N O I S E   L E V E L S

Compare Helicopter NOISE to Everyday Sound:
[Each 10-decibel increase in sound level is perceived as approximately a doubling of loudness.]

Sound Decibel Level Rustling Leaves 20 dB Whispering 25 dB Library 30 dB   40 dB Average Home 50 dB Normal conversation 60 dB Telephone ring 65 dB Idling motorcycle 70 dB Busy Traffic 75 dB Accelerating motorcycle 80 dB Electric drill, weed whacker at 6 feet 85 dB Screaming Child 85 dB   95 dB Jack Hammer 100 dB Helicopter 105 dB

Normal speech at 3-5 feet.    Idling motorcycle sounds twice as loud as normal conversation, because 10 dBs louder. Motorcycle at full throttle sounds twice as loud as at idle, because 10 dBs louder. This is the predicted noise level that nearby residents will hear at night with windows closed. Imagine sleeping through the noise of an electric drill at the foot of  your bed.  Jackhammer another doubling of the noise level. Helicopter at 100 feet is 50% louder than a jackhammer.

Helicopter Noise

Noise from the large twin-engine medical transport helicopters in a metropolitan area is a serious problem. It will rattle windows and knock pictures off the wall, because there is a strong low and subsonic frequency component to this type of noise.

Structural Vibration is created by helicopter noise.

A helicopter produces long-wave infrasound that is NOT blocked by walls and windows, acoustic absorbers or atmosphere to the same degree as audible sound. The vibration and rattle induced in buildings by helicopters caused human test subjects a level of “annoyance” equivalent to control noise that was 20 dB higher.  See: FAA Aviation Noise Effects, p. 70. http://www.nonoise.org/library/ane/ane.htm

Effect of Aircraft Noise on Property Values

Many studies have tried to establish the impact on land values that results from overhead aircraft noise. Learn more about the effects of air traffic noise on property values.