05.C Hearing Protection and Noise Control.
05.C.01
The employer must evaluate the workplace for noise hazards initially and regularly during the course of work.
Protect your ears from excessive noise.
When noise hazards are known or expected, the employer must develop a Hearing Conservation Program that includes identification and assessment of noise hazards and the measures to be taken to protect personnel against them.
- USACE workplace hearing conservation programs must comply with the requirements of ER 385-1-89.
- Contractors programs must comply with American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) and this manual at a minimum.
05.C.02 Identification of noise hazards.
- Noise measurements must be made whenever there is difficulty in communicating at distances greater than 2 ft (0.6 m), upon worker complaint of excessive noise, or whenever hazardous noise levels are suspected.
- Noise assessments and/or measurements must be performed and documented when any new facility or new equipment is placed in service and when areas that in the past were not noise hazardous become noise hazardous for any reason.
05.C.03 Assessment of noise hazards.
- Instruments used to measure noise must meet or exceed the requirements listed below.
- For continuous (steady-state) noise and impact (impulse) noise, the instrument settings must be in accordance with Table 5-3.
Table 5-3
| Feature | Dosimeter (ACGIH) |
Dosimeter (DoD and USACE)* |
Type 2 (or better) Sound Level Meter for Continuous Noise (USACE)* |
Type 1 Sound Level Meter for Impulse Noise (USACE)* |
|---|---|---|---|---|
| Criterion Time | 8 hours | 8 hours | 8 hours | 8 hours |
| Criterion Level | 85 dB | 85 dB | 85 dB | 85 dB |
| Weighting | A | A | A | Unweighted, linear or Z |
| Peak Weighting | Unweighted | Unweighted, linear, or Z |
Unweighted, linear, or Z |
Unweighted, linear, or Z |
| Threshold Level | 80 dB | 80 dB | 80 dB | 140 dB |
| Upper bound on integration |
130 dB | None | None | None |
| Time Weighting | Slow | Slow | Slow | Impulse |
| Exchange Rate | 5 dB | 3 dB | 3 dB | 3 dB |
NOTE* When used for the purposes of delineating noise hazardous areas or evaluating noise exposures to personnel.
- Dosimeters must measure the entire employee's work shift to be considered full-shift sampling.
- Calibration of noise measuring equipment must be in accordance with manufacturer's instructions (USACE refer to ER 385-1-89).
- Workplaces known or suspected to include hazardous noise will be surveyed initially, annually and whenever site conditions change impacting noise generation.
- Exposure standards.
- (1) For impact (impulse) noise, personnel exposures may not exceed 140 dBA (unweighted) without effective hearing protection devices.
- (2) For continuous (steady-state) noise, personnel exposures may not exceed 85 dBA without effective hearing protection devices.
- (3) Contractor personnel must comply with the ACGIH, TLV continuous noise exposure standards, outlined in Table 5-4.
- (4) USACE personnel must refer to ER 385-1-89.
- (5) When the daily noise exposure is composed of two or more periods of noise exposure of different levels, the combined effects must be considered. Exposure to different levels for various periods of time must be computed according to the following formula:
TABLE 5-4 - Non-DoD Continuous Noise Exposures
(OSHA Standard)
| Duration per day (hours) | Permissible sound-pressure level (dBA) |
|---|---|
| 8 | 85 |
| 4 | 88 |
| 2 | 91 |
| 1 | 94 |
| 0.5=30 min | 97 |
| 0.25=15 min | 100 |
Cn = T1 / L1 + T2 / L2 + . . . + Tx / Lx
Where:
- Cn = combined noise exposure factor;
- T = the total time of exposure at a specified sound-pressure level (in hours), and
- L = the total time of exposure permitted at that level (in hours), from Tables 5-2 or 5-3, as appropriate
- If the sum exceeds 1, the mixture of exposure periods exceeds the TLV.
Knowledge Check Choose the best answer for the question.
5-4. What are the maximum workplace exposure levels for impact noise and for continuous steady-state noise?
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