1.  System design must provide for control of exhaust system noise (combination of fan-generated noise and air-generated noise) in the laboratory. Systems must be designed to achieve an acceptable Sound Pressure Level (SPL) frequency spectrum (room criterion) as described in the 1991 HVAC Applications Handbook.

_{ANSI/AIHA Z9.5, 10}

1991 HVAC Applications Handbook

Acceptable SPL may vary depending on the intended room use. A Noise Criteria (NC) curve of 55 dBA is generally adequate for a standard laboratory.