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Feeling the Heat – Managing Risks from Heat Stress at Work Mike Slater (President Elect)
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Transcript of Feeling the heat for slideshare
Feeling the Heat – Managing
Risks from Heat Stress at Work
Mike Slater (President Elect)
Human beings create heat
100 Watts 200 Watts 800 Watts
100 Watts 200 Watts 800 Watts
The more physically demanding our activity, the more heat we’re producing
We have to lose heat to the environment – but not too much
But we can gain heat from to the environment too
Radiation Convection
Radiation Convection
Evaporation
Heat stroke
Heat exhaustion
Heat syncope
Heat cramps
Prickly heat
Heat stroke
Heat exhaustion
Heat syncope
Heat cramps
Prickly heat
Source: WHO
Heat stroke
Heat exhaustion
Heat syncope
Heat cramps
Prickly heat
Radiation Convection
Evaporation
Air temperature
Mean radiant temperature
Humidity Air velocity
These are the environmentl factors we have to consider when assessing the risk of heat stress
Air temperature
Mean radiant temperature
Humidity Air velocity
Clothing
Metabolic rate
Air temperature
Mean radiant temperature
Humidity Air velocity
Clothing
Metabolic rate
Acclimatisation
And there are other factors we need to consider
Air Temperature
Standard thermometer
Humidity
Radiant heat
Globe thermometer
Air Velocity
Metabolic rate
1 Met = 58 Wm-2
Clothing
1 Clo = Insulation value of 0,155 m2 oC/W
Acclimatisation
YES ? OR NO?
Heat stress
index
Air temp.
Mean radiant temp.
Humidity
Air movement
Work rate
Clothing
Acclimn
Assess Risk using screening methods
WBGT Index
Expert analysis PHS Index
Expert analysis Physiological measures
Identify Hazards
Identify Controls
A Structured Approach to Heat Stress Risk Assessment
Assess Risk using screening methods
WBGT Index
Expert analysis PHS Index
Expert analysis Physiological measures
Identify Hazards
Identify Controls
A Structured Approach to Heat Stress Risk Assessment
Assess Risk using screening methods
WBGT Index
Expert analysis PHS Index
Expert analysis Physiological measures
Identify Hazards
Identify Controls
A Structured Approach to Heat Stress Risk Assessment
Screening methods
Talking to people
Observations
Checklists
This looks complicated, but we can probably identify the risk factors fairly easily
Assess Risk using screening methods
WBGT Index
Expert analysis PHS Index
Expert analysis Physiological measures
Identify Hazards
Identify Controls
A Structured Approach to Heat Stress Risk Assessment
WBGT Index
Indoors WBGT = 0.7 tnwb + 0.3 tg
Outdoors WBGT = 0.7 tnwb + 0.2 tg + 0.1 ta
ACGIH TLVs for Heat Stress
Allocation of work in work cycle
Workload
Light Moderate Heavy V ery heavy
75% to 100% 31.0 28.0 - -
50% to 75% 31.0 29.0 27.5 -
25% to 50% 32.0 30.0 29.0 28.0
0 to 25% 32.5 31.5 30.5 30.0
Assess Risk using screening methods
WBGT Index
Expert analysis PHS Index
Expert analysis Physiological measures
Identify Hazards
Identify Controls
A Structured Approach to Heat Stress Risk Assessment
Assess Risk using screening methods
WBGT Index
Expert analysis PHS Index
Expert analysis Physiological measures
Identify Hazards
Identify Controls
A Structured Approach to Heat Stress Risk Assessment
Physiological assessment
Temperature Heart rate
Source: OHTA.
Miner’s Core Temperature & Heart Rate
The risks here are more complex – an expert evaluation is likely to be needed
Assess Risk using screening methods
WBGT Index
Expert analysis PHS Index
Expert analysis Physiological measures
Identify Hazards
Identify Controls
A Structured Approach to Heat Stress Risk Assessment
Hierarchy of Control
Prevention
Engineering
Working Practices
Personal Protection
Hierarchy of Control
Prevention
Engineering
Working Practices
Personal Protection
Let’s look at some examples of typical
controls
www.lubisol.com
Insulation of hot surfaces to reduce radiant and convective heat
Extracting hot air
http://mikegigi.com
Blowing in cool air
Providing protective clothing
Regular drinks of water
Management Measures
Screening & health surveillance
Information, instruction, training
Supervision
Self regulation
Provide water
Hierarchy of Control
Prevention
Engineering
Working Practices
Personal Protection
Supervision
Maintenance
Auditing
Water
Health surveillance
Monitoring
Information
Training
Further Information
http://www.hse.gov.uk/temperature/thermal/index.htm
http://www.bohs.org/resources/res.aspx/Resource/filename/840/TG12.pdf http://www.bohs.org/resources/res.aspx/Resource/filename/1473/04_TG12_Addendum_to_2nd_Edition.pdf
[email protected] www.bohs.org Twitter: @bohsworld www.slideshare.net/mikeslater
