Systematic Management of Heat Stress

Systematic Management

of Heat StressPresented by

Christine Killip

Managing Director Katestone

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


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.



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.


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 AND SAFETY


Ramsey et al (1983) Effects of workplace thermal comfort on safe work behavior.

Journal of safety Research, Vol. 14, pp. 105-114, 1983


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



LEAD TIME TO IMPLEMENT CONTROLS

• Mechanical aids to lower

metabolic workload

• Screens / barriers to shield

heat source



• Dehumidifying the air

• Roofs / walls to use light

reflective colours

• Structure design for good

airflow




• 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


(if available)


(if available)

LEAD TIME:

IMMEDIATE

HEAT STRESS & STRAIN INSTRUMENTS TAKE DIRECT

MEASUREMENTS & GIVE NO LEAD TIME TO IMPLEMENT

CONTROLS



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



WEATHER FACTORS ARE CHANGING

Source: Bureau of Meteorology. http://www.bom.gov.au/climate/change/index.shtml#tabs=Tracker&tracker=timeseries


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



• 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




• Dehumidifying the air

• Light reflective colours on roof / walls



• Hot objects insulation





• Light coloured material clothing


ADAPTING TO CHANGING FACTORS

CHANGING FACTORS MONITORING CONTROLS


SYSTEMATIC MANAGEMENT OF

HEAT STRESS RISK

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


Daily Targeted

Action

Develop a Heat Safe Plan

Status – Triggers – Actions

Be Prepared

Assess Risk Pre-Summer


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


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


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%


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%


Light activity

Results of a risk

assessment for a

single job profile


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


Daily Targeted

Action



Be Prepared



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









• Consider medical screening prior to work

• Use heat stress indices to assist in determining work-rest regimes





• Chose light coloured

materials to promote good air

flow across the skin

2. Mitigation/Controls


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


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


Daily Targeted

Action



Be Prepared



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


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


Daily Targeted

Action



Be Prepared



• 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


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


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?


Thank you

For more information visit:

Heat Manager.com.au

www.heatmanager.com.au

[email protected]

+61 7 3369 3699

Proudly brought to you by:


http://www.heatmanager.com.au/

mailto:[email protected]

Date post:	16-Jul-2015
Category:	Science
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Systematic Management of Heat Stress

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