Working in Hot Environments

8/4/2019 Working in Hot Environments

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Emergency Information

Company Emergency Phone Number

Poison Control Centre

Doctor

Ambulance

Fire

Police

Prepared by

Canadian Centre for Occupational Health and SafetyHamilton, Ontario, Canada

CCOHS, 2005


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First Edition

Working in HotEnvironments: A Health

and Safety Guide

Published 2005

P05-1EISBN 0-660-19453-8

DSS Catalogue Number CC273-2/05-1E

Canada: $10.00 (+ GST)

US/Others: $10.00 (USD)(Prices subject to change without notice)


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Personal Information

This handbook belongs to:

Name

Company

Position

Address

Telephone

Doctor

Telephone

Allergies

Medical Conditions

In case of emergency please notify:

Name

Relation

Address

Telephone


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Working in Hot Environments: A Healthand Safety Guide

Objectives

The guide will help health and safety committeemembers and representatives as well as supervisors,managers, engineers and other health and safetyprofessionals to:

1. Conduct hazard assessment of heat exposure inthe workplace.

2. Identify risk factors for work in hot environments.

3. Develop prevention programs and practices toreduce injury and illness.

4. Plan problem-solving actions through employeeand management involvement.

5. Develop hazard controls based on the mostcurrent knowledge in the field of occupationalhealth and safety.

6. Comply with legal requirements.

Scope

The guide provides:

Practical guidance for the identification, assess-ment and control of the health and safety hazardsrelated to working in hot environments; and

Applicable legislation, standards and guidelines

addressing heat stress.

Detailed information on specific workplace hazardscan be obtained from the Inquiries Service of theCanadian Centre for Occupational Health and Safety(CCOHS).


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Target Audience

The guide is intended to serve as a handy reference for

health and safety committee members, health and safetyrepresentatives, employees, supervisors and managers.

For training sessions, the guide can serve as a practicalhandout for future reference.

Summary

Heat stress is the net heat load on the body from thecombined effect of hot environmental conditions (airtemperature, radiant heat, humidity and air movement),internal body heat due to physical activity, and clothingrequirements. Workplaces and occupations associatedwith excessive heat exposure include: foundries, steelmills, bakeries, construction sites, kitchens, grounds

maintenance, dishwashing and steaming.Heat strain is the overall response of the body resultingfrom heat stress. It can cause a wide variety of healthdisorders. Heat stroke is the most serious health risk,which can be fatal if medical attention is not availablepromptly. People doing heavy physical work in hot andhumid conditions are affected more than those doing

light work.

Heat stress is largely preventable by engineering andadministrative control methods. As a last resort or inextreme conditions, the use of personal protection iswarranted. Engineering controls are designed toeliminate or minimize the level of heat exposure at thesource of the hazard. Administrative controls reduceheat exposure at the worker. These measures includeestablishing procedures for acclimatization of newworkers, training in safe work practices, reducing theduration of work in hot environments and providingplenty of drinking water. Workers and supervisorsmust receive adequate training and education to beable to recognize early symptoms of health disordersand seek timely medical help.


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Under excessively hot working conditions, personalprotective equipment such as cooling vests, hats andother body cooling equipment may be necessary.

It might be necessary to stop work in extremely hotconditions.

Employers can prevent or minimize heat stress hazardsby implementing appropriate policies and programs.A workplace heat stress policy must include clearlydefined procedures for working safely in hotenvironments and for providing care to potential heat

stroke victims.


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Table of Contents

IntroductionSection 1. Legal Responsibilities to Prevent Heat Stress

1. Responsibilities as set out in Health

and Safety legislation...............................................2

2. Ways of meeting responsibilities: being prepared.......3

Section 2. The Bodys Response to Hot Environments1. The bodys heat balance ..............................................8

2. Heat exchange between the body

and the environment.................................................9

3. Effect of clothing.......................................................13

4. Other contributing factors .........................................13

Section 3. Safety and Health Concerns

1. Safety Concerns.........................................................16

2. Health Concerns

(a) Heat Strain ..........................................................16

(b) Heat-related illnesses..........................................18

Section 4 Measures of Heat Exposure

1. Measures of Occupational Heat Exposure: ..............26

The WBGT index

2. Environmental Measures of Heat Exposure..............30

Section 5 Heat Exposure Standards and Guidelines

1. Occupational exposure limits ....................................32

2. Thermal comfort guidelines for offices.....................40


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Section 6. Control Measures

1. Engineering Controls.................................................42

2. Administrative Controls ............................................45

3. Personal Protection....................................................50

4. Sample Safe Work Practices......................................53

Section 7. Occupational Health and Safety Legislation.

1. Canadian Legislation.................................................58

2. US Legislation...........................................................61

Section 8. Sources of Additional Information.

1. Canadian Government Departments with .................64

ResponsibilityOccupational Health and Safety

2. US Federal Safety and Health Agencies ...................69

Section 9. Bibliography and Internet Links 73

Section 10. Appendices

A. A summary of health hazards and ...........................78

preventive measures

B. The Humidex ............................................................79C. Safety tips for different levels of the UV index ......81

D. Glossary ....................................................................83

E. Abbreviations ...........................................................85

F. Sample heat stress policy and checklist ...................87

G. Case histories: fatalities from occupational ............ 92

heat exposure


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Introduction

Everyone likes warm weather. However, when it

becomes too hot we feel discomfort. Working undervery hot conditions can cause serious adverse healtheffects. Examples of hot working conditions include:

Working in foundries, steel mills, smelters andglass factories.

Working near furnaces and extremely hot ormolten metals.

Outdoor work such as construction, road repair,open-pit mining and farming in summer months.

Working in laundries, restaurant kitchens, bakeriesand canneries.

In a hot working environment, how hot we feeldepends on the following factors:

air temperature;

relative humidity (moisture content of the air);

air movement;

physical exertion (heavy workload produces morebody heat than light work); and,

clothing.The combined effect of the environmental factors (airtemperature, relative humidity and air movement) areexpressed as the wet bulb globe temperature index,commonly known as WBGT. For occupationalexposures WBGT is used as an overall measureof heat exposure.

In this guide we frequently use the terms heat stress,heat strain and heat-related illnesses. Heat Stress isthe overall heat load on the body, including environ-mental heat and inner body heat production due toheavy workload. Heat Strain refers to the bodysresponse to heat stress. Heat-Related Illnesses refers toadverse health effects due to heat stress.


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The bodys defense mechanisms make adjustments todeal with moderate excess heat exposure. In extremelyhot working conditions, the risk of heat-related illnesses

increases. Heat stroke is the most severe adversehealth effect related to heat exposure. It can be fatalunless medical attention is provided immediately.

In a particular hot environment, everyone is not affect-ed equally. Some individuals are more susceptiblethan others to extreme heat and may be at greater risk.Personal factors such as body weight, diet, level of

acclimatization, medications and alcohol consumptioncontribute to how an individual responds to hot work-ing conditions. It is important to consider individualsusceptibility when developing safe work practices.

The guide provides information to assist workers andtheir supervisors with the recognition and prevention

of heat-related illnesses. The main purpose of theguide is to emphasize the importance of developingsafe work practices and implementing preventivemeasures to prevent (or minimize) worker exposureto extreme heat.


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Section 1

Legal Responsibilitiesto Prevent Heat Stress

1. Responsibilities as set out in Health and

Safety legislation.

2. Ways of meeting responsibilities:being prepared.


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2

Employers are obliged to prevent heat-related illnessesand fatalities. Such responsibilities are the same asthose for other occupational hazards such as noise,

chemicals and radiation.

1. Responsibilities as set out in Healthand Safety legislation.

Some jurisdictions may not have health and safetyregulations specifying occupational heat exposure limits.

This does not mean that employers do not haveobligations to protect employees from harmful heatexposures.

Under the general duty clause of the OccupationalHealth and Safety Act (Canada Labour Code Part IIfor federal jurisdiction), employers are responsible to

protect the health and safety of employees. For example,the Canada Labour Code Part II states:

Every employer shall ensure that the health and safetyat work of every person employed by the employer isprotected. Canada Labour Code Part II, section 124.

All provincial and territorial OSH acts have similar

provisions. Therefore, employers have a legalresponsibility to protect employees from harmfulheat exposure.


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2. Ways of meeting OHS responsibilities:being prepared.

The purpose of being prepared to meet OHSresponsibilities is to prevent heat-related illnesses fromoccurring and reduce the impact of potentially harmfulheat exposure situations.

In order to meet their health and safety responsibilities,employers must:

1. Identify conditions that pose a risk of heat-relatedillness;

2. Evaluate the risk of adverse health effects;

3. Develop and implement a prevention program inconsultation with the health and safety committee;

4. Evaluate the effectiveness of the program; and,

5. Periodically review the heat stress policy andprogram and make continuous improvements inconsultation with the health and safety committee.

Supervisors have legal responsibilities to ensure thatemployees work safely. In order to meet theirresponsibilities, supervisors must:

1. Identify potential heat stress situations in theirworkplace;

2. Ensure that employees follow safety proceduresrequired by the employer;

3. Take every precaution reasonable in thecircumstances for the protection of employees; and,

4. Ensure that changes of equipment or process aredone only after evaluation of their impact onemployee health and safety.

Workers are responsible too. They must:

1. Follow safe work practices established by theemployer; and,

2. Report unsafe conditions to their supervisor.


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4

A heat stress policy and program is a systematic planof action designed to prevent heat stress and relatedadverse health effects. Because needs differ from one

workplace to another, a prevention program developedfor one workplace may not serve the needs of others.It is vital to develop and implement a workplace-specificprevention program in consultation with the workplacehealth and safety committee.

Following are the basic elements of a heat stressprevention program.

Conformity with the company healthand safety policy.

Conformity with the occupational healthand safety legislation.

Conformity with the overall workplace healthand safety policy and program.

A time frame for implementation and completion.

Provision for regular monitoring and review.

Procedures for keeping records of the successesand problems of the program.

Clearly defined roles and responsibilities.

Employee orientation. Job specific training.

Reporting and investigating incidents.

Emergency procedures.

Medical and first aid procedures.


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All persons working in hot conditions must receiveadequate training and education so that they are ableto recognize early warning signs and symptoms of

heat-related illnesses, especially heat stroke.Individuals affected by heat stroke are usually unableto recognize their own symptoms. The survival of heatstroke victims depends on the coworkers ability toidentify the signs and symptoms of heat stroke andtake timely action.

Provide prompt medical attention to heat stroke victims


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Section 2

The Bodys Response toHot Environments.

1. The bodys heat balance.

2. Heat exchange between the bodyand the environment.

3. Effect of clothing.

4. Other contributing factors.


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1. The bodys heat balance.A healthy human body maintains its internal temperature

(core temperature) around 37C. Variations, usually ofless than 1C, may occur with the time of the day,level of physical activity or emotional state.

In order to maintain a constant body temperature, thebody must continuously lose as much heat as it gains.This implies that when it is hot, our body must lose moreheat compared to the heat loss in a cool environment.

Hot

Very Hot

EX

TREME

CA

UTION

CAUTION

LESSHAZARD

OUS


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The body gains heat in two ways:

1. Metabolic (inner body) heat production.

2. Heat gain from the environment.Metabolic heat is the heat produced within the body. Itis a result of the physical and chemical processes thattake place within the body for continued growth,functioning and movement. Even when we are sittingquietly, the bodys internal processes are active andproduce some amount of metabolic heat. The

metabolic heat production increases with increase inthe physical activity.

Heat gain from the environment occurs from contactwith the surrounding hot air and from hot objects inthe vicinity. As the environment warms-up, the bodytends to warm-up as well. The body's internalthermostat maintains constant inner body temperature

by increasing the body heat loss to offset increasedheat gain from the environment.


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2. Heat exchange between the body andthe environment

There are three main ways the body exchanges heatwith its surroundings:

Radiation

Convection

Sweat evaporation

Radiation is the direct heat exchange between the bodyand an object without direct contact with the object.

The body gains heat from surrounding hot objects,such as hot metal, furnaces or steam pipes.

The body loses heat to cold objects, such aschilled metallic surfaces.

No radiant heat gain or loss occurs when thetemperature of surrounding objects is the same asthe skin temperature (about 35C).

When we stand in the sun, we feel warm because ourbody receives heat from the sun by the radiation process.

Radiant heat is the main concern when working near

hot objects or outdoors on a hot and sunny summerday. Radiant heat can come directly from hot objectsand also as reflection from nearby surfaces.

Convection is the process by which the bodyexchanges heat by contact with the surrounding air.

The body gains heat from the hot air that comes incontact with the body; for example, hot air comingfrom heating vents.

The body looses heat to cold air that comes incontact with the skin; for example, cold draftfrom leaky outside doors.


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Convective heat exchange increases when:

Air speed increases; and/or

The difference between air temperature and skintemperature increases.

Sweat Evaporation cools the body. Cooling by sweatevaporation increases when:

Wind speed increases; and

Relative humidity (the moisture content of the air)

decreases.

Besides radiation, convection and sweat evaporation,a small amount of heat is lost through conduction andrespiration.


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Conduction is the process in which the bodyexchanges heat with an object that comes in contactwith the body. Usually, bodys heat gain or loss by

conduction process is very small compared to the heatexchange by radiation, convection and sweat evapora-tion processes.

Respiration contributes to a very small amount ofheat exchange between the body and the inhaled hotair. The amount of heat exchanged through breathingis very small and can be ignored in assessing heat

stress.

1. When body core temperature rises

Blood flow to skin increases

Sweating increases Heart rate increases to move blood to the skin

2. When this works well

Core temperature drops or stabilizes at a safe level

Normal Cooling Mechanisms

1. Heat exhaustion and heat stroke occur when the body issubjected to more heat than it can cope with

Heat Stress


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1. The body becomes unable to control its innerbody temperature

2. Death or permanent damage may occur if medical treatment is

not given promptly

3. Symptoms

No sweating

Red, hot, dry skin Throbbing headache Dizziness Nausea

Heat Stroke


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3. Effect of ClothingClothing affects heat exchange between the body and

the environment. Heavy clothing that fails tobreathe does not allow the body to cool off by aircirculation and sweat evaporation processes.

Cool Down by removing clothes

4. Other contributing factorsIn addition to high temperature and humidity, theeffect of heat stress on the body depends on severalindividual factors such as general health and lack ofacclimatization. Certain medications such asantihistamines, cold remedies, diuretics, tranquilizers,etc. may cause heat intolerance by decreasing sweat-

ing or increasing urination. People taking such medica-tions must consult their doctor about their ability towork in hot environments.


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Section 3

Safety and HealthConcerns.

1. Safety Concerns

2. Health Concerns

(a) Heat Strain

(b) Heat-related illnesses


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1. Safety concernsHeat stress can cause safety problems by impairing a

workers ability to work safely. Heat can lead to accidentsresulting from the slipperiness of sweaty palms and toaccidental contact with hot surfaces. Heat causesdizziness. Heat may also affect mental alertness andphysical ability to work increasing the risk of incidents.As a worker moves from a cold to a hot environment,fogging of eyeglasses can briefly obscure vision,

presenting a safety hazard.

2. Health Concerns

(a) Heat Strain

Heat strain is the response of the body to heat exposure.

It is a series of physiological responses to heat stress.Excessive and prolonged heat strain can causeheat-related illnesses. An early recognition of heatstrain signs and symptoms will help in preventingpotentially serious health disorders.

The severity of heat strain varies greatly from one personto another. Some highly susceptible individuals are

affected sooner than others. However, as the level ofexposure and/or the exposure duration increases moreand more people are likely to be affected. The signsand symptoms of heat strain include:

Sweating

Discontinued sweating

Increased heart rate

Increased inner body temperature

Urinating less frequently than normal

Small volume of dark-colored urine

Irritability

Lack of coordination Lack of judgement


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Sweating:

The presence of sweat on the skin, or sweat-soakedclothing, is a sign of heat strain.

Sweat evaporation cools the body. Commonly usedmethods to increase the sweat evaporation rate are:

Increasing the air flow rate over skin and clothingsurfaces.

Lowering the ambient temperature and relative

humidity. Reducing radiant heat gain from the sun and hot

objects in the vicinity.

Reducing the level of physical activity (metabolicheat production).

Discontinued sweating:

Absence of sweating in a very hot environment canbe a sign of potential heat stroke. Affected personsrequire immediate first aid and medical attention.

Increased heart rate:

An increase in the heart rate is an indication that thebody has to work harder than normal to cope withthe increased heat load.

Increased inner body temperature:

When the body is unable to cope with the hotenvironment, the bodys heat gain exceeds the bodyscapability to lose heat. As a result, the inner bodytemperature rises increasing the risk of heat-relatedillnesses.


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Decreased frequency and volume of urination andchange in the colour of urine:

In hot environments the volume of urine and thefrequency of urination decrease because of loss ofbody fluids through sweating. These are warning signsof dehydration. People need to develop a habit ofdrinking adequate volumes of water at frequent intervalsto maintain their normal frequency ofurination, urine colour and urine volume.

(b) Heat-Related illnesses

Prolonged exposure to hot working conditions cancause a wide range of adverse health effects.Commonly known heat illnesses are:

Heat rash

Heat edema Heat cramp

Heat exhaustion

Heat syncope (fainting)

Heat stroke

Signs and symptoms of heat illnesses include:

Excessive sweating

Rapid breathing

Weakness or fainting

Tiredness

Headache

Confusion

Heat Rash,also called prickly heat or miliaria, is acondition in which areas of the skin itch intensely andoften feel prickly, or sting. Heat rash looks like tinybumps surrounded by a zone of red skin. It usuallyoccurs on clothed parts of the body, such as the back,abdomen, neck, upper chest, groin, or armpits andgoes away within a few days.


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Heat edema is swelling which generally occursamong people who are not acclimatized to working inhot conditions. Swelling is often most noticeable in

the ankles.

Heat cramps are painful muscle cramps, which resultfrom excessive loss of salt from the body. Muscles ofthe extremities and the abdominal wall are usuallyinvolved. Heat cramps are promptly relieved when theindividual takes drinks that replace the body electrolytes,and rests in a cool environment.

Heat exhaustion occurs as a result of excessive lossof water and salt from the body. The symptoms includeheavy perspiration, flushed skin and low blood pressure.

Prompt recovery occurs when the affected individualmoves to a cool environment, takes rest and drinks wateror beverages with adequate water and electrolyte content.

Heat Syncope is a sudden dizziness experienced afterphysical exertion in a hot environment. The skinappears pale and sweaty but is generally moist andcool. The pulse may be weakened, and the heart rate isusually rapid. Body temperature is normal.

Heat Stroke

Heat stroke is a medical emergency, which can be fatalunless first aid and medical help is promptly provided.If you or someone you are with becomes ill, hasdifficulty in breathing, or feels confused or disoriented,SEEK MEDICAL ATTENTION IMMEDIATELY.


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Heat stroke signs and symptoms include:

Extremely high body temperatures (above 41C).

Mental confusion, delirium, or coma. Absence of sweating.

Complete or partial loss of consciousness.

Red, hot, and dry skin (no sweating).

Rapid, strong pulse.

Throbbing headache.

Dizziness.

The following actions are basic elements of a first response:

TAKE the affected person to a cooler area (for example,an air-conditioned shed or air-conditioned vehicle).

REMOVE excess clothing (hard hat, boots, shirt).GIVE the person water to drink, if conscious.

ALLOW the person to rest.

COOL the persons body with cool water, coldcompresses, and/or rapid fanning.

TAKE the person to medical facility for propermedical care.

Risk of heat stroke is higher than normal if a person is:

Not fully acclimatized;

Not in good physical health;

Ill as a result of pre-existing diarrhea or fever; or,

Recovering from a heat-related illness.

A case of heat stroke should be taken as a warning. Itindicates a possibility that other workers could beaffected. It is important to take immediate remedialaction to prevent future recurrence of heat strokes insimilar environments.


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Illnesses caused by long-term (chronic) heatexposure

Some researchers have reported that certain disordersof the kidney, liver, heart, digestive system, centralnervous system and skin may be linked to long-termheat exposure. Other probable effects include: chronicheat exhaustion, sleep disturbances and susceptibilityto minor injuries. There is no conclusive scientificevidence linking such effects and long-tem exposureto heat.

Effect on the eye due to long-term (chronic) heatexposure

The eye has no heat sensors and no blood vessels tocarry heat away. The lens of the eye is particularlyvulnerable to radiant heat from red-hot objects

(infrared radiation). Following are some examples ofsources of radiant heat exposure:

Glass products manufacturing plants.

Iron, steel and nonferrous foundries.

Brick-firing and ceramics operations.

Bakeries.Glass blowers and furnace-men may develop cataractsafter many years of exposure to radiant heat from hotobjects. Foundry workers, blacksmiths and ovenoperators are also exposed to potentially harmful levelsof infrared radiation.

Medications that may affect heat illnessesCertain medications can affect heat tolerance. Peopletaking medications must ask their doctor if they needto be extra careful when working in hot environments.

The following table summarizes the symptoms,treatment and preventive actions for common

heat-related illnesses.


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Recognitionand

PreventionofHeatRelatedIllne

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23

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Fain

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HeatExhaustion

Sympto

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24

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Section 4

Measures of HeatExposure

1. Measures of Occupational Heat Exposure:

The WBGT index

2. Environmental Measures of Heat Exposure


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1. Measures of Occupational HeatExposure: The WGBT Index.

How hot we feel depends on the combined effect ofthe following environmental and workload factors:

Temperature of the surrounding air.

Radiant heat from the sun and other hot objects inthe vicinity.

Relative humidity (moisture content of thesurrounding air).

Speed of air movement.

Level of physical activity.

WBGT (Wet Bulb Globe Temperature) index

The Wet Bulb Globe Temperature (WBGT) indextakes into account all the environmental factors, i.e.,air temperature, radiant heat, humidity and airmovement speed, and gives a single number measureof the perceived heat.

WBGT is calculated by using one of the followingtwo formulas:

1. With direct exposure to sunlight:

WBGTout = 0.7 Tnwb + 0.2 Tg + 0.1 Tdb

2. Without direct exposure to the sun:

WBGTin = 0.7 Tnwb + 0.3 Tg

Abbreviations used in the above formula are as follows:Tnwb = natural wet-bulb temperature (accounts for

cooling due to sweat evaporation).

Tg = globe temperature (accounts for the radiantheat exposure).

Tdb = dry-bulb (accounts for air temperature).

Occupational exposure limits are generally given inWBGT units.


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Instrumentation for measuring WBGT

A WBGT monitoring instrument consists of:

1. A dry-bulb thermometer to measure air tempera-ture (Tdb).

2. A natural (static) wet-bulb thermometer to meas-ure evaporative temperature (Tnwb).

3. A black globe thermometer to measure radianttemperature (Tg).

A Dry bulb thermometer is an ordinary thermometercommonly used to measure the air temperature. The bulbof the thermometer must be shielded from the sun andother hot objects in the vicinity to prevent radiant heatfrom reaching the thermometer bulb. However the shieldshould not interfere with the airflow around the bulb.

A Natural wet bulb thermometer has a wet wickcovering its bulb.

The wick must be wetted by direct application ofwater from a syringe one-half hour before eachreading.

The wick must cover the bulb of the thermometer

and an equal length of additional wick must coverthe stem above the bulb.

The wick must be replaced periodically to avoidsalt and dirt accumulation.


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A Globe thermometer consists of a 15 cm (6 inch) indiameter hollow copper sphere painted on the outsidewith a matte black finish. The thermometer bulb or

another temperature sensor is fixed in the center of theinterior of the sphere.

The following diagram illustrates the components of aWBGT monitoring instrument.

Helpful tips for using a WBGT monitor

FOLLOW operating instructions provided by theequipment manufacturer.

PLACE the monitor as close as possible to theposition of the worker involved.

AVOID placing the monitor close to a hot surface orin a draft unless this represents an actual conditionof the workers environment.


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ENSURE that the wick is damp at all times. Use onlydistilled water.

ALLOW about 25 minutes for the unit to stabilizeafter it has been set up.

Personal Heat Stress Monitors

Personal heat stress monitors are commerciallyavailable. These are convenient to use to monitor theworker exposure during a work shift. Personal

monitors are generally equipped with a data loggingsystem, which stores and displays temperature dataand warns the worker when pre-set temperaturethresholds are reached.


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30

2. Environmental measures of heat exposureEnvironmental measures are generally based on air

temperature and relative humidity but do not take intoaccount the effect of radiant heat and air movement inthe workplace. Therefore, such measures cannot be usedto determine occupational heat stress in the industry.

Two commonly used environmental measures are:

1. The Humidex; and,

2. The Heat Index.

The Humidex

Environment Canadas Weather Service uses thehumidex as a measure of how hot people feel in outdoorenvironmental conditions. The humidex gives a

combined effect of air temperature and relativehumidity as a single number that is intended to reflectperceived heat (see Appendix B). Humidex levels canbe obtained on the Environment Canada website:http://www.weatheroffice.ec.gc.ca/canada_e.html.

Heat Index

The US National Weather Service has developed aHeat Index Chart to express perceived heat for differentenvironmental conditions of temperature and humidity.A heat index chart is available from the NationalWeather Service (NWS), the US National Oceanicand Atmospheric Administration (NOAA).Website:http://www.srh.noaa.gov/lzk/images/hindex1.gif.


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Section 5

Heat Exposure Standardsand Guidelines.

1. Occupational exposure limits.

2. Thermal comfort guidelines for offices.


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32

1. Occupational exposure limitsThe purpose of occupational exposure limits is to

eliminate or minimize the risk of heat-related illnesses.Exposure limits are set by provincial, territorial andfederal jurisdictions responsible for workplace healthand safety. Many regulatory agencies use the exposureguidelines recommended by the American Conferenceof Governmental Industrial Hygienists (ACGIH). Forfurther details please refer to the most recent version

of the ACGIH publication Threshold Limit Valuesfor Chemical Substances and Physical Agents &Biological Exposure Indices. The occupationalexposure limits are generally given as work/restregimen for working in hot environments.

An Example of Heat Stress Exposure Limits

Saskatchewan (Canada) Hot Conditions Guidelinesand Saskatchewan Labour publication "http://www.labour.gov.sk.ca/safety/thermal/hot/index.htm"Working Under Hot Conditions recommend thefollowing rest break schedule for working in hotenvironments. For exposure limits applicable to yourworkplace, please consult your health and safety

regulations.


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33

Sources: "http://www.labour.gov.sk.ca/safety/thermal/hot/page%208%20.htm"http://www.labour.gov.sk.ca/safety/thermal/hot/page%208%20.htm, and"http://www.worksafesask.ca/topics/specific_hazards/physical/heat.html"http://www.worksafesask.ca/topics/specific_hazards/physical/heat.html

Recommended

RestBreakSche

dulesforAcclimatizedWorkers

WetBulbGlobeTempe

rature(WBGT)Index

Heavy

Moderate

Light

Continuo

us

work

upto25.

0C

upto27.

0C

upto30.

0C

15

minutes

restperh

our

25.0

C

to2

6.0

C

27.0

C

to2

8.0

C

30.0

C

to3

0.

6C

30

minutes

restperhour

26.

0C

to28

.0C

28.

0C

to29

.0C

30.

6C

to31

.4C

45

minutes

restperhour

28.0

C

to30

.0C

29.0

C

to31

.0C

31.

4C

to32

.2C

WorkLoad

WorkRate


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34

Notes and definitions for the above table

The WBGT index in the above tables is based on

American Conference of Governmental IndustrialHygienists (ACGIH) TLV Documentation.

These indices are not equivalent to regular thermometerreadings. The tables apply only to acclimatized workerswithout special needs who are wearing lightweight, lightcoloured, loose-fitting cotton clothing. Adjustments mustbe made to these indices for workers with special needs.

Heavy work Intermittent lifting, pushing orpulling (such as pick and shovel work) or hardsustained work, such as assembly line activitieswhere workers are paced by machines andcannot stop.

Moderate work (1) Work done in a sitting posi-

tion, but requiring heavy arm and leg motions; or(2) work done while standing and involving mod-erate work at a machine or bench; or (3) workdone while walking about and involving moderatelifting or pushing activities.

Light work Sitting or standing; work at amachine or bench that requires mostly arm work.

Continuous work Assumes that there are shortmorning and afternoon breaks and a longer lunchbreak in an eight hour day.

Rest breaks This includes all breaks, such asregular work breaks and unscheduled pauses duringwork. If rest breaks occur in an area that issignificantly cooler than the work position,

the WBGT is modified.


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Applying the Recommended Rest Break Schedule

The recommended rest break schedule applies to

workers who are fully acclimatized. New workers andworkers returning from more than two weeks vacationor sick leave should be allowed a week to acclimatize.Start with a short exposure to hot worktwenty percentof the time on the first day. Another twenty percentshould be added each day after that.

The recommended rest break schedule assumes that

the WBGT index of the resting place is the same orsimilar to that of the workplace. Where the WBGT ofthe work area is different from that of the rest area, atime weighted average should be used. The weightedaverage should not exceed a WBGT of 30C for lightwork, 27C for moderate work and 25C for heavywork for any one hour of continuous work. The

weighted average is determined by the equation:WBGT1 x t1 + WBGT2 x t2

_____________________ = weighted average

t1 + t2

Where:

WBGT1 is the work area index

WBGT2 is the rest area index

t1 is the time worked every hour

t2 is the length of the rest period every hour


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36

Special Situations

If a job requires specialized clothing such as heavy

coveralls, "turn out gear" for firefighters orchemical-resistant clothing, the WBGT index mustbe adjusted down. The WBGT index should also beadjusted down for special needs workers, such as:

persons over 40

the obese

alcohol abusers unconditioned or unacclimatized workers who are

likely more susceptible to heat stress disorders

In these situations, obtain advice from a competentperson or a physician if needed.

If a job requires heavy coveralls, the WBGT index must be adjusted down


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37

When WBGT Indices Exceed the Table Guidelines

Higher heat exposures than shown in the table should

only be permitted where: A competent person will determine the maximum

length of work exposure to extreme heat that issafe, based on past experience in similar conditions.

Each worker will pace the speed of work and willbe able to terminate any particular heat exposurebecause of strain or discomfort.

A doctor will determine the fitness of each workerfor work in extreme heat.

Workers will be watched by a trained supervisoror worker who can recognize signs of heat effects.

Appropriate protective clothing or equipment willbe provided to reduce the intensity of heat exposure.

An emergency plan will be in place to rescue andtreat workers who become ill.


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38

Canadian Regulations

The following table summarizes requirements for the

thermal conditions in the workplace.

ACGIH TLVs: Threshold Limit Values (TLVs) recommended by the AmericanConference of Governmental Industrial Hygienists (ACGIH). The ACGIH TLVbooklet is updated annually.

Wet Bulb Globe Temperature Index (WBGT)

ACGIH TLVs

ACGIH TLVs

Similar to ACGIH TLVs

Hot Conditions Guidelines in WBGT units

ACGIH TLVs

Heat Stress (Health and Safety Guidelines)

April 2003 ACGIH TLVs

Safety in mines: Occupational exposure limitsWBGT similar to ACGIH TLVs

ACGIH TLVs

ACGIH TLVs

ACGIH TLVs

ACGIH TLVs

Jurisdiction

Canada, Federal

British Columbia

Alberta

Saskatchewan

Manitoba

Ontario

Quebec

New Brunswick

Nova Scotia

Prince EdwardIsland

Newfoundland

Canadian Regulations


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The Occupational Health Clinics for Ontario Workers(OHCOW) has developed a simplified screening to assessworkplace heat stress using humidex as a measure of the

environmental heat. The following table summarizes theHumidex Based Heat Response Plan.

Source: http://www.ohcow.on.ca/menuweb/hhrplan.pdf.

Response

- supply water to workers on an as needed basis

- post Heat Stress Alert notice.

- encourage workers to drink extra water.

- start recording hourly temperature andrelative humidity.

- post Heat Stress Warning notice.

- notify workers that they are drinking extra water.

- ensure workers are trained to recognize symptoms.

- provide 15 minutes relief per hour.

- provide adequate cool (1015C) water, at least 1cup (240 mL) of water every 20 minutes.

- workers with symptoms should seek

medical attention.

- provide 30 minutes relief per hour in addition to theprovisions listed previously.

- if feasible provide 45 minutes relief per hour inaddition to the provisions listed above.

- if a 75% relief period is not feasible then stop work

until the Humidex is 42C or less.

- stop work until the Humidex is 44C or less

Humidex

25-29C

30-33C

34-37C

38-39C

40-42C

43-44C

45C or over

Humidex Based Heat Response Plan


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2. Thermal comfort guidelines for officesThe occupational heat exposure limits are not applicable

to office work. There are no regulations specific tooffice work. However, there are guidelines for thermalcomfort in offices.

The following table shows the temperature and relativehumidity ranges recommended by the CanadianStandard Association's Standard CAN/CSA Z412-00 -"Office Ergonomics.

% Relative Humidity

50%

50%

Heating Season

Cooling Season

Temperature

2023.5C6875F

2326C7379F

Temperature and Humidity of an OfficeEnvironment taken from CSA Z412-00


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Section 6

Control Measures

1. Engineering Controls

2. Administrative Controls

3. Personal Protective Equipment

4. Sample Safe Work Practices


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1. Engineering ControlsEngineering controls are the most effective means of

reducing heat exposure in industrial work environments.Following are some examples of commonly usedengineering controls:

Automation and mechanization of tasks

Automation and mechanization of tasks reduces the need

for heavy physical work. Reducing heavy physical effortreduces the inner body heat production rate, and hence,the risk of heat stress.

Use of mechanical aids

Mechanical aids such as carts, turn tables, etc. reducethe amount of physical effort needed to perform a task

and hence reduce metabolic heat production.

Location of work stations away from hot objectsand processes

Increasing distance from hot surfaces reduces radiantheat exposure.

Insulating hot surfaces

Insulation reduces the surface temperature of aradiant heat source and hence reduces the radiantheat exposure of workers.


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Shielding

Shields stop radiated heat from reaching the worker.

Two types of shields can be used. Shields that reflect heat: Stainless steel, aluminum

or other bright metal surfaces reflect heat backtowards the source.

Shields that absorb heat: Absorbent shields, suchas water-cooled jackets made of black-surfacedaluminum, can absorb heat.

Ventilation and air conditioning

Ventilation, localized air conditioning and cooled observationbooths are commonly used to provide cool work stations.Cooled observation booths allow workers to cool down afterbrief periods of intense heat exposure while still allowing

them to monitor equipment.

Using local exhausts

Local exhaust systems remove the hot air and steamproduced by a process before it mixes with the ambientair in the work area.

Reducing the relative humidity

Air conditioning, dehumidification, and elimination ofopen hot water baths, drains, and leaky steam valveshelp reduce relative humidity.

Increasing air movement

If the air temperature is less than the skin temperature(35C or 95F), a fan can increase air movement. Briskair movement causes body cooling by convection andincreased sweat evaporation.


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Using fans to cool off

Fans don't cool the air they just move air around. Fans

keep you cool by increasing the rate of sweat evaporation.Following are some helpful tips for using fans.

USE your fan in or next to a window, box fans arethe best.

USE a fan to bring cool air in from outside.

USE your fan by plugging it directly into the wall outlet.

If you need an extension cord, it should be CSAapproved and should not present a trip hazard.

DO NOT use fans if the room is closed and filled withhot air. Blowing hot air on the body will increase therisk of adverse health effects.

DO NOT use a fan to blow extremely hot air on yourself.

This can cause heat exhaustion to happen faster.


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2. Administrative ControlsThe purpose of administrative controls is to minimize

heat stress risks by controlling work schedules, worklocations and work procedures. Administrative controlsinclude the following:

Acclimatization

Safe work practices

Training

Exposure time reduction

Prevention strategies for workers

Acclimatization

Acclimatization is the most important administrativecontrol. The concept of acclimatization is based on the

fact that the longer people work in hot environments, themore tolerant they become. People who are not used toworking in hot environments should be given a week ortwo to get acclimatized to the heat. Some individualsmay need longer than others. Also, persons with poorhealth may need more time to acclimate.

Helpful tips for the acclimatization of employees:ACCLIMATIZE new employees before assigning a full

workload. It is advisable to assign about half of thenormal workload to a new employee on the first dayof work and gradually increase on subsequent days.

INCREASE the duration of work gradually when a

new or transferred employee starts working in a hotenvironment.

INCREASE the level of physical activity gradually start with light work on the first day and graduallyincrease the work-load on subsequent days.

MONITOR heat strain symptoms during the acclimati-

zation period. If an individual shows symptoms ofexcessive strain, reduce the duration of exposureand/or the level of activity.


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ADVISE employees who are on medication to consulttheir doctor and inquire if the medication will affecttheir heat tolerance ability.

Loss of acclimatization

Loss of acclimatization occurs gradually when a personis moved permanently away from a hot environmentor after several days of absence from work.

Safe Work PracticesREDUCE physical effort needed for performing a task.

PROVIDE an appropriate work-rest regimen asrecommended in the health and safety legislation.The American Conference of GovernmentalIndustrial Hygienists (ACGIH) has recommended a

work-rest regimen which can be found in the currentversion of the ACGIH publication Threshold Limits(TLVs) for Chemical Substances and PhysicalAgents & Biological Exposure Indices.

SCHEDULE jobs to minimize heat stress.

SCHEDULE outdoor jobs so that people perform

physically demanding jobs during cooler periods ofthe day.

PAY attention to employees with special needs.Advise and encourage pregnant workers and workerswith a medical condition to discuss any limitationsand special precautions needed for working in hotenvironments with their doctor.

PROVIDE appropriate training and education toenable employees to:

Develop a high degree of awareness about thepotential hazards of working in hot environments;and

Ways of preventing adverse health effects due tosuch hazards.


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47

Provide appropriate training and education

A training program should include the following topics:

Employers responsibilities in providing a safeworkplace and establishing safe work practices;

Hazards and potential health effects of heat stress;

Use of WBGT monitor and interpretation of results;

Principles of work-rest regimen design;

Predisposing factors, danger signs and symptomsof heat-related illnesses;

First-aid procedures for heat-related disorders;

Possible side effects of certain medications whentaken in a hot environments;

Proper use and maintenance of protective clothingand equipment.


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ALLOW adequate recovery time. Provide adequate restperiods to reduce the risk of adverse health effects.

USE the Buddy System. In hot working environmentsthe buddy system is a must. Individuals are lesslikely to notice their own symptoms. The survival ofthe affected person depends on the co-workersability to recognize the symptoms and seek timelymedical help.

MINIMIZE metabolic heat production by:

Reducing work pace;

Reducing work duration;

Reducing the physical exertion required to per-form a task;

Increasing the frequency and duration of rest

breaks; Substituting light tasks for heavy ones;

Increasing assigned staff so that more workersshare the workload;

Reducing the use of heat generating devices; and,

Reducing the time and frequency of working with

or near heat sources.

Prevention Strategies for Workers

In hot environments, workers can use certain preventivestrategies to minimize the risk of adverse health effects.Such strategies include:

REPORT discomfort and early symptoms of heat-relatedillnesses to your supervisor.

DRINK plenty of water even if you do not feel thirsty.Sweating results in the loss of body fluids. Excessivewater loss may cause dehydration. Thirst is not areliable indication of bodys need for fluid replace-

ment. A person should drink approximately 250millilitres (one cup) of cool water every 20 minutes.Coffee, sweet beverages and alcohol must be avoided.


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49

MAINTAIN a healthy diet. On hot days, eat lightfoods such as fruits and vegetables, and avoid heavyfoods such as proteins which increase body heat.

LIMIT non-work heat stress exposures.

REPORT any changes in health status to yoursupervisor. Pregnant workers and those with medicalconditions should consult their physician about theiroccupational exposures to heat stress. Older workersshould be particularly cautious due to a decreased

ability to sweat.

CONSULT your doctor if you are taking medicationsthat may cause heat intolerance or inhibited sweat-ing. Certain antibiotics will cause photosensitivity.People taking such drugs should avoid strongmid-day sunlight.

Alcohol Consumption increases the risk of heart related illness


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50

3. Personal ProtectionEngineering controls are the most desirable method

of controlling heat exposure. Personal protectiveequipment (PPE) should be used as an interim measurewhile engineering controls are being explored.

Eye protection

Eye protection that absorbs infrared radiation (heat

rays), may be needed when working near very hotobjects, such as molten metals and red-hot objects.

Clothing

Ordinary clothing provides someprotection from heat radiated bysurrounding hot surfaces. Light

clothing allows maximum skinexposure and efficient bodycooling by sweat evaporation.

Cotton clothing is cooler thanpolyester clothing. However, cottonwill absorb water and wet clothing

tends to be uncomfortable.When selecting clothing,heat stress prevention should bebalanced with other health andsafety risks. For example, foroutdoor workers, a balance mustbe achieved between heat stress

prevention and the ultravioletexposure.

Cooling Vest


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Impermeable clothing

Work that requires the use of impermeable clothing

presents an added heat burden. Impermeable clothingreduces the body's ability to dissipate heat. Therefore,it is necessary to provide a cooler working environ-ment than that recommended for workers wearinglight clothing.

Protective clothing

The selection of protective clothing depends on thespecific circumstance. Working in certain hotenvironments may require insulated gloves, insulatedsuits, reflective clothing, infrared-reflecting face shieldsand safety footwear (e.g., foundry boots, welder's boots).For extremely hot conditions, thermally conditionedclothing is available. Examples of such protective

clothing are:

A self-contained air conditioner in a backpack.

A compressed air source which feeds cool air intothe jacket or coveralls through a vortex tube.

A jacket which has pockets that can be filled withcontainers of ice.

Check with your local safety equipment supplierregarding the types of personal protective equipmentavailable and the degree of protection such clothing isexpected to provide.

In a high radiant heat situation, people generally usereflective clothing. However, this advantage may benullified if the clothes interfere with the sweatevaporation. For very hot environments air, wateror ice-cooled insulated clothing may be used.

Workers who move back and forth between very hot,dry indoor environments and cold, winter outdoorenvironments find that long underwear moderates

the extremes in temperatures.


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52

Method of Control

Reduce body heat production

Stop exposure to radiated heatfrom hot objects

Reduce convective heat gain

Increase ventilation

Clothing

Acclimatization

Duration of work

Rest area

Water

Pace of work

First aid and medical care

Action

Mechanize tasks

Insulate hot surfaces. Use reflectiveshields, aprons, remote controls

Lower air temperature. Increase air speedif air temperature below 35C. Increaseventilation. Provide cool observationbooths

Reduce humidity. Use a fan to increase airspeed (movement)

Wear loose clothing that permits sweat

evaporation but stops radiant heat. Usecooled protective clothing for extremeconditions

Allow sufficient acclimatization period fornew workers

Shorten exposure time and use frequentrest breaks

Provide cool (air-conditioned) rest-areas

Provide cool drinking water

If practical, allow workers to set their ownpace of work

Establish emergency procedures. Assignone person trained in first aid to eachwork shift. Train workers in recognition

of signs and symptoms of heat stroke

Table 3 - Summary of Heat Stress Control Measures

Engineering controls

Administrative controls


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4. Sample safe work practicesThe following are some examples of safe work practices

for preventing heat stress.

(a) Working outdoors during prolonged heat spells

In the summer months, outdoor workers are simultane-ously exposed to two main health hazards:

i. Heat stress as air temperature and/or humidity

increases; and,

ii. UV rays from sunlight.

Preventing health effects of heat Stress

AVOID unnecessary or unusual stressful activity.

PERFORM stressful tasks during the cooler parts of

the day (early morning or at night).

AVOID double shifts and overtime whenever possible.Employers must not permit double shift or overtimeto workers in hot environments.

ADOPT a recommended work-rest regimen to recoverfrom the heat stress.

DRINK plenty of water in frequent small portions.Employers are required to provide plenty of drinkingwater in hot workplaces.

AVOID alcohol consumption. The consumption ofalcoholic drinks increases the risk of dehydrationand other heat-related illnesses.

CONSULT your doctor about potential side effects ifyou are taking blood pressure control medication,diuretics or water pills.

TAKE sufficient sleep and good nutrition for maintaininga high level of heat tolerance.


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Preventing health effects of UV exposure

During outdoor work, the safety measures for UVprotection depend on the intensity of UV rays in

the sunlight.

The weather service of Environment Canada expressesthe intensity of UV rays in the units of UV index.The UV index is the highest during noon hours inthe summer months and lowest in the mornings andevenings of winter days. Appendix C gives safety tips

for different levels of UV index.

(b) Working near extremely hot objects

People who work near extremely hot objects are at ahigh risk of heat stress. The main source of heatexposure is radiant heat from hot surfaces such asfurnaces and molten metals. Examples of suchworkplaces include:

Iron, steel and nonferrous foundries

Brick-firing and ceramics operations

Glass products manufacturing plants

Rubber products manufacturing plants

Bakeries Restaurant kitchens

Smelters

You must pay special attention if:

You are unacclimatized;

You have a history of heat intolerance; You are recovering from a fever;

You are dehydrated;

You have circulatory disorders;

You are taking medication; or,

You are in overall poor health.


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Basic Safety tips

PROVIDE adequate ventilation and air movement.

INSTALL shields to reduce radiant heat exposurefrom hot surfaces.

PROVIDE cool work stations.

PROVIDE adequate protective clothing and equipmentincluding gloves, safety footwear and eye protection.When selecting protective clothing, consider the

following important factors:

Protection from radiant heat; and

Allowance for sweat evaporation.

ENSURE that all new and transferred employees areacclimatized before assigning them a full work-load.

Acclimatization may also be needed for employeeswho return to work after several days of vacation.

PLAN job rotation to reduce duration of heat exposure.

PROVIDE cool drinking water and make sure thatemployees understand the importance of drinkingwater at frequent intervals.

PROVIDE adequate rest breaks. Work-rest periodsrecommended in the ACGIH TLV bookletmay be used as a guideline todevelop a company policy.

Drink plenty of water

55


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Hands free water system provides ready access to drinking water

Hands FreeDelivery Tube

Two-LiterResevoir

Harness

56


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Section 7

Occupational Health andSafety Legislation

1. Canadian Legislation

2. US Legislation


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1. Canadian LegislationThe purpose of Occupational Health and Safety

(OH&S) legislation is to protect you, the employee,against any hazards on the job. The occupationalhealth and safety act outlines the rights andresponsibilities of employers, supervisors andemployees in ensuring workplace health and safety.

The Canadian health and safety legislation is basedon the internal responsibility system. In this system,

everyone in the workplace is responsible for healthand safety. Employers have legal responsibility toprovide a safe workplace and ensure that work iscarried out in a safe manner.

Employers responsibilities

Employers must provide a safe workplace to preventrisk of injury and illness. Therefore, it is the employersresponsibility to protect employees from harmfulheat exposure.

In some Canadian jurisdictions, there are no regula-tions with respect to heat stress. However, the generalduty clause in the health and safety act holds theemployer responsible for the overall health and safetyof employees. Therefore, employers are responsiblefor implementing an adequate heat stress preventionprogram.


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Employee responsibilities

In general, employees must take all reasonable and

necessary precautions to ensure their own health andsafety and that of other employees and any personswho might be affected by their activities. Followingare some examples of employee responsibilities:

Follow safe work practices established bythe employer.

Use safety equipment required by the employer.

Report any unsafe conditions or practices tothe employer.

Report every accident or incident (near miss).

Employees Rights

Employees have the following three basic rights:

Right to know: The employer must provide informationabout any actual or potential hazards, and trainemployees in safe work practices.

Right to participate: Employees have the right toparticipate in workplace health and safety activitiesthrough health and safety committees or an employee

health and safety representative.

Right to refuse unsafe work: Employees have theright to refuse performing work that poses a danger totheir health and safety. Health and safety legislationoutlines procedures to be followed in resolving workrefusals. The following chart summarizes steps

involved in resolution of work refusals. Please consultyour appropriate health and safety act for details. Thesteps involved in the resolution process may vary fromone jurisdiction to another.

In Ontario, certified members of the health and safetycommittee have the right to stop work following theprocedure outlined in the Ontario Health and Safety Act.


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Work Refusal Chart

Supervisor

Union/H&S Rep

H&S Comm. Member

Investigate

UNRESOLVED

UNRESOLVED

BACK TO WORK

RESOLVED

Call GovernmentInspector

Assign reasonablealternative work

Assign work beingrefused to another

worker

Decision of theInspector

Further GovernmentAction

Further EmployerAction or Appeal of

Government Directives

Supervisor and Workerattempt to resolve

problem

Worker OH&S Concern(Work Refusal)

Reports to Supervisor

RESOLVED

RESOLVED

RESOLVED


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2. U.S. LegislationIn the United States of America (USA) the

Occupational Safety and Health Act is popularlyknown as the OSH Act. The Occupational Safety andHealth Administration (OSHA) is responsible foradministering the OSH Act.

The OSH Act does not cover the following fourcategories of employees:

Self-employed persons; Farms which employ only immediate family

members of the farm employer;

Workers covered by other legislation; and

State and local government employees.

Regulations dealing with OSHA are published in Title29 of the Code of Federal Regulations as:

29 CFR Part 1910 Occupational Safety and HealthStandards; and

29 CFR Part 1926, Construction Standards.

These standards define exposure limits, exposure

monitoring methods, medical surveillance andprotective measures.

Duties of Employer

The OSH Act sets out two main duties for employers:

Employers must provide a workplace which is freefrom hazards that are known to cause of likely tocause death or serious physical harm to employees.

Employers must comply with occupational safetyand health standards under the Act.


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Duties of Employees

Employees must comply with occupational safety and

health standards, rules, regulations and orders whichare applicable to their own conduct and actions.

Key Provisions

Some key provisions of the OSH Act:

To assure, insofar as possible, that every employee

has safe and healthy working conditions. To require employers to maintain accurate records

of exposures to potentially toxic materials orharmful physical agents and inform employeesof the monitoring results.

To allow at least one employee representative tobe present during the walkaround inspection.

To encourage free and open exchange of informa-tion between employees and the inspector.

To implement procedures for investigating allegedviolations, at the request of any employee oremployee representatives, issuing citations andassessing monetary penalties against employers.


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Section 8

Information Sources

1. Canadian Government Departments withResponsibility for Occupational Healthand Safety

2. US Federal Safety and Health Agencies


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1. Canadian Government DepartmentsResponsible for Occupational

Health and Safety

Canadian Centre for OccupationalHealth and Safety (CCOHS)

Inquiries & Client Services(free answers to your OH&S questions)135 Hunter Street EastHamilton, ON L8N 1M5Phone: 905-570-8094(8:30 AM to 5:00 PM EST Time)Toll-free: 1-800-668-4284 (Canada and US only)

Fax: 905-572-4500E-mail: [email protected] Answers Web Site: www.ccohs.ca/oshanswersWeb Site: www.ccohs.ca

General ContactPhone: 905-572-2981

Fax: 905-572-2206

Federal Jurisdiction

Workplace Health and SafetyHuman Resources and Social Development Canada

1-800-641-4049Ottawa ON K1A 0J2

Web Site: http://www.hrsdc.gc.ca/en/labour/workplace_health/index.shtml

Regional and District Offices:Web Site: http://www1.servicecanada.gc.ca/en/

gateways/where_you_live/menu.shtml


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Provincial Jurisdictions

AlbertaWorkplace Health and SafetyAlberta Employment, Immigration and Industry

10030-107 StreetEdmonton, AB T5J 3E4(Edmonton and surrounding area)Phone: (780) 415-8690Toll-free in Alberta: 1-866-415-8690

Fax: (780) 422-3730E-mail: [email protected] Site: http://employment.alberta.ca/cps/

rde/xchg/hre/hs.xsl/53.html

British ColumbiaWorkSafeBC (Workers' Compensation Board

of British Columbia)6951 Westminster Highway (Richmond, BC)PO Box 5350 Stn TerminalVancouver, BC V6B 5L5Workplace Safety and Health InquiriesPhone: (604) 276-3100Toll-free in B.C.: 1-888-621-7233 (SAFE)

Fax: (604) 244-6490Emergency and Accident ReportingToll-free in B.C.: 1-888-621-7233 (SAFE)After hours: 1-866-922-4357 (WCB-HELP)Web Site: www.worksafebc.com

Manitoba

Workplace Safety and Health DivisionManitoba Labour and Immigration

200-401 York AvenueWinnipeg, MB R3C 0P8General Inquiries: (204) 945-3446Toll free in Manitoba: 1-800-282-8069After hours: (204) 945-0581Fax: (204) 945-4556E-mail: [email protected] Site: www.gov.mb.ca/labour/safety/


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New BrunswickWorkplace Health, Safety and CompensationCommission of New Brunswick

1 Portland StreetPO Box 160Saint John, NB E2L 3X9Phone: (506) 632-2200Toll free: 1-800-222-9775Fax: (506) 642-0718E-mail: [email protected] Site: www.whscc.nb.ca

Newfoundland and LabradorOccupational Health and Safety BranchDepartment of Government Services

15 Dundee AvenueMount Pearl, NL A1N 4R6General Inquiries: (709) 729-2706Toll-free in NL: 1-800-563-5471Fax: (709) 729-3445Serious Workplace Accident ReportsPhone: (709) 729-4444 (24 Hours)Web Site: www.gs.gov.nl.ca/ohs/

Northwest Territories and NunavutWorkers' Safety and Compensation Commissionof Northwest Territories and Nunavut

PO Box 8888Yellowknife, NT X1A 2R3

General Inquiries: (867) 920-3888Toll free: 1-800-661-0792Fax: (867) 873-4596Toll Free Fax: 1-866-277-3677E-mail: [email protected] Site: www.wcb.nt.ca


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IqaluitPO Box 669Iqaluit, NU X0A 0H0Phone: (867) 979-8500Fax: (867) 979-8501Toll-free: 1-877-404-4407Toll Free Fax: 1-866-979-8501E-mail: [email protected]: www.wcb.nt.ca

Nova ScotiaOccupational Health and Safety Division Nova ScotiaDepartment of Environment and Labour andWorkforce Development

5151 Terminal Rd., 6th FloorPO Box 697

Halifax, NS B3J 2T8General Inquiries: (902) 424-5400Toll free in NS: 1-800-952-2687Fax: (902) 424-5640E-mail: [email protected] Site: http://www.gov.ns.ca/enla/ohs/

OntarioMinistry of LabourOccupational Health and Safety Branch

505 University Avenue, 19th FloorToronto ON M7A 1T7416-326-3835Fax 416-326-7761

1-800-268-8013 (province-wide)E-mail: [email protected] Site: www.labour.gov.on.ca/english/hs/index.html


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Prince Edward IslandWorkers Compensation Board of PEIOccupational Health and Safety

PO Box 757, 14 Weymouth StreetCharlottetown, PE C1A 7L7General Inquiries: (902) 368-5680Toll-free (in Atlantic Canada): 1-800-237-5049Occupational Health & Safety24 Hr Emergency Tel: (902) 628-7513Customer Liaison Service: 1-866-460-3074

Fax: (902) 368-5705Web Site: www.wcb.pe.ca

QubecCommission de la sant et de la scurit du travaildu Qubec (CSST) (Occupational Health & Safety

Commission)1199, rue de BleuryC.P. 6056, Succursale centre-villeMontral QC H3C 4E1Tel: 514-906-3780/514 906-3061, poste 2214

1-866-302-2778Fax: 514-906-3781/514 906-3016

www.csst.qc.ca(514) 906-2911 Urgence 24 h Services deprvention-inspectionWeb Site: http://www.csst.qc.ca/portail/fr/

SaskatchewanAdvanced Education, Employment and LabourOccupational Health and Safety Division

400 - 1870 Albert StreetRegina, SK S4P 4W1Phone: (306) 787-4496Toll-free in SK: 1-800-567-7233Fax: (306) 787-2208Web Site: www.labour.gov.sk.ca/


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Saskatoon Office:122-3rd Avenue NorthSaskatoon, SK S7K 2H6

Phone: (306) 933-5052Toll-free: 1-800-667-5023Fax: (306) 933-7339

Yukon TerritoryYukon Workers' Compensation, Health and Safety

Board Occupational Health and Safety Branch401 Strickland StreetWhitehorse, YT Y1A 5N8General Inquiries: (867) 667-564524-hour Emergency Line for Reporting SeriousWorkplace Accidents and Injuries: (867) 667-5450Toll free across Canada: 1-800-661-0443Fax: (867) 393-6279E-mail: [email protected] Site: www.wcb.yk.ca

For an up-to-date listing of information sources visithttp://www.ccohs.ca/oshanswers/information/govt.html


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2. US Federal Safety and HealthAgencies

US Environmental Protection Agency (EPA)Ariel Rios Building1200 Pennsylvania Avenue NW,Washington, DC 20460Phone: (202) 272-0167Web Site: www.epa.gov

National Institute for Occupational Safetyand Health (NIOSH)

Education and Information Division (EID)4676 Columbia Parkway

Cincinnati, OH 452261-800-CDC-INFO (1-800-232-4636)Outside the US: (513) 533-8328Fax: 1-513-533-8347E-mail: [email protected] Site: www.cdc.gov/NIOSH/

Occupational Safety & Health Administration(OSHA)200 Constitution Ave., NWWashington, DC 20210Phone: (202) 693-2000Emergency reporting or if you have workplace safety

and health related questions

Toll Free: 1-800-321-OSHA (6742)Web Site: www.osha.gov


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Section 9

Bibliography andInternet Links


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A Guide to Heat Stress in Agriculture (summary).OSHA/EPA guide (1993, May).

Environment Canada Fact Sheet: Summer

Severe Weatherhttp://www.mb.ec.gc.ca/air/summersevere/index.en.html

Environment Canada Humidex Calculatorhttp://lavoieverte.qc.ec.gc.ca/meteo/Documentation/Humidex_e.html

Environment Canada Weather Office

http://www.weatheroffice.ec.gc.ca/canada_e.htmlProvince of Ontario Heat Stress Guideline

http://www.labour.gov.on.ca/english/hs/guidelines/gl_heat.html

US Dept. of Labour Heat Stresshttp://www.osha.gov/SLTC/heatstress/

OSHA Heat Stress Cardhttp://www.cdc.gov/niosh/topics/heatstress/

Extreme Heathttp://emergency.cdc.gov/disasters/extremeheat/index.asp

FEMA Federal Emergency Management AgencyExtreme Heathttp://www.fema.gov/hazard/heat/index.shtm

The Australian Council of Trade Unions ACTUGuidelines for Working in Seasonal Heathttp://www.actu.asn.au/Archive/Papers/ACTUGuidelinesForWorkingInSeasonalHeat.aspx

Prevent Heat Stresshttp://www.wsib.on.ca/wsib/wsibsite.nsf/public/PreventHeatStress

Heat Stress in Constructionhttp://www.cpwr.com/search.php?zoom_query=heat+stress&zoom_per_page=100&zoom_and=0&zoom_sort=0

OR-OSHA: The Heat Equationshttp://www.cbs.state.or.us/external/osha/pdf/pubs/3333.pdf

Working Outdoors Factsheethttp://www.twcc.state.tx.us/information/videoresources//s_working_outdoorspdf


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Ultra violet radiation from the sunhttp://www.cdc.gov/elcosh/docs/d0100/d000146/D000146.html

Hot Environments Health Effectshttp://www.ccohs.ca/oshanswers/phys_agents/heat_health.html

Hot Environments Control Measureshttp://www.ccohs.ca/oshanswers/phys_agents/heat_control.html

US Department of Labour Confined space

Hazardshttp://www.osha.gov/SLTC/smallbusiness/sec12.html: This document on confined space hazards has asection on thermal hazards.

MNOSHA heat-stress guidehttp://www.doli.state.mn.us/heatstrs.html

1. CDC. Illness and death due to environmentalheat--Georgia and St. Louis, Missouri, 1983.MMWR 1984;33:325-6.

2. Ramsey JD, Burford CL, Beshir MY, Hensen RC.Effects of workplace thermal conditions on safework behavior. Journal of Safety Research1983;14:105-14.

3. State of California, Department of Health,Occupational Health Branch. Occupational diseasein California. Annual Reports 1973-1976.

4. Dukes-Dobos FN. Hazards of heat exposure. Areview. Scand J Work Environ Health 1981;7:73-83.

5. Bartley JD. Heat stroke: is total prevention possible?Milit Med 1977;142:528,533-5.

6. World Health Organization. Health factors involvedin working under conditions of heat stress.WHO Technical Report Series 1969; no. 412.

7. Criteria for a recommended Standar; OccupationalExposure to Hot Environments, National Institutefor Occupational Safety and Health. DHHS(NIOSH) publication No. 72-10269, 1972

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Section 10

Appendices

A. A summary of health hazards andpreventive measures

B. The Humidex

C. Safety tips for different levels of theUV index

D. Glossary

E. Abbreviations

F. Sample heat stress policy and checklist

G. Case histories: fatalities from occupationalheat exposure


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APPENDIX AA summary of health hazards and preventive measures.

Type of work

Working nearextremely hot

objects such asfoundries,furnaces, red hotmetals, bakeryovens

Working outdoorson hot summerdays such asconstructionwork, road repair,farming andgrounds keeping

Health andSafety Concerns

Heat-related illnesses andheat stroke due to:

1. Radiant heat emissionfrom hot objects

2. Temperature andhumidity of the workingenvironment

3. Dehydration due toexcessive sweating

4. Excessive inner bodyheat production due toheavy workload

5. Risk of cataracts due toinfrared radiationexposure of the eyes

1. Radiant heat fromthe sun

2. Hot environmentaltemperature and relativehumidity

3. Heavy work load

Risk of skin cancer and

eye disorders due to UV(sunlight) exposure

Prevention

Reduce radiant heat emissionfrom hot objects by shieldingthe object

Reduce heat reaching theworker by using adequateshielding

Provide cool air

Provide plenty of drinkingwater

Use mechanical aids toreduce physical exertion

Provide appropriate eyeprotection

Wear wide brim hats, fullsleeve shirts and long pants

Wear loose cotton clothing

Drink plenty of water atfrequent intervals

Perform heavy work duringcooler parts of the day.

Avoid skin and eyeexposure to direct sunlightby using wide brim hats,full sleeve shirts and longpants

Sunglasses with UVprotection

Sun blocking cream withat least SPF 15

Health Hazards and Preventive Measures

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APPENDIX B

The HumidexThe Weather Service of Environment Canada uses thehumidex to provide the public with a sense of how hotit feels when we are outdoors. At a given temperature,the humidex increases as relative humidity increases.

Environment Canada has provided the following

relationship between humidex and perceived heat:In addition to temperature and humidity, weatherconditions such as the amount of sunshine and windspeed will also affect the how hot a person feels.

Determining the Humidex

The following chart can be used to determine thehumidex. For example, if the temperature is 30Cand the relative humidity is 70%, the humidex is 41C.This is considered a level of great discomfort. For 50%relative humidity and 30C temperature, the humidex is36C, which is a condition of some discomfort.

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Source: Environment Canada: websitehttp://www.wul.qc.ec.gc.ca/metro/documentation/Humidex/humidex_a.html

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Working in Hot Environments

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