Physical Hazards Flashcards
Dosemeter
Personal Sound Level Meter to measure noise.
Used when worker is highly mobile
Place microphone on shoulder and side of head
Whole Body Vibration
In construction, agriculture and land transport
Risk of LBP, sciatica
EAV 0.5m/s (action needed)
ELV 1.15 m/s (limit)
Hand Vibration
EAV - 2.5m/s daily amount at which controls should be in place with regular health surveillance.
ELV - 5m/s max exposure in any given day
Lighting
Too much illuminance can lead to glare
Too little illuminance can lead to eye strain
Photo Retinitis
Photochemical damage from exposure for more than 10s.
Blue light hazard
Photokeratitis
Tender eye condition following exposure to UV rays without protection
Luminous intensity
Luminous flux emitted per solid angle
Candela (Cd)
Illuminance
Symbol E
Amount of light falling on a surface divided by the area over which it is falling. Measured in lux (lumens/sq meter)
Measured with light meter
Luminance
Symbol L Amount of light reflected from a surface Cd/m2 Measured with luminance meter Considered the human perception of brightness
Light meter
Measures illuminance
Reflectance
Ratio of light falling on a surface to light reflected from the surface as a %
Measured with reflectometer
Reflectometer
Measures reflectance
Luminance Equation
Luminance = Illuminance x Reflectance/Pie (candela/m2) = lux x %/ Pie
Luminance meter
Measures luminance which is the amount of light reflected from a surface
Parameters for heat stress
- air temperature
- air velocity
- radiant temperature
- relative humidity
Dry Bulb Thermometers
Measure air temperature
AKA - Electric thermometers
Wet Bulb Thermometer
Dry bulb covered in a clean cotton wick wetted with distilled water
Psychrometers
Wet and dry bulb thermometer mounted in a frame
Used determine relative humidity
2 types sling and aspirated
Globe Thermometer
Used to measure radiant temperature (mercury in glas thermometer with bulb in the centre of a matt black sphere.
Kata Thermometer
Used to measure air velocities less than 0.5m/s
Personal Heat Stress Monitors
Signals from various sensors including heart rate, temperature. Can have an alarm
Static Instruments
Provide a signal for wet bulb globe temperatures and
air velocities
WBGT
Wet Bulb Globe Temperature
Most widely accepted index for assessment of heat
WBGT Indoor Use
WBGT = 0.7 WB + 0.3 GT
WB is natural wet bulb temp, GT is globe temp
WBGT Outdoor Use
WBGT = 0.7 WB + 0.2 GT + 0.1DB
WB is natural wet bulb temp, GT is globe temp and DB is dry bulb temp
Acclimatization
Full heat acclimatization requires 3 weeks of physical activity under the heat stress conditions.
Ability of body to sweat increases, sweat increases, salt content in sweat decreases.
Risk Control to reduce heat strain
Planning of work - eg maintenance work
Modifying the environment - reduce process heat, improve ventilation, evaporative cooling
Worker - medical pre selection, acclimitization, report sx
Managerial - Monitor heat stress conditions, work rest, training, appropriate controls
Protective Clothing - ice cooled jackets
Climate factors for Cold Stress
Air temperature
Air velocity
Risk Control for cold Temperatures
Below 16 for sedentary
4C for light
-7C for moderate work
Total body protection
If work performed in a temp of 4 or less
PMV
Predicted Mean Vote
7 point scale for assessment of thermal comfort
PPD
Predicted percentage dissatisfied
Percentage of thermally dissatisfied people who feel too hot or too cool. Calculated from PMV
Peak Sound Noise
Lower EAV - 80 db, 135 db
Upper EAV - 85 db, 137 db
ELV - 87 db, 140 db
HACCP
Hazard Analysis and Critical Control Points
System for food hygiene with the aim of identifying hazards and placing controls to minimise risks.
Cold Stress HSE Guidance
HSE does not issue specific requirements.
Suggests:
Appropriate PPE
Provide mobile warm facilities and encourage hot drinks
More frequent rest breaks
Educate workers on early signs of cold stress
Hygrometer
Measures humidity and water vapour
Minimum Lighting Requirements
- Level of illumination - depends on work being done, speed and age of person
- Appropriate illumination ratios - difference between brightness in 2 places
- Glare exclusion zone
Accelerometer
Instrument used to measure arm vibration.
Disability Glare
Individual disabled from carrying out given visual task
Discomfort Glare
Not disabled but experience discomfort
Veiling Reflection
Incident light that partially or totally obscures the details to be seen on a surface by reducing the contrast.
Hard to read text on DSE as reflections obscure it.
