Fly Neighborly Guide - Helicopter Association International

Fly Neighborly Guide Appendix 1What do these sound levels mean? Table A1 provides sound levels for illustrative noisesources heard both outdoors and indoors. Human judgment of the relative loudness(relative to a reference level of 70 dB(A) of different sound levels is also given.Table A1Illustrative NoisesdB(A) Overall Level Community (Outdoors) Home or Industry (Indoors) Human Judgment of Loudness130 uncomfortably loud military jet takeoff from aircraft carrier at 50ft (130)120 Oxygen Torch (121) 120dB(A) 32 times as loud110 very loud turbofan aircraft takeoff at 200ft (118) riveting machine (110) 110 dB(A) 16 times as loudrock-and-roll band (108-114)100 Jet flyover at 1,000 ft (103) 100dB(A) 8 times as loud90 Power mower (95) newspaper press (97) 90dB(A) 4 times as loud80 moderately loud car wash at 20 ft (89) food blender (88) 80dB(A) twice as louddiesel truck at 40mph at 50ft (84) milling machine (85)high urban ambient sound (80) garbage disposal (80)70 car at 65mph at 25ft (77) living room music (76) 70dB(A)[reference]TV audio, vacuum cleaner (70)60 A/C unit at 100ft (60) electric typewriter at 10ft (64) 60dB(A) half as louddishwasher (rinse) at 10ft (60)conversation (60)50 quiet large transformer at 100ft (50) 50 dB(A) 1/4 as loud40 bird calls (44) 40dB(A) 1/8 as loudlower limit of urban ambient sound (40)10 just audible0 threshold of hearing24produced by the Helicopter Association International n Fly Neighborly Committee