Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Unit B > B6 Ollie > Flashcards

B6 Ollie Flashcards

1
Q

Noise

A

Noise at WorkRegulations 2005:
Any audible sound
Oxford English Dictionary:
A sound, especially one that is loud or unpleasant or that causes disturbance
Sound:
Vibrations or pressure changes passing through a medium, usually air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Sound

A

Amlitude- Strength in which sound travels
Frequency - Number of wave fronts hitting the ear drum

Time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Sound Intensity and Decibels

A

Intensity is sound power per unit area
A measure of the flow of sound energy - units W/m2 Lowest value detected by human ear is 10-12 W/m2 Highest likely to be encountered is 1 W/m2
Very large range so Decibel (dB) used for convenience Logarithmic scale
Usually express ed as sound pressure level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Decibel Scale

A

Threshold of pain -
130 Noisy factory - 90 Busy traffic - 70

Normal conversation -60 Soft whisper - 20
Threshold of hearing - 0

Logarithmic scale, so increase of 3 dB means doubling of sound intensity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Adding Decibels

A

If adding similar values , add 3dB
e.g. 90dB + 90 dB = 93dB
If adding dissimilar values , use graph or table

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Frequency

A

Pitch of note
Sounds us ally a mixture of frequencies
Human hearing range given as 20Hz to 20KHz
Frequencies often divided into octave bands ,
represented by central value
Frequency important in control, and selection of hearing defenders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Frequency-Octave bands

A

Graph- dB vertical and Hertz (Hz) Horizontal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

A-Weighting

A

Tones of the same pressure level do not sound equally loud to the ear, nor do they have the same potential for causing hearing loss
High frequencies sound louder and are more likely to cause damage
Low frequencies sound quieter and are less likely to cause damage
A- weighting compensates for this difference After A-weighting is adopted - dB(A)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

C-Weighting

A

A-weighting is not appropriate at high noise levels
Ear becomes better at hearing high/low frequencies Almost linear response
Used for peak values -dB(C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Noise Dose

A

Noise measurements usually averaged over a time period
Known as Leq:
L can be any length of time
Control of Noise at Work Regulations refer to Daily noise exposure:
Averaged over 8 hour period
Known as daily noise exposure or LEP,d
Also make reference to peak values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Mechanism of Hearing

A

Vibrations directed by pinna into auditory canal
Eardrum vibrates
Vibrations carried across middle ear by ossicles to cochlea
Vibrations pass through fluid in cochlea in inner ear Detected by sensory hairs (stereocilia)
Conveyed to brain by auditory nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Noise-AdverseHealth Effects

A

Nuisance and stress
Tinnitus
Noise induced hearing loss (NIHL)
Temporary threshold shift - reversible damage (auditory fatigue)
Permanent threshold shift - failure of her cells to
respond to frequencies
Acoustic trauma
TTS & PTS (NIHL) generally occurs in the 4000hz octave band- 4K dip

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Acoustic Shock

A

Sudden, unexpected loud sound through headset May be below Action Values
No loss of hearing

Symptoms:
Early: tinnitus , dizziness , nausea
Intermediate: headaches , fatigue, anxiety
Late: hypersensitivity, anxiety returning to telephone work

Controls:
Protection devices
Reduce background noise
Prompt repair of equipment
Manual control of voice levels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Audiometry - Basic Principles

A

Routine health surveillance
Health surveillance required if risk assessment identifies risk to health
Guidance suggests this is regular exposure above upper exposure action value
Shall include test of hearing –audiometry
Used as base line assessment
Also implications in Civil Law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Audiometry - Method

A

Details given in s tandard (EN26189:1991)
Quiet environment
No significant noise for 16 hours previously
Pure tones played - subject presses button if heard Software produces graph (audiogram)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Audiometry - Action to be Taken

A

Category& Action
1: Acceptable:
No action required

2: Mild hearing impairment:
Formal notification
Reinforcement of training and importance of controls Good practice to issue copy of audiogram

3:Poor hearing:
Referral to medical practitioner

4: Rapid hearing loss
Referral to medical practitioner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Control of Noise at Work Regulations (CNWR)2005-Regulation 4 & 5

A

Reg.4:
Exposure action values and exposure limit values

Reg.5:
Assessment to be carried out where exposure likely to reach lower exposure action value (80 dB(A))

To cover:
Level, type, duration of exposure
Manufacturers information
Availability of alternative equipment 
Results of health surveillance 
Availability of PPE
Recorded and reviewed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

CNWR -Action Values

A

Lower Exposure Action Value - 80 dB ( A )
LEP,d / Peak 135 dB ( C ) :

Make PPE available
Provide information and training Assessment Upper Exposure Action Value -85dB(A)
LEP,d/Peak137 dB(C):

Reduce ALARP by means other than PPE
Hearing Protection Zones
Health surveillance (audiometry)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

CNWR - Limit Values

A

Upper Exposure Limit Value - 87 dB ( A ) LEP , d / Peak 140 dB ( C ) :
Not to be exceeded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

CNWR - Limit Values Exceeded

A

Exposure is not permitted above exposure limit value (87dB(A))

If exposure does occur, employer must reduce
exposure to noise to below the exposure limit value
Identify the reason for that exposure limit value being exceeded

Modify the organisational and technical measures to prevent it being exceeded again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

CNWR -Regulation 7

A

Hearing protection:
To be made available at or above lower exposure action value
Must be worn above upper exposure action value (if cannot be controlled by other means )
Hearing Protection Zones:
Designated and signage displayed
Employer to maintain PPE and ensure use SFARP (Reg 8)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

CNWR -Regulation 9 & 10

A

Reg.9 -Health surveillance:
Where the risk assessment indicates that there is a risk to health Risk to health:
If there is regular exposure above the upper exposure action value
Must include a hearing test (audiometry)
If hearing damage is identified then the employer must refer the individual to a medical practitioner.
Reg. 10:
Employer to provide information, instruction and training where lower exposure action value is reached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

CNWR -Employees Duties

A

To comply with the employers arrangements for controlling noise

To use hearing protectors and noise control equipment

To take care of such equipment, and to report any defects (all Reg 8)

To co-operate with employer and attend hearing tests (Reg 9)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Noise Measurement - Basic Principles

A

Sound Level Meter:

Simple measures dB or dB(A) at a moment in time Integrating if measures Leq

Leq - equivalent continuous noise level

Need to measure A-weighted Leq (LAeq)

Need C-weighting for peak levels

Need to be calibrated each time they are used

25
Noise Measurement-Classes of Device
Lower the class of SLM, higher the quality Class 0-Research Clas s 1 - Laboratory/Field Class 2 -General Field Class 3-Non integrating Calibrators also different classes Selection depends on objectives of survey Increasing accuracy and response from Class 3 toClass 0 Class 1 or 2 for occupational safety measurements
26
Noise Measurement - Personal Dose Meters & Frequency Analysers
Personal dose meters: Worn by person exposed in hearing zone Measures actual dose for referenced time period Frequency analysers: Measure sound pressure levels at particular frequencies Required for accurate assessment of hearing defenders Combination of above and accessories e.g. storage of data, print outs , software
27
Work place Noise Survey
Planning: Objectives and scope ``` Information sources: Previous assessments Employees Manufacturers information Complaints Selection of measuring equipment including calibrators Battery check Number of employees exposed/duration Areas to be surveyed Recording of data Route Safety issues/risk assessment ```
28
The Ready Reckoner - Estimate (L108)
Estimate of noise exposure: Try this : 1) 30mins spent working on a grinding machine - manufacturers info says 95dB 2) 3hours working in yard with vehicles - check suggests 85dB 3)1.5hours in office-check suggests 80dB 4 ) 2 hours back in yard at 85d B
29
Estimating LEPd - Static Measurements
Static measurements taken at operating positions at each machine Static measurements taken during normal operation Sound measured as LAeq Use integrating SLM Note the time operator spends at each machine Calculate using points system/HSE s preadsheet Assess or assume insignificant exposure during breaks
30
Noise Propagation
Walls-Screens--steel Cladding
31
Effect of Distance - Inverse Square Law
Inverse square law: Refers to decrease in noise energy (and other energy forms ) as it moves away from a point source Energy/intensity is proportional to 1/d2* (d = dis tance) At 1 unit distance = 1/1 2* = 1 At 2 units distance=1/22*=1/4 At 3 units distance=1/32*=1/9 Note: 2*denotes squared
32
Effect of Distance - Doubling Distance
Doubling of distance means a reduction of noise of 6 dB
33
Controlling Noise-General Principles
Eliminate at source, or control so far as is reasonably practicable at source (e.g. by relocation, redesign and maintenance) Control along the transmission path (e.g. by using isolation, barriers and enclosures) Control exposure at the receiver (e.g. by enclosures , acoustic havens , hearing protection zones and PPE, limiting exposure time, audiometry)
34
Controlling Noise-Methods (1)
Engineering controls Selection of equipment (presses instead of hammers ) Location of pipe-work and ducting Reduce operation speeds Distance/orientation Maintenance (balancing, sharpening, tightening)
35
Controlling Noise-Methods (2)
Enclosure (noise enclosures ) Isolation(noise havens,springs to absorb energy) Silencers (air movements /absorptive reactive) Lagging Damping (pads,stiffening) Screens Absorption PPE
36
Acoustic Enclosure - Design (1)
``` Keeps noise in Heavy outer wall (plasterboard and brickwork) Inner lining of acoustically absorbent material Absorbent covered in protective mesh Flexible pipes to form vibration breaks Services in through ground Inspection door double/triple glazed Access panels for maintenance ```
37
Acoustic Enclosure - Design (2)
``` Access doors air tight Any joints to outside sealed Motors on dampers Machines covered in enclosures Avoid contact between equipment and walls Sound absorbent material on floors Silencers on any ventilation exits Self-closing doors Exterior controls ```
38
Acoustic Haven
``` Keep noise out Air conditioned/lighting/thermal comfort/works stations Viewing windows Emergency response (fire alarms etc) Above workplace for better view External surface reflective Internal acoustic absorbent Internal walls cleanable Isolated from floor and ceiling Double/triple glazed Air supply through lagged pipework ```
39
Hearing Protection - Basics Principles (1)
``` Selection is critical Matched to noise characteristics Will only be effective when used Types and specifications: Ear defenders Semi-inserts Earplugs Active hearing protection ```
40
Hearing Protection - Basics Principles (2)
Mean attenuation values at frequency bands 63-8000 Hz Subjective tes t - 16 test subjects Standard deviation values for each (+/-84%) Assumed protection values at each frequency ( = mean – one standard deviation) HML (high, medium, low) values SNR (single number rating)
41
Hearing Protection - Selection
Use HML (apply formula) Use SNR Octave band frequency
42
Hearing Protection - Single Number Rating (SNR)
Simple guide to hearing protection required: Noise Level dB(A)&SNR Required 85-90-20or less 90-95- 20-30 95-100 - 25-35 100-105- 30 or more
43
Vibration - Basic Principles
Oscillating movement of a fixed point due to applied energy
44
Vibration - Basic Terms
Displacement (amplitude) – maximum distance moved from the point of oscillation Frequency – number of complete oscillations per second (Hertz ) Velocity – speed of the oscillating object at a fixed point in time (m/s ) Acceleration – maximum rate of increase in s peed (m/s 2 ) Magnitude – Vibration at Work Regulations 2005= acceleration
45
Measurement of Vibration
Accelerometer Average (root-mean-s quare) of acceleration in three planes Weighting given to most harmful frequencies (8-20Hz) Expressed as A(8)-daily exposure
46
Hand Arm Vibration Syndrome (HAVS)
Impaired circulation to fingers - blanching (white finger) Numbness in fingers , reduced sensitivity, tingling Loss of dexterity Loss of grip strength Pain (especially in cold weather) Infection/gangrene Carpal Tunnel Syndrome and associated symptoms
47
Whole Body Vibration
``` Range of health effects Back pain Nausea Gastrointestinal upsets General feeling of discomfort, including headaches Loss of equilibrium (balance) Abdominal pain ```
48
Factors Contributing to Risk
``` Damage depends on: Vibration magnitude Vibration frequency Duration of exposure Individual susceptibility (diabetics /smokers more at risk) External temperature Tightness of grip ```
49
Control of Vibration at Work Regulations (CVWR) 2005- EAVs & ELVs
Exposure limit values and exposure action values : Hand-armvibration: EAV 2.5ms -2 A(8) ELV 5.0 ms -2 A(8) Whole body vibration: EAV 0.5ms -2 A(8) ELV 1.15ms -2 A(8) A(8) vibration dose averaged over an 8-hour shift
50
CVWR - ELV
Must not be exceeded If exceeded then: Reduce exposure to vibration to below the limit value Identify the reason for that limit being exceeded Modify the measures taken to ensure it does not happen again
51
CVWR - ELV
Provide appropriate health surveillance (Regulation 7) Provide adequate information, instruction and training (Regulation 8).
52
CVWR -Risk Assessment
Reg 5: Risk assessment required if employees are exposed to risk due to vibration Assessmentto consider: The frequency and magnitude of vibration The health effects of exposure to vibration Any information provided by the manufacturers of work equipment The availability of replacement equipment designed to reduce exposure to vibration Specific working conditions such as low temperatures appropriate information obtained from health surveillance
53
Estimating Daily Exposure
Graph | Points system
54
Hand Arm Vibration - Controls
``` Automation Change of work method Modify/use alternative equipment Purchasing policy Maintenance Monitor exposure and enforce limits Job rotation Instruction and training Health surveillance PPE - gloves to keep hands warm Warm temperatures ```
55
Hand Arm Vibration - Health Surveillance
Tier 1 - A short questionnaire used for new workers Tier 2 - A short questionnaire for employees already exposed Tier 3 - This involves a HAVS health assessment by a qualified person, if the assessments hows that the employee has HAVS, Tier 4 will apply Tier 4 - Formal diagnosis by occupational health physician Tier 5 - Optional: referral for further tests
56
Hand Arm Vibration - Tier 3/4 Assessment
``` Grip strength Muscular dexterity Vascular Finger rewarming after cold provocation Finger systolic blood pressure Sensorineural Vibrotactile perception threshold Thermal perception threshold ```
57
Hand Arm Vibration - Stockholm Workshop Scales | (Sensorineural)
Stage -Description: 0 SN - Vibration exposed & no symptoms 1 SN - Intermittent numbness with or without tingling 2 SN - Intermittent or persistent numbness , reduced sensory perception 3 SN - Intermittent or persistent numbness , reduced tactile discrimination and/or manipulative dexterity
58
Hand Arm Vibration - Stockholm Works hop Scales | (Vascular)
Stage -Grade -Description: 0 - No grade - No attacks 1V - Mild - Occasional attacks affecting tips of one or more fingers 2V-Moderate-Occasional attacks affecting distal and middle(rarely also proximal) phalanges of one or more fingers 3V - Severe - Frequent attacks affecting all phalanges of most fingers 4V-Very severe-As in stage 3 with trophic skin changes in the fingertips
59
Whole Body Vibration - Controls
As for HAVS e.g. maintenance/automation etc Specific examples: Drive vehicles more slowly Ergonomic design of vehicle cabs Mount seats on springs or compression pads / provide cushions Provide rubber mats for standing tasks

Unit B (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions