The goal of the Threshold Limit Values (TLV) for noise is to protect the median of the population against a noise-induced hearing loss after a lifetime of occupational exposure, but will not protect all workers from the adverse effects of noise exposure.
|
Sound Level dBA |
Duration per Day in seconds |
|
80 |
122,400 (34 hours) |
|
82 |
57,600 (16 hours) |
|
85 |
28,800 |
|
88 |
14,400 |
|
91 |
7,200 |
|
94 |
3,600 |
|
97 |
1,800 |
|
100 |
900 |
|
103 |
450 |
|
106 |
225 |
|
109 |
112.8 |
|
112 |
56.4 |
|
115 |
28.12 |
|
118 |
14.06 |
|
121 |
7.03 |
|
124 |
3.52 |
|
127 |
1.76 |
|
130 |
0.88 |
|
133 |
0.44 |
|
136 |
0.22 |
|
139 |
0.11 |
This data can be approximated by the equation:
LOG10(time exposure in seconds per day) =
= (-0.100868 * (dBA))+13.052083
If noise exposure consists of different levels of noise, the threshold limit value is based on the combined effect of the sum of the fractions of the total duration of the exposure relative to the TLV for that noise:
mixed noise = sum ((duration of exposure) / (TLV for that noise level))
If the value exceeds 1, then the TLV is considered to be exceeded.
Specialty: Emergency Medicine, Critical Care, Otolaryngology
