Term
Purposes of Noise Measures:
-identify & label ___ with hazardous noise
-identify ___ exposed to hazardous noise
-determine if noise levels ___ or ___ regulatory standards
-see if ___ ___ ___ is needed
-determine if ___ ___ ___ is needed; & amount needed
-monitor any ___ in noise that may necessitate a change in recommendations
-predict if loss resulted from __________ (workers’ compensation claims)
-data collection re: changes in hearing with and without _________ & the ____ of noise exposure
-data collection re: interactions of noise & other ___ |
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Definition
| areas; workers; meet or exceed; hearing conservation program; HPD; changes; noise on the job; HPDs; type/amt; exposures |
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Term
| What are the 4 characteristics of noise? |
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Definition
| level, overall duration, temporal pattern, and frequency content |
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Term
| What is the frequency content of typical industrial noise? |
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Definition
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Term
| How do you measure frequency content? |
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Definition
| With an octave-band analyzer which attached to a SLM |
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Term
| SPLs judged to be equally loud by listeners (with headphones or in the sound field) |
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Definition
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Term
| May use ___ ___ or ___ that have different frequency weighting options when measuring continuous noise |
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Definition
| sound level meter (SLM); dosimeter |
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Term
| Ear is more sensitive to ___-freqs than ___ freqs |
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Definition
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Term
| unit of measure of subjective loudness of a tone, referenced to that of a 1000-Hz pure tone at a specified intensity level |
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Definition
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Term
-Weighting networks (A, B, C) come from ___ ___
-Noise is often measured in dB__ & dB__ |
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Definition
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Term
| energy is summed to simulate freq response of the ear at low but audible level |
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Definition
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Term
A-Weighting:
-Gives good estimate of ___ to hearing
-___ & others require using dBA levels |
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Definition
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Term
| simulates sensitivity of ear at medium SPLs |
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Definition
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Term
| __-weighting isn't usually used in hearing conservation |
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Definition
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Term
| approximates sensitivity of ear at high SPLs |
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Definition
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Term
C-Weighting:
-Energy at all freqs is summed almost ___ (flat freq response)
-Used to measure peak SPLs of high-level ___ sounds
-Noise measures in dB can be used with dBA measures to see if a sound has mostly ___ frequency energy |
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Definition
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Term
C-A Values (dB) dBC Minus dBA Noise Levels:
-To see if a sound has mostly ___ frequency energy or not |
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Definition
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Term
-___ C-A values : If dBC & dBA values are similar for the same sound, then the noise does not have significant low-freq energy
-___ C-A values: If dBC levels are significantly higher than dBA levels (for the same sound), the measured noise has significant low freq energy |
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Definition
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Term
| What are the duration limits for the following noise levels? 90, 95, 100, 105, 110, and 115 |
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Definition
| 8 hours, 4 hours, 2 hours, 1 hour, .5 hours, and .25 hours or less |
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Term
| If perissible exposure levels (PEL) of 90 dBA is exceeded, then feasible engineering & administrative ___ ___ are REQUIRED |
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Definition
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Term
| trading relationship between level & duration allowed; An increment of dB that requires halving the exposure time |
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Definition
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Term
-OSHA exchange rate: __ dB, requires that noise exposure
time be halved for each __-dB increase in noise level
-NIOSH exchange rate: __ dB , requires that noise exposure
time be halved for each __-dB increase in noise level |
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Definition
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Term
| What exchange rate does AAA recommend and why? |
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Definition
| NIOSH because it's more protective than OSHA regulations |
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Term
amount of damage caused by noise is determined by the total
amount of energy |
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Definition
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Term
Equal amts of sound energy are expected to produce
___ ___, regardless of how exposure is distributed over time. Example: 85 dBA for 8 hrs results in same damage as
88 dBA for 4 hrs or 91 dBA for 2 hrs |
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Definition
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Term
| The constant sound level in dB that, if continued for the criterion exposure duration (TC) (usually 8 hrs), will result in a 100% noise dose. |
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Definition
| Criterion Sound Level (LC) |
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Term
-A 100% noise dose is 100% of a worker’s ___ noise exposure.
-OSHA recommends an LC of ___ dBA for 8 hrs.
-NIOSH recommends an LC of ___ dBA for 8 hrs. |
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Definition
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Term
| a measure of noise exposure as a percentage; amt of noise experienced by a worker relative to the amt of allowable exposure |
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Definition
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Term
| What is the equation for noise dose? |
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Definition
D=C1/T1 + C2/T2=...Cn/Tn) X 100
C=actual time in noise
T=reference duration (allowable time in noise) |
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Term
| The averaging of different exposure levels during an exposure period; Calculation of overall exposure by considering different noise levels over various durations during an exposure period |
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Definition
| Time-Weighted Average (TWA) |
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Term
Time-Weighted Average (TWA):
NIOSH: For noise, given an 85-dBA exposure limit and a 3-dB exchange rate, the TWA is determined by: TWA = ____________ |
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Definition
10.0 x log (D/100) + 85
D=dose |
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Term
| Maximum level of exposure permitted in dBA (not TWA) |
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Definition
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Term
-OSHA ceiling limit: no unprotected exposure above ___ dBA
-NIOSH ceiling limit: no protected or unprotected exposure to any sounds above ___ dBA |
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Definition
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Term
Exposures that Require Implementation of a Hearing Conservation Program:
-OSHA requires implementing a program for exposures > an 8-hr TWA of ___ dBA
-NIOSH recommends implementing an HCP for exposures > an 8-hr TWA of ___ dBA |
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Definition
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Term
| When are Noise Measures Required by OSHA? |
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Definition
-an 8-hour TWA of 85 dB
– or maximum SPLs exceed 115 dBA
– or peak SPLs exceed 140 dB |
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Term
| Who are some personnel responsible for noise measures? |
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Definition
| industrial hygienist, safety specialist, noise control engineer, and an audiologist |
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Term
| How Often Should Noise Measures Be Made? |
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Definition
-At least once before operations begin
-At the beginning of employment for new hires
-Within 3 months of any changes
-at least once in 2 years where levels are > 95 dBA
-once every 5 years where levels are < 95 dBA |
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Term
Types of SLMs:
-Type __: precision SLM (errors < 1 dB)
-Type __: general purpose SLM (errors < 2 dB)
-Type __: special purpose SLM; not required to have all of the functions of 1 or 2
-Type __: used in labs, NOT for industrial purposes |
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Definition
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Term
-Slow time constant is ___ second
-OSHA guidelines say set the SLM to the “___” setting to
make noise measures |
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Definition
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Term
| A fast time constant is ___ seconds |
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Definition
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Term
| Crest factor=______/_______ |
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Definition
| Peak pressure (Ppeak)/Root mean square pressure (Prms) |
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Term
| Difference between maximum values and minimum values (noise floor) that can be measured with SLM. Specified in decibels |
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Definition
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Term
| What is the typical dynamic range of a SLM? |
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Definition
-“low” 30-100 dB
– “high” 70-140 dB |
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Term
| Eliminates “slow” or “fast” response; the filtered pressure- squared signal is averaged |
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Definition
| Integrating/averaging SLM |
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Term
Calibrating SLM:
-Pre-survey calibration; don’t adjust SLM until off by +___
dB. If adjust SLM, record magnitude of adjustment
-If post-survey calibration shifts more than + ___ dB, then question data |
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Definition
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Term
| Small integrating SLM that automatically calculates noise dose using A or C networks. |
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Definition
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Term
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Definition
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