hearing loss can occur when:
• continuously exposed to sounds of 85 decibels or more
• exposed just once to sounds exceeding 120 decibels
Maximum Daily Exposure Times
For every 3 dB over 85 dB, the PEL for damage to occur is cut in half. In other words, the difference between 85 dB & 88 dB isn’t just the number three, it’s exponential:
30 dB = whisper
40 dB = quiet room
50 dB = moderate rainfall
60 dB = conversation
70 dB = vacuum cleaner
Hearing Loss:
85 dB = 8 hours (busy city)
88 dB = 4 hours
91 dB = 2 hours (lawnmower, hair dryers)
94 db = 1 hour
97 dB = 30 minutes
100 dB = 15 minutes
103 dB = 7.5 minutes (rock concerts)
106 dB = 3.75 minutes
109 dB = 1.875 minutes (machinery)
112 dba = .9375 minutes (chainsaw)
115 dba = .46875 seconds
118 dba = .242 seconds (jackhammers, jet plane take off, band practice)
140 dba = 0 sec (firearms, sirens, fireworks, jet engine)
OSHA (federal Occupational Safety and Health Administration) guidelines dictate that levels above 105 DB in a work place are “unsafe” for more than one hour and could lead to hearing damage.