Actionable levels of workplace noise are set by the Occupational
Safety and Health Administration (OSHA) of the US Department of Labor.
These levels are non-place specific, applicable to all workplaces,
regardless of type.
Occupational Safety & Health Administration
http://www.osha.gov
Ergonomics Program. - 64:65768-66078
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=FEDERAL_REGISTER&p_id=16305
"Physical hazards such as noise and radiation are highly
organ-specific or have universally accepted risk profiles. For such
hazards, exposure assessment does not require significant attention to
individual work factors or personal factors, or there may be a
consensus test for disease (as for noise)."
Occupational Safety & Health Administration
Regulations (Standards - 29 CFR)
Occupational noise exposure. - 1910.95
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9735
*1910.95(a)*
"Protection against the effects of noise exposure shall be provided
when the sound levels exceed those shown in Table G-16 when measured
on the A scale of a standard sound level meter at slow response. When
noise levels are determined by octave band analysis, the equivalent
A-weighted sound level may be determined as follows:"
[...]
TABLE G-16 - PERMISSIBLE NOISE EXPOSURES
___________________________________
Duration per day, |Sound level dBA
hours | slow response
___________________|_______________
|
8..................| 90
6..................| 92
4..................| 95
3..................| 97
2..................| 100
1 1/2 .............| 102
1..................| 105
1/2 ...............| 110
1/4 or less.......| 115
___________________|______________
[...]
"Hearing conservation program."
"*1910.95(c)(1)*
The employer shall administer a continuing, effective hearing
conservation program, as described in paragraphs (c) through (o) of
this section, whenever employee noise exposures equal or exceed an
8-hour time-weighted average sound level (TWA) of 85 decibels measured
on the A scale (slow response) or, equivalently, a dose of fifty
percent. For purposes of the hearing conservation program, employee
noise exposures shall be computed in accordance with appendix A and
Table G-16a, and without regard to any attenuation provided by the use
of personal protective equipment."
*1910.95(c)(2)*
For purposes of paragraphs (c) through (n) of this section, an 8-hour
time-weighted average of 85 decibels or a dose of fifty percent shall
also be referred to as the action level."
[...]
"Where circumstances such as high worker mobility, significant
variations in sound level, or a significant component of impulse noise
make area monitoring generally inappropriate, the employer shall use
representative personal sampling to comply with the monitoring
requirements of this paragraph unless the employer can show that area
sampling produces equivalent results."
Regulations (Standards - 29 CFR)
Noise exposure computation - 1910.95 App A
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9736
""This Appendix is Mandatory
I. Computation of Employee Noise Exposure
(1) Noise dose is computed using Table G-16a as follows:
(i) When the sound level, L, is constant over the entire work shift,
the noise dose, D, in percent, is given by: D=100 C/T where C is the
total length of the work day, in hours, and T is the reference
duration corresponding to the measured sound level, L, as given in
Table G-16a or by the formula shown as a footnote to that table.
(ii) When the workshift noise exposure is composed of two or more
periods of noise at different levels, the total noise dose over the
work day is given by:
D = 100 (C(1)/T(1) + C(2)/T(2) + ... + C(n)/T(n)),
where C(n) indicates the total time of exposure at a specific noise
level, and T(n) indicates the reference duration for that level as
given by Table G-16a.
(2) The eight-hour time-weighted average sound level (TWA), in
decibels, may be computed from the dose, in percent, by means of the
formula: TWA = 16.61 log(10) (D/100) + 90. For an eight-hour workshift
with the noise level constant over the entire shift, the TWA is equal
to the measured sound level.
(3) A table relating dose and TWA is given in Section II."
TABLE G-16A
__________________________________
Reference
A-weighted sound level, duration,
L (decibel) T (hour)
___________________________________
80....................... 32
81....................... 27.9
82....................... 24.3
83....................... 21.1
84....................... 18.4
85....................... 16
86....................... 13.9
87....................... 12.1
88....................... 10.6
89....................... 9.2
90....................... 8
91....................... 7.0
92....................... 6.1
93....................... 5.3
94....................... 4.6
95....................... 4
96....................... 3.5
97....................... 3.0
98....................... 2.6
99....................... 2.3
100...................... 2
101...................... 1.7
102...................... 1.5
103...................... 1.3
104...................... 1.1
105...................... 1
106...................... 0.87
107...................... 0.76
108...................... 0.66
109...................... 0.57
110...................... 0.5
111...................... 0.44
112...................... 0.38
113...................... 0.33
114...................... 0.29
115...................... 0.25
116...................... 0.22
117...................... 0.19
118...................... 0.16
119...................... 0.14
120...................... 0.125
121...................... 0.11
122...................... 0.095
123...................... 0.082
124...................... 0.072
125...................... 0.063
126...................... 0.054
127...................... 0.047
128...................... 0.041
129...................... 0.036
130...................... 0.031
_________________________________"
[...]
"Sound Level
Compliance with paragraphs (c)-(r) of this regulation is determined by
the amount of exposure to noise in the workplace. The amount of such
exposure is usually measured with an audiodosimeter which gives a
readout in terms of "dose." In order to better understand the
requirements of the amendment, dosimeter readings can be converted to
an "8-hour time-weighted average sound level." (TWA).
In order to convert the reading of a dosimeter into TWA, see Table
A-1, below. This table applies to dosimeters that are set by the
manufacturer to calculate dose or percent exposure according to the
relationships in Table G-16a. So, for example, a dose of 91 percent
over an eight hour day results in a TWA of 89.3 dB, and, a dose of 50
percent corresponds to a TWA of 85 dB.
If the dose as read on the dosimeter is less than or greater than the
values found in Table A-1, the TWA may be calculated by using the
formula: TWA = 16.61 log(10) (D/100) + 90 where TWA=8-hour
time-weighted average sound level and D = accumulated dose in percent
exposure.
TABLE A-1 - CONVERSION FROM "PERCENT NOISE EXPOSURE" OR "DOSE" TO
"8-HOUR TIME-WEIGHTED AVERAGE SOUND LEVEL" (TWA)
__________________________
Dose or percent TWA
noise exposure
__________________________
10 ................. 73.4
15 ................. 76.3
20 ................. 78.4
25 ................. 80.0
30 ................. 81.3
35 ................. 82.4
40 ................. 83.4
45 ................. 84.2
50 ................. 85.0
55 ................. 85.7
60 ................. 86.3
65 ................. 86.9
70 ................. 87.4
75 ................. 87.9
80 ................. 88.4
81 ................. 88.5
82 ................. 88.6
83 ................. 88.7
84 ................. 88.7
85 ................. 88.8
86 ................. 88.9
87 ................. 89.0
88 ................. 89.1
89 ................. 89.2
90 ................. 89.2
91 ................. 89.3
92 ................. 89.4
93 ................. 89.5
94 ................. 89.6
95 ................. 89.6
96 ................. 89.7
97 ................. 89.8
98 ................. 89.9
99 ................. 89.9
100 ................ 90.0
101 ................ 90.1
102 ................ 90.1
103 ................ 90.2
104 ................ 90.3
105 ................ 90.4
106 ................ 90.4
107 ................ 90.5
108 ................ 90.6
109 ................ 90.6
110 ................ 90.7
111 ................ 90.8
112 ................ 90.8
113 ................ 90.9
114 ................ 90.9
115 ................ 91.1
116 ................ 91.1
117 ................ 91.1
118 ................ 91.2
119 ................ 91.3
120 ................ 91.3
125 ................ 91.6
130 ................ 91.9
135 ................ 92.2
140 ................ 92.4
145 ................ 92.7
150 ................ 92.9
155 ................ 93.2
160 ................ 93.4
165 ................ 93.6
170 ................ 93.8
175 ................ 94.0
180 ................ 94.2
185 ................ 94.4
190 ................ 94.6
195 ................ 94.8
200 ................ 95.0
210 ................ 95.4
220 ................ 95.7
230 ................ 96.0
240 ................ 96.3
250 ................ 96.6
260 ................ 96.9
270 ................ 97.2
280 ................ 97.4
290 ................ 97.7
300 ................ 97.9
310 ................ 98.2
320 ................ 98.4
330 ................ 98.6
340 ................ 98.8
350 ................ 99.0
360 ................ 99.2
370 ................ 99.4
380 ................ 99.6
390 ................ 99.8
400 ................ 100.0
410 ................ 100.2
420 ................ 100.4
430 ................ 100.5
440 ................ 100.7
450 ................ 100.8
460 ................ 101.0
470 ................ 101.2
480 ................ 101.3
490 ................ 101.5
500 ................ 101.6
510 ................ 101.8
520 ................ 101.9
530 ................ 102.0
540 ................ 102.2
550 ................ 102.3
560 ................ 102.4
570 ................ 102.6
580 ................ 102.7
590 ................ 102.8
600 ................ 102.9
610 ................ 103.0
620 ................ 103.2
630 ................ 103.3
640 ................ 103.4
650 ................ 103.5
660 ................ 103.6
670 ................ 103.7
680 ................ 103.8
690 ................ 103.9
700 ................ 104.0
710 ................ 104.1
720 ................ 104.2
730 ................ 104.3
740 ................ 104.4
750 ................ 104.5
760 ................ 104.6
770 ................ 104.7
780 ................ 104.8
790 ................ 104.9
800 ................ 105.0
810 ................ 105.1
820 ................ 105.2
830 ................ 105.3
840 ................ 105.4
850 ................ 105.4
860 ................ 105.5
870 ................ 105.6
880 ................ 105.7
890 ................ 105.8
900 ................ 105.8
910 ................ 105.9
920 ................ 106.0
930 ................ 106.1
940 ................ 106.2
950 ................ 106.2
960 ................ 106.3
970 ................ 106.4
980 ................ 106.5
990 ................ 106.5
999 ................ 106.6
__________________________"
Regulations (Standards - 29 CFR)
Definitions - 1910.95 App I
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9744
"Action level - An 8-hour time-weighted average of 85 decibels
measured on the A-scale, slow response, or equivalently, a dose of
fifty percent."
[...]
"Criterion sound level - A sound level of 90 decibels."
[...]
"Noise dose - The ratio, expressed as a percentage, of (1) the time
integral, over a stated time or event, of the 0.6 power of the
measured SLOW exponential time-averaged, squared A-weighted sound
pressure and (2) the product of the criterion duration (8 hours) and
the 0.6 power of the squared sound pressure corresponding to the
criterion sound level (90 dB)."
[...]
"Representative exposure - Measurements of an employee's noise dose or
8-hour time-weighted average sound level that the employers deem to be
representative of the exposures of other employees in the workplace.
Sound level - Ten times the common logarithm of the ratio of the
square of the measured A-weighted sound pressure to the square of the
standard reference pressure of 20 micropascals. Unit: decibels (dB).
For use with this regulation, SLOW time response, in accordance with
ANSI S1.4-1971 (R1976), is required."
[...]
"Time-weighted average sound level - That sound level, which if
constant over an 8-hour exposure, would result in the same noise dose
as is measured."
Meat Packing Company Fined for Exposing Workers to Hazardous
Chemicals, Dangerous Working Conditions
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=NEWS_RELEASES&p_id=9759
"Additionally, the company was cited with nine alleged serious health
violations for exposing employees to a high level of noise, failing to
follow bloodborne pathogens standards and failing to properly fit test
employees with respirators."
SEE ALSO:
Safety and Health Topics:Assistance to the Meat Packing Industry
http://www.osha.gov/SLTC/meatpacking/index.html
OSHA SEARCH TERMS
NOISE
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