The Heat Exposure Assessment Related to Health Risk at an Indoor

Workplace.

Introduction:

Nowadays, many workplaces were designed with operating system

which some of them will producing heat such as iron and steel foundries,

nonferrous foundries, brick-firing and ceramic plants, glass products

facilities, rubber products factories, electrical utilities (particularly boiler

rooms), bakeries, confectioneries, commercial kitchens (restaurant kitchen),

laundries, food canneries, chemical plants, mining sites, smelters, and steam

tunnels. Most of them still need to be handled manually by the workers and

this will give chances for the workers to expose to the risk of getting or might

possibly considered as suffering heat stroke or heat strain in hot indoor

environment (once it is rise as extremes temperatures) especially in the

summer days when the temperature and humidity are high. [Reference:

2008 TLVs and BEIs: Threshold Limit Values for Chemical Substances and

Physical Agents and Biological Exposure Indices. Cincinnati, Ohio: American

Conference of Governmental Industrial Hygienists, 2008. p. 217.]

Perspiration is the mechanism by which the body cools itself. As

perspiration evaporates from the skin, the cooling effects lower body

temperature. Blood vessels in the outer surface of the skin dilate, allowing

more blood flow to the skin surface where heat can be dissipated. Air

movement from wind or fans as well as boy movement help enhance the

evaporation process. The body can also reduce its internal temperature

throught respiration, when cooler air is brought into the body (lungs) where it

comes into contact with blood.

Understanding the dynamics of body temperature regulation and the

role it must play requires distinguishing between the concept of heat stress

and that of heat strain. They are related, but they are not the same. Heat

stress is described in terms of external demands and limits placed on a

person. Heat strain reflects the extent to which the individual has to

assemble defenses to keep total body heat content and deep body

temperature in a workable and livable range.

a) Heat Stress.

Heat stress is the cumulative of environmental and physical work

factors that constitute the total heat load imposed on the body. The

environmental of heat stress include air temperature, relative humidity, air

flow velocity, radiant heat exchange, air movement, and water vapor

pressure. While the physical work will contributes to the total heat stress of

the job by producing metabolic heat in the body in proportion to the intensity

of the work. Clothing requirements also will affect the heat stress.

All these factors defining potential heat stress, which are assessed with

varying degrees of precision and accuracy. Such measures provide valuable

and useful information about the thermal load to which humans must adjust.

These measurements, however, provide no information about the safety of

the exposure or the extent to which humans are compromised in their

abilities to adjust to it.

Measurements of thermal stress, no matter how accurately they are

assessed, only quantify the internal and external thermal demands that

challenge thermoregulation. They are unreliable predictors of how safe

someone will be when working in that environment. Accurate measurements

of heat stress provide the basis for an assessment of how hot an

environment is.

Usually, the more factors are evaluated, the more reliable the net

information. Measuring just air temperature, for instance, seldom provides

much useful insight. Additional data about ambient humidity, air velocity,

infrared radiant intensities, and emissivity of clothing and nearby objects

provide a much more complete picture for the level of heat stress. A mild or

moderate heat stress may cause discomfort and may adversely affect

performance and safety, but it is not harmful to health. As the heat stress

approaches human tolerance limits, the risk of heat-related disorders

increases.

b) Heat Strain.

Heat strain is the series of physiological response resulting from heat

stress. These responses reflect the degree of heat stress. When the strain is

excessive for the exposed individual, a feeling of discomfort or distress may

result, and will finally a disorder may ensue. The severity of strain will

depend not only on the magnitude of the existing stress, but also the age,

physical fitness, degree of acclimatization and dehydration of the worker.

Heat strain reflects the extent to which the individual has to organize

defenses to keep total body heat content and deep body temperature in a

workable and livable range. It is a characteristic that is unique to each

person and will, in fact, change even for the same person from time to time.

Heat strain is the cost of adjusting to heat stress. It is not a measure of how

successfully the adjustment is made. Unpleasant measures of heat strain

include body core temperature, heart rate, and sweat loss. Other important

responses are allocations of the fluid volumes in the body, electrolyte

concentrations in the intra- and extra-cellular spaces, levels of hormones,

and blood pressure.

Heat strain is not reliably predicted from heat stress. This means that

environmental measurements cannot safely or accurately predict heat strain,

the amount of discomfort, or the degree of danger being faced by an

individual at any time. The predictive gap is largely explained by personal

risk factors. These are each person’s unique strengths and weaknesses for

distributing heat in the body and for dissipating it to the surrounding

environment.

c) Heat Disorders.

Heat disorders generally are caused by the body’s inability to shed

excess heat. The body is cooled by losing heat through the skin and by

perspiration. When heat gain exceeds the amount the body can remove, the

body’s inner temperature begins to rise, and heat-related illness may

develop.

Heat disorders share one common feature which is once the individual

has been overexposed to heat, or over-exercised for his age and physical

condition on a hot day, the severity of heat disorders tends to increase with

age for example it can be a heat cramps in a 17-year-old but may become as

a heat exhaustion in someone 40 and heat stroke in a person over 60 years

old. Sunburn can significantly retard the skin’s ability to shed excess heat.

Elderly people, young children, people on certain medications or drugs, and

people with weight and alcohol problems are particularly susceptible to heat

reactions.

d) Heat-related Illness

Heat-related illness can occur during work in hot weather, in hot ambient

conditions, or when workers are wearing layers of protective gear that

interfere with perspiration( the mechanism by which the body cools itself).

Below are the following descriptions of the forms of heat-related illness.

i. Heat rash.

Heat rash can be called as prickly heat which appears as little red

bumps on the skin, which is in fact inflamed sweat gland. It usually appears

on areas of the body that become and stay damp, as under sweat soaked

shirt, pants and gloves. Heat rash is not usually serious, although it can

become infected. Treatment includes allowing the skin to dry and keeping

affected areas as dry as possible. Infections can be treated with a topical

antibiotic ointment.

ii. Heat cramps.

It is typically caused by heavy perspiration with resultant loss of body

fluid, causing an imbalance in the salts and minerals of the muscles, which in

turn can causes cramping. Heat cramps can be very painful but do not

usually last very long and do not cause permanent disability. Treatment for

heat cramps include removing the individual from the hot environment and

providing plenty of water to drink.

iii. Heat syncope.

This is a fainting or near-fainting condition that occurs among people

who have been standing in one position for a period of time, usually in the

sun, but it can occur in any warm environment. Standing still causes of the

blood to pool in the lower region of the body, which leads to fainting after

some time. In summer, this is not uncommon at outdoor receptions or

weddings. It may also occur at construction sites, affecting the worker who

stands on the streets in the hot sun directing traffic. Individuals with heat

syncope should lie down in a shady spot and drink water. Flexing leg muscles

and moving around periodically during the work shift along with regular

intake of water all help prevent the condition.

iv. Heat exhaustion.

Typically, it will develop among individuals who have experienced loss

of body fluids due to heavy perspiration. Symptoms of heat exhaustion

include nausea, dizziness, headaches, tiredness, and possibly fainting. An

individual suffering from heat exhaustion is usually sweating profusely and

may be confused or disoriented. Treatment includes removing the individual

from the hot environment and providing cool water (7–10 ˚C) to drink. The

individual should be monitored by someone with first aid training and

medical attention should be sought immediately if the condition deteriorates.

v. Heat stroke.

This is the most serious form of heat-related illness. The individuals

who are suffering from heat stroke may or may not be perspiring and will

have an elevated body temperature at or above 40˚C. Symptoms of heat

stroke include a red, hot face and skin, lack of or reduced perspiration,

erratic behavior, confusion or dizziness, and collapse or unconsciousness.

This condition is extremely dangerous medical emergency, which the person

should be moved to cool area and aggressively cooled, using wet blankets

and fanning. Victims should be transported by a medical team to the nearest

hospital immediately or the outcomes include possible coma and death.

They are several factors that can affect the potential for workers to develop

heat-induced conditions.

i) Acclimatization: the workers experience and acclimatization period

during the first ten days to two weeks of work in hot environment.

During this time, their body gradually adjusts to operating in very

warm conditions. After the body has acclimated, workers are less

likely to experience heat-related problems. While individuals need

10-14 days to become heat-acclimated, they may lose this

acclimation after only a few days away from hot environment. For

this reason, workers returning from long weekends or vacations

should monitor themselves closely to detect early signs of heat

stress.

ii) Physical fitness: it is known that workers who are in good physical

condition are less likely to experience heat-related illnesses. In fact,

obesity also may contribute to a worker’s inability to handle heat

stress due to the added insulation that prevents the body from

cooling efficiently.

iii) Age: the older workers may have some more difficulty working in

hot environment and may take longer period to become

acclimatized.

iv) Alcohol and drug usage: alcohol consumption may contribute to the

dehydration and makes workers much more likely to experience

heat-related illness. Some prescription and over-the-counter drugs

may also increase a worker’s susceptibility to heat stress.

v) Atmospheric conditions: high humidity, direct sunlight, and radiant

heat greatly increase heat stress conditions, which are likely with

personal protective equipment (PPE) usage at temperatures of 21˚C

or greater.

vi) Workload: workers performing strenuous work are more likely to

suffer from heat-induced illness since they are generally losing

more body fluids through perspiration. In addition, the heat

produced by the body’s metabolism adds to the overall heat load of

the body.

Heat transfer deal with how quickly heat energy can be passed from one

object to another. It can be transferred through several mechanisms which

are conduction, convection and radiation.

i) Conduction.

Conduction is the transfer of heat between materials that contact each

other. Heat passes from the warmer material to the cooler material. For

example, a worker's skin can transfer heat to a contacting surface if that

surface is cooler, and vice versa.

ii) Convection.

Convection is the transfer of heat in a moving fluid. Air flowing past the

body can cool the body if the air temperature is cool. On the other hand, air

that exceeds 35°C (95°F) can increase the heat load on the body.

iii) Radiation.

Radiation is the transfer of heat energy through space. A worker whose

body temperature is greater than the temperature of the surrounding

surfaces radiates heat to these surfaces. Hot surfaces and infrared light

sources radiate heat that can increase the body's heat load.

General Objective:

To conduct a heat stress assessment among workers at Nando’s Kitchen,

Pavilion Shopping Complex, Kuala Lumpur at 10th of September 2009.

Specific Objective:

i. To determine the temperature at working area in Nando’s

Kitchen.

ii. To determine the workload category of all the workers based on

their work task whether as worker at administrative or production

part.

iii. To determine whether the workers are having any heat stress or

not based on their workload category and WBGT reading (heat

exposure).

iv. To determine the degree of comfort at working area by using

Humidex Table.

Problem Statement:

When the air temperature or humidity rises above the optimal ranges

for comfort, problems can arise. Exposure to more heat stress can cause

physical problems which impair workers' efficiency and may cause adverse

health effects.

Some of the problems and their symptoms experienced in the

temperature range between a comfortable zone (20˚C-27°C) and the highest

tolerable limits (for most people) are summarized in Table 1.

The risk of heat-related illness varies from person to person. A person’s

general health also influences how well the person adapts to heat (and cold).

Those with extra weight often have trouble in hot situations as the body has

difficulty maintaining a good heat balance.

Age (particularly for people about 45 years and older), poor general

health, and a low level of fitness will make people more susceptible to feeling

the extremes of heat. Medical conditions can also increase how susceptible

the body is. People with heart disease, high blood pressure, respiratory

disease and uncontrolled diabetes may need to take special precautions.

In addition, people with skin diseases and rashes may be more

susceptible to heat. Substances (both prescription or otherwise) known can

also have an impact on how people react to heat. Heat exposure causes the

following illnesses such as heat edema, heat rashes, heat cramps, heat

exhaustion, heat syncope, and also heat stroke and hyperpyrexia (elevated

body temperature).

Certain kidney, liver, heart, digestive system, central nervous system

and skin illnesses are thought by some researchers to be linked to long-term

heat exposure. However, the evidence supporting these associations is not

conclusive. Chronic heat exhaustion, sleep disturbances and susceptibility to

minor injuries and sicknesses have all been attributed to the possible effects

of prolonged exposure to heat. (Reference: Occupational exposure to hot

environments. Revised Criteria. Cincinnati, Ohio: National Institute for

Occupational Safety and Health, 1986).

Methodology:

i) Monitoring location.

The heat exposure monitoring was done at Nando’s Kitchen, Pavilion

Shoping Complex, Kuala Lumpur at 10th of September 2009. The purpose of

this monitoring is to determine the heat level at the kitchen which there is a

stoves as a source of heat exposure to the workers which work inside the

kitchen as a cooker.

ii) Research sampling.

The selection of the respondent were done randomly among workers

which including the managers (administrative part) and workers inside the

kitchen (production part).

iii) Data collection method.

There are two types of data collection methods that we were used

which are the heat temperature monitoring equipment and also the

questionnaires. The heat monitoring was done around 20 minutes from 8.57

p.m untill 9.20 p.m on that particular day.

The heat monitoring was done by using the Wet Bulb Globe

Temperature (WBGT) meter model QUESTemp˚ 34 Thermal Environment

Monitor.

Questionaires was done through the selection of research respondents.

The selection of the respondents were done randomly and the questions

asked in the questionaires were based on their personal information, medical

history, job information, and also to know the symptoms of heat stress if

they ever had any.

Instrument:

A number of approaches that can be used for monitoring the work

environment. The most common method is one published in the ACGIH TLV

booklet. The ACGIH TLVs for heat stress are based on an index called the

Wet Blub Globe Temperature (WBGT) that provides the information on the

heat load of the environment. It measures temperatures with a dry bulb

thermometer, a wet bulb thermometer and a large, matte, black globe.

The dry bulb thermometer measures the ambient temperature. This

thermometer is exposed to the air just as any thermometer is used to

measure air temperature. A dry bulb thermometer consist of a hollow glass

tube with a bottom reservoir of mercury. The range of the thermometer

should be -5 to +50oC and accurate to ±0.5oC. temperature beyond the

range of a dry bulb thermometer may break the thermometer. When the

measurements are taken, the dry bulb thermometer must be shielded from

radiant heat sources so that only the temperature of the ambient air will be

detected. Thermoelectric thermometers or thermocouples are also

commonly used to measure the ambient air temperature.

Wet-bulb temperature is measured using a standard mercury-in-

glass thermometer, with the thermometer bulb wrapped in wick, which is

kept wet in distilled water. The wick is made of highly absorbent woven

cotton. As the wick evaporates water, a certain amount of heat energy is

dissipated through evaporative cooling. The bulb is then cooled by the heat

absorbed by water during evaporation of the water, and equilibrium is

reached between the evaporation rate and the water vapor pressure in air.

The temperature is indicated on the thermometer. At full saturation, the wet

bulb thermometer temperature will equal the dry bulb temperature since no

evaporative cooling will be experienced. The evaporation of water from the

thermometer has a cooling effect, so the temperature indicated by the wet

bulb thermometer is less than the temperature indicated by a dry-bulb

(normal, unmodified) thermometer. The rate of evaporation from the wet-

bulb thermometer depends on the humidity of the air - evaporation is slower

when the air is already full of water vapor. For this reason, the difference in

the temperatures indicated by the two thermometers gives a measure of

atmospheric humidity.

The black globe thermometer, or Vermon globe, is the standard

method for measuring radiant heat. A black globe thermometer consist of a

6-in. diameter hollow copper sphere that is painted matte black. a

thermometer is inserted so that its bulb is centered inside the globe. The

range of the thermometer should be -5 to +100oC and accurate to ±0.5oC.

the black globe absorbs radiant heat increasing the temperature of air within

the globe proportional to the amount of heat energy absorbed. The

thermometer inside the globe is allowed to reach equilibrium. The

temperature calculated from globe temperature is termed the mean radiant

temperature, which is indicative of the average temperature of surrounding

environment.

Quality Control:

The range of the dry and natural wet bulb thermometer should be 5oC

to ±50oC. The dry bulb thermometer must be shielded from the sun and the

other radiant surfaces of the environment without restricting the airflow

around the bulb. The wick of the natural wet bulb thermometer should be

kept wet with distilled water for at least one-half hour before the

temperature reading is made. It is not enough to immerse the other end of

the wick into the reservoir of distill water and wait until the whole wick

becomes wet by capillarity. The wick must be wetted by direct application of

Globe Thermomete

r

Wet Bulb Thermomete

r

Dry Bulb Thermomet

er

water from a syringe one-half hour before each reading. The wick must cover

the bulb of the thermometer and an equal length of additional wick must

cover the stem above the bulb. The wick should always be clean, and new

wicks should be washed before using.

A globe thermometer consisting of a 15cm (6-inch) in diameter hollow

copper sphere painted on the outside with a matte black finish, or

equivalent, must be used. The bulb or sensor of the thermometer (range -5oC

to +100oC with an accuracy of ±0.5oC) must be fixed in the center of the

sphere. The globe thermometer should be exposed at least 25 minutes into

the environment atmosphere before it is used.

A stand should be used to suspend the three thermometers so that

they do not restrict free air flow around the bulbs and the wet bulb and globe

thermometer are not shaded. The QUESTemp˚ 34 should be placed at a

height of 0.1m (feet), 1.1m (abdomen) and 1.7m (head) for standing

individuals or 0.1m (feet), 0.6m (abdomen) and 1.1m (head) above the floor

for seated individuals. Tripod mounting is recommended to get the unit away

from anything that might block radiant heat or airflow. A 1/4"x20 threaded

bushing on the bottom of the instrument allows mounting to a standard

photographic tripod. Do not stand close to the unit during sampling. The

thermometers must be placed so that the readings are representative of the

employee’s work or rest areas, as appropriate.

Result and Discussion:

WBGT Reading:

Measurement Sensor 1

(abdomen) ˚C

Sensor 2

(head) ˚C

Sensor 3 (feet)

˚C

WBGT In 26.5 28.5 24.7

WBGT Out 26.3 28.1 24.6

Wet Bulb 23.6 24.4 22.2

Dry Bulb 31.5 34.7 29.5

Globe 33.5 38.1 30.6

Heat Index 32 36 30

Relative

Humidity

47 % 40 % 49 %

By using the WBGT indoor (with no exposure to light) calculation:

WBGT = 0.7WB + 0.3GT

Sensor Calculation

Sensor 1: WBGT = 0.7 (23.6) + 0.3 (33.5)

= 26.57 ˚C

Sensor 2: WBGT = 0.7 (24.4) + 0.3 (38.1)

= 28.51 ˚C

Sensor 3: WBGT = 0.7 (22.2) + 0.3 (30.6)

= 24.72 ˚C

Then, the assessment of heat exposure was calculated by using the WBGT

(TWA) calculation:

Average

WBGT =

(2) WBGT1+ (1) WBGT2 + (1)

WBGT3 or

0.5 WBGT1 + 0.25

WBGT2 + 0.25

WBGT34

=

(2) (26.57) + (1) (28.52) + (1)

(24.72)

4

= 26.59 ˚C

The correction calculation factor for heat stress exposure was calculated by

using the following method:

TABLE III: 4-3. WBGT CORRECTION FACTORS IN °C

Clothing type Clo* value

WBGT correction

Summer lightweight working clothing

0.6 0

Cotton coveralls 1.0 -2

Winter work clothing 1.4 -4

Water barrier, permeable 1.2 -6

*Clo:   Insulation value of clothing. One clo = 5.55 kcal/m2/hr of heat exchange by radiation and convection for each degree °C difference in temperature between the skin and the adjusted dry bulb temperature.

Note: Deleted from the previous version are trade names and "fully encapsulating suit, gloves, boots and hood" including its clo value of 1.2 and WBGT correction of -10.

Since all the workers at Nando’s Kitchen Restaurant were wearing summer

lightweight working clothing, thus the correction factor is 0.

WBGT = 26.59 ˚C – 0 ˚C

= 26.59 ˚C

However, in order to determine whether the workers are having any heat

stress or not, the work load should be known first then compared with the

standard given.

Work Load Category

Category kcal/hour

Light Work Up to 200 kcal/hour

Medium Work 200–350 kcal/hour

Heavy Work 350–500 kcal/hour

The workload calculation was done by referring to the following table:

TABLE III: 4-1. ASSESSMENT OF WORK

Body position and movement

kcal/min*

Sitting 0.3Standing 0.6Walking 2.0-3.0Walking uphill add 0.8 for every meter (yard)

rise

Type of work Average kcal/min

  Range kcal/min

Hand work  Light 0.4   0.2-1.2  Heavy 0.9

Work: One arm  Light 1.0   0.7-2.5  Heavy 1.7

Work: Both arms  Light 1.5   1.0-3.5

Heavy 2.5

Work: Whole body  Light 3.5   2.5-15.0

 Moderate

5.0

  Heavy 7.0

 Very heavy

9.0

* For a "standard" worker of 70 kg body weight (154 lbs) and 1.8m2 body surface (19.4 ft2).

** The workload calculation should be added with basal metabolism which is 1.0 kcal/min.

Source: ACGIH 1992 (updated in 2001).

Respondent Work load calculationWork load

category

1

(administrat

ive part)

2.0 kcal/min (walking) + 3.5 kcal/min

(working with whole body) + 1.0 kcal/min

(basal metabolism)

= 6.5 kcal/min

6.5 kcal/min × 60 min = 390 kcal/hour

Heavy

2 0.6 kcal/min (standing) + 1.5 kcal/min Heavy

(production

part)

(working with both arm) + 3.5 kcal/min

(working with whole body) + 1.0 kcal/min

(basal metabolism) = 6.6 kcal/min

6.6 kcal/min × 60 min = 396 kcal/hour

3

(production

part)

0.6 kcal/min (standing) + 1.5 kcal/min

(working with both arm) + 3.5 kcal/min

(working with whole body) + 1.0 kcal/min

(basal metabolism) = 6.6 kcal/min

6.6 kcal/min × 60 min = 396 kcal/hour

Heavy

4

(production

part)

2.0 kcal/min (walking) + 1.5 kcal/min

(working with both arm) + 3.5 kcal/min

(working with whole body) + 1.0 kcal/min

(basal metabolism)= 8.0 kcal/min

8.0 kcal/min × 60 min = 480 kcal/hour

Heavy

5

(administrat

ive part)

2.0 kcal/min (walking) + 3.5 kcal/min

(working with whole body) + 1.0 kcal/min

(basal metabolism)

= 6.5 kcal/min

6.5 kcal/min × 60 min = 390 kcal/hour

Heavy

All the workers including at the production part (working at the kitchen as

cookers) and administrative part (working at counter as money reception or

manager which sometimes helps at the kitchen) were performed a heavy

workload task.

However, to indicate whether they are having or getting any heat stress or

heat-related illness or not, we were using the following table as a reference.

Since the WBGT value for all of those workers are 26.59˚C and the suggested

temperature is 27.5˚C (maximum), thus all the workers can be considered as

not getting any heat stress or heat-related illness. The present temperature

condition at working area can be considered as acceptable for all workers.

However, to indicate whether the environmental condition (surrounding) at

work area comfortable or not, the following step were used.

SensorDry Bulb

(˚C)

Relative

Humidity

1

(abdome

n)

29.5 47 %

2 (head) 34.7 40 %

3 (foot) 31.5 49 %

Average 31.9 45.3%

Since the temperature is 31.9˚C (assumed as 32˚C) and the relative

humidity is 45.3% (assumed as 45%), thus condition at the workplace can be

considered as “some discomfort”.

However, based on the questionnaire given the workers were claimed that

they are comfortable with the current working area condition. It may due to

the installation of air-conditioner in whole building of Pavilion Shopping

Complex (since this Nando’s Kitchen is placed inside the Pavilion Shopping

Complex). Thus, it will be able to balancing the distribution of heat and

making the environment not too hot when the workers are cooking at the

kitchen.

Conclusion:

Based on the study and the monitoring of the heat stress above, we

can conclude that all of the respondents who worked at Nando’s Kitchen,

Pavilion Shopping Complex, Kuala Lumpur were not experiencing any heat

stress or heat-related illness yet. This conclusion was made due to the WBGT

reading and workload level of the respondents which have been monitored at

10th September 2009.

The conclusion of the heat stress were done complying to the

guidelines given by the American Conference Governmental of Industrial

Health (ACGIH) 1992 which the monitoring was done by using the WBGT

meters and questionnaires. The questionnaires were distributed first to all six

respondent to determine if they are having any heat-related symptoms like

nausea, dizziness and so on. The WBGT was used after that to determine the

temperature at the respondents working area (at the kitchen). Based on the

heat index, all the respondent were considered as not having any heat stress

since they work there.

Standardization:

The standard used in determining the heat stress, experiencing by the

six respondent at Nando’s Kitchen, Pavilion Shopping Complex, Kuala

Lumpur was done according to the American Conference of Governmental

Industrial Hygienist (1992) which have states that all workers should not be

permitted to work when their deep body temperature exceeds the value of

38.0oC (100.4oF).

By using the WBGT meter and questionaires as suggested by the

AGCIH and the previous reserach, we can determined weather or not that

each respondent have experiencing the heat stress during working hours.

Beside that, from using the questionaires we were able to know the

symptoms of the heat stress experienced by the respondents.

Belows are related standards and guideline used in heat stress

i. NIOSH (Minnesota, USA)

Criteria Document for Heat Stress – One-hour TWA for continuous

exposure or two-hour TWA for intermittent exposure 79oF WBGT

ii. International Standard ISO 7243: 1989-08-01

Hot environments – estimation of the heat stress on working man,

based on the WBGT index.

Recommendation:

Since all the workers are not experiencing any heat stress or heat-related

illness, the following table was provided as the employer can taking any

actions if any heat-related symptoms arise in the future.

There are other prevention actions which can be used to avoid the workers

from having any heat stress or heat-related illness. The reduction of heat

stress can be accomplished through the following controls which are:-

a) Train employees to recognize heat stress.

b) Allow time for employee acclimation to hot environments.

Source:

http://www.thezenith.com/employers/services/pi/indsaf/agr/rmb/Agriculture_PreventingHea

tStress

c) Encourage workers to drink adequate replacement fluids. A person

should drink 1 1/2 gallons of water per day. Salt pills or sport drinks

with added salt are unnecessary as the typical people has enough salt

in their diet. If a person loses 1.5% of their total body weight in a

workday, they are not drinking enough fluids (for example, if a 200

pound employee loses more than 3 pounds in a day, they need to drink

more fluid).

d) Someone who develops symptoms of heat exhaustion or heat stroke

should be removed to a cool area, provided fluids and be medically

evaluated.

e) Use the buddy system (never working alone in hot areas) to monitor

co-worker for heat stress.

f) Encourage employees to maintain physical fitness.

Through our group’s observation, there are engineering controls at this

workplace which are an installation of LEV system and air-conditioning

system. While for the administrative control is by giving the entire worker

the same type of clothes which are summer lightweight working clothes.

LEV system Proper clothing Air-conditioning in whole

building

References:

1) OSHA Technical Manual: Heat Stress (online). Retrieved September 4,

2009 from United States Department of Labor, Occupational Safety &

Health Administration. Available at

http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_4.html#5

2) NIOSH Safety & Health Topic: Heat Stress (online). Retrieved September

4, 2009 from National Institute for Occupational Safety and Health.

Available at http://www.cdc.gov/niosh/topics/heatstress/

3) Preventing Heat Stress (online). Retrieved October 26, 2009 from The

Zenith.Com, Zenith Insurance Company. Available at

http://www.thezenith.com/employers/services/pi/indsaf/agr/rmb/Agricultur

e_PreventingHeatStress_rm123.pdf

4) Risk Assessment Work Sheet: Heat Stress Risk Assessment Checklist

(online). Retrieved September 4, 2009 from Health and Safety Executive.

Available at

http://www.hse.gov.uk/temperature/information/heatstress/riskassessmen

t.pdf

5) ACGIH heat stress 7th edition (online). Retrieved September 4, 2009.

http://www.worksafe.org/images/contentEdit/docs/ACGIH%20heat

%20stress%207th%20edition.pdf

6) Hot Environment: Health Effects & Control Measures (online). Retrieved

October 28, 2009 from Canadian Centre for Occupational Health & Safety.

Available at

http://www.ccohs.ca/oshanswers/phys_agents/heat_health.html &

http://www.ccohs.ca/oshanswers/phys_agents/heat_control.html

7) Heat Stress Disorder (online). Retrieved October 28, 2009 from Extension

Specialist, North Carolina Cooperative Extension Service. University of

Florida; Institute of Food and Agricultural Sciences’ Disaster Handbook. .

Available at

http://www.ces.ncsu.edu/disaster/factsheets/pdf/heatstress.pdf

8) Heat Stress Prevention Program (Doc. No: OHS-4.6.20, page 3 of 8, issue

date: July 18, 2008) (online). Retrieved October 28, 2009 from University

of Windsor Occupational Health & Safety. Available at

http://web4.uwindsor.ca/

9) Nims D. K. (1999). Basics of Industrial Hygiene. Canada: John Wiley &

Sons, Inc.

10) Martin B. Stern, S. M. (1999). Applications & Computational Elements

of Indutrial Hygiene. U.S.A: Lewis Publisher (imprint of CRC Press LLC).