Comparison of Noise Levels. Typical Sound. Approximate noise level (dBA). Whether aircraft are arriving or departing which can affect the amount of engine thrust they are using (and therefore the noise level) and the amount of air resistance around the fuselage, wings and undercarriage.sound pressure wave will cause the noise level to increase by about 6 dBa. The dBa scale is structured to the human ear, the lowest noise a human can hear is around 0 dBa and a rivet gun is around 100 dBa. Ear protection should be considered when noise levels are above 85 dBa. Uncontrolled noise is a significant problem that can lead
Note: Air velocities for the initial 10 ft of duct extending from supply register or return grilles should not exceed the values given in the table by more than 20 percent. Reference D.L. Klepper, W.J. Cavanaugh, and L.G. Marshall, "Noise Control in Music Teaching Facilities," Noise Control Engineering Journal, September-October 1980,p.75.