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Which is worse for heat stress?
Condition B
29°C Temp
75% RH
0.2 m/s Wind
Based on TWL
Condition A
44°C Temp
25% RH
5 m/s Wind
How hot is too hot?
• In 1947 E. Schickele plotted 157 heatstroke deaths in military training camps against temperature and humidity
• Identified the ‘heat death line’
• Air temperatures ranging from 26 to 49◦C and relative humidities of 10 to 100%
• She commented that ‘Death can occur at surprisingly low temperatures, provided the evaporative power of the air is sufficiently reduced’
Source: Environment and fatal heat stroke; an analysis of 157 cases occurring in the Army in the U.S. during World War II.
Safe
to work
NOT Safe
to work
HEAT STRESS CHALLENGE No. 1
HEAT STRESS CHALLENGE No. 1
THERE IS NO EASY SAFE/NOT SAFE WORK LIMIT
WeatherAir temperature, humidity, air
speed, radiant surfaces.
ClothingPPE
Work RateStrenuous work, when and how
often breaks scheduled.
The IndividualAcclimatisation, age, medical
conditions.
MAJOR FACTORS CONTRIBUTING TO HEAT STRESS
+ HIDDEN FACTORS
IsolationWorking alone and/or
remote locations.
CultureWorking without breaks, drinking
energy drinks & alcohol.
Monitoring & ControlsReactive controls, poor monitoring,
wrong choice of heat stress
variables / indices to monitor.
EducationLack of knowledge on signs of
heat stress & dehydration,
amount of water to drink.
HEAT STRESS CHALLENGE No. 1
HEAT STRESS CHALLENGE No. 2
HIDDEN FACTORS / INTERACTION EFFECTS
Isolation
Culture
Monitoring & Controls
Education
Working alone
and/or remote
locations.
Working without breaks,
drinking energy drinks &
alcohol.
Reactive controls, poor
monitoring, wrong choice
of heat stress variables /
indices to monitor.
Lack of knowledge on
signs of heat stress &
dehydration, amount of
water to drink.
HEAT STRESS CHALLENGE No. 2
UNDERSTANDING IMPACTS OF HEAT STRESS ON WORKERS
SYMPTOMS OF DEHYDRATION
Reaction time
Visual motor tracking
Coordination
Short term memory
Long term memory
Attention
SYMPTOMS OF HEAT
STRAIN
Heat rash
Heat oedema
Heat cramps
Heat syncope
Heat exhaustion
Heat stroke
Incre
asin
g s
eve
rity o
f sym
pto
ms
HEAT STRESS CHALLENGE No. 2
Ramsey et al (1983) Effects of workplace thermal comfort on safe work behavior.
Journal of safety Research, Vol. 14, pp. 105-114, 1983
HEAT STRESS CHALLENGE No. 3
Engineering
Administrative
PPE
Elimination / Substitution
Source: Di Corleto, R., Firth, I., & Mate, J. (2013). A Guide to Managing Heat Stress: Developed for Use in the Australian Environment. AIOH.
• Reschedule work
• Roofs / walls to use light reflective colours
• Structure design for good airflow
• Walls / roofs insulated
• Hot objects to be insulated
• Fans & chiller units installed
• Screens / barriers to shield heat source
• Relocate hot processes
• Ready access to cool palatable water
• Cool area for breaks
• Consider medical screening prior to work
• Use heat stress indices to assist in determining work-rest regimes
• Training / education of workers
• Self paced work encouraged
• Phase change vests
• Vortex tube air cooling
• Chose light coloured
materials to promote good air
flow across the skin
MITIGATION AND CONTROLS
HEAT STRESS CHALLENGE No. 3
HEAT STRESS CHALLENGE No. 4
LEAD TIME TO IMPLEMENT CONTROLS
• Mechanical aids to lower
metabolic workload
• Screens / barriers to shield
heat source
• Fans & chiller units installed
• Cool area for breaks
• Dehumidifying the air
• Roofs / walls to use light
reflective colours
• Structure design for good
airflow
• Walls / roofs insulated
• Hot objects to be insulated
• Relocate hot processes
• Training / education of
workers
LEAD TIME > 7 DAYS
• Reschedule work
• Use heat stress indices to
assist in determining work-
rest regimes
LEAD TIME > 1 DAY
• Self paced work
• Ready access to cool
palatable water
• Phase change vests
(if available)
• Vortex tube air cooling
(if available)
LEAD TIME:
IMMEDIATE
HEAT STRESS & STRAIN INSTRUMENTS TAKE DIRECT
MEASUREMENTS & GIVE NO LEAD TIME TO IMPLEMENT
CONTROLS
HEAT STRESS CHALLENGE No. 4
HEAT STRESS CHALLENGE No. 5
MEASUREMENT - TIME & RESOURCE
Measuring heat stress requires:
1. Technical instrumentation to measure meteorological variables.
2. A competent operator who can correctly use meteorological
instrumentation.
3. The working knowledge in order to interpret instrumentation
readings and use to be compliant with site heat stress
management procedures.
4. Only provide information on the environmental load and don’t
actually indicate personal heat accumulation status
5. Time and human resources are available every hazardous hour of
every hazardous day heat stress may pose a threat.
HEAT STRESS MEASUREMENTS TAKE TIME & MONEY
AND MAYBE OVERLOOKED
HEAT STRESS CHALLENGE No. 5
HEAT STRESS CHALLENGE No. 6
WEATHER FACTORS ARE CHANGING
Source: Bureau of Meteorology. http://www.bom.gov.au/climate/change/index.shtml#tabs=Tracker&tracker=timeseries
HEAT STRESS CHALLENGE No. 6
Weather
Work Rate
Culture
Isolation
Education
The Individual
Clothing Level 3
Monitoring
Level 2
Monitoring
Level 1
Monitoring
Va
rian
ce / a
bility
to c
ha
ng
e
Co
mp
lex
ity / re
qu
ired
res
ou
rce
Le
ad
time
to im
ple
me
nt
IMMEDIATE
• Self paced work encouraged
• Ready access to cool palatable water
• Electrolytes available where applicable
> 1 DAY
• Reschedule work
• Use heat stress indices to assist in
determining work-rest regimes
> 7 DAYS
• Mechanical aids to lower metabolic
workload
• Screens / barriers to shield heat source
• Fans & chiller units installed
• Cool area for breaks
• Dehumidifying the air
• Light reflective colours on roof / walls
• Structure design for good airflow
• Walls / roofs insulated
• Hot objects insulation
• Relocate hot processes
• Training / education of workers
• Phase change vests
• Vortex tube air cooling
• Light coloured material clothing
HEAT STRESS CHALLENGE No. 7
ADAPTING TO CHANGING FACTORS
CHANGING FACTORS MONITORING CONTROLS
HEAT STRESS CHALLENGE No. 7
Heat Management
1. Preparedness
Risk profiling and establishing triggers
2. Mitigation/Control Determine actions for your triggers and daily status
3. Daily monitoring
Monitoring your triggers and
determine your daily status
4. Alerts
Targeted alerts with predefined actions
5. Review
Post summer analysis to update
triggers
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Daily Targeted
Action
Develop a Heat Safe Plan
Status – Triggers – Actions
Be Prepared
Assess Risk Pre-Summer
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
A review should be conducted to assess the preparedness and adequacy of site infrastructure and management strategies prior to the summer season.
GOAL - identify at-risk jobs; determine the adequacy of current control measures; and prepare management plans to guide activities during the summer months.
SCOPE – Baseline risk profiling, identify controls required to mitigate risk and categorise lead time required to implement control, inventory and control implementation strategy, training
1. Pre-Summer Preparation
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Hazard 0 1 2 3 Value
Work Environment
Sun exposure Indoor Shade Part Shade No shade 2
Hot surfaces Neutral Warm on contact Hot on contact Burn on contact 1
Work setting Open area Air flow restricted
due to structures
Working in a pit or
hole
0
Distance from cool rest
area
< 10 m < 50 m 50 - 100 m > 100 m 1
Distance from drinking
water
Can drink freely < 30 m 30 - 50 m > 50 m 3
Confined spaces No Yes 0
Activity
Exposure Period <30 minutes 30- 60 minutes 1-2 hours > 2 hours 1
Task complexity Simple Moderate Complex 1
Climbing, up/down stairs
or ladders
None One level Two levels > two levels 1
Clothing and PPE
Clothing (permeable) Single Layer
(light)
Single Layer
(mod)
Multi Layer 1
Respiratory protection (-
ve pressure)
None Disposable half
face
Rubber half face Full face 0
Personal factors
Understanding of heat
strain risk
Training given No training given 0
Acclimatisaton Acclimatised Unacclimatised 3
Job risk factor 14
Example Basic Thermal Risk Assessment (Field work)
Level of activity could be low, moderate or high – assess all 3
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
0%
20%
40%
60%
80%
100%
All Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Moderate activity
0%
20%
40%
60%
80%
100%
All Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Heavy activity
Category Interpretation of risk
Low Risk of a heat related illness –
low to moderate
Moderate Potential for heat-induced illness
occurring if conditions are not
addressed.
High Onset of heat-induced illness is
very likely
0%
20%
40%
60%
80%
100%
All Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Light activity
Results of a risk
assessment for a
single job profile
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Site Wide Risk Profile
Job Profile All Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AdminField_Lte 26 33 29 26 25 25 25 25 25 25 25 26 29
AdminField_Mod 32 50 45 36 27 25 25 25 25 26 27 34 45
AdminField_Hvy 49 64 61 53 45 43 43 42 42 44 44 51 61
OpsField_Lte 26 33 29 26 25 25 25 25 25 25 25 26 29
OpsField_Mod 35 56 51 39 27 25 25 25 25 26 28 38 50
OpsField_Hvy 54 72 70 64 48 43 43 42 42 45 47 58 70
MaintField_Lte 27 36 31 26 25 25 25 25 25 25 25 26 30
MaintField_Mod 35 56 51 39 27 25 25 25 25 26 28 38 50
MaintField_Hvy 54 72 70 64 48 43 43 42 42 45 47 58 70
Pipeline_Lte 26 33 29 26 25 25 25 25 25 25 25 26 29
Pipeline_Mod 32 50 45 36 27 25 25 25 25 26 27 34 45
Pipeline_Hvy 49 64 61 53 45 43 43 42 42 44 44 51 61
LandEnv_Lte 27 36 31 26 25 25 25 25 25 25 25 26 30
LandEnv_Mod 35 56 51 39 27 25 25 25 25 26 28 38 50
LandEnv_Hvy 54 72 70 64 48 43 43 42 42 45 47 58 70
Wells_Lte 27 36 31 26 25 25 25 25 25 25 25 26 30
Wells_Mod 35 56 51 39 27 25 25 25 25 26 28 38 50
Wells_Hvy 54 72 70 64 48 43 43 42 42 45 47 58 70
Contract_Lte 27 36 31 26 25 25 25 25 25 25 25 26 30
Contract_Mod 48 62 58 50 44 43 43 42 42 44 43 49 58
Contract_Hvy 78 78 77 79 79 78 78 77 76 80 75 75 80
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Daily Targeted
Action
Develop a Heat Safe Plan
Status – Triggers – Actions
Be Prepared
Assess Risk Pre-Summer
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Engineering
Administrative
PPE
Elimination / Substitution
Source: Di Corleto, R., Firth, I., & Mate, J. (2013). A Guide to Managing Heat Stress: Developed for Use in the Australian Environment. AIOH.
• Reschedule work
• Roofs / walls to use light reflective colours
• Structure design for good airflow
• Walls / roofs insulated
• Hot objects to be insulated
• Fans & chiller units installed
• Screens / barriers to shield heat source
• Relocate hot processes
• Ready access to cool palatable water
• Cool area for breaks
• Consider medical screening prior to work
• Use heat stress indices to assist in determining work-rest regimes
• Training / education of workers
• Self paced work encouraged
• Phase change vests
• Vortex tube air cooling
• Chose light coloured
materials to promote good air
flow across the skin
2. Mitigation/Controls
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Status
Possible
Trigger
High or moderate risk event predicted 3-7 days
out
Actions
Review at risk profiles
Review inventory of controls
Ensure adequate staff available if monitoring is
required
Status
Imminent
Trigger
High or moderate risk event predicted for
tomorrow
Actions
Reschedule high risk jobs (if possible) or ensure
workers are acclimatised
Warning to at risk job profiles (be hydrated)
Ensure adequate controls and monitoring equipment
are available if needed
Status
Immediate
Trigger
High risk event forecast for TODAY
OR
Reported heat illness
Actions
Issue warnings to all jobs
Provide additional controls (if possible)
Hydration testing for high risk jobs
Direct monitoring for high risk jobs
Ensure all workers for high risk jobs are acclimatised, have adequate hydration
and can self pace
Status, Triggers and Actions
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
OUTPUT from
your Pre-Summer
Preparation
should be a plan
with defined
controls, and
actions for each
status level
Set up your
foundation. Plan
what actions you
may take based on
the daily status
Heat Safe Plan
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Daily Targeted
Action
Develop a Heat Safe Plan
Status – Triggers – Actions
Be Prepared
Assess Risk Pre-Summer
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Daily monitoring is required to manage heat stress as conditions change on a day-to-day basis due to changing weather conditions. The overall concept of daily monitoring is to determine your daily status, much in the same way a bush fire hazard is communicated to the community.
Status is a useful concept to help
communicate the current heat stress threat
to staff and help drive the implementation
of actions and allocation of resources,
particularly prior to an event.
3. Daily Monitoring
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Importance of communication
• Determine your daily status and then
disseminate the appropriate
information to others
• Simple target messages
• Clear actions for TODAY
Examples
• E-mail and or sms alerts
• Chart on a notice board
• Summary for tool box talk
All your hard work in
setting up your site
should be paying off!
Everyone should be
clear about what they
each need to do to
mitigate the risk of a
heat related illness
4. Alerts
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Daily Targeted
Action
Develop a Heat Safe Plan
Status – Triggers – Actions
Be Prepared
Assess Risk Pre-Summer
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
• Post Summer review
• Assess accidents/incidents
• Review risk assessments
• Rethink triggers
• Apply risk modifiers,if required –a way to address those hidden factors
5. Review
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Recap
1. There is no easy safe/not safe to work limit
2. Hidden factors to consider
3. Flow on effect to safety
4. Lead time to implement controls
5. Monitoring requires time and money
6. Need to adapt to a changing environment
7. Complexity of many changing factors
Systematic Heat Stress Management
• Use a risk based approach
• Review annually to update and account for hidden factors
• Use a forecast to be proactive and plan
• Use risk assessment to identify high risks and only monitor when required
• Setup action plan based on basic daily status to allow a targeted response
Heat Stress Challenges
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
1. Preparedness
Risk profiling and establishing triggers
2. Mitigation/Control Determine actions for your triggers and daily status
3. Daily monitoring
Monitoring your triggers and
determine your daily status
4. Alerts
Targeted alerts with predefined actions
5. Review
Post summer analysis to update
triggers
What can help you with
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK?
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK
Thank you
For more information visit:
Heat Manager.com.au
www.heatmanager.com.au
+61 7 3369 3699
Proudly brought to you by:
SYSTEMATIC MANAGEMENT OF HEAT STRESS RISK