Term
OSHA & HPDs:
-If an employee does NOT have an STS, then OSHA requires that HPDs reduce a worker’s TWA to __ dBA or less
-If an employee has an STS, then OSHA requires that HPDs
reduce a worker’s TWA to ___ dBA or less |
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Definition
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Term
| What are the 4 C's of HPDs often used to recommend HPDs? |
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Definition
| Comfort, convenience, cost, and communication |
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Term
| What are some challenges of HPDs? |
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Definition
-Less than 50% of those who should wear HPDs actually wear them
-There are hundreds of HPDs available!
-No particular types or brands of HPDs are recommended or
proscribed by OSHA |
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Term
| What are the 3 classifications of HPDs? |
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Definition
| Physical styles, attenuation characteristics, and electronic versus non-electronic |
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Term
| What are some physical styles? |
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Definition
| Earplugs (user molded/"roll down", pre-molded/flanged, custom), semi-inserts, earmuffs, helmets, and earphones |
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Term
What does this describe:
- most popular style
-made of soft polymer foam
-may be made out of silicone putty
-Can order these with or without an attached cord
[image] |
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Definition
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Term
Advantages of Earplugs:
-more ___ than earmuffs if fitted & worn correctly
-___, may be better option in ___ spaces, no ___ from headband
-___ than earmuffs
-compatible with other safety ___ |
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Definition
| comfortable; cooler; confined; pressure; cheaper; gear |
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Term
Disadvantages of Earplugs:
-___ is more variable (more dependent on proper fit/insertion)
-More difficult to ___ proper use
-More difficult to use in ___ noise (especially if need to communicate)
-Some work loose with ___ movements
-Frequent ___ may be problem |
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Definition
| Attenuation; monitor; intermittent; jaw; reinsertion |
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Term
What kind of HPDs does this describe:
-Made of foam, vinyl, silicone
-Many have flanges or sealing rings; may be “cap-like”
-Flexible, durable, range of sizes & colors
-May need to size plugs
[image] |
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Definition
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Term
What kind of HPDs does this describe:
-For on-and-off use; good option for workers entering and leaving noisy areas
-Quick insertion & removal (compared to roll-down plugs)
-uncomfortable if worn for a long time
-Do not provide enough attenuation for very high noise levels
[image] |
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Definition
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Term
| What are some Semi-insert Advantages? |
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Definition
| Can be put on & removed quickly and Good in intermittent noise |
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Term
Semi-insert limitations:
-Provides ___ attenuation than other HPDs
-May be ___
-Cap style produces more ___ effect
-Hitting ___ ___ may make a sound that annoys the user |
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Definition
| LESS; uncomfortable; occlusion; head band |
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Term
What kind of HPDs does this describe:
-Require ear impressions
-More expensive the roll-down or pre-molded ear plugs
-Variety of colors & styles
-Can order from many different earmold labs
-Cords can be helpful or harmful
-Different styles may offer various amounts of attenuation
[image] |
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Definition
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Term
Ear Muffs:
-Not used as much as ___
-Some worn with ___; over head, behind head, or under
chin
-Not available in lots of ___, some are larger/smaller than
others; need to fit individual
-Color options
-Large-volume earmuffs often attenuate ___ than small-
volume earmuffs
-Can be attached to other ___ ___ |
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Definition
| earplugs; band; sizes; more; safety gear |
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Term
Advantages of Earmuffs:
-___ to fit to most individuals
-Attenuation is less ___
-Easier to ___ use, but may not be able to identify “modified” earmuffs
-Comfortable in ___ & for ___ use
-When fitting: position band directly over ___ of the head & align cushions with ___ opening |
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Definition
| Easier; variable; enforce; cold; intermittent; center; EAC |
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Term
Disadvantages of Earmuffs:
-Headband ___ can be uncomfortable
-Can be uncomfortable in ___ temperatures
-May not be ___ with other safety gear (i.e. safety glasses)
-All HPDs make it hard to ___; earmuffs make it the most difficult to ___ (EarLog 3) |
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Definition
| pressure; hot; compatible; localize; localize |
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Term
Attenuation Characteristics Related to Frequency:
-Typical: ____ attenuation
-Essentially ___ attenuation |
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Definition
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Term
Attenuation Characteristics Related to Input Level:
-Constant: Provides ___ amount of attenuation regardless of
the noise levels
-Level dependent: Provides less attenuation for ___ or ___ levels; provides more attenuation for ___ levels of noise |
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Definition
| same; soft; moderate; higher |
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Term
Flat Attenuation:
-A.k.a. ____ plugs
-ER-9, ER-15, ER-25
-provide less ___ frequency attenuation than conventional HPDs
-Orifice/filter in earplug allows ___ amount of sound directly into EAC
-Offers ___ protection in noise with significant high- frequency energy |
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Definition
| musician’s; HF; controlled; less |
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Term
Noise Reduction Rating:
-overall average noise reduction (in dB) provided in __-weighted sound levels (EPA, 1979)
-___-recovery earplugs have highest overall NRRs (30-45 dB > 2000 Hz)
-Differences of less than __ dB in NRRs have no practical importance |
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Definition
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Term
Real Attenuation:
-foam earplugs attenuate about ___% of NRRs
-earplugs (other than foam) protect about ___% of NRRs
-ONLY foam earplugs & earmuffs generally attenuate > __ dB for 84% of the population
-But…some HPDs with lower attenuation (if have more comfort) may protect more if worn ___ and ___ |
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Definition
| 40; 25; 10; correctly; consistently |
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Term
Electronic or Active HPDs:
-Hearing enhancement & protection
-___ noise reduction (ANR)
-___ manipulate incoming sounds
-Require ___
-Cost?
-May be reported to be “more ___” |
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Definition
| Active; Electronically; batteries; more expensive; comfortable |
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Term
-For more than 90% of noisy industries, the TWA exposure levels are ___ than 95 dBA
-Implication for HPDs: All that is needed is ___ dB of attenuation
-Most HPDs ___ provide this |
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Definition
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Term
| What is the BEST Hearing Protection? |
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Definition
| Those worn correctly and consistently |
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Term
Non-electronic HPDs:
-Has structural elements to ___/___ sound
-No ___ elements or ___ circuits
-___ expensive
-Do not need ___
-___ maintenance, ___ durable
-How much are they used?
-More closely resemble ___ HPDs |
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Definition
| block/control; acoustic; electronic; Less; batteries; Less; more; Widely used; traditional |
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Term
| What are level-dependent HPDs also known as? |
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Definition
| amplitude-sensitive or nonlinear protectors |
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Term
Level-dependent HPDs:
-Amount of attenuation varies with ___ ___. Attenuation ___ as sound levels increase
-Useful in ___ periods & ___ noise exposure
-Divided into “___ ” & “___” devices |
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Definition
| sound level; increases; quiet; intermittent; passive; active |
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Term
Passive Level-Dependent Hearing Protection:
-amt of attenuation depends on relative ___ ___
-valve system ___ ___ sound channel when activated by high levels |
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Definition
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Term
Hearing Protection with Active Noise Reduction:
-May be designed for ___ ___
-May be designed for ___
-Work best at cancelling ___-frequency noise
-___, but can be effective |
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Definition
| hearing protection; communication; low; Expensive |
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Term
Active Hearing Protection Devices:
-“___-sensitive”; “___-dependent”
-Modified conventional earmuffs or earplugs that have ___ and ___ in them to transmit external sounds to earphones mounted inside HPDs
-Amplifier limits sounds to ___ level (often 85 dBA)
-Good choice to use in ___ noises
-Limitation: can make a ___/___ noise in high levels of continuous noise |
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Definition
| Amplitude; level; microphones; amplifiers; predetermined; intermittent; cracking/popping |
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Term
| Electronic earmuffs can be used to ___ noise exposure for persons with hearing loss ___ compromising speech understanding |
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Definition
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Term
Hearing Protection with Active Noise Reduction:
-Circuits analyzes incoming sound, generates an _________ signal that is played in the space under the hearing protector
-ANR works best for noise with energy below ___ Hz |
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Definition
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Term
Noise-Canceling HPDs:
-Main benefit is for use in ___-frequency noise (i.e. aviation, military)
-Users also report that they feel more “___”
-Have to consider: Reliability in ___ environments, ___/___, ___ replacement/recharge, and the cost is $____ (more expensive than other HPDs). |
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Definition
| low; comfortable; harsh; Maintenance/repair; Battery; 150-$1000 |
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Term
Communication Head Set with Active Noise Reduction:
-Allows ___ or ___-way communication
-Amplification provided for ___ and ___ inputs
-Attenuation is provided for ___-level inputs |
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Definition
| one- or two; soft; average; high |
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Term
Communication Headsets:
-Receiver built into earmuff allows ___ communication (FM, infrared) & earmuff ___ noise
-Some have limiting devices to prevent radio signal from
reaching ___ level.
-Newer option: comm. system connected to an ___ so
earmuff can be worn over ___ |
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Definition
| radio; attenuates; hazardous; earplug; plug |
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Term
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Definition
| Slowly roll and compress foam plugs into a very thin crease-free cylinder. While compressed, insert plug well into the earcanal. Fitting is easier if you reach around the head to pull the ear outward and upward during insertion |
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Term
| How do you use pre-molded plugs? |
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Definition
| Reach around the back of your head and pull outward and upward on the ear while inserting the plug until you feel it sealing. This may seem tight at first. Carefully twist the plug to break the seal for a slow, safe removal. |
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Term
| How do you use semi-inserts? |
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Definition
| Hold the large ends of the pods and swivel them to direct the tips into the EC openings. Firmly push and wiggle the pods into the canals until a snug seal is obtained. Pulling on the outer ear while pushing on the pods will be helpful to most wearers. |
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Term
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Definition
| Muffs must fully enclose the ears to seal against the head. Pull hair back and out from beneath the cushions. |
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Term
How to know if earplugs are properly inserted:
-A properly inserted foam earplug will generally create a ___ or ___ up feeling
-If sounds seem more ___ when you cup your hands over your ears (without the earplug in place), the earplug may not be inserted properly
-If the initial fit is unacceptable remove the earplug, ____, and reinsert the earplug |
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Definition
| plugged; blocked; muffled; re-roll |
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Term
| What are some tests you can do to check the adequacy of the seal? |
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Definition
| Noise attenuation test, tug resistance test, and occlusion hum test |
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Term
Noise Attenuation Test:
-Worker puts ___ ___ inserted earplugs
-If earplugs are inserted correctly, there will be ___ ___ reduction of noise |
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Definition
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Term
Tug resistance test:
-Worker ___ ___ on earplug handles
-If perceives sensation of ___ resistance then earplug will not come out easily & the seal is likely adequate |
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Definition
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Term
Occlusion hum test:
-After inserting 1 earplug, the worker __________________
-If his/her voice sounds ___ in the ear with the plug, the seal is probably adequate |
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Definition
| says or hums “ahhh”; louder |
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Term
HPD Sabotage:
-Let employees know to return for re-fit if hearing protection is
___
-Some sabotage HPDs to make HPD ___ or ___ better
-Examples? |
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Definition
| uncomfortable; feel or sound; Cutting length or diameter of foam plugs, Punching holes in HPDs, Stretching headbands, etc. |
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Term
Common Concerns & Possible Solutions:
-Needs to wear comfortable HPDs for long durations: Use ___ ___
-Difficulty manipulating ear plugs: Try ___ or ____
-Complains of poor attenuation when using earmuffs in noise: Check ___ of earmuff cushions and/or ___ cushions; consider ___
-Has pre-existing hearing loss: Use ___-attenuation HPDs or ___ HPDs w/VC |
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Definition
| foam earplugs; earmuffs; semi-inserts; seal replace; earplugs; flat; electronic |
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Term
Non-Linear HPDs:
-___ widely used in industry
-do not work well in ___ industrial noise
-Non-linear HPDs are mainly used in ___-level ___-duration noise (e.g. ___ ___) |
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Definition
| not; typical; high; short; firing range |
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Term
General HPD Recommendations:
-If significant low-frequency (125-250Hz) energy is present, recommend ___ or ___ ___ (___ is poorer choice)
-If significant energy at 1000 Hz, ___ are a better recommendation
-If TWA exposures exceed 105 dBA {especially if primarily LF (<500 Hz) noise}, recommend ___ protection |
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Definition
| foam or premolded plug; earmuff; earmuffs; dual |
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Term
Ways To Measure HPD Attenuation:
-REAT: _________
-MIRE: __________
-with ATFs: ____________ |
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Definition
| Real ear attenuation at threshold; Microphone in real ear; Acoustical test fixtures |
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Term
Real-Ear Attenuation at Threshold REAT:
-___ ___ used method
-___ in levels a subject can hear with HPDs (occluded thresholds) & without HPDs (open thresholds)
-procedure required by EPA to compute ____
-Measures are made in a diffuse sound field using ___ octave bands of noise & at least ___ subjects whose occluded and open thresholds are measured X3 each
-Mean attenuation represents protection that about ___% of subjects meet or exceed. |
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Definition
| most commonly; difference; NRR; 1/3; 10; 50 |
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Term
Microphone-in-Real-Ear MIRE:
-Using a miniature microphone, measures ___ in ear canal with and without HPDs in place
-May be difficult to measure with ___, since it is hard to place earplugs & microphone
-Less ___ consuming than REAT
-shows more accurate attenuation values in ___ frequencies than REAT
-Good procedure to use when studying ___ intensity levels (i.e. explosives) |
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Definition
| SPL; earplugs; time; low; high |
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Term
Acoustical Test Fixture ATF:
-Same as MIRE, but uses ___
-ATF has microphone at ___ location, may match ME impedance with an acoustic coupler
-Can be used for ___ development and ___ control
-Not suitable for direct prediction of real-ear ___
-Used to determine level-dependent responses of ___ & ___ HPDs |
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Definition
| KEMAR; TM; product; quality; attenuation; passive; active |
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Term
-De-rate NRRs by ___% (OSHA recommendation) to evaluate the relative efficacy of HPDs & engineering noise controls
-derating NRRs by 50% adjusts labeled NRRs to “_______” values |
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Definition
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