• Exposure to high levels of noise in the workplace can lead to hearing loss, as well as increased muscle tension, quickened pulse and increased blood pressure. This affects safety and productivity.
• Noise generally is classified as continuous, intermittent, or impact.

Noise is a by-product of many industrial processes and exposure to high levels of noise can cause hearing loss. It can also cause stress on other parts of the body, resulting in increased muscle tension, a quickened pulse rate, and increased blood pressure. Workers exposed to excessive noise sometimes experience nervousness, sleeplessness, and extreme fatigue, all of which can affect productivity, quality, and safety.

Noise can cause temporary or permanent hearing loss. Temporary hearing loss results from short-term exposures to noise, with normal hearing returning after a period of rest. Prolonged exposure to high noise levels over a period of time gradually causes permanent damage, which equally affects both ears.

Noise can be broken down into three general classifications:

• Continuous — wide-band noise of about the same constant level of amplitude, frequency content, and duration (such as is found with engines and fans). Sounds repeated more than once each second are considered constant or steady.
• Intermittent — exposure to wide-band noise several times during the work shift (such as is found with power tools and discharges from steam or air-pressure relief valves).
• Impact — temporary pulsing or a sharp burst of sound, usually less than a half second in duration, which is not repeated more than once each second (such as is found with power punch presses and jack hammers).