7- Self Test questions Flashcards
Describe BE’s responsibilities in the occupational noise and hearing conservation program.
(1) Perform noise surveys and dosimetry to quantify noise hazards and document the results in
DOEHRS-IH module.
(2) Work with a PMEL and/or BE personnel to ensure proper calibration and certification of noise
meters.
(3) Complete the SEG OEHED for the OEHWG, including the 8-hour TWA and required controls.
(4) Provide PH and shop supervisors the results of noise surveys, dosimetry, and required controls
(i.e., engineering, administrative, and/or HPD).
(5) Assess the adequacy of all controls used to reduce noise exposures, including hearing protectors,
and, in conjunction with the shop supervisor, the feasibility of engineering controls for hazardous
noise equipment/areas.
(6) Assist with fitness and risk evaluations upon request of provider.
(7) Review facility and operations plans for new or modified facilities to ensure noise exposure
control is appropriately considered.
(8) Conduct workplace assessments to support occupational illness/injury investigations, claims for
hearing loss, and areas where adverse hearing loss trends exists.
(9) Certifying the audiometric testing environment on an annual basis.
Describe the squadron commanders’ and workplace supervisors’ responsibilities in the
Occupational Noise and HCP.
(1) Participate in the review of the workplace hazards as process owners to identify actions taken to
mitigate hazardous noise.
(2) Eliminate exposure to potentially hazardous noise and protecting the hearing of assigned personnel
(by engineering controls).
(3) Properly mark hazardous noise areas and equipment with signs and/or decals to alert personnel of
the potential hazard.
(4) Inform BEE/PH staff of workplace equipment or practices and procedures involving potentially
hazardous noise change.
(5) Ensure compliance and availability of approved HPD for workers exposed to hazardous noise.
(6) Instruct personnel on the HCP, care/hygiene, and proper use of their approved HPDs.
(7) Ensure workers with an occupational exposure to hazardous noise complete an initial/reference
audiogram and receive HCP training from PH.
(8) Conduct initial and annual workplace-specific hearing conservation training on shop or unit
hazardous noise exposures and equipment.
(9) Notify each employee exposed at or above the 8-hour TWA of 85 dB(A) of the noise monitoring
results performed by BE.
How does a sound source cause variations in atmospheric pressure?
The surface of a sound source first bends in one direction and the air molecules next to it become
compressed. This causes a slight increase in atmospheric pressure. As the sound source moves in the
opposite direction, molecules near its surface are drawn away from the surrounding air to create an area
of lower atmospheric pressure. This process is known as rarefaction. The vibrating sound source
repeats this process over and over, causing alternate areas of compression and rarefaction in the
molecules near the source. These air molecules, in turn, cause compression and rarefaction in the
molecules next to them. This forms a repetitive wave-like motion, known as a sound wave.
Explain the difference between a pure tone and complex sounds.
A pure tone is a sound wave characterized by one single frequency. Complex sound is a wide variety of
different tones and amplitudes mixed together so that no single one is recognizable.
What characteristic or quality of a sound wave represents the speed of sound?
Velocity.
Describe sound pressure and state its unit of measure.
It is what is actually measured and reported when quantifying sound; additionally, it is the difference
between normal atmospheric pressure and the actual pressure during compression and rarefaction. It is
expressed in newtons per square meter or pascals.
What does weighting mean in relation to sound?
Sound measuring instruments are calibrated to respond to frequencies in the same way as the human
ear. Different frequencies are weighted by different amounts so that they are all perceived to have the
same loudness when they have the same number of weighted dBs.
Describe auditory effects of noise.
Auditory effects include hearing loss, tinnitus and acoustic trauma. Hearing loss due to noise is the
result of damage to the hair cells and accompanying degeneration of the nerve fibers in the ear. The
change in hearing, or threshold shift, can be temporary or permanent. Tinnitus is the condition in which people perceive they hear sounds (e.g., ringing, roaring, whistling, humming, hissing, etc.) in one or
both ears when there is no actual sound around them. Acoustic trauma is the temporary or permanent
hearing loss due to a sudden extremely high intensity noise, such as an explosion.
Describe non-auditory effects of noise.
Non-auditory effects are undesirable effect on the body other than hearing effects. They are also known
as whole body effects. Symptoms are similar to those associated with general reactions to stress. There
may be an upset sense of balance, dilated pupils, speech and sleep communication problems, increased fatigue, nervousness, irritability, high blood pressure and overall stress levels. Noise may have an
adverse effect on job performance and community relations.
What noise levels define potentially hazardous noise?
Steady-state noise having an 8-hour TWA noise level greater than or equal to 85 dB(A), or
impulse/impact noise levels greater than 140 dB peak SPL, regardless of duration.
Distinguish between criterion level and exchange rate.
The criterion level is the sound level allowed for an 8-hour exposure and is used as the basis for
measurement of a noise standard. The AF criterion level is 85 dB(A). The AF exchange rate (doubling
rate), is 3 dB. The exchange rate deals with the relationship between the sound level and the allowed
exposure time. For every increase of 3 dB, the allowable exposure time is cut in half. For every
decrease of 3 dB, the allowable exposure time is doubled.
What is the purpose of noise exposure limits?
They are sound levels and durations to which nearly all workers may be exposed without permanent
adverse effect on their ability to hear and understand normal speech.
What information about the workroom should you gather to help when evaluating noise
sources/areas?
You should sketch the room to show its shape, size, layout of equipment, workstations, and break
areas. Identify the materials used in the construction of the walls, floor, and ceiling. Note any
acoustical treatment (such as ceiling tiles), or the potential for treatment. Describe if secondary sources
or spill-over noise from other areas contribute to the noise at a particular workstation. In your sketch of
the room or facility, show the type and location of any shields/barriers or enclosures and whether they
seem to be effective.
When must you calibrate a SLM?
Before and after each period of measurement.
To what setting do you set the SLM to perform a noise source survey?
A-weighting, slow response.
