: Investigation on the relation of Heat Stress to Construction Labor Productivity for Rebar workers Case Study: Phnom Penh

ក្រសួងអប់រំយុវជន និងរីឡា
វិទ្យាស្ថា នបច្ចេរវិទ្យារម្ពុជា
ច្េប៉ា តឺម្៉ាង់ ច្ទ្យពច្ោសល្យឧសាហរម្ម និងច្ម្ោនិរ
គច្ក្ោងសញ្ញា បក្តវិសវររ
ក្បធានបទ្យ: ោរសិរាក្ស្ថវក្ជាវររទ្យំនារ់ទ្យំនងននច្្សេសរច្តេ ជាម្ួយ
ផល្ិតភាពោរងាររបស់រម្មររសំណង់ផ្ផែរចងផ្េរ
និសស ិត : គុំ វិស្ថល្ និង អ៊ូ ពុទ្យឋី
ឯរច្ទ្យស : ច្ទ្យពច្ោសល្យឧសាហរម្ម និងច្ម្ោនិរ
ក្គូទ្យទ្យួល្បនទុរ : បណឌិ ត គីនណាច្ល្ត វង់ច័នទ
ឆ្ែ ំសិរា : ២០១៨-២០១៩
MINISTERE DE L’EDUCATION,
DE LA JEUNESSE ET DES SPORTS
INSTITUT DE TECHNOLOGIE DU CAMBODGE
DEPARTEMENT DE GENIE INDUSTRIEL ET MECANIQUE
MEMOIRE DE FIN D’ETUDES
Titre: INVESTIGATION ON THE RELATION OF HEAT STRESS TO
CONSTRUCTION LABOR PRODUCTIVITY FOR REBAR
WORKERS
Etudiants : KUM Visal et OU Puthy
Spécialité : Génie Industriel et Mécanique
Tuteur de stage : Dr. Kinnaleth VONGCHANH
Année scolaire : 2018-2019

ក្រសួងអប់រំយុវជន និងរីឡា
វិទ្យាស្ថា នបច្ចេរវិទ្យារម្ពុជា
ច្េប៉ា តឺម្៉ាង់ ច្ទ្យពច្ោសល្យឧសាហរម្ម និងច្ម្ោនិរ
គច្ក្ោងសញ្ញា បក្តវិសវររ
របស់និសិសត: គុំ វិស្ថល្ និង អ៊ូ ពុទ្យឋី
ោល្បរិច្ចេទ្យោរពារនិច្រខបបទ្យ: នងៃទ្យី ផ្ែ ឆ្ែ ំ២០១៩
អនុញ្ញា តឲ្យោរពារគច្ក្ោង
នាយរវិទ្យាស្ថា ន:
នងៃទ្យី ផ្ែ ឆ្ែ ំ ២០១៩
ក្បធានបទ្យ: ោរសិរាក្ស្ថវក្ជាវររទ្យំនារ់ទ្យំនងននច្្សេសរច្តេ ជាម្ួយ
ផល្ិតភាពោរងាររបស់រម្មររសំណង់ផ្ផែរចងផ្េរ
សហក្ាស: បនទប់ពិច្ស្ថធន៍ផល្រច្តេ
ក្បធានច្េប៉ា តឺម្៉ាង់: ច្ោរ ប៉ា ន់ សុវណាា
ក្គូទ្យទ្យួល្បនទុរ: បណឌិ ត គីនណាច្ល្ត វង់ច័នទ
ក្គូទ្យទ្យួល្បនទុរទ្យី២: បណឌិ ត ចាន់ ស្ថរិនទ
អែរទ្យទ្យួល្ែុសក្តូវរែុងសហក្ាស: បណឌិ ត គីនណាច្ល្ត វង់ច័នទ
រាជធានីភ្ែំច្ពញ
ក្គូទ្យទ្យួល្បនទុរទ្យី១:

MINISTERE DE L’EDUCATION,
DE LA JEUNESSE ET DES SPORTS
INSTITUT DE TECHNOLOGIE DU CAMBODGE
DEPARTEMENT DE GENIE INDUSTRIEL ET MECANIQUE
MEMOIRE DE FIN D’ETUDES
DE M.KUM Visal et M. OU Puthy
Date de soutenance: le juillet 2019
« Autorise la soutenance du mémoire »
Directeur de l’Institut:
Phnom Penh, le juillet 2019
Titre: INVESTIGATION ON THE RELATION OF HEAT STRESS TO
CONSTRUCTION LABOR PRODUCTIVITY FOR REBAR WORKERS,
CASE STUDY: PHNOM PENH
Etablissement du stage: Thermal Laboratory
Chef du département: M. PAN Sovanna
Tuteur de stage: Dr. Kinnaleth VONGCHANH
Tuteur du stage 2: Dr. CHAN Sarin
Responsable de l’établissement:innaleth VONGCHANH
PHNOM PENH
Tuteur du stage 1:

i
ACKNOWLEDGMENTS
Foremost, we have a great honor to acknowledge our parents who give financial
supports, morale, encouragement, and inspiration.
We would like to thank H.E. Dr. OM Romny Director General of ITC, who keeps
trying to lead our university to be forward. He has provided and found cooperation with other
universities to forward developing study program.
The special thanks to Mr. Pan Sovanna, Chief of Department Mechanical and
Industrial Engineering. He always tries to promote and develop the department, lecturers, and
students.
We can’t achieve our completion research without whom we are deeply grateful to our
lecturers Dr. Kinnaleth Vongchanh and Dr. Chan Sarin who have always given all their
highest effort to our thesis, and they spent time to correct our mistakes. With their rigorous
guidance, we could see an effective project success and productivity.
In addition, we also would like to give very special thanks to Techno-Construction and
Design Co., LTD to conduction field site measurement.
Furthermore, we especially thank Cambodia Climate Change Alliance (CCCA) to grant
this project.
Finally, we would like to thank Dr. Jakie Yang for sharing ideas, experiences
encouragement, and advice for our thesis. We also thank to all lecturers and students for sharing
the helpful recommendation for our thesis.

ii
អត្ថបទសង្ខេប
ដោយដោងតាមការសិក្សាស្រាវជ្រាវបានរក្សដ ើញថា ការរស់ដៅ និង ការអភិវឌ្ឍន៍
ដសដ្ជក្សិច្ចដៅក្សនុងជ្ររដេសក្សមពុារច្ចុរបនន តជ្រមូវដោយមានការសិក្សាស្រាវាវកាន់តតខ្ល ាំង
ដលើការដក្សើនដ ើងក្សដតៅ តដ្លជះឥេធិពលមិនជ្រតឹមតតដ្ល់ររិាា នដេ រុតនៅវាបានជះឥេធិពល
ដ្ល់ផលិតភាពការងារ។ តដ្លក្សនុងជ្ររដេសមិនទាន់មានការសិក្សាេូលាំេូលាយដៅដ ើយ។
ដ្ូដច្នះដ ើយដេសៅសក្សាំដៅតដ្លជះឥេធិពលដ្ល់ផលិតភាពការងារ ជ្រតូវបានដលើក្សយក្សមក្ស
សិក្សាស្រាវជ្រាវ។ ាការពិតក្សដតៅ ពិតារះពាល់ដ្ល់សក្សមមភាពររស់ក្សមមក្សរោងខ្ល ាំង
តដ្លោច្រណ្តៅ លឲ្យដជ្ររះថាន ក្ស់ដ្ល់រាងកាយ និង បាត់រង់ផលិតភាពការងារ។ ក្សនុងដ្ាំដ ើ រ
ការសិក្សាដនះជ្រតូវបានដ្វើដ ើងដៅអាំ ុងដពលរដ្ូវដតៅ ាដពលមួយតដ្លដតៅ រាំផុតដៅក្សនុង
ជ្ររដេសក្សមពុា។ ការសិក្សាដនះបានចារ់ដផៅើមពីតែមីនា ដ្ល់ តែមិថុនាឆ្ន ាំ២០១៩ តដ្លជ្រតូវ
ដ្វើការសដងេត និង ស្រសង់េិនធន័យដលើការោា នច្ាំនួនពីរដផេងរន ។ ដរលរាំ ងននការសិក្សា
ដនះ គឺដដ្ើមបីតសវងរក្សផលិតភាពការងារដៅក្សនុងការោា ន និង អញ្ញា តតដ្លដ្វើឲ្យបាត់រង់ផលិ
តភាពការងារ។ ដោយដោងតាមការសិក្សាស្រាវជ្រាវ អញ្ញា តតដ្លបានដ្វើការសដងេត និង
បានរក្សដ ើញថា គឺភាពាក្ស់តសៅងននសីតុ ហ ភាព WBGT តដ្លមានសីតុ ហ ភាពច្ដនាល ះពី
២៥.០៨°C ដៅ ៣៥.៤០°C ោយុចារ់ពី១៨ឆ្ន ាំដៅ៤៥ឆ្ន ាំ ក្សាំរិតលាំបាក្សអតិររមាននោរមម ៍
ដពលដ្ើវការ RPE (១៧.១៨) អជ្រតាច្ងាវ ក្ស់ដរះដ្ូង HR (ចារ់ពី៦៩.៨៤ bpm ដៅ១៣៣.០២
bpm) ោរមម ៍ តដ្លរងតាមរយ:ក្សដតៅ TS មាន ៣២.១៣% ជ្ររដភេការងារ (work activity)
ម្យមផលិតផលការងារររស់ក្សមមក្សរមាន៦៧.៤៦% ម្យមផលិតភាពការងារមិនផ្ទា ល់
១៦.៧១%និង ម្យមឥតបានផលិត ១៥.៨៣%។ ាលេធផលោយុ (Age), ោរមម ៍ តដ្ល
រងតាមរយ:ក្សដតៅ (RPE) សីតុ ហ ភាពជ្រតដច្ៀក្ស (Ear-T) និង ច្ងាវ ក្ស់ដរះដ្ូងអតិររិមា
(HRmax%) មានេាំនាក្ស់េាំនង ដៅនឹង CLP% តដ្លមាន P-value រាងរន គឺ 0,001, 0,009, 0,02,
និង 0,023 ។

iii
RESUME
Au Cambodge, l’ergonomie de l’environnement thermique n’est pas une étude
approfondie; il faut donc tenir compte de l’influence du stress thermique sur la productivité.
Les effets de la chaleur sur les activités quotidiennes des travailleurs peuvent entraîner des
blessures graves et une faible productivité. Les études sur le terrain ont été menées pendant la
saison sèche, cette période étant considérée absolument comme la période la plus chaude du
Cambodge. Cette étude a débuté de mars à juin 2019 pour seulement deux sites de construction.
Le but de cetteétude est de connaître la productivité du travail de construction des ouvriers des
barres d’armature et de découvrir les paramètres de corrélation avec la productivité du travail.
Les données ont été collectées, telles que la WBGT (température du globe à bulbe humide) de
Moniteur de stress thermique, Indice de contrainte physique (Hr., Fréquence cardiaque,
Température auriculaire), Evaluation de l'effort perçu (RPE), Sensation thermique (TS), Taux
de sudation, tapez activité de travail. La température minimale est de 25 ° C et la plus élevée,
de 35,40 ° C. La fréquence cardiaque la plus élevée est comprise entre 87,69 et 133,02, valeur
maximale exprimée par le maximum. L'évaluation de l'effort perçu (RPE) a révélé que les votes
les plus fréquents étaient les votes les plus fréquents (17,18%) et les moins nombreux (3,33%).
dur et très facile de travail. La sensation thermique a été découvert que TS = 32,13% dont les
conditions de travail maximales des travailleurs travaillaient à chaud. Le temps de travail total
d'environ 1440 ensembles de données a été analysé de la même manière: DWT = 67,46%, IWT
= 16,71% et TNO = 15,83%. Comme le CLP était représenté comme la variable dépendante,
selon SPSS, l'âge, l'EPR, la température auriculaire et la FCmax étaient fortement corrélés au
compte du CLP pour P-valeur = 0,001, 0,009, 0,02, et 0,023 chacun, respectivement.

iv
ABSTRACT
In Cambodia, the ergonomics of the thermal environment is not extensive study, so the
influence of heat stress on productivity must be considered. Heat effects on daily workers’
activities can extremely cause physical injury and low productivity. The field studies were
conducted during the dry season that this time is absolutely considered the hottest period across
Cambodia, this study started from March to June 2019 for only two construction sites. The aim
of this study is to find out construction labor productivity on the rebar workers and discover
the correlation parameters to labor productivity. The data was collected such as WBGT (wet-
bulb globe temperature) from Heat stress monitor, Physiological Strain Index (Hr., heart rate,
Ear temperature), Rating of Perceived Exertion (RPE), Thermal sensation (TS), Sweat rate,
type work activity. The lowest WBGT is 25°C, and the highest is 35.40°C. The highest heart
rate is range from 87.69 to 133.02 which its maximum value presented the peak, rating of
perceived exertion (RPE) was shown that most frequent RPE votes were (17.18%), and the less
vote was (3.33%) account for somewhat hard and very easy of work. The thermal Sensation
was discovered that TS=32.13% whose maximum working condition of workers worked in hot
condition. The overall within the approximately 1440 data sets work time was analyzed equally
to, DWT=67.46%, IWT=16.71%, and NWT=15.83%. As CLP was represented as the
dependent variable which according to SPSS resulted that Age, RPE, ear temperature, and
HRmax% was correlated to CLP account for P(value)=0.001, 0.009, 0.02, and 0.023 each of,
respectively.

v
ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS DESCRIPTION
HR Heart Rate
WBGT Wet Bulb Globe Temperature
TS Thermal Sensation
RPE Rating of Perceived exertion
PeSI Perceptual Strain Index
PSI Physiological Strain Index
HI Heat Index
RH Relative Humidity
CLP Construction Labor Productivity
DWT Direct Work Time
IWT Indirect Work Time
NPT Non-Productive Time
Ear-T Ear temperature
AACE Association for the Advancement of Cost
Engineering
Hrmax Heart rate maximum
Hrmax% Heart rate maximum percentage
SPSS Statistical Package for the Social Sciences
MCL Medical Check List

vi
NOMENCLATURES
Symbols Definition Units
T Temperature °C
Tg Global thermometer °C
Ta Dry Bulb thermometer °C
Tnwb Natural Wet- Bulb thermometer °C

vii
TABLE OF CONTENTS
ACKNOWLEDGMENTS ......................................................................................................... I
អត្ថបទសង្ខេប....................................................................................................................... II
RESUME .................................................................................................................................III
ABSTRACT.............................................................................................................................IV
ABBREVIATIONS AND SYMBOLS.....................................................................................V
NOMENCLATURES ..............................................................................................................VI
TABLE OF CONTENTS....................................................................................................... VII
LIST OF FIGURES .................................................................................................................IX
LIST OF TABLES....................................................................................................................X
1. INTRODUCTION .................................................................................................................1
1.1. Background.....................................................................................................................1
1.2. Statement of problems ....................................................................................................1
1.3. Objectives .......................................................................................................................2
1.4. Scopes of the project.......................................................................................................2
2. LITERATURE REVIEW ......................................................................................................3
2.1. Principle of WBGT.........................................................................................................3
2.1.1. Component of WBGT...........................................................................................4
2.2. Productivity.....................................................................................................................5
2.2.1. Labor productivity.................................................................................................6
2.3. Heat Stress ......................................................................................................................8
2.3.1. Factors Influencing Heat Stress ............................................................................9
2.3.2. Measurement of Heat stress ..................................................................................9
2.4. Physical activity measurement......................................................................................10
3. MATERIAL AND METHOD .............................................................................................12
3.1. Participants....................................................................................................................12
3.2. Heart Rate .....................................................................................................................13
3.3. Construction Productivity.............................................................................................14
3.4. Heat Stress monitor (QUESTemp° 36) and Measurements..........................................14
3.4.1. Wet Bulb Globe Temperature.............................................................................15
3.4.2. Heat Index/Humidex and Prevention..................................................................15
3.5. Questionnaire ................................................................................................................16
3.5.1. Medical Check List.............................................................................................16
3.5.2. Perceptual Strain Index (PeSI)............................................................................16
3.5.3. Ear Temperature..................................................................................................17

viii
3.5.4. SPSS Statistics ....................................................................................................18
3.6. Procedure of Analysis...................................................................................................19
3.7. Experimental Procedure................................................................................................20
3.7.1. Measurement Procedure......................................................................................22
4. RESULT AND DISCUSSION ............................................................................................25
4.1. Web-Bulb Globe Temperature......................................................................................25
4.2. Ear Temperature............................................................................................................26
4.3. Thermal Sensation ........................................................................................................27
4.4. Rating of Perceived Exertion........................................................................................28
4.5. Heart Rate .....................................................................................................................30
4.6. Construction Labor Productivity...................................................................................31
4.7. Parameter correlation....................................................................................................33
5. CONCLUSION AND DISCUSSION..................................................................................35
REFERENCES ........................................................................................................................36
APPENDIX A..........................................................................................................................39
APPENDIX B..........................................................................................................................45
APPENDIX C..........................................................................................................................55
APPENDIX.D..........................................................................................................................58
APPENDIX E. .........................................................................................................................73

ix
LIST OF FIGURES
Figure 2:1. Productivity Factor.................................................................................................5
Figure 2:2. Thermal environment on human activity performance and productivity...............6
Figure 2:3. Working under direct sunlight on rebar worker.....................................................9
Figure 2:4. Heat Stress Monitor Measurement.......................................................................10
Figure 3:1. Measuring Heart Rate...........................................................................................13
Figure 3:2. Fixing Rebar Workers ..........................................................................................14
Figure 3:3. Heat Stress monitor (QUESTemp° 36)................................................................15
Figure 3:4. Omron MC-523 Ear Thermometer – White.........................................................17
Figure 3:5. IBM SPSS Statistics.............................................................................................18
Figure 3:6. Data input in SPSS...............................................................................................18
Figure 3:7. The procedure of analysis data.............................................................................20
Figure 3:8. Measurement and Observation.............................................................................21
Figure 3:9. Upper building activity........................................................................................22
Figure 3:10. QUESTemp°36, Australia..................................................................................23
Figure 3:11. TS and RPE Response........................................................................................23
Figure 3:12. Productivity observation ....................................................................................24
Figure 4:1. Data WBGT during working time in 6 days ........................................................25
Figure 4:2. Level risk of WBGT following Daytime (AM, PM) ...........................................26
Figure 4:3. Measurement Ear Temperature ............................................................................27
Figure 4:4. The difference of Thermal Sensation by daytime ................................................27
Figure 4:5. Mean of Thermal Sensation voted .......................................................................28
Figure 4:6. The difference of Rating of Perceived Exertion by daytime................................29
Figure 4:7. Rating of Perceived Exertion voted .....................................................................29
Figure 4:8. Relative of HRmax (%) and Daytime ..................................................................30
Figure 4:9. Comparing type of working time .........................................................................31
Figure 4:10. Total percentage of type working activity..........................................................32

x
LIST OF TABLES
Table 2.1. Wet Bulb Globe Temperature, (ISO, 1989).............................................................3
Table 2.2. Breakdown of direct, indirect, non-productivity.....................................................8
Table 2.3. The three risk categories (Yi, 2017).......................................................................11
Table 3.1. Descriptive personal information statistic of rebar workers ..................................12
Table 3.2. Preventive measurement Heat Stress Index ...........................................................15
Table 3.3. Perceptual Stain Index............................................................................................17
Table 3.4. Selection Methods..................................................................................................19
Table 4.1. Descriptive statistics of the WBGT data................................................................25
Table 4.2. Mean Heart rate and %HRmax(%) ..........................................................................30
Table 4.3. Direct, indirect, and non-productivity work activity..............................................32
Table 4.4. Test normality with Shapiro-Wilk .........................................................................33
Table 4.5. Correlations of Variable with CLP%.....................................................................34
Table A.1 The procedure for measurement at Construction site.............................................39
Table A.2 Medical check list...................................................................................................40
Table A.3 Rebar workers for every 15 minutes interval.........................................................41
Table A.4 List Ear Temperature and Sweat rate .....................................................................42
Table A.5 List devices for do experiment...............................................................................43

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1. INTRODUCTION
1.1. Background
The global warming influences on the construction industry, like construction rebar
workers are exactly contained the heat stress effect by extremely peak temperature and it
generally governs to a bad health condition and less productivity (Yi, 2017). Within the finding
of (Xiang, 2015) showed that about 90% and 19% of 180 participants’ response were very
afraid of high heat impact, and felt uncomfortable respectively. Occupational heat controlling
and prevention styles suggested preventing heat stress effects. For the last 100 years, the heat
stress index is progressed as a device which can analyze tolerance times for the different
activities for extremely heat environment (Tikuisis, 2002). The previous research “drinking
habit, age, and work duration are 3 peak predictors to determine construction workers’
physiological responses; other predictors include percentage of body fat, resting heart rate, air
pollution index, WBGT, smoking habit, energy consumption, and respiratory exchange rate
according to (Chan A. P., 2012)”. (Yi, 2017) said that “construction workers, particularly those
who undertake scaffolding tasks, steel bar fixing, structural steel erection, formwork, concrete
pouring, are considered the most vulnerable population to heat stress”. The potential risk of the
workplace is produced the low productivity of workers who works under sun-load. The
changing of global warming is caused of changes of a heatwave which effects harmfully on
direct sun-load workers such construction workers so that the great amount of heat stress is
extremely influenced on the physiological response to less productivity, death, and even worst
accident (Yi, 2017). According to (Kjellstrom, 2009) reports that labor productivity will be
fallen about 11%-27% by the impact of climate change by 2080s. The heat index is also a
potential risk which is influenced on outdoor workers. Heat index situation of heat-related
illness begins bigger as the change of local climate obtains hotter and more humid
(Occupational Safty and Health Administration, 2018). (Chan A. P., 2012) found that the bar
bending is completed about 30 %, and rebar fixing about 70% for workers who obligated to
work in construction rebar site. According to (Steadman, 1979) wrote that the same 50% of
the relative humanity with following at 20°C and 40°C is noticed as dry but it’s very humid,
respectively.
1.2. Statement of problems
Construction workers are key persons whose labor force is required to complete the task
on a high-rise building, and the impact from the sunlight during their working time. According

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to (Yi, 2017) found out that steel bar fixing is thought to be a high risk of work. Construction
workers are spending too much time away because heat is effect to working condition as a long
whole day. By seeing the part of the world, the high impact of global warming is considered
the most noticeable managed workers’ working circumstance avoiding the heat that reduces
productivity. The physical working activity must be studied to highlight the vulnerable labor
force of rebar worker and especially leaders of organization whose responsible management.
1.3. Objectives
The objectives of this study are to:
• Conduct measurement on heat stress to construction rebar workers
• Find out the work productivity of rebar workers
• Find out the correlated parameters with construction labor productivity
1.4. Scopes of the project
This research project scope is:
• conducted on 12 rebar workers for two construction sites which site survey
consisted of three months from mid-March to the end of April 2019
at Phnom Penh
• data collection was gathered by two research investigators
• record productivity activity, rating of perceived of exertion (RPE), thermal
sensation (TS), personal information, medical checklist, height, and weight
• measured ear temperature, heart rate, Wet Bulb Globe Temperature (WBGT)
• SPSS software that is used to find the correlation variables with productivity.

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2. LITERATURE REVIEW
2.1. Principle of WBGT
The wider ranges of using the measurable climatic recorder in direct sunlight, Wet Bulb
Globe Temperature which consisted of temperature, humanity, HI, and wind flow. According
to (Habibi, 2015) approved that “the WBGT, oral temperature, and heart rate (HR) were
measured, and the data were analyzed based on descriptive statistics and Pearson correlation
tests to determine the relationship between WBGT and Physiological strain index in Muslim
women in hot try condition”. Heat stress Standard ISO 72433, which accorded to Wet Bulb
Globe temperature index (WBGT) this is the application for not only global usage by its display
and measure hot climate area but also its validity, reliability and usability are constantly existed
according to (Parsons, 2006). (Budd, 2008) concluded that evaporation of sweat is restricted
by high humidity or low air movement than when evaporation is free”.
Table 2.1. Wet Bulb Globe Temperature, (ISO, 1989)
According to (Ma, 2019) proposed that “to examine the association between WBGT index
and work relate-injury, we fit a quasi-poisson regression with the distributed lag non-linear
model”. The study of Ergonomics of the thermal environment (ISO 7243:2017(E), 2017)
reported that “the wet bulb globe temperature (WBGT) is a heat stress index and its value
represents the thermal environment to which an individual is exposed ”. The WBGT was

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initiated in 1950s, and control determination within the air temperature and humidity depend
on, and can be used all trainee, and reported that is useful based on (Budd, 2008). Furthermore,
(Parsons, 2014) pointed out that “air temperature, radiant temperature, humanity, air velocity,
clothing, and activity” are crucial parameters to store heat, so it’s vulnerable to the human body.
With previous research shown that Meta-analysis study is “a set of qualitative procedure for
systematically integrating and analyzing the findings of previous research by (Tanaka, 2001)”.
2.1.1. Component of WBGT
The combination of the Natural Wet Bulb Temperature combined four thermal
components: ambient air temperatures, relative humidity, air velocity, and radiant heat. As it
was mentioned above, WBGT can be used to establish guidelines for activity modifications
during physical activity in the heat according to (Sheridan, 2016). Moreover, (Budd,
2008)introduced the history of WBGT summarized the mains for the following:
• WBGT is an accurate measure of environmental heat stress.
• WBGT is used to protective measurement during exercise in the heat by creation
activity modifications as WBGT rises.
• By improvement guidelines for activity change using WBGT, it is necessary to
include work: rest ratios, length of activity, hydration breaks, equipment to be worn,
and a level in which activity is canceled.
• Replacing the temperature and humidity measurements with WBGT
• WBGT's most thoughtful limitation is that environments are stressful when the
evaporation of sweat is restricted by high humidity or low air movement.
Similarly, (Lemke, 2012) compared that the previously proposed methods to determine
indoor and outdoor WBGT from standard climate data as dew point, wind speed solar
temperature and air temperature. WBGT is widely introduced heat stress index worldwide, and
it was developed in a US Navy investigation into heat fatalities during training according to
(Parsons, 2014). It is given by for conditions with solar radiation, and for indoor conditions
with no solar radiation.
WBGTout=0.7Tnwb+0.2Tg+0.1Ta (Eq. 2.1)
WBGTin=0.7Tnwb+0.3Tg (Eq. 2.2)
where
Tnwb : temperature of a naturally ventilated wet bulb thermometer (°C)
Ta : air temperature (°C)
Tg : black globe thermometer (°C)

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2.2. Productivity
According to (Liou, 1986) found that the “Productivity” defines the term of the strong
connection between output and input for identifying procedure of any productions which
denoted as the ratio of output to input. Within the necessity of previous researcher (Li, 2016)
found that the peak temperature environments can cause physical working activity to lose about
0.57% of productive work activities but about 0.74% is rose during attending additional more
1°C of WBGT, workers who contain the heat stress physical working activities because of
working in heat environment area will exactly reduce the production of their working activity
in the construction industry. Furthermore, according to (Arditi, 1985) constructed that
construction tasks have been divided into headquarter-type functions, and site type functions.
It can be observed that there are overlaps among the functions such as the "Procurement"
function in headquarters and the "Materials" and "Equipment" functions in sites.
Figure 2:1. Productivity Factor
Some functions such as "Labor" problems cited as a site function, could also be cited
as a headquarter function, and vice versa. Finally, a few other factors such as capital
availability, inflation, and taxation could also be included in the model.

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2.2.1. Labor productivity
Labor productivity is an essential piece of information for estimating and arranging a
construction project according to (Song, 2008). The current practice of labor productivity
estimation relies primarily on either published productivity data or an individual’s experience.
There is a lack of a systematic approach to measuring and estimating labor productivity. The
collected productivity data were used to develop labor productivity models using such
techniques as artificial neural network and discrete-event simulation. These productivity
models were developed and validated using actual data collected from a steel fabrication
company.
Figure 2:2. The thermal environment on human activity performance and productivity.

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Labor productivity proposed by (Parsons, 2014) can be defined as the ratio of output to
input in the sense that output is usually measured by the production level such as number of
columns poured on number of cubic yards of soil moved, while input is usually
measured in units of time, such as labor hours or labor days. Productivity governed to the goals
of the organization and any measurement should be related to those goals. They are usually
stated in general terms as part of the ‘corporate mission’ of a company and interpreted by
individual departments and groups within the company in terms of their own work. An
individual may perform well, but in this context, he may or may not be productive. If the
thermal environment causes a decrement in individual performance, and performance is related
to productivity, then productivity will fall within according to (Parsons, 2014).
The labor productivity is a measure of work process efficiency, which is defined as the
ratio of the value labor produced to the value invested in labor. Thus, the American Association
of Cost Engineers (Allmon, 2000), stated that productivity as a “relative measure of labor
efficiency, either good or bad when compared to an established base or norm”. According to
(Mani, 2015) had discussed that “labor productivity can be expressed in many ways, such as
output per labor cost and output per labor hour. This research adopts output per labor hour or
output per crew-hour as a metric to measure labor productivity. Moreover, the labor hour
considered for labor productivity frontier is the shortest duration because the minimum value
of duration means the highest productivity”.
There are many factors that affect construction labor productivity, such as mental
fatigue, physical fatigue, stress fatigue, boredom, overtime, morale, and attitude, stacking of
trades, joint occupancy, beneficial occupancy, concurrent operations, absenteeism, and
turnover, mobilize/demobilize, errors and omissions, start/stop, reassignment of manpower,
late crew build-up, crew size inefficiency, site access, logistics, security check, learning curve,
ripple effect, confined space, hazardous work area, dilution of supervision, holidays, shorter
daylight hours, weather, and season changes, rain, shift work, working in operating area, over-
manning, tool and equipment shortage, area practices, proximity of work, alternating,
staggered, and rotating work, within further summarized by (Mani, 2015). Productivity is a
significant component in the construction industry around the world. Labor productivity in the
construction industry has drawn great attention, as the industry faces multiple problems related
to its workforce. Construction labor productivity (CLP) is often influenced by variations in
work conditions. The complex relationship between CLP and hot environments has received
attention in academia for decades, and yet interest in this field has never diminished had
provided by (Yi, 2017).

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Table 2.2. Breakdown of direct, indirect, non-productivity
A. Direct/Productive Work Time
A-1 Make use of wrenches to connect, cut, bend, and modify reinforcing steel bars
A-2 Place reinforcing steel bars
A-3 Modify reinforcing steel bars
A-4 Carry reinforcing steel bars
A-5 Use meter sticks for measurements
A-6 Bending
B. Indirect Work Time
B-1 Walk towards equipment, tools, materials
B-2 Wait for materials to be carried
B-3 Review the list of materials to understand the work
B-4 Talk with foreman and co-workers about the tasks
B-5 Take materials
C. Non-Productive Time
C-1 Employees or machines, or both, due to work stoppage from any causes
C-2 Chat, smoke, drink, sit, use cell phones, go to the washroom
According to (Yi, 2017) is utilized the ACCE method of categorized outdoor working
activities. In that study, they found that the model discovered that heat stress reduces CLP, with
the percentage of direct work time decreasing by 0.33% when the WBGT increased by 1°C.
AACE International classified work activities into three categories: (1) direct task—assigned
work that needs specific efforts or the use of tools/equipment that productively and directly
contribute to the completion of the task scope; (2) indirect task—support work or assistance
that are not directly conducive to the completion of the task scope; and (3) non-productive time
personal time and non-utilization time due to work stoppage from any cause. Based on the
AACE International method, we carried out continuous direct observations throughout the
workday of the participating steel bar fixers. The above table shows the breakdown of direct,
indirect, and non-productive activities for rebar workers.
2.3. Heat Stress
According to (Parsons, 2014) defined that “where human thermal environments (in
terms of air temperature, radiant temperature, humidity, air velocity, clothing, and activity)
provide a tendency for body heat storage the body’s thermoregulation system responds to
attempt to increase heat loss”. When thermal contained in the body because of the effect of
thermal environment and physical effort, it will appear stain on the body, and it can eventually
collapse down or even heat related-illness if thermal can’t get out. Where people used to more

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temperate climates are exposed to hot environments there can be major problems if those
exposed are neither behaviorally nor psychologically acclimatized to the heat.
2.3.1. Factors Influencing Heat Stress
According to declaration of (OHSCO, 2007) introduced the factors influencing heat
stress which are both heating and cooling balance in the body be determined by the following
factors: air temperature, humidity (moisture in the air), radiant heat load (sun, furnaces, molten
material, steam, etc.) physical activity (how hard you’re working) cooling (by the evaporation
of sweat) body adjustments (acclimatization). There are two sources of heat exposure, the
outside environment, and internal muscle activity. (80% of muscle energy is turned into body
heat.) High temperatures and high levels of physical work create heat stress. The body cools
itself by evaporating sweat. High humidity hinders sweat from evaporating.
2.3.2. Measurement of Heat stress
Heat Stress Monitor Model QUES TEMP 36 is measured WBGT that is applied to
calculate the four directly senses: ambient or dry bulb temperature, natural wet bulb
temperature, globe temperature, and relative humanity. Within the extended summarized report
by (OHSCO, 2007) also used Heat stress monitor to determine heat stress. Because Heat Stress
monitor is taken into account air temperature, radiant heat, and humidity. Exposure standards
are divided into categories based on physical activity and workers’ acclimatization.
Adjustments are made for wearing types of clothing and personal protective equipment. Taking
WBGT measurements properly requires specialized equipment and expertise. Workplaces with
very hot work processes or where workers have experienced heat-related illnesses should
Figure 2:3. Working under direct sunlight on rebar worker

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measure the WBGT. Most workplaces don’t have “hot processes” but hot weather can pose
health risks to their workers. For these hot work environments, a Hot Weather Plan is
appropriate. This is a simplified heat stress prevention program and should establish
implementation criteria, or “triggers,” to put the plan into effect. Criteria may include:
Humidex reaching or exceeding 35, Environment Canada Humidex advisory (air temperature
exceeding 30ºC and Humidex exceeding 40 ºC or Ontario Ministry of the Environment smog
alert, Heatwaves (three or more days of temperatures of 32ºC or more)
Generally, Hot weather plans should be in place between March 1st
and June 30th
. This
tool kit provides a simplified version of the WBGT by converting it into Humidex values. It
allows workplaces to measure heat stress using only workplace temperature and humidity.
2.4. Physical activity measurement
The global applicable of exercise-heat strain is recommended to use the physiological
strain index (PSI) accord to (Tikuisis, 2002), and “the perceptions of thermal sensation and
perceived exertion were combined, and PeSI, was compared with its physical counterpart
denoted as PSI, for the exercise-heat specific to this study.” In the hot condition, the uniform
of worker is not easy to take off, but they must be adjusted to work to gain more acclimatized
working condition according to (Parsons, 2014). Heat stress is the reason for avoidable and
even extremely bad deaths that construction workers affected by working hot and humid
environmental conditions in Hong Kong by (Chan A. P., 2012). The previous research
measurement proved that currently innovative clothes which consisted of fabrics with superior
Figure 2:4. Heat Stress Monitor Measurement

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heat/moisture-transferring properties and loose-fitting innovation could condense the
populations’ heat stress and increase well-being and work activity by (Chan A. P., 2016). (Liou,
1986) designed “work sampling” for finding notation any categories of work activities which
are information to be collected. The method to find the Heat Stress or apparent temperature is
calculated by heat index which consists of relative humanity and air temperature as stated by
(Steadman, 1979). Work in the heat may tend to be collapse down during working whose
physical effort is not seen relax according to (Parsons, 2014).
Table 2.3. The three risk categories (Yi, 2017)
WBGT ( C) Risk Classification Description
<29.3 Risk I Low risk
29.4-32.1 Risk II Moderate risk
>32 Risk III Hight risk

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3. MATERIAL AND METHOD
3.1. Participants
The 12 construction workers participated for 8 hours of observation. The field study,
medication checklist had checked before allowing to study field. (Chan A. P., 2016) the medical
checklist was checked workers’ personal data within health problem (including diabetes,
hyperlipidemia, hypertension, cardiovascular disease, and neurological problem) and major
signs or symptoms of heat-related illness (such as pallor, fainting, headache, confusion, vertigo,
drenching sweats and decrease in sweating, a rapid pulse, cramp, nausea, and shortness of
breath). Some drinks are banned for the day observation not only win and drinks contain
caffeine. The consent form is assigned rebar worker to sign the peaceful participation with this
study.
There are 12 male steel bar fixers and benders participated in the field studies. The
sample size was determined based on previous quasi-experimental field studies at construction
sites which had produced some statistically significant data points (Yi Wen, 2013). The
participants were randomly selected from two construction sites in Phnom Penh, Cambodia.
They were invited to participate in the field study on a voluntary basis and could withdraw from
any time. The field studies were conducted between mid-March and the end of April 2019 that
is the hot season in Cambodia. The participants had acclimated to work in hot weather for at
least about one month. They were provided with a standard summer uniform that was designed
for alleviating heat strain for construction workers (Chan et al., 2016). They were briefed on
the research purpose and procedures and were requested to sign a written consent form. Their
mean age, height and body mass, were 39.83±8.18 years, 1.63±0.07 m, 58.9±7.72 kg,
respectively.
Parameters Mean ± SD Range
Age (years) 29.83 ± 8.18 18 45
Height (m) 1.63 ± 0.07 1.54 1.72
Weight (Kg) 58.91 ± 7.72 43.90 69.40
The personal information must be given such as name, age, height, body weight. The
clothes were put on rebar workers after wearing the HR belt during the observation. For the
Heart rate, monitor and Heat stress monitor is synchronized for the operation. For the HR data,
core temperature, rating of perceived exertion and thermal sensation must be recorded in
Table 3.1. Descriptive personal information statistic of rebar workers

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written note papers for every 15mins interval. After doing the experiment, rebar workers are
provided an incentive to praise their participation
3.2. Heart Rate
In this study, The Polar H10 Bluetooth & ANT+ Heart Rate Sensor is an integrated
chest strap and heart rate monitor designed to measure heart rate. The H10 sends data wirelessly
via either a Bluetooth to a smartphone, and connect with Polar Beat application with supported
heart rate service applications. The previous study has found maximum heart rate which
“Where the need for the highest performance is less persuasive one can calculate maximum
predicted oxygen consumption per minute per kilogram by use of the rough formulation
according to (P.Naughton, 1972)
Maximum Heart Rate = 220 - age (years) (Eq. 3.1)
Figure 3:1. Measuring Heart Rate

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3.3. Construction Productivity
Within the definition of productivity of (Parsons, 2014, p. 328) said that productivity
is such successfully level of activities is given a completed performance in order to reach the
structural goal, and determine not only the amount of a product is produced but also product
quality. In the construction engineering and management area, productivity is defined as labor
productivity and its units of work placed or produced per labor-hour. According to (Liou, 1986)
found that the “Productivity” defines the term of the strong connection between output and
input for identifying procedure of any productions which denoted as the ratio of output to input.
𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑣𝑖𝑡𝑦 =
Output
Input
(Eq. 3.2)
According to (Parsons, 2014) presented that working performance is caused to low
productivity by its parameters are influenced by people workforce such cold, moderate or hot
places.
3.4. Heat Stress monitor (QUESTemp° 36) and Measurements
QUESTemp° 36 has its own four directly senses: ambient or dry bulb temperature (DB),
natural wet bulb temperature (WB), globe temperature (G) and relative humanity (RH). (ISO
7243:2017(E), 2017) presented that WBGT is the “heat stress index”, and its index is
convenient to calculate the environment.
Figure 3:2. Fixing Rebar Workers

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Figure 3:3. Heat Stress monitor (QUESTemp° 36)
3.4.1. Wet Bulb Globe Temperature
The WBGT is a weighted average of the 3 temperature sensors, a globe thermometer,
wet bulb thermometer, and a dry-bulb thermometer, the following equations
WBGT(indoor)=0.7Tnwb+0.3Tg (Eq. 3.3)
WBGT(outdoor)=0.7Tnwb+0.2Tg+0.1Ta (Eq. 3.4)
3.4.2. Heat Index/Humidex and Prevention
The heat index is calculated using dry bulb temperature and relative humanity. The HI
showed the average person feels relative to environmental condition. Higher HI is higher
humidity which a given temperature. The HI is defined as over a temperature range (21°C).
According to (Sheridan, 2016) had produced the preventive method that avoiding the
heat stress impact, he said that immediately must fulfill the desired hydration. The hydration
Table 3.2. Preventive measurement Heat Stress Index

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should be needed according to workloads because physical working can generate
approximately 8 to 12 liters of sweat in a day. Water and salt much be body equilibrium to
sweat out of the body, and outdoor worker activity much keeps in touch with the preventive
method to avoid heat stress effect.
The preventive method has been adapted from (Sheridan, 2016) who introduced the
essential preventive procedure avoiding heat stress. For the extended outdoor workers or
physical effort to complete a task should drink plenty of water, and along with the day, water
consumption should drink small amounts frequently. Loose-fitting clothes are rather large and
do not fit tightly on your body. Clothes are a key role to prevent evaporation of sweat. Out-
door work activity is engaging the strenuous physical effort, so alcohol and caffeinated should
be avoided. The education of the effect of heat can make a sense of awareness of heat injury
symptoms. When performing the hardest task or work, it should modify activity schedule and
acclimatized working condition.
3.5. Questionnaire
In the questionnaires, they have included the participants’ information as the parameter
for additional data for analyzing such as the main subjects medical checklist which consisted
of major history health problems. The collected personal information is like height, weight,
core temperature, sweating rate, water consumption, and they are used. The rate of perceived
exertion and thermal sensation are used for measuring physical feeling condition under the
working and environment circumstances. Different working hours are recorded as a subjective
measurement which is chosen rebar workers and fixers to classify different tasks within
different activities an hour. The manually written data of 15minute interval collected heart rate
data is recorded accordingly.
3.5.1. Medical Check List
The Medical Check List was assigned to workers to detect the major health problems
before doing the survey. This list had provided researchers to select workers right ways who
workers themselves had acclimatized with environment condition and they were no heat-related
illness. MCL also provides additional personal information of workers.
3.5.2. Perceptual Strain Index (PeSI)
PeSI is established by (Tikuisis, 2002) who found the method to cope with Strain Index,
and Strain Index is studied Perceived Exertion (PE) and Thermal Sensation (TS). The following

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table is recorded 15 minute interval along with 8 hours. The rating of the mark was given from
0 to 10 points which were considered from rest to maximal of working.
Thermal sensation
7 Neutral and comfortable
8 Slightly warm
9 Warm
10 Hot
11 Very hot
12 Extremely hot
13 Intolerably hot
Rate Perceived Exertion
0 Rest
1 Very, very easy
2 Easy
3 Moderate
4 somewhat hard
5
Hard
6
7
Very Hard8
9
10 Maximal
According to (Chan A. P., 2016) found that PeSI is the parameter to make understanding
of WBGT and physical activity, and PeSI is not a complex measurement tool. The reality of
the working condition of workers was provided the more accurate feeling of the environment
within immediately emotional working. The given score is from 7 to 13, and it’s represented
such neutral and comfortable to intolerably hot.
3.5.3. Ear Temperature
The core temperature was measured on workers every15 minute interval, and it was
used Omron Ear Temperature.
Figure 3:4. Omron MC-523 Ear Thermometer – White
Table 3.3. Perceptual Stain Index

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The core temperature of construction site workers was measured synchronously with
Perceptual Strain Index (PeSI). The list of measurement of core temperature was also included
water consumption and participants’ weight. The core temperature was measured by the device.
3.5.4. SPSS Statistics
The “Statistical Package for the Social Sciences” (SPSS) is a package of programs for
manipulating, analyzing, and presenting data; the package is widely used in the social and
behavioral sciences.
The core program is called SPSS Base and there is the number of add-on modules that
extend the range of data entry, statistical, or reporting capabilities. In our experience, the most
important of these for statistical analysis is the SPSS Advanced Models and SPSS Regression
Models add-on modules. SPSS Inc. also distributes stand-alone programs that work with SPSS.
Figure 3:6. Data input in SPSS
Figure 3:5. IBM SPSS Statistics

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The text is not intended in any way to be an introduction to statistics and, indeed, we
assume that most readers will have attended at least one statistics course and will be relatively
familiar with concepts such as linear regression, correlation, significance tests, and simple
analysis of variance. According to (Yi, 2017) is used SPSS for establishing a model to predict
CLP.
This software, SPSS when you need a flexible, customizable way to get super granular
on even the most complex data sets. This gives you, the researcher, more time to do what you
do best and identify trends, develop predictive models, and draw informed conclusions
3.6. Procedure of Analysis
The following the flow chart Figure 3:7 that summary data analysis in SPSS is definitely
followed each step to the end. Throughout each process, the data input is a mean 15mins for
each parameter, and they are HRmax, WBGT, TS, RPE, Te, and CLP within collected as
synchronized parameters. Along with correlation parameters, SPSS is categorized whether
normality. Whether normality or not are determined when parameters had input in SPSS
software, and this program will be explored. SPSS found that parameters above are the normal
distribution (P-value < 0.05), which this must be conducted with Spearman’s correlation
coefficient, and parameters were discovered that CLP% and other parameters were determined
as the dependent variable and independent variable, respectively. CLP%, according to 339 data
set is defined as the dependent variable, and others are independent variable within the
regression model was used to construct the equation of the CLP. The data set was rejected
automatically according to SPSS P-value > 0.05.
Table 3.4. Selection Methods

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Figure 3:7. The procedure of analysis data
3.7. Experimental Procedure
Heat Stress monitor was firstly chosen for a suitable place to install near the workers’
working environment. Then participants were allowed to wear a heart rate belt (Polar®, United
States) and uniform, and filled out the medical check, and helped by investigators. The consent

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form was signed by workers who were voluntary participants in this research. Workers’ weight
was weighing immediately, and the first measurement is heart rate, core temperature, TS, RPE
that they were asked. Subsequently, workers started working, the heart rate and WBGT were
recording in 1 s and 1 min interval, respectively. The recording of the productivity was observed
straight eye-seeing with most of the time and recorded manually in the paper. A total of two
field studies were conducted, in which two participants participated in a one-day study.
Construction work included daily morning (7:00–11:00) and afternoon sessions (1:00–17:00).
Prior to the measurement in the morning, the participants were asked to wear the assigned work
uniform and a heart rate belt (Polar®, United States).
Figure 3:8. Measurement and Observation
Real-time heart rate data were recorded by the Polar Flow app. Body mass (including
clothes) was measured by using a digital scale with 0.1 kg precision (Tanita®, Japan). Body
height was measured by a mounted-wall scale. Afterward, the participants were asked to report
their demographic information, including age and ethnics. Body height was measured by a
mounted-wall scale. Afterward, the participants were asked to report their demographic
information, including age and ethnics.

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A short health questionnaire survey was conducted before the field studies in order to
screen out the participants without diagnosed health problems, heat-related illnesses, or regular
medication intake Figure 3:8 They were allowed to drink water when they desired, take breaks
and self-pace their workload as they desired. The procedure in the afternoon was the same as
that in the morning. They were allowed to drink water when they desired, take breaks and self-
pace their workload as they desired. The procedure in the afternoon was the same as that in the
morning. No participants quitted the experiment. Then they started to work as their normal
work routine. All the participants performed outdoor works at the upper floor of the building
throughout the entire field measurement Figure 3.9 The research was fully approved by the
Human Subjects Ethics Sub-committee of the Institute of Technology of Cambodia.
3.7.1. Measurement Procedure
Environmental, physiological, and perceptual data were recorded throughout the field
study. A heat stress monitor (QUESTemp°36, Australia) was located near to the participants to
record the web bulb globe temperature (WBGT) at every minute within Error! Reference source
not found. Heart rate (HR) was recorded at a one-second interval. WBGT and HR during direct
work activities were converted into 15-minute averages. According to the study (Gagge, 1969)
Figure 3:9. Upper building activity

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is to compare observations of thermal comfort and temperature sensation with the physiological
changes occurring over a parametrically chosen range of exercise levels and ambient air
temperature.
Temperature ranges from cold to hot are associated with ambient air temperatures found
in this research. The participants were requested to report the rating of perceived exertion (RPE
on a scale from 0 to 10) (Borg, 1987), and thermal sensation (TS on scale 7 to 13 (Gagge, 1969)
every 15 minutes which attached with below.
Figure 3:10. QUESTemp°36, Australia
Figure 3:11. TS and RPE Response

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Body mass was measured four times before and after the morning and afternoon
working sessions attached with The mass of water they consumed each time was also measured.
Sweat rate (L/h) was then estimated by the change of body mass corrected by water mass.
Warm discomfort is principally linked to skin sweating and skin conductance
AACE International classified work activities into three categories: (1) direct task -
assigned work that needs specific efforts or the use of tools/equipment that directly contributed
to the completion of the task scope:(2) indirect task - support work or assistance that are not
directly conducive to the completion of the task scope; and (3) non-productive time - personal
time and non-utilization time due to work stoppage from any causes. Labor productivity was
measured by the percentage of time spent in direct work activities (Yi and Chan, 2017) in this
study. Two research investigators observed the work activities of the two participants,
respectively, throughout the work-day of the participating steel bar fixers and benders. Shows
the breakdown of direct, indirect, and non-productive activities of the participants.
According to (Yi, 2017) Productivity is a major component in the construction industry
around the world. Labor productivity in the construction industry has drawn great attention, as
the industry faces multiple problems related to its workforce. Each time activity of workers was
recorded in manual with real-time they performed as usual. Within 3 categories of productivity
had been identified as previous research design adapted from ACCE.
Figure 3:12. Productivity observation

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4. RESULT AND DISCUSSION
4.1. Web-Bulb Globe Temperature
Figure 4:1 illustrates every minute WBGT data monitored in the morning and afternoon
working session. They can be seen overall 6-day differences of WBGT, and the sixth day
represented the peak WBGT, but the lowest was the first day.
Figure 4:1. Data WBGT during working time in 6 days
The measurement of WBGT conducted two different shifts both morning (7:00-11:00)
and afternoon (1:00-5:00). According to Table 4.1 represented the hourly data WBGT value. It
showed that the lowest 25.08°C and the peak are 35.40°C which they were indicated between
7:00-800AM, and 1:00-200PM each of, respectively.
Table 4.1. Descriptive statistics of the WBGT data
24.00
26.00
28.00
30.00
32.00
34.00
36.00
07:00
07:30
08:00
08:30
09:00
09:30
10:00
10:30
11:00
01:00
01:30
02:00
02:30
03:00
03:30
04:00
04:30
05:00
Day 1 Day 2 Day 3 Day 4 Day 5 Day 6
mean ± sd
7:00-8:00 27.64 ± 1.86 25.08 31.78
8:00-9:00 28.65 ± 1.64 26.82 32.54
9:00-10:00 29.60 ± 1.83 27.16 32.74
10:00-11:00 30.35 ± 2.04 27.23 34.11
1:00-2:00 32.64 ± 1.44 30.35 35.40
2:00-3:00 32.25 ± 1.65 29.60 34.95
3:00-4:00 31.15 ± 1.45 28.27 33.72
4:00-5:00 29.64 ± 1.59 27.59 32.68
WBGT(˚C)
time Range

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Moreover, the WBGT was gradually increased from work start session to work stop
session in the morning (25.08-34.1 1°C), and work start session in the afternoon was the peak
(35.40°C). It gradually decreased to 32.68°C. The previous research (Yi, 2017) had involved
the risk categories, and WBGT had differently three groups for analysis. For additional analysis
on three risks, for the declaration of WBGT introduced that low, moderate and high risk.
Though Figure 4.2 also illustrated that the 3 classifications of the WBGT were adopted in
defining the risk zone of the worker's condition. According to the chart, in the morning session,
workers were safety in risk I which compared to the afternoon session account for 30% and
8.05%, respectively. Within the work risk II, afternoon working session was higher risk than in
the morning session approximately 25% and 15%, respectively, and the workers worked in the
morning and afternoon was considered as risk II account for 8% and 19%, respectively.
Figure 4:2. Level risk of WBGT following Daytime (AM, PM)
4.2. Ear Temperature
Figure 4:3 shows every 15 minutes continuously mean data ear temperature of workers
both in the morning session and in the afternoon session. The noticeable points are that ear
temperature slightly raised from 7:15AM to 11:00AM, and it’s continuously increased ear
temperature to peak approximately 37.2 C at 2:35PM. The Te was slowly decreased to the end of
working at 5:PM about 36.9 °C. The lowest of Te was 36.2 C at 7:15AM which compared to 36.9 C
at 11:00AM.

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Figure 4:3. Measurement Ear Temperature
4.3. Thermal Sensation
Figure 4:4 illustrated both in the morning and afternoon session of workers’ responses
to thermal sensation (TS). It can be pointed out that extremely hot (12) is most responses from
workers in the afternoon approximately 98% which compared to the highest morning session
approximately 75% that was hot (10).
Figure 4:4. The difference of Thermal Sensation by daytime
35
36
37
38
07:00
07:30
08:00
08:30
09:00
09:30
10:00
10:30
11:00
01:00
01:30
02:00
02:30
03:00
03:30
04:00
04:30
05:00
Temperature(%)
Ear Temperature

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Overall of the responses were asked to workers during the working condition. This can
be identified as a pyramid type which increased steadily, over the peak of 32.13%. Then the
bar (hot) jumped down dramatically to reached very hot and extremely hot, by each is 16.97%
and 12.34%, respectively. The working condition of workers was working hot environment as
on high rise building, and they were acclimatized to work with that environment. Asking about
Thermal sensation (TS), the responses mainly ranged from (32.13%). According to Figure
4:6.showed that the percentage of TS adopted from workers’ response. The bars are given as
TS percent which ranged from 8.74% to 32.13% account for neutral and comfortable and hot,
respectively.
Figure 4:5. Mean of Thermal Sensation voted
4.4. Rating of Perceived Exertion
According to in the afternoon session, and jumped up dramatically in the morning
session from 2% to 35%. Beside the TS, the RPE was extremely grown to the peak and fallen
down dramatically bottom account for 14%, and 1%, in the morning session respectively. In
the afternoon session, the working circumstance of workers is extremely jumped up from rest
to easy ( 0 to 2), continuously, the bar was collapsed down dramatically, and it increased
slightly (moderate to hard).
According to Figure 4.7 showed the correlations with each other, TS and PRE within
increasing synchronized which means that during work condition harder and more temperature
sensation increased. According to Figure 4.8, the most frequent RPE vote was (17.18%), and
the less vote was (3.33%). Reflecting the fact that workers perceived the physical workload as
somewhat hard, and very, very easy, respectively
8.74%
10.80%
19.02%
32.13%
16.97%
12.34%
0.00%
Neutral and
comfortable
Slightly warm
Warm
Hot
Very hot
Extremely hot
Intolerably hot
Thermal Sensation

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Figure 4:6. The difference of Rating of Perceived Exertion by daytime
The graph above showed that the percentage of thermal sensation between 7 to 12 and the
rating of perceived exertion between 0 to 12-period working session both morning session and
afternoon session. It can be identified that TS has increased steadily the peak of
approximately15%.
Figure 4:7. Rating of Perceived Exertion voted

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4.5. Heart Rate
Table 4.2. Mean Heart rate and %HRmax(%)
Figure 4:2.figured out the general description of workers’ heart rate, and the hourly
heart rate and heart rate maximum from morning session (7:00-11:00) and afternoon (1:00-
5:00). We found that hourly HR direct working time ranged from approximately 95 bpm to
105 bpm during the work. Generally, the HR values during times close to 1:00pm noon were
higher than those during other periods (7:00am-11:00am and 2:00pm – 5:00pm).Table 4.2
Shows the hourly HR value measure at different times. We found that hourly
Figure 4:8. Relative of HRmax (%) and Daytime
Time Mean ± SD mean ± SD
7:00-8:00 97.94 ± 10.07145 81.50 123.78 51.93% ± 6.75% 44.54% 70.73%
8:00-9:00 94.31 ± 10.39993 72.27 119.51 49.74% ± 6.61% 39.49% 68.29%
9:00-10:00 91.06 ± 13.73369 69.84 127.92 48.13% ± 8.77% 35.61% 73.10%
10:00-11:00 89.29 ± 12.17248 70.00 124.90 47.08% ± 8.00% 34.65% 71.37%
1:00-2:00 104.54 ± 11.09298 87.69 133.02 55.12% ± 6.75% 45.44% 74.60%
2:00-3:00 100.45 ± 11.72051 77.11 120.53 53.18% ± 7.41% 40.16% 68.87%
3:00-4:00 97.76 ± 12.85575 70.78 126.96 51.77% ± 8.24% 36.86% 68.45%
4:00-5:00 95.93 ± 12.4421 74.46 131.58 50.68% ± 8.28% 38.78% 75.19%
Range Range
Heart Rate(bpm) % Hrmax(%)

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Furthermore, according to healthy science classified in three-level work intensity
different group, more than half of the %HRmax values are less than 54% (light work intensity).
During the work period, most %HRmax value belongs to 55-69% HRmax ( moderate work
intensity), and more than 70% of % HRmax the high work intensity. The percentage HRmax
of workers who spent on high rise building, and the two sessions are classified to more accurate
about %HRmax. showed that construction workers were reached about 43% in the morning
and 33% in the afternoon according to their hard rate is at the first level.
4.6. Construction Labor Productivity
The CLP in terms of direct work time (DWT), indirect work time (IWT), and non-
productive time (NPT). Figure 4:9 summarizes the descriptive statistics for DWT, IWT, and
NPT in different periods. This is found that DWT takes up the most working periods is
(67.46%), IWT (16.71%), and NPT (15.83%).
Figure 4:9. Comparing the type of working time
The DWT is denoted (Make use of wrenches to connect, cut, bend, and modify
reinforcing steel bars, place reinforcing steel bars, modify reinforcing steel bars, carry
reinforcing steel bar, use meter to stick for measurement and bending) the most bar fixing
required the most produced bar fixing productivity had in DWT.
Table 4.3 During the morning work session, the proportion of DWT increase from
8:00am to 10:00am, because slightly reduce from10:00am to 11:00am. During the afternoon
work session, the proportion of DWT keep reduce between 1:00pm and 3:00pm, increase a
67.46%
16.71% 15.83%
DWT IWT NPT

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little bit between 3:00pm to 4:00pm, however slightly reduce again between 4:00pm and
5:00pm. In generally, the highest DWT emerged from 8:00am to 10:00am. The lowest DWTs
occurred from 7:00am to 8:00am, and from 4:00pm to 5:00pm. According to
Table 4.3 was figured out the specific tasks, and 68.06%±24.05% is highest work
productivity from 3pm to 4pm.
Table 4.3. Direct, indirect, and non-productivity work activity
The increase of DWT at the start of the work session might be explained by the fact that
the workers need time to adapt to the task and work environments the proportion of IWT
decrease from the start in the peak at the morning, increase of IWT at afternoon, and reaches
its high point. Figure 4:10 represents that make use of wrenches to connect, cut, bend, and
modify reinforcing steel bars is peak (24.51%). Furthermore, place reinforcing steel bars is
7.19% modify reinforcing steel bars (10.13%), carry reinforcing steel bars (15.84%) use meter
to stick for measurement (3.61%) and bending (4.72%).
Figure 4:10. Total percentage of type working activity
Mean ± SD Mean ± SD Mean ± SD
7:00-8:00 55.64% ± 20.44% 20.64% ± 17.57% 23.72% ± 12.97%
8:00-9:00 72.50% ± 15.75% 14.17% ± 14.51% 13.33% ± 10.74%
9:00-10:00 85.42% ± 11.79% 7.50% ± 7.47% 7.08% ± 9.58%
10:00-11:00 68.47% ± 22.99% 11.94% ± 14.90% 19.58% ± 13.63%
1:00-2:00 62.78% ± 14.80% 17.92% ± 13.70% 19.31% ± 13.01%
2:00-3:00 61.67% ± 18.48% 18.47% ± 16.69% 19.86% ± 15.30%
3:00-4:00 68.06% ± 24.05% 16.94% ± 22.66% 15.00% ± 17.69%
4:00-5:00 54.17% ± 25.33% 22.64% ± 22.94% 23.19% ± 20.46%
DWT (%) IWT (%) NPT (%)
Time
24.51%
7.19%
10.13%
15.84%
3.61%
4.72%
2.79%
6.94%
0.17%
6.23%
0.23%0.83%
14.65%
0%
5%
10%
15%
20%
25%
30%
A-1 A-2 A-3 A-4 A-5 A-6 B-1 B-2 B-3 B-4 B-5 C-1 C-2
DWT IWT NPT
Percentage(%)
Total percentage of type working activity

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For the indirect work time, we found that walk toward equipment, tools, materials
(2.79%), wait for material to be carried (6.94%), review the list of material to understand the
work (0.17%), talk with foreman and coworkers about the tasks (6.23%), and take materials
(0.23%). The overall of the IWT is 16.71% of work. Besides this, non-productive time is
15.83% which workers presented chat, smoke, drink, use cell phone, go to the bathroom
(14.65%) and employees or machines, or both due to work stoppage from any causes (0.83%).
Within overall of NPT is equivalent to carry reinforcing steel bars is (15.84%) of IWT.
4.7. Parameter correlation
The data was synchronized mean data in 15 mins (CLP%, WBGT, RPE, TS, Ear-T, and
%HRmax.) in a unique group. and SPSS is used to test the normality of each data one by one.
The result of test normality is summarised below. Test normality was chosen to describe them
by method Shapiro-wilk. According to Appendix D presented the data set less than 2000 set
According to the data set of Construction Labor Productivity is 343 data set. Non-
parametric correlation is identified as Spearman Correlations, and as CLP is the dependent
variable. The identification of the data set is shown as a relationship to CLP, and parameters
that co-related with CLP as known as P-value<0.05. The parameters have associated with such
as RPE, Te, HRmax, Age and Daytime account for P-value is 0.005, 0.020, 0.023, 0.001, 0.003
each parameter, respectively. This relationship of RPE, Te, HRmax, Age, and Daytime are a
very significantly related factor to effect CLP which Spearman's’ correlation was used to
identify this relationship.
Table 4.4. Test normality with Shapiro-Wilk
Parameters Statistic N P-value
CLP% 0.91 343 0.000
Age 0.947 339 0.000
HRmax% 0.954 343 0.000
Ear-T 0.99 339 0.019
RPE 0.953 343 0.000
TS 0.931 343 0.000
WBGT 0.978 343 0.000
P-value < 0.05

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Throughout results shows that the age of the workers extremely associate parameter
with CLP, WBGT, and core temperature accounts for (P value<0.05). Within the WBGT is an
entire correlation with RPE, Te, HRmax, Age, and Daytime except for CLP (Pvalue=0.662).
The daytime parameter is associated with WBGT, CLP, and Te, but age and RPE are 0.812 and
0.168, respectively. Physiological Strain Index (Hr, heart rate, Ear temperature), and PeSI
(perceived exertion RPE, Thermal sensation TS, Sweat rate), type work activity and age. The
CLP% is the dependent variable; analyzed in SPSS with the independent variables (HRmax%,
Ear-T, HR, WBGT, RPE, TS, Age, daytime). Showed that the parameters have a correlation
with CLP% was classified in three varied groups. Classification is based on P-value was
conducted two statistics analysis; the first method was done by Bivariate correlation and
identify based on Statistics significant or P-value. P(value)<0.05 was a correlation with CLP%.
Table 4.5. Correlations of Variable with CLP%
Parameter
Correlation
coefficient
P-value N Comments
Age 0.173 0.001 339 Very weak Relationship
HRmax% 0.123 0.023 343 Very weak Relationship
Ear-T 0.126 0.020 339 Very weak Relationship
RPE 0.142 0.009 343 Very weak Relationship
TS 0.033 0.542 343 No relationship
WBGT 0.024 0.662 343 No relationship
P-value < 0.05
The RPE described the good relation with CLP, WBGT, and Te, but it is not related to
age and daytime. The Te is very strongly correlated with all parameters except CLP account
for Pvalue=0.02. The data was synchronized mean data in 15 mins (CLP%, WBGT, RPE, TS,
Ear-T, and %HRmax.) in a unique group. and SPSS is used to test the normality of each data
one by one according to appendix E . The result of test normality is summarised below. Test
normality was chosen to describe them by method Shapiro-wilk.

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5. CONCLUSION AND DISCUSSION
The study found that direct work activity (DWT) is 67.46%, and rebar workers are most
use of wrenches to connect, cut, bend, modify the reinforce steel bar and carry reinforce steel
bar. In addition, indirect work Time (IWT) is 16.71% that workers spent their time on waiting
material to be carried such as steel, and they were mostly talked with the foremen and co-
workers to discuss works. Although non-productive time (NPT) is 15.83%, and this considered
that they were chatting with co-workers, sit and smoke cigarettes. Moreover, this study also
resulted that workers reacted to environmental condition within responded hot (32.13%), and
according to the range of WBGT actual environmental record was the lowest and highest
account for 25.08°C to 35.40 C, respectively. The 12 rebar workers were considered no major
health problems, and they mostly young men with a range of 18 to 45-year-old. The age and
heart rate maximum were identified correlated with productivity, and these 2 parameters were
correlated because the older insisted the more heart rate maximum get reached. The equation
and statistical analysis also approved that age and heart rate maximum were correlated with
productivity account for P-value equal to 0.001 and 0.023, respectively. The workers voted
about 17.18% that working condition was somewhat hard to do. The rating of perceived
exertion (RPE) was identified as correlation with productivity by P-value presented 0.009 and
ear temperature was 0.02. Workers’ body temperature was gradually increased according to
working condition.

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APPENDIX A.
Table A.1 The procedure for measurement at the Construction site
ProtocolA
Find the company Email
Phone Number
Allowed Letter
Investigators
Visit the site and survey the
worker
Selected participants
Appointment
Phone numbers of
participants
Explanation of the
experiment
Investigators
Day/
Time
Task for participants Task for observers Equipment and
responsible person
6:30-6:40
There are two rebar
workers arrived at the site
measurement
Install Heat stress monitor
and fill distilled water
Install Camera
Assign clothes to uniform
for participants
Heat stress monitor
Camera
Clothes uniform
6:40-6:45
Wear clothes uniform
Sit down
Wear Heart rate belt for
workers
Connect and turn on Heart
rate Polar H10
Heart rate Belt
polar H10 connect with
Phone devices
6:45-7:00
Participants take a rest
15min
Response to the
information
Measure height, weight
Medical Checklist
Demographic information
Measure Ear Temperature
RPE, TS
Camera
Heat stress monitor
Heart rate belt
Omron
Balance and meter
Medical checklist paper
7:00-11:00
Working on-site 4h Measure Ear Temperature
RPE, TS, Productivity
observation, heart rate
Data collection for 15min
interval
Heat Stress monitor
Heart Rate belt
Omron
RPE, TS, HR,
Productivity Checklist
11:00-
11:15
Preparation for break Measure body weight,
water consumption
Turn off Heart rate belt,
Heart rate belt, water,
balance, camera

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12:45-
12:13:00
Workers arrived at the site
survey
Preparation: heart rate belt
put on the workers
Bodyweight
Measure RPE, TS, HR,
ear temperature
Heat stress monitor
Camera
Omron
Heart rate belt
RPE, TS, HR,
13:00-17:00
Working on-site 4h Measure Ear Temperature
RPE, TS, Productivity
observation, heart rate
Data collection for 15min
interval
Heat Stress monitor
Heart Rate belt
Omron
RPE, TS, HR,
17:00-17:30
Undressed clothes uniform Bodyweight, water
consumption
Turn off heat stress
monitor
Turn off the heart rate belt
Wash devices
Prepare devices to be back
Stress monitor
Heart rate belt
balance
Camera
Clothes uniform
Phone
Table A.2 Medical checklist
No. Questions Yes No
Do you have known major health problems?
ង្ត្ើអនកបានដឹខពីបញ្ហា សំខានៗននសុខភាពរឺង្ទ?
1 Hypertension
ជំខឺង្ ើសឈាម
2 diabetes
ជំខឺទឹកង្ោមផ្អែម
3 Cardiovascular problem
បញ្ហា សរនសឈាមង្បេះដូខ
4 Neurological disease
ជំខឺសរនសប្បសាទ
Have you experienced the heat illness symptoms in hot weather?
ង្ត្ើអនកធ្លា ប់មានង្ោគសញ្ហា ផ្ដ បណ្តា មកពីកង្តា ង្ៅកនុខរដូវង្តា
ផ្ដររឺង្ទ?
1 Confusion
វផ្ខែខសាា រត្ី

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2 Drenching sweats
ហូរង្ ើស
3 Headache
ឈឺកា
4 Fainting
ដួ សោា ប់
5 Nausea
ចខ់កែួត្
Table A.3 Rebar workers for every 15 minutes interval
ង្ព
ង្វលា ១ ការងារផ្ដ អនកកំពុខង្្ែើយ៉ាខង្មចផ្ដរ? ២ង្ត្ើអនកមានអារមាណ៍ យ៉ាខណ្តផ្ដរ?
សំោក
ពិត្ជាស្សួណ្តស់
ស្សួ
ាម
ំបាកបនាិច
ំបាក
ំបាកណ្តស់
ំបាកបំអុត្
ស្សស់ស្សាយ
កក់ង្តា
ង្តាឧណឌ
ង្តា
ង្តាណ្តស់
ពិត្ជាង្តាណ្តស់
ង្តាប្រំមិនបាន
6:55
០ ១ ២ ៣ ៤ ៥ ៦ ៧ ៨ ៩ ១
០
៧ ៨ ៩ ១
០
១
១
១
២
១៣
7:00
7:15
7:30
7:45
8:00
8:15
8:30
8:45
9:00
9:15
9:30

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9:45
10:00
10:15
10:30
10:45
11:00
Table A.3 List Rebar workers for every 15 minutes interval (Cont-)
1:00
1:15
1:30
1:45
2:00
2:15
2:30
2:45
3:00
3:15
3:30
3:45
4:00
4:15
4:30
4:45
5:00
Table A.4 List Ear Temperature and Sweat rate
Morning Afternoon
Time Ear-T Heart rate Time Ear-T Heart rate
weight:
Kg
Weight:
Kg
7:00 1:00
7:15 1:15
7:30 1:30
7:45 1:45
8:00 2:00
8:15 2:15
8:30 2:30

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8:45 2:45
9:00 3:00
9:15 3:15
9:30 3:30
9:45 3:45
10:00 4:00
10:15 4:15
10:30 4:30
10:45 4:45
11:00 5:00
weight: Kg weight: Kg
water consumption: Kg water consumption: Kg
Table A.5 List devices for do experiment
Devices unit
Check
Day1
Day2
Day3
Day4
Day5
Day6
1 camera video recorder(go pro) 1
2 The USB cable for camera 1
3 tripod small for a camera 1
4 power bank for camera 1
5 battery camera 3
6
memory card for camera 64 G and
128G 1
7 charger battery camera 1
8 polar sensor 2
9 heat stress monitor 1
10 H2O small battle 1
11 balance 1
12 meter 1
13 big tripod for heat stress monitor 1
14 ear temperature 2
15 Observer's safety uniform 2
16 question paper for rebar worker 2
17 medical check list paper 2
18 temperature data paper 2

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19 work activity paper 2
20 safety clothes for workers 2
21 big water bottle 6
22 adapter for camera 1
23 phone support with polar sensor app 2
24 umbrella 2
25 roller electric Cord 1
26 alcohol prep pad

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APPENDIX B.
B.1 Installation Process
Heat Stress Monitor Model QUESTEMP 36
The four directly senses ambient or dry bulb temperature, natural wet bulb temperature,
globe temperature, and relative humanity.
Step one: How to install Detection Management Software for the software is attached
with USB in a bag of Heat Stress Monitor, and we have plug-in the computer. It will show the
following figures:
Select folder and select word Install
Select word Complete and press Next. It will go the other folder to fill User Name and
Organization.

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Fill the license key: 262E-5D96 and press Apply license, then select Enlish and Apply
localization
After selecting the Apply localization is optional, and we can start the program.
B.2 Setting Up Device
The setup screen is used to change the following parameters temperature unit
languages, time, date logging rate, selecting between Heat Index and humidex and setting
stay time parameters. To set up parameters do the following:
➢ From the menu, select Set up by pressing The I/O Enter key.
➢ Use the arrow keys to select an item ( listed below)
-Temperature (Celsius)
-Language (English)
-Time

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-Date
-Log rate (1minute)Hea
-Heat Index (United States)
➢ Press I/O Enter
➢ Exit set up by pressing the Run/Stop key.
B.3 Transfer Data
Before starting the recording, setting up parameters for using data we had set up in our
useful work.
Fill the distilled water in wick
Before starting transfer the data, Heat stress monitor must turn on and connect with
socket and also Detection Management Software. The following figures are shown:
Connect socket with computer
New Desktop: select the DMS software and select Heat Stress

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Press English and Celsius and then press Download
After pressing the download button, select the file and it will go to the following graph, and
select the button download.
After selecting the download, it goes to save files and then select OK

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This is Excel file data from Heat stress monitor:

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How to use the polar heart rate belt monitor H10
B.4 Process of measurement
Heart rate monitor (HRM) is a monitoring device that allows one to measure or display
your heart rate in real-time or record the heart rate for every 1 second. It is largely used to gather
heart rate data while performing various types of physical exercise
Step1: How to create account polar
Before recording the data, we have to register or create a new account
Step2: After creating a new account, we can register to our application polar and
website
Step3: Preparation the device before put heart rate monitor on your chest use water
(H2O) to get wet on belt sensors
Step 4: Put your heart rate monitor on put heart rate monitor around your chest with connect
elastic strap, and then, adjust the strap length to fit snugly and comfortably. check that your
polar sensor is firmly against the skin and polar logo is in central
Step5: Pair a heart rate sensor with polar belt app mobile
*Make sure that your GPS and Bluetooth mobile open.

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The first, open polar belt app on your mobile device and sign in account
go to setting HR sensor pair the device
Step 4: start and stop
The first, we choose the type of sport on the symbol (+), Other outdoor was chose in
our measurement. and then press on Start. It will show the detail of your exercises such as
distance, spend, Calories, Duration, location, and heart rate. when you want to stop recording
your heart rate. you just swipe to unlock on the symbol key. and then it will show a symbol (II)
and press on it, the next press on (Stop), finally press on Save.

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click on (+) choice the activity type click on Star
Step5: Download the data from heart rate monitor
Check that your mobile has Internet or Wife access and turn on Sync.The first, go to
web site https://flow.polar.com and sign in account polar, and then go to Daily and find the
real date and redpoint which you want to download and then click on the Export session.
Finally choose type file Session (CSV).

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Step 6: clean the heart rate monitor after doing exercise
-Carefully wash the transmitter with the water solution
-Rinse it with pure water
-Dry the transmitter carefully with a soft towel.
-Store the heart rate monitor in a clean and dry place.
Turn on sign in account polar data will display in
real date

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How to use Model OMRON Ear Temperature
B.5 Process of measurement
Step 1: Preparation before measurement
- Replace the probe cover in the following cases:
- when it is dirty, broken, or damaged
- After someone else has used it
insert the probe cover with the tool until it clicks
Step 2: Press the switch on
- The power is turned on. After the display
check is completed, "°C" flashes
Step 3: Insert the probe into the ear
. Insert the probe in the ear as far as it goes in
when we want to measure continuously. wait about 10 to 20 seconds after you remove the
unit the direction of the eardrum When it beeps, we can start the measurement
from the ear, a "°C" mark flashes
and do the same previous for 2 times more with wait 15s to 20s interval for one time. Take
the result maximum value
Step 4: Press the switch while the unit is in the ear
When the unit beeps repeatedly, the measurement is finished. Measurement finishes in
approximately 1 second. Press the switch to illuminate the backlit screen for 2 seconds. You
can quickly read the results.
Step 5: After the measurement is finished
To end the measurement: In approximately 1 minute, the unit will be turned off
automatically. It cannot be turned off manually.
Memory: The last measurement value is stored automatically. It can be recalled when the unit
is turned on. The value will be displayed with ‘M’ symbol.

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APPENDIX C.
Table C.1 Equipment
Name of the equipment Specifications
Go Pro 7, Black Camera Features
Key Features
SuperPhoto | HyperSmooth Video Stabilization
Audio Features
3.5mm Audio Mic Input With Pro 3.5 Mic Adapter
(sold separately) | Stereo Audio
Connected Features
Wi-Fi + Bluetooth® | GPS Enabled | Connects to
GoPro App
Tripod
Tripod small for camera and Heat Stress monitor
are used support for investigating or observing the
activity of the worker
Water 1.5 L for investigators and workers
Extension Cord Wire Heavy Duty Retractable Extension Cord Wire
Cable Real Cart Spool Roller Reel

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Tape-meter Tape-meter, Body height was measured by a mounted-
wall scale
Portable Alcohol Pads Portable 100pcs Alcohol Swab Pads Prep Wipes
Antiseptic Cleanser Cleaning Alcohol Wipes
Sterilization Alcohol Pad First Aid
Umbrella Rainbow stick umbrella, against the sun-load
Omron OMRON Healthcare introduces Ear Thermometer
TH-839S which is suitable for both adults and
children. 1-second measurement and fever alarm
with a beeper (for body temperature 37.5°C
Tanita, body weight Body mass (including clothes) was measured by
using a digital scale with 0.1 kg precision
(Tanita®, Japan)

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Heat Stress Monitor QUESTemp°36, Australia, This monitors measure
parameters including temperature and relative
humidity, and compute the Wet Bulb Globe
Temperature (WBGT).
Polo T-shirt Construction uniform that consisted of a polo T-
shirt
Safety Helmet construction Safety Helmet Construction-grade hard hat
adjustable for any size fit, and Wearing high
visibility clothing for investigators
Polar heart rate H10 The Polar H10 Bluetooth & ANT+ Heart Rate
Sensor is an integrated chest strap and heart rate
monitor designed to measure heart rate. The H10
sends data wirelessly via either a Bluetooth to a
smartphone, and connect with Polar Beat
application with supported heart rate service
applications

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APPENDIX.D
Table D.1 Data measurement Sweat rate
Day1
P1: E MI P2: CHORK CHINCHAV
morning morning
weight before working 54.4kg weight before working 55.2kg
weight after working 53.4kg weight after working 54.8 kg
water consumption 0kg water consumption 0.7 kg
afternoon afternoon
weight before working 52.4 kg weight before working 54.4kg
weight after working 53.6kg weight after working 55.2kg
water consumption 1.7kg water consumption 2 kg
Day2
P3: YEOM NUY P4: LORY CHORN
morning morning
weight before working 48.4kg weight before working 63kg
weight after working 49kg weight after working 62kg
water consumption 1.2kg water consumption 0.6kg
afternoon afternoon
weight after working weight after working 62kg
water consumption 1.5kg water consumption 2kg
Day3
P5: REN DARA P6: HORN SEANHAI
morning morning
weight before working 44.9 kg weight before working 56.6kg
weight after working 45kg weight after working 54.4kg
water consumption 1 kg water consumption 0.8kg
afternoon afternoon
weight after working 45.8kg weight after working 56.4kg
water consumption 2kg water consumption 1.8kg

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Day4
P7: Kung VI P8: Hor RIN
morning morning
weight before
working 69.4kg weight before working 68.2kg
weight after
working 68.6kg weight after working 67.2kg
water
consumption 1.5kg water consumption 1.4kg
afternoon afternoon
weight before
working 69kg weight before working 67.8kg
weight after
working 68.4 kg weight after working 66.6kg
water
Day5
P9: Eheom sim P10: Aom Phun
morning morning
weight before
weight after
working 63.6kg weight after working 60kg
water
afternoon afternoon
weight before
weight after
working 64.6kg weight after working 60kg
water
Day6
P11: Seom Mo P12:Ring Mang
morning morning
weight before
weight after
water
afternoon afternoon
weight before
weight after
water

: Investigation on the relation of Heat Stress to Construction Labor Productivity for Rebar workers Case Study: Phnom Penh

: Investigation on the relation of Heat Stress to Construction Labor Productivity for Rebar workers Case Study: Phnom Penh

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: Investigation on the relation of Heat Stress to Construction Labor Productivity for Rebar workers Case Study: Phnom Penh