Control noise before using hearing protection
A noisy workplace may conjure images of hearing protection, but employers must consider engineering and work practice controls before mandating personal protective equipment. Reducing or eliminating noise can not only protect workers’ hearing, it can save the company money by decreasing the number of workers in a hearing conservation program.
To get started, conduct a noise assessment. Focus on areas where communication is difficult in a normal voice. Identify noise sources and determine how the sound is transmitted. Noise sources include motors, gears, belts, points of operation, and other moving parts. The frames and housings of equipment may vibrate and amplify noise, or walls may bounce the sound in specific directions.
Once you’ve identified the sources, consider ways to reduce noise, or to redirect the noise away from workers.
Source controls
Source controls reduce the amount of noise generated. Examples include: Maintaining motors and moving parts in top operating condition.
- Reducing operating speeds to the lowest level consistent with production goals.
- Ensuring that equipment does not contact other equipment or walls.
- Isolating noisy equipment using springs or rubber footings.
- Applying vibration-reducing materials and constructing sound-absorbent hoods around points of operation.
Path controls
Path controls involve isolating, blocking, diverting, absorbing, or otherwise reducing noise intensity before it reaches employees’ ears. Examples include:
- Moving noisy equipment away from employees (noise intensity decreases with distance).
- Using sound-absorbing acoustical tiles and blankets on floors, walls, and ceilings.
- Enclosing equipment in barriers that absorb noise or deflect it in harmless directions, such as toward ceilings covered with sound absorbent material.
Even if hearing protection is still necessary, effective source and path controls that reduce total noise levels will also reduce the risk of hearing loss.
Work practice controls
If engineering controls don’t reduce noise to acceptable levels, consider work practice controls. These are changes in work or production schedules such as operating noisy machines on a second or third shift when fewer people are exposed, or rotating employees through quieter jobs to reduce noise exposure time.
Work practice controls are limited because changing jobs or production schedules is not always possible. In addition, rotating employees between jobs may decrease the risk of severe hearing loss in some workers, but increase the risk of minor hearing loss in many workers.
Since hearing loss is permanent and irreversible, employers should evaluate every available option to protect employees’ hearing.