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# Noise Exposure - Permissible Levels and Duration

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

The maximum time of exposure at a noise level can be calculated as:

t = 480 / 2(L - 85)/3                                   (1)

where

t = maximum exposure duration (minutes)

L = noise exposure level (dB(A))

3 = exchange rate (dB)

#### Example - Maximum Exposure Time to Noise

The maximum time a person can be exposed for a noise level 100 dB can be calculated as

t = 480 / 2((100 dB) - 85)/3

= 15 minutes

### Maximum Noise Exposure Time Calculator

Combinations of noise exposure levels and maximum duration time:

Maximum Duration Time vs. Noise Level and Exposure Time
Noise Exposure Level
(dBA)
Duration Time
HoursMinutesSeconds
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
-140 < 1

## Related Topics

### • Acoustics

Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.

## Related Documents

### Human Effects when Exposed to Low-Frequency Noise or Vibration

Physiological effects from low-frequency noise or vibrations.

### Human Life Expectancy

Age and life expectancy for men and women.

### Noise - Acceptable dBA Level

Acceptable noise - dBA - level at typical common locations.

### Noise - EPA Protective Levels

The noise level should not exceed certain values to protect public health and welfare.

### Noise - Maximum Daily Dose Level

Maximum daily noise dose level when exposed to periods with different levels.

### Noise - Recommended Exposure Limits (REL)

The NIOSH noise Recommended Exposure Limit - REL - for occupational noise

### Sound - Hearing Threshold vs. Age

Shift in hearing threshold for men and women vs. age.

### Sound Intensity, Power and Pressure Levels

Introduction to decibel, sound power, intensity and pressure.

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