this noise is increasing as advanced equipment is installed in rooms where limited machine noise was present before. The noise criteria for rooms in which equipment is installed are usually based on annoyance and speech interference, and expressed in sound pressure levels.

Standard measurement methods for computer and business equipment noise emissions have been prepared by groups in the U.S.A. and Europe. These standards specify A-weighted sound power level as the basic descriptor of machine noise emissions. This descriptor is appropriate since the equipment is normally used in a variety of rooms and arrangements. Manufacturers and users want to relate equipment noise emissions with room noise critei,ia, therefore reliable methods of sound pressure level prediction are needed. The Product Acoustics Subcommittee of the Computer and Business Equipment Manufacturers Association is involved in a study to define these relationships. The study has included measurements by ten investigators in about twenty rooms. This paper will describe the test methods, preliminary test results, and future alternatives to solve problem areas.