This makes speech difficult to understand. Excessive noise may have other effects such as continuous ringing in the ears, tiredness and, at very high levels, physical pain. Loud noises can prevent spoken messages being heard properly and, consequently, can affect job performance and safety. If you have to speak in a raised voice to be understood by a listener one metre away, then you are probably in a hazardous noise environment. The amount of damage caused by noise depends on the total amount of energy over a period of time, therefore the louder the noise the faster it causes damage.
Some noises are so loud they can cause immediate permanent damage.
Gunshots, for example, can cause this type of damage. The modules in this package provide information on specific methods of noise control. The modules are suitable for use by employers, and employees who have responsibilities for matters such as purchasing of plant and equipment, maintenance, operation of plant and equipment, fabrication of acoustic enclosures and soundproofing of work areas. The materials are also suitable for use as handouts to students on courses and training sessions covering the above-mentioned principles of noise control. In particular the materials are appropriate for use in TAFE classes, especially in apprenticeship courses so that students may learn about noise control at the same time that they are learning about their chosen vocation.