Noise is define as unwanted sound and reaches the ear in the form of pressure waves,
exposure to excessive noise results in the destruction of hair- like cells in the ear canal.
Once cells have been destroyed the effect is permanent. When engineering controls are
not feasible as a permanent method of elimination or attenuation of noise at its source,
personnel protective devises for noise control are required to be worn, provided hearing
protectors-ear muff or ear plug.