FAN FILTER UNIT NOISE SPECIFICATION AND PREDICTION

摘要

It often happens that the noise level in cleanrooms served by Fan Filter Units (FFU’s) significantly exceeds the levelrnexpected by the design team. Sometimes it even exceeds the level measured in a mock-up cleanroom. This paper examinesrnthe reasons for the discrepancy. It shows by theoretical analyses and laboratory test results how some factors affect the noiserngenerated by FFU’s and the noise in cleanrooms served by FFU’s. These factors include the flow rate and total staticrnpressure of FFU fans, and the amount of sound absorption and number of FFU’s in a cleanroom. It also explains the commonrnmistakes with mock-up tests. In the end, the paper recommends several ways to specify FFU noise and provides methods tornpredict cleanroom noise levels.