BLOCK 5: PHYSICAL/BIOLOGICAL HAZARDS AND CONTROLS - Unit 2: Noise Surveys (complete)

Question 1

The sound level allowed for an 8 hour exposure used as the basis for the measurement of a noise standard (acceptable standard 85dBA).

Answer 1

CRITERION LEVEL

Question 2

Exposure to steady-state noise having an 8-hour TWA noise level > (greater than or equal to) 85 dBA, or exposure to impulse/impact noise levels greater than 140dB peak SPL, regardless of duration.

Answer 2

POTENTIAL HAZARD NOISE

Question 3

Any area where personnel could be exposed to steady state noise having an 8 hour TWA noise level > (greater than or equal to) 85 dBA, or exposure to impulse/impact noise levels greater than 140dB peak SPL, regardless of duration.

Answer 3

POTENTIALLY HAZARDOUS NOISE AREA

Question 4

Noise regulations and guidance related to the community

Answer 4

COMMUNITY NOISE

Question 5

The trade-off relationship between an increase (or decrease) in sound level and the corresponding change in allowed exposure duration.

Answer 5

EXCHANGE RATE

Question 6

Determined based on sound level and duration of exposure; in other words how many decibels and for how long.

Answer 6

NOISE EXPOSURE STANDARDS (LIMITS)

Question 7

The first stage in evaluating potential noise problems in a shop involves identifying all noise-producing equipment by using an ____________________.

Answer 7

INVENTORY

This can be done by reviewing the existing shop data in DOEHRS, questioning the supervisor and workers, and thoroughly examining the shop. Many hand-held tools can be quite loud and may be kept stored away where they are not readily noticeable. There may also be a number of sources that are kept “on the road,” such as those that are stored in vehicles for on-site use.

Question 8

TRUE OR FALSE:

When finding out if any workers in a shop have had complaints about noises or hearing threshold shifts, BE may consult with Public Health, who is able to determine which shops have personnel with standard threshold shifts.

Answer 8

TRUE

BE may also question the shop supervisor, if possible, to find out if there’s any noticeable hearing trouble attributable to the work or complaints about noise.

Question 9

Conversation tends to become difficult when the environmental noise level exceeds _____ dBA.

Answer 9

70 dBA

Question 10

What are the 4 major Noise Evaluation Factors?

Answer 10

–> Inventory
–> Complaints/Surveillance Data
–> Worker Positions and Actions
–> Details about the Processes and Machinery Affecting the Noise

Question 11

How many types of noise surveys are conducted to evaluate the noise environment?

Answer 11

3

–> NOISE SOURCE SURVEY
–> WORKER EXPOSURE SURVEY
–> HAZARDOUS NOISE AREA SURVEY

Question 12

“This survey is used to classify whether a particular noise source output exceeds the criterion level of 85 dBA and could present a potential exposure hazard to workers.” (AFI 48-127)

Answer 12

NOISE SOURCE SURVEY

Question 13

“Where the potential to exceed the (hearing noise exposure) limits in paragraph 3.1 (AFI 48-127) exists, worker exposures shall be evaluated by direct measurements with noise dosimeters, or indirectly with noise exposure calculations.” (AFI 48-127)

Answer 13

WORKER EXPOSURE SURVEY

Question 14

“These surveys are used to define work areas where noise exposures are assumed hazardous based on routine operations. These surveys can be used to define a work area enclosed by clear borders as a hazardous noise area or to identify a hazardous noise zone around a certain piece of equipment.” (AFI 48-127)

Answer 14

HAZARDOUS NOISE AREA SURVEY

Question 15

____________________ survey is used to classify whether a particular noise source
exceeds the criterion level of 85 dBA and could present a potential exposure hazard to workers.

Answer 15

NOISE SOURCE SURVEY

This will identify if a process or piece of equipment is a hazardous noise producer. This does not, however, determine if an individual is exposed to hazardous noise because only intensity, and not duration, is considered in this measurement. Sound level measurements shall be made using A-weighting with slow response.

Question 16

The most common piece of equipment used to evaluate noise exposures in the BE career field is the _______________________ shown here.

Answer 16

SOUND LEVEL METER (SLM)

Sound level meters are used to perform a variety of sound measurements including noise source surveys, octave band analysis, speech interference level surveys, and hazardous noise area surveys.

Question 17

Picks up sound; responds to sound pressure variations and produces an electrical signal that is processed by the sound level meter.

Answer 17

MICROPHONE

Question 18

Held at 0 degrees or straight at the source.

Answer 18

PERPENDICULAR or FREE-FIELD

Question 19

Changes the noise waves received from the microphone into electronic current changes. These changes are measured, and a reading is displayed.

Answer 19

AMPLIFIER or ATTENUATOR

Question 20

Displays the final reading in the appropriate weighting of dB (A, B, or C). There are three modes of operation or meter response times - fast, slow, and impulse.

Answer 20

INDICATING METER

Question 21

There are various environmental factors that can affect the performance of noise-measuring instruments and their readings, including: ________________, ____________________, ____________________, and ____________________

Answer 21

–> TEMPERATURE
–> HUMIDITY
–> ATMOSPHERIC PRESSURE
–> MAGNETIC FIELDS

Question 22

When performing a noise source survey, measure sound levels at the equipment operator’s _______ position.

Answer 22

EAR

Question 23

Identify the PURPLE labelled part of the Sound Level Meter.

Answer 23

MICROPHONE

Question 23

Identify the RED labelled part of the Sound Level Meter.

Answer 23

WINDSCREEN

Question 24

Identify the GREEN labelled part of the Sound Level Meter.

Answer 24

KEYPAD

Question 25

Dosimetry results indicate whether or not a ____________________ (SEG) is routinely exposed to hazardous noise.

Answer 25

SIMILAR EXPOSURE GROUP (SEG)

Question 26

Calculated to determine if combined periods of noise exposure exceed the standard:

Answer 26

COMPLIANCE FACTOR

Question 27

Like a sound level meter except that it stores sound level measurements and
integrates these measurements over time, providing an average noise exposure reading for a given period of time, such as an 8-hour workday.

Answer 27

DOSIMETER

With a dosimeter, a microphone is attached to the employee’s clothing, and the exposure measurement is simply read at the end of the desired time period. Since the dosimeter is worn by the employee, it measures noise levels in those locations in which the employee travels.

Question 28

What information is found by use of this formula, where the time of actual exposure is obtained by asking the worker/worker supervisor of the process?

Answer 28

ALLOWABLE EXPOSURE LIMIT (in minutes)

You also have this table to reference:

Question 29

Octave Band Analysis is preferred when the 8 hour TWA exceeds ______ dB(A).

Answer 29

92 dB(A)