Noise Exposure - Level and Duration

Noise exposure should be controlled so that exposure is less than the combination of exposure level and duration.

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According the National Institute for Occupational Safety - NIOSH - noise exposure should be controlled so that the exposure is less than the combination of exposure level - L - and duration - t.

The maximum time of exposure can be calculated as:

t = 28,800 / 2^{(L - 85)/3} (1)

where

t = exposure duration (seconds)

L = exposure level (dBA)

3 = exchange rate (dB)

85 = Recommended Exposure Limit - REL

Combinations of noise exposure levels and maximum duration time can be expressed as in the table below.

Exposure Level (dBA)	Duration Time - t - (s)
	Hours	Minutes	Seconds
80	25	24
81	20	10
82	16
83	12	42
84	10	5
85	8
86	6	21
87	5	2
88	4
89	3	10
90	2	31
91	2
92	1	35
93	1	16
94	1
95		47	37
96		37	48
97		30
98		23	49
99		18	59
100		15
101		11	54
102		9	27
103		7	30
104		5	57
105		4	43
106		3	45
107		2	59
108		2	22
109		1	53
110		1	29
111		1	11
112			56
113			45
114			35
115			28
116			22
117			18
118			14
119			11
120			9
121			7
122			6
123			4
124			3
125			3
126			2
127			1
128			1
129			1
130			1
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