Hearing Conservation Program Glossary
- Administrative control
A method of controlling workplace hazards by changing workers' activities to reduce their exposure to a hazard.
- Action level
An 8-hour time-weighted average of 85 decibels measured on the A-scale, slow response, or equivalently, a dose of fifty percent.
Increase the volume of (sound).
A graph that shows the softest sounds that a person can hear at different frequencies.
A measuring instrument used to conduct hearing tests.
- Audiometric zero
The lowest sound pressure level that the average young adult with normal hearing can hear.
The testing of a person's ability to hear various sound frequencies. The test is performed with the use of electronic equipment called an audiometer.
Of or relating to the sense of hearing.
A substance that can cause unconsciousness or death by suffocation (asphyxiation).
- Baseline audiogram
The reference audiogram against which future audiograms are compared.
Of, relating to, or used with both ears.
The unbroken and consistent existence or operation of something over a period of time.
- Criterion sound level
A sound level of 90 decibels.
- Decibel (dB)
A unit of sound-pressure level, abbreviated dB. Decibels indicate the pressure of sound. Sound waves transfer that pressure from place to place and are measured in units on a logarithmic scale.
- DeciBel A-weighted filter (dBA)
A decibel rating commonly used for measuring sound levels. Used for lower levels, it corresponds to people's natural hearing recognition and is less sensitive to very low and very high frequencies.
A device worn by a worker for determining accumulated noise exposure.
Often refers to the status of wearing a personnel badge that measures and monitors dose. It may also refer to dose history and the records where dose history is maintained.
A membrane in the ear canal between the external ear and the middle ear.
- Eight-hour time-weighted average
An average exposure weighted to account for time and changing noise levels over eight hours.
The number of times per second that the sine wave of sound repeats itself, or that the sine wave of a vibrating object repeats itself. Now expressed in hertz (Hz), formerly in cycles per second (cps).
- Hair cells
Sensory cells in the inner ear that transform the mechanical energy of sound into nerve impulses.
- Hearing threshold
The sound level below which a person's ear is unable to detect any sound. For adults, 0 dB is the reference level. A threshold shift is an increase in the hearing threshold for a particular sound frequency.
Unit of measurement of frequency, numerically equal to cycles per second, abbreviated Hz.
- Industrial Hygiene
The science of anticipating, recognizing, evaluating, and controlling workplace conditions that may cause workers' injury or illness. Industrial hygienists use environmental monitoring and analytical methods to detect the extent of worker exposure and employ engineering, work practice controls, and other methods to control potential health hazards.
- Inner ear
The inner portion of the ear involved in hearing and balance.
Of or relating to more than one branch of knowledge.
- Logarithmic scale
A scale that expresses values over a very large range. Each interval on a logarithmic scale is some common factor larger than the previous interval. A typical factor is 10; the values on such a scale read: 1, 10, 100, 1,000, 10,000, and so on.
- Middle ear
The middle portion of the ear consisting of the eardrum and an air-filled chamber lined with mucous membrane.
Of or involving one ear.
The capability of inducing adverse effects in the central nervous system, peripheral nerves or sensory organs. A chemical is considered to be neurotoxic if it is capable of inducing a consistent pattern of neural dysfunction or change in the chemistry or structure of the nervous system.
Sound that is noticeably unpleasant or undesired or that interferes with one's hearing.
- Noise-induced hearing loss
The result of exposure to sound of sufficient intensity and duration to cause a decrease in hearing ability.
- 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.
The interval of eight diatonic degrees between two tones of the same name, the higher of which has twice as many vibrations per second as the lower.
- Optical card
A card with information recorded on an optical memory stripe, similar to compact discs.
- Outer ear
The external portion of the ear, including the canal leading to the eardrum.
A physician specializing in diagnosis and treatment of disorders of the ear, nose and throat.
Damage to the ear (oto-), specifically the cochlea or auditory nerve and sometimes the vestibular system, by a toxin.)
The study of disease. Pathology has been defined as "that branch of medicine which treats of the essential nature of disease."
- Personal monitoring
A method of measuring sound levels near individual workers, usually over eight hours.
- Permanent threshold shift
A permanent decrease in hearing ability at a specified frequency as compared with a previously established reference level.
The property of a sound determined by the frequency of the waves that produce it; the highness or lowness of sound.
- Safety climate
The general level of safety awareness and commitment among management and workers in the organization.
A substance, usually a liquid, capable of dissolving another substance.
The subjective sensation of hearing something - usually transmitted in a material medium, typically air. Sound is measured in decibels.
- Sound survey
Describes a variety of methods for measuring sound levels, including basic survey, detailed survey, and engineering survey; includes monitoring exposure levels over extended time periods, such as an eight-hour work day.
- Standard Threshold Shift – OSHA
A change in hearing threshold, relative to the baseline audiogram for that employee, of an average of 10 decibels (dB) or more at 2000, 3000, and 4000 hertz (Hz) in one or both ears.
- Temporary threshold shift
A temporary impairment of hearing ability.
- Time-weighted average (TWA) sound level
That sound level, which if constant over an 8-hour exposure, would result in the same noise dose as is measured.
Ringing in the ear or noise sensed in the head. Onset may be due to excessive sound and persist in the absence of acoustical stimulation (in which case, it may indicate a lesion of the auditory system).
The degree to which a substance (a toxin or poison) can harm humans or animals.
Of or relating to a vestibule, particularly that of the inner ear, or more generally to the sense of balance.
- Work-practice control
A type of administrative control; emphasizes safe work practices and procedures.
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