IB-6 Physical Agents - Noise & Vibration Flashcards

0
Q

outline the areas to consider in a vibration risk assessment

A
  • identify the source of vibration & tasks
  • identify workers at risk
  • estimate exposure
  • seek advice from suppliers of equipment
  • measurement of vibration magnitude
  • consider exposure limits
  • health surveillance
  • are additional controls needed
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1
Q

identify the risk factors associated with HAV (Hand Arm Vibration) syndrome

A
  • exposure
  • magnitude of exposure
  • direction & frequency of vibration
  • duration
  • force needed
  • cold or wet working conditions
  • previous health conditions - circulatory problems
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2
Q

how do you estimate the Lepd (daily personal noiseexposure)

A
  1. measure the equivalent noise level at each machine -Leq. this can be done using an integrated sound meter - positioned at operators head
  2. how much time is spent completing each task
  3. these figures can be calculated using a logarithmic scale.- use ready reckoner or hse website based tool
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3
Q

what does noise induced hearing loss look like on a graph

A

threshold shift (db) 70 going up to -10 vs frequency (hz) 125 going across to 16k

4k dip shows hearing loss

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4
Q

outline the benefits & limitations of audiometry as part of a hearing conservation programme

A

benefits

  • monitoring evidence of effectiveness of programme
  • pre employment identification of pre existing conditions
  • identification of early signs of noise induced hearing loss
  • basis to defend claims of noise induced hearing loss

limitations

  • not preventative
  • information may trigger claims
  • possible inaccurate data - make sure operatives are not exposed to high levels of noise prior to test (temporary threshold shift)
  • dose not identify source of noise induced hearing loss
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5
Q

identify the different types of equipment that can be used to measure noise in the workplace

A

sound level meters

  • used for spot checks & initial surveys
  • identifies sound pressure on A weighted and C weighted matrices with analogue or digital readouts
  • can be read by the eye

integrating sound level meter

  • A weighted mode - equivalent daily noise exposure calculated.
  • peak action level used to make noise measurements for the purpose of noise regulations
  • measures the sound levels over a period of time then joins the. Together to calculate the average exposure
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6
Q

explain the purpose, design and construction characteristics of an acoustic enclosure

A

encloses the equipment

design considerations

  • sound reduction of the panelling of the enclosure - to meet the octave band of the noise exposed
  • protection of the internal absorbent lining
  • robust construction
  • sealing between the panel, floor and around penetrating ducts & pipes
  • access for operation and maintenance
  • robust locks to doors and hatches
  • observation windows
  • adequate internal space
  • adequate lighting & ventilation
  • flexible pipes
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7
Q

what is the purpose, design and construction of an acoustic haven

A

enclose the worker

design considerations

  • noise reduction properties of the haven using an octave band analysis
  • similar properties to a noise enclosure except that noise absorbent lining is not required
  • observation windows
  • adequate internal space
  • adequate lighting & ventilation
  • adequate seating
  • inclusion of as many controls as possible

haven must be sealed from all sounds and locks fitted

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8
Q

identify the factors to be considered when completing a noise survey

A
  • basic survey completed first
  • noise levels (can you hear someone speak within 2 meters)
  • who is at risk
  • how will measurements be taken and for how long
  • duration of exposure
  • machine sources and associated tasks
  • existing controls
  • work pasterns
  • results of previous tests and surveys
  • group sampling
  • mobile workers

If the exposure is at or exceeded the upper exposure action value then a more detailed survey will be needed using an ne’er grated sound level meters

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9
Q

outline the range of control measures to minimise the effects of WBV to drivers of heavy equipment

  • consider controls for
    - vehicle
    - traffic routes
    - individual
A

controls implemented on the vehicle - right for terrain & activities / suspension fitted / adjustable seats / tyres correctly inflated / maintained / vibration damping characteristics

controls implemented on traffic routes - avoid uneven surfaces / roadways maintained

controls implemented with driver - limit hours of exposure / rest breaks & shift rotation / trained on driving technique to avoid vibration / ensure exposure is kept below the threshold

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10
Q

what are the ill health effects of exposure to noise

A
  • noise induced hearing loss - loss of sensitivity to sound in the speech range
  • tinnitus
  • threshold shift
  • neuro psychological disturbances - headache / fatigue / insomnia
  • cardiovascular system disturbances - hypertension & cardiac disease
  • digestive disorders - peptic ulcers & colitis
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11
Q

what is threshold shift

A

is the reduction in a persons ability to hear it can be permanent or temporary. when the hair cells in the cochlea are fatigued and lay flat

noise induced hearing loss seen as a 4Kz dip - the amount of dip from a 0dB average level

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12
Q

outline the benefits and limitations of audiometry as part of a hearing conservation programme

A

audiometry is the process of scientifically quantifying hearing performance in order to detect a problem with the persons hearing

advantages

  • early identification of individuals with hearing loss will allow them to be further protected to prevent deterioration
  • early detection of poor controlled noise exposure - allow other workers to be protected
  • negative test results confirm programme is working effectively
  • establishment of pre employment baseline - prevention of claim
  • compliance with legal regulations

disadvantages

  • subjective - based on cooperation of the of test person
  • reactive - confirms hearing loss after it has occurred
  • inaccurate for technical reasons or headphone fit
  • can be difficult to operate in practice where there are large numbers of workers to be tested
  • can trigger claims
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13
Q

identify the signs and symptoms of HAVS

A

starts at the tip of the finger and with continued exposure can move to the base of the finger

  • numbness and tingling in the finger
  • reduced sense of touch & temperature
  • difficult to feel and handle small objects
  • periodic blanching attacks
  • vibration induced white finger - finger feel numb as blood circulation returns fingers can be throbbing and red & painful
  • joint pain
  • carpel tunnel syndrome (compression of the nerves in the wrist)
  • stiffness in hand & arm

those affected often have to give up outside activities

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14
Q

explain the meaning of whole body vibration and what work activties are exposed

A

is the shaking, jolting or vibration of the body which is transmitted to the worker through seated, standing or supporting surfaces

typical work activities - drivers of heavy vehicles / forklift trucks / operators of heavy machinery

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15
Q

what are the standardised test for HAVS

A
  • stockholm workshop scale
    - Vascular (blood flow) test
    - sensorineural tests (assessing nerve damage)
  • griffin method - blood flow - blanching of each part of the finger is given a score
16
Q

how do you measure vibration exposur

A
  • using a accelerometer or vibration meter ( which takes 3 readings form electronic sensors)
  • the device is attached to the handle, surface or workpiece which is in contact with the worker
  • magnitude of vibration is calculated using vibration calculators such as the UK HSE ready reckoner HAV tool - which works on a points based system
17
Q

what are the control measures for vibration exposure (hierarchy of control)

A
  • automation - elimination
  • change the work method
  • equipment selection and purchasing policy - low vibration or anti vibration features
  • care and maintainance
  • job rotation
  • information, instruction & training
  • PPE
18
Q

What is an octave band analyser and how does it work

A
  • integrating sound level meter
  • important for the analysis of sound when choosing ear protection and designing noise abatement controls.
  • can give the noise contributions at various frequency bands across the human hearing spectrum
19
Q

What is a dosimeter and how is it used

A
  • intergratng sound level meter
  • measures personal noise exposure over a working day
  • worn by the worker
  • data can be downloaded wirelessly
  • often small and does not display a readout to the user. using for assessing the noise level where the worker moves around or the noise level fluctuates