HEAT STRESS PREVENTION – A CASE STUDY | Dr. Divyang Shah, – Occupational Health & Medical Services

Technical Session # (Include session no.)Topic : (Include topic name)

HEAT STRESS

PREVENTION – A CASE

STUDY

Dr. Divyang Shah

MD (PSM), DIH

Deputy General Manager – Occupational Health & Medical Services,

Alan Shreeve

Head - ConstructionCairn India Ltd.


Agenda

What is heat stress

Problem statement

Intervention Strategy


Heat Storage =Metabolism ± Radiation ± Conduction ± Convection - Evaporation

Heat Stress is the burden or load of heat that must be dissipated if the body is to remain in thermal equilibrium.

What is heat stress?


Causal Factors

Personal Risk Factors-

• Age- 40 or more• Weight (BMI > 35)• Poor Physical fitness• Lack of Acclimatization• Alcohol & medication• Hypertension/ Heart

disease• Previous heat related

illness

Environmental Factors-

• Ambient air temperature• Radiant heat• Air movement• Relative humidity

Job factors-• Types of clothing's/ PPEs• Work load


Effect on Body Due To Increase of Core Temp.

Exposure to hot environment

Body temperature rises

To get rid of excess heat heart rate increases

Blood flow to skin increases which carried away the excess heat from vital organs to skin

Body sweats

Evaporation of sweat

Results in decrease in body temp


Effects of Heat Stress

HEAT CRAMPS


Rajasthan, situated in the western part of India is known for the largest desert in Indian subcontinent. The largest discovery of oil in Indian soil was made in 2006.


Problem Statement

The death toll is expected to rise with experts forecasting temperatures approaching 50 oC (122 oF) in coming months. More than 100 people are reported to have died in the state of Gujarat where the mercury topped at 48.5 oC last week. At least 90 died in Maharashtra, 35 in Rajasthan and 34 in Bihar.


Problem Statement

• 2009-10 The peak of construction activities

• More than 18000 workforce were involved in construction and commissioning activities

• The temperature in this area usually reaches up to 480C (1200F) in summer,

• Being a mega construction project, all personnel were pressed against tight project execution schedule.

Jan/

04

May

/04

Sep/0

4

Jan/

05

May

/05

Sep/0

5

Jan/

06

May

/06

Sep/0

6

Jan/

07

May

/07

Sep/0

7

Jan/

08

May

/08

Sep/0

8

Jan/

09

May

/09

Sep/0

9

Jan/

1020

25

30

35

40

45

50Maximum Temperature over last 6 years

Average Max.

Highest

Tem

p o

C


Major Activities

Work at Height

Excavation

Manual Material Handling

Civil / Earthen work

Travel


INTERVENTIONS


Management commitment

Rahul Dhir, CEO & MDElango P, Interim CEOExecutive Directors


Heat Stress Prevention Guidelines

Table of ContentsDOCUMENT CHANGE HISTORY

2TABLE OF CONTENTS

21. PURPOSE

32. SCOPE

33. DEFINITIONS

34. RECOGNIZE THE HEAT STRESS HAZARD IN TERMS OF BODY TEMPERATURE:

45. EVALUATION:

56. CONTROL:

67. ACCLIMATISATION

88. MONITORING REGIME

89. TRAINING AND SUPPORT

910. RESPONSIBILITIES

911. REFERENCES

10APPENDIX–A FITNESS FOR WORK IN HEAT STRESS ENVIRONMENT 11APPENDIX-B HEAT STRESS INDICES

12APPENDIX-C FLAG SIGNS AND RECOMMENDED ACTIONS

14APPENDIX-D WBGT AND RECOMMENDED WORK REST REGIME 16APPENDIX–E SELF EVALUATION

17APPENDIX-F GUIDELINES FOR ACCLIMATISATION AND RE-ACCLIMATISATION

18APPENDIX-G EFFECTS OF HEAT STRESS

19


Cairn India HSS 12 April 2023

Control of Heat Stress

Acclimatization

Fluid Replacement

Engineering Controls

Work Practices

Administrative Controls

PPEs


Cairn India HSS 12 April 2023

Acclimatisation

Activity (Percentage of full work assignment)

Day Experienced Worker New Worker

1st 50% 20%

2nd 60% 40%

3rd 80% 60%

4th 100% 80%

5th 100% 100%


Awareness campaign

Self EvaluationUrine Colour

Interpretation and remedyExtremely Dehydrated

Drink water immediately

Mildly Dehydrated

Drink More Water

Not dehydrated

Drink water regularly


Heat index chart

Relative Humidity in %

100% 95%

90%

85%

80%

75%

70%

65%

60%

55%

50%

45%

40%

35%

30%

25%

20%

15% 10%

Air Temp (in OC)

49 50 49

48 49 48

47 50 47 47

46 49 46 46

45 50 47 45 45

44 49 46 43 44

43 49 47 45 42 43

42 50 48 46 43 41 42

41 48 46 44 42 40 41

40 49 47 45 43 41 39 40

39 49 47 45 43 41 40 37 39

38 49 47 45 43 42 40 39 36 38

37 49 47 45 44 42 40 38 37 35 37

36 50 49 47 45 43 42 40 39 37 36 34 36

35 50 48 47 45 43 42 40 39 37 36 35 33 35

34 49 48 46 45 43 42 40 39 37 36 34 34 31 34

33 50 48 47 46 44 43 41 40 38 37 36 34 33 33 30 33

32 50 49 48 46 45 44 42 41 40 38 37 35 34 33 32 30 29 32

31 50 49 48 47 45 44 43 42 40 39 38 37 35 34 33 32 30 29 28 31

30 48 47 46 44 43 42 41 40 39 37 36 35 33 32 31 30 29 28 27 30

29 46 45 43 42 41 40 39 38 37 36 35 33 32 31 30 29 28 27 26 29

28 43 42 41 40 39 38 37 36 35 34 33 32 30 30 29 28 27 26 25 28

27 41 40 39 38 37 36 35 34 33 32 31 30 29 28 28 26 25 27

26 39 38 37 36 35 34 33 33 32 31 30 29 27 27 26 25 26

25 37 36 35 34 33 33 32 31 30 29 28 27 26 26 25 25

24 35 34 33 33 32 31 30 29 28 28 27 26 25 24

23 33 32 31 31 30 29 28 28 27 26 25 23

22 31 30 30 29 28 27 27 26 25 25 22

21 29 29 28 27 26 26 25 21

100% 95%

90%

85%

80%

75%

70%

65%

60%

55%

50%

45%

40%

35%

30%

25%

20%

15% 10%

Old chartLimitation: Requires WBGT meter, in absence of which interpretation in incorrect

New chartAdvantage: Based on recent research and publication, does not require special equipment, interpretation is based on air temperature and relative humidity only.


Flag signsDanger

Category/ Flag

Colour

WBGT Index

Humidex (Based on temp. and humidity)

Heat related Health Risk

Water Requirement(1 cup = ½

litre)

Work: Rest

Period(Minute

s)

Controls

Humidex -1Moderate physical

Work, unacclimatised worker,

OR Heavy physical work, acclimatised worker

Humidex -2Moderate physical work, acclimatised

worker,OR

Light physical work, unacclimatised

worker

IV. Extreme Danger

≥40 ≥46 ≥50 Heat stroke or sunstroke imminent

1 cup every 10 minutes

- A. For drilling & well services activity*: Work rest regime of 20:10 minutes, worker must be acclimatizedB. For other Activities and Operations: Work inside the buildings and under well ventilated shed/ shade areas. No work at elevation or where exposed to direct sun

III. Danger 34-39 38-45 43-49 Sunstroke, Heat Exhaustion or Heat cramps likely. Heat Stroke possible with prolonged exposure and physical activity


30:10 Work under shade, Elevated work stopped

II. Extreme Caution

28-33 30-37 36-42 Heat stroke, Heat Exhaustion or Heat cramps possible with prolonged exposure and physical activity


45:15 No working alone, Self-pace

I. Caution 22-27 Up to 29 Up to 35 Fatigue possible with prolonged exposure and physical activity.


Continuous

work

Continuous visual monitoring of workers in direct sun and heavy work

*There are certain jobs (like preparing casings, cleaning, housekeeping etc) which can be planned during other than “Red Flag” period. Rest periods do not necessarily mean that the workers are on break; these can be productive times. During the rest periods, workers may continue to perform mild or light work, such as completing paperwork, sorting small parts, attending a meeting, or receiving training (e.g., instructions for upcoming work, a time out for safety or a tailgate safety talk).



•Heat Stress induction training

•Frequent workshops and road shows for workforce

•>700 earthen pots at worksite

•All workforce provided with insulated water bottle before entering the

site

•Rest shelters

•Hourly monitoring and broadcasting of heat index

•Flag signs at work locations

to ensure continuous focus


Success: Zero Incident of Heat Related Illness throughout the Project Period

Prime Minister of India with First oil from the facility

Business

HEAT STRESS PREVENTION – A CASE STUDY | Dr. Divyang Shah, – Occupational Health & Medical Services