Noise pollution is a major workplace hazard which affects many workers. Once the nature and magnitude of a noise problem has been identified, a noise control program can be put in place. The three key priorities are to:
- Engineer the problem out by buying low noise equipment, changing the process or changing operating procedures
- Apply conventional methods of noise control such as enclosures or silencers
- Where neither of the above approaches can be used, providing personal protection should be considered
Although the control of noise at source is the most obvious solution, the feasibility of this method is often limited by machine design, process or operating methods. While immediate benefits can be obtained, this method should be regarded as a long term solution.
Control of the sound may be achieved by moving the source away from the noise sensitive area. In other cases, where the machine does not radiate equally in all directions, turning it round can achieve significant reductions.
Silencers can be used to suppress the noise generated when air, gas or steam flow in pipes or ducts or are exhausted to atmosphere. There are two types:
- Absorptive, where sound is absorbed by an acoustical absorbent material
- Reactive, where noise is reflected by changes in geometrical shape