Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-307 - Safety standards for agriculture › SPECIALIZED OPERATIONS › Part Y-7 - Hearing Loss Prevention (Noise) › Third-party Audiometric Tests › Section 296-307-640 - Noise definitions

Current through Register Vol. 24-14, July 15, 2024
A-weighted.
An adjustment to sound level
						measurements that reflects the sensitivity of the human ear. Used for
						evaluating continuous or average noise levels.
Audiogram.
A chart, graph, or table
						resulting from an audiometric test showing an individual's hearing threshold
						levels as a function of frequency.
Audiologist.
A professional, specializing in
						the study and rehabilitation of hearing, who is certified by the American
						Speech, Hearing, and Language Association, or the American Academy of
						Audiology, and is licensed by the state board of examiners.
Baseline audiogram.
The audiogram against
						which future audiograms are compared. The baseline audiogram is collected when
						an employee is first assigned to work with noise exposure. The baseline
						audiogram may be revised if persistent standard threshold shift (STS) of
						improvement is found.
Continuous noise.
Noise with peaks spaced no
						more than one second apart. Continuous noise is measured using sound level
						meters and noise dosimeters with the slow response setting.
Criterion sound level.
A sound level of
						ninety decibels. An eight-hour exposure to constant 90 dBA noise is a one
						hundred percent noise dose exposure.
C-weighted.
An adjustment to sound level
						measurements that evenly represents frequencies within the range of human
						hearing. Used for evaluating impact or impulse noise.
Decibel (dB).
Unit of measurement of sound
						level. A-weighting, adjusting for the sensitivity of the human ear, is
						indicated as "dBA." C-weighting, an even reading across the frequencies of
						human hearing, is indicated as "dBC."
Fast response.
A setting for a sound level
						meter that will allow the meter to respond to noise events of less than one
						second. Used for evaluating impulse and impact noise levels.
Hertz (Hz).
Unit of measurement of
						frequency, numerically equal to cycles per second.
Impulsive or impact noise.
Noise levels
						which involve maxima at intervals greater than one second. Impulse and impact
						noise are measured using the fast response setting on a sound level
						meter.
Noise dose.
The total noise exposure
						received by an employee during their shift. It can be expressed as a percentage
						indicating the ratio of exposure received to the noise exposure received in an
						eight-hour exposure to constant noise at 90 dBA. It may also be expressed as
						the sound level that would produce the equivalent exposure during an eight-hour
						period (TWA8).
Noise dosimeter.
An instrument that
						integrates a function of sound pressure over a period of time in such a manner
						that it directly indicates a noise dose.
Occupational hearing loss.
A reduction in
						the ability of an individual to hear either caused or contributed to by
						exposure in the work environment.
Otolaryngologist.
A physician specializing
						in diagnosis and treatment of disorders of the ear, nose and throat.
Permanent threshold shift.
A hearing level
						change that has become persistent and is not expected to improve.
Qualified reviewer.
An audiologist,
						otolaryngologist, or other qualified physician who has experience and training
						in evaluating occupational audiograms.
Slow response.
A setting for sound level
						meters and dosimeters in which the meter does not register events of less than
						about one second. Used for evaluating continuous and average noise
						levels.
Sound level.
The intensity of noise as
						indicated by a sound level meter.
Sound level meter.
An instrument that
						measures sound levels.
Standard threshold shift (STS).
A hearing
						level change, relative to the baseline audiogram, of an average of 10 dB or
						more at 2000, 3000, and 4000 Hz in either ear.
Temporary threshold shift.
A hearing level
						change that improves. A temporary threshold shift may occur with exposure to
						noise and hearing will return to normal within a few days. Temporary threshold
						shifts can be indicators of exposures that lead to permanent hearing
						loss.
TWA8 - Equivalent eight-hour
						time-weighted average sound level.
That sound level, which if constant
						over an eight-hour period, would result in the same noise dose measured in an
						environment where the noise level varies.
Statutory Authority:
						  RCW
						   49.17.010,
						  49.17.040,
						  49.17.050,
						  49.17.060. 05-01-166, §
						  296-307-640, filed 12/21/04, effective
						  4/2/05.