Heat stress assessment of construction workers in hanoi

VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY ANNEX LIST OF FORMS FOR MANAGEMENT PHAM CAM VAN HEAT STRESS ASSESSMENT OF CONSTRUCTION WORKERS IN HANOI MASTER'S THESIS Hanoi, 2018 VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY PHAM CAM VAN HEAT STRESS ASSESSMENT OF CONSTRUCTION WORKERS IN HANOI MAJOR: ENVIRONMENTAL ENGINEERING RESEARCH SUPERVISORS: Prof Dr KENSUKE FUKUSHI Associate Prof Dr DO QUANG TRUNG Hanoi, 2018 ACKNOWLEDGEMENT First of all, I would like to express my sincere thanks to Vietnam Japan University, the University of Tokyo, Japan International Cooperation Agency (JICA) for creating favorable conditions for me to study and develop in the last two years I would like to send my deep thanks to the lecturers in Environmental Engineering Department; Professor Jun Nakajima, Associate Professor Cao The Ha, Associate Professor Hiroyuki Katayama and Doctor Nguyen Thi An Hang, Ms Nguyen Phuong Thao, who were always willing to help and motivate me in all aspects of studying and living in school I would like to express my deepest gratitude to my supervisor Professor Kensuke Fukushi for all the knowledge he taught me Thanks for always caring and encouraging me; even when he was strict or when he understood for me, he still gave me a lot of motivation Thank him for inspiring me to have more will to learn and become a teacher like him I sincerely thank Associate Professor Do Quang Trung for his enthusiasm, he was always trying to help me and looking for the most useful methods to complete my thesis I would like to express my sincere thanks to all employees of JICA, JICA and IR3S for their assistance in all cases I would like to thank my friends and all workers who attended my study and supported me on the way I implemented my thesis Finally, I sincerely thank my family, my parents, and my husband for always being there, giving me the motivation to overcome all the hardships, to have the strength to achieve today's results Sincerely thank Pham Cam Van TABLE OF CONTENT INTRODUCTION Background Objective of the study Scope of the study CHAPTER LITERATURE REVIEW 1.1 Definition of terms 1.2 Impact of heat stress on human health 1.3 Heat stress indices 10 1.3.1 Wet Bulb Globe Thermometer (WBGT) 10 1.3.2 Thermal Work Limit (TWL) 11 1.3.3 Heat Stress Index (HSI) 11 1.3.4 Universal Thermal Climate Index (UTCI) 12 CHAPTER METHODOLOGY 13 2.1 Experiment 15 2.1.1 The first data collecting period 17 2.1.2 The second data collecting period 17 2.2 Calculation of data 19 2.2.1 Outer environmental data 19 2.2.2 Inner health data 21 2.3 Questionnaire 22 2.4 Data analysis 25 CHAPTER RESULTS AND DISCUSSION 26 3.1 The first data collecting period 26 3.1.1 University of Commerce Dormitory Construction Site 26 3.1.2 Le Trong Tan Construction Site, Hanoi 30 3.2 The second data collecting period 32 3.3 Individual assessment of construction workers 38 CHAPTER CONCLUSIONS AND RECOMMENDATIONS 43 4.1 Conclusions 43 4.2 Recommendations 44 REFERENCES 45 LIST OF TABLES Table 1.1 Heat-related illnesses symptoms and causes Extracted from University of Manitoba’s guideline (2007) Table 2.1 UTCI category 14 Table 2.2 Data collecting periods 15 Table 3.1 UTCI calculation in University of Commerce on January 27 Table 3.2 The correlation between UTCI and other outer parameters 28 Table 3.3 Health parameters of respondents on January 29 Table 3.4 UTCI calculation of Le Trong Tan construction on January- 30 2018 Table 3.5 The correlation between UTCI and outer parameters 30 Table 3.6 Health parameters of respondents in Le Trong Tan, Ha Dong 32 Table 3.7 UTCI calculation of Le Trong Tan, Ha Dong on March and 33 April Table 3.8 Correlation between UTCI and outer parameters 34 Table 3.9 Health parameters of respondents on March and April 35 Table 3.10 The correlation between UTCI, temperature 36 and other health parameters Table 3.11 UTCI and WBGT in University of Commerce Dormitory 37 Table 3.12 The correlation between three value, temperature, UTCI and 37 WBGT LIST OF FIGURES Figure 1.1 Physical and psychological effects of excessive heat exposure and the impacts on productivity Reproduced from Kjellstrom et al (2016) Figure 1.2 Body response to excessive heat Reproduced from University of Manitoba’s guideline (2007) Figure 2.1 Factors impact to human heat balance 13 Figure 2.2 Construction sites in University of Commerce Dormitory 16 Figure 2.3 Construction sites in Le Trong Tan, Ha Dong 16 Figure 2.4 Location of construction site in University of Commerce Dormitory (Ho Tung Mau, Hanoi) 16 Figure 2.5 Location of construction site in Le Trong Tan, Ha Dong 16 Figure 2.6 (a) Watch Logger 255F - Fujita (b) Heatstroke Meter Data 18 Loggers Hi -2000SD, (c) NISSEI WS910 wrist blood pressure monitor, (d) DRETEC Non-contact Thermometer Temperature Measurement Figure 2.7 Measure blood pressure for workers during lunch time 21 Figure 2.8 Construction workers accomodation in University of Commerce Dormitory site 21 Figure 2.9 A sample of questionnaire 25 Figure 3.1 Correlation between UTCI and other outer parameters 28 Figure 3.2 Correlation between UTCI and other outer parameters 31 Figure 3.3 Correlation between UTCI and Outer parameters 34 Figure 3.4 Answer of the hottest time in day that workers feel 39 Figure 3.5Answer of heat related symptons of workers 40 Figure 3.6 Answer of actions that workers want to reduce the effect of heat to workers 41 Figure 3.7 Answer of impact of heat stress to working productivity 41 Figure 3.8 Answer of workers about their changing job intention 42 LIST OF ABBREVIATIONS Universal Thermal Climate Index Wet Bulb Globe Thermometer Thermal Work Limit Heat Stress Index UTCI WBGT TWL HSI INTRODUCTION Background In the context of global warming, the effects of high temperatures on human life are also being investigated There are many studies that show the effect of heat on human health, but these researches focus on older people, young people, and people with weak health and chronic illness However, the effect of heat on people also depends on the living and working places as well as the work characteristics Exposure to high temperatures for long time will also affect to people health and cause heat diseases On the other hand, workers and outdoor workers are people who always under harsh weather conditions and are directly affected by natural conditions In addition, the heavy labor activities of the workers cause the workers to have strong transformations and heat exchanges According to G Jendritzky and R de Dear (2015), heat can be exchanged by pathways: convection (sensible heat flux), conduction (contact with solids), evaporation (latent heat flux), radiation (long and short wave) and respiration (latent and sensible) Vietnam National Institute of Occupational Safety and Health (VNNIOSH) (2015) stated that the body of workers reacted with the high temperature by blood circulation to the skin which increase the skin temperature and allow the body release the heat over the skin However, the energy and muscle using for hard work will make the available blood for blood circulation decrease, for this reason the released heat would be less Sweat moisture excretion is an effective way to release the heat and keep the body’s core temperature constant as well as still cool However, if the humidity is not enough for the evaporation of sweat and the water and salt in the body cannot be filled, sweat moisture excretion will be dangerous for human As can be seen in Table 3.9, in the hottest day 2nd April, UTCI became one of the highest number, together with the average body temperature, blood pressure and heart beat rate were also reached the peak at 36.84±0.3, 149.29±14.26/99.5±12.53 and 88.71±9.25 respectively Additionally, other values in other days likely had a tend to match with UTCI tendency The correlation of UTCI with other health parameters was also calculated to prove this relationship with the result shown in Table 3.10: Table 3.10 The correlation between UTCI, temperature and other health parameters Blood pressure Body Temperature Upper limit Lower limit Heart beat UTCI 0.585 0.661 0.615 0.663 t (ºC) 0.859 0.953 0.918 0.902 As Table 3.10, UTCI had positive correlation with all health parameters, however, temperature had much higher correlation with health parameters in comparison with UTCI UTCI also were dominated other factors like relative humidity, water vapour pressure, wind speed Moreover, data collection of this period was only in sunny day in days; data of relative humidity, wind speed could not express the change of weather, lead to water vapour pressure was also affected Although the data was still limited, this result can prove the relationship between UTCI as well as temperature and construction worker’s health parameter  UTCI and WBGT Comparing kinds of index is an approach to find out the suitable application in Hanoi condition 36 WBGT is measured by Heatstroke Meter Data Loggers Black Ball Type Supported SD card record Hi -2000SD Table 3.11 UTCI and WBGT in University of Commerce Dormitory Date UTCI WBGT 27/03/2018 27.82 22.80 29/03/2018 26.32 23.58 02/04/2018 27.48 24.13 04/04/2018 25.39 24.50 05/04/2018 24.34 24.13 09/04/2018 24.74 25.55 10/04/2018 23.72 26.60 To identify the relationship between UTCI and WBGT and how it application in this area, the correlation was calculated as listed in Table 3.12: Table 3.12: The correlation between three value, temperature, UTCI and WBGT Temperature (ºC) UTCI WBGT Temperature (ºC) - 0.620 -0.533 UTCI 0.620 - -0.799 WBGT -0.533 -0.799 - Table 3.12 shows that between WBGT and temperature in this place had negative relationship, it tends to be against the theory By contrast, UTCI and temperature have positive effect each other For that reason, in this location, UTCI and WBGT have negative correlation and UTCI seems to become more suitable index to evaluate heat stress in this location 37 3.3 Individual assessment of construction workers During the two periods of measurement and data collection, 34 respondents were interviewed Everyone is in the 20 to 60 age range, 20.5% are female, and 79.5% are male All of them work as construction workers are full time workers and not another job Most construction workers drink alcohol at a fairly high frequency, as 74% of respondents have a habit of drinking and drink alcohol in their daily meals However, 32.3% of respondents have a habit of smoking and, 67.7% of non-smokers It can be said, the habit of drinking more often will greatly affect the health conditions of construction workers (according to Health Promotion Agency) In discussion part, there is a similarity in the construction worker's answer in the first question 100% of respondents agreed that April to June was the hottest time of the year, indicating that May and June were the peak of the summer, affecting their jobs and their lives During April – Jun period, period from 11h to 14h was considered the hottest time with 70.6% of people agreeing, 8.8% of workers thought that the afternoon from 15h-17h is the hottest Others said that from 11h to 17h is their answer and they could not choose one, 17.6% of respondents agreed, only 2.9% of workers said that after 17 hours is the hottest time (Fig 3.4) 38 17.6% 2.9% 8.8% 70.6% at noon (11-14h) in the afternoon (15-17h) after 17h both noon and afternoon Figure 3.4 Answer of the hottest time in day that workers feel 11h-14h is the time of sun going to the highest point, this is also the time chosen to measure the outer environmental parameters and health parameters of workers because of the effect of this time period supposed to be the largest During the hottest time, people recognized various symptoms associated with heat One person may have multiple symptoms at the same time 91.2% of workers exhibited thirst in hot weather Followed by hyperhidrosis or sweating with 88.2% and headache, dizziness, distraction with 52.9% Heat rash, heat cramps were relatively low with 5.9% and 8.8%, respectively None of the workers fainted or had a heat stroke Construction workers in these two areas not have serious symptoms due to the effects of heat However, at the time of the questionnaire conducting, the weather is quite comfortable, Hanoi was in the end of winter and the beginning of spring, the temperature remained in cool state, which will also affect the objectivity of the answer; respondents may not be able to fully remember all the symptoms at that time (Fig 3.5) 39 heat stroke 0.0% heat cramps 8.8% heat rash faint 5.9% 0.0% headache, dizziness, loss of concentration 52.9% sweat 88.2% thirsty 91.2% 0.0% 20.0% 40.0% 60.0% 80.0% 100.0% Figure 3.5 Answers of heat related symptons of workers Under the insufficient conditions of site facilities, the first solution that construction workers think of to minimize the impact of heat on their work and health is to add a cooling devices such as a electric fans, steam fans with 73.5% of workers Only 5.9% of workers needed water; 2.9% of workers would like to provide extra water and roof coverings 17.6% of workers wanted all five solutions to be applied to reduce the effect of heat Fig 3.6 40 5.9% 17.6% 2.9% 73.5% supply more water supply more equipment like fans supply more water and roof all solutions Figure 3.6: Answer of actions that workers want to reduce the effect of heat to workers About the effect of heat stress to working productivity, 58.8% of workers admitted that hot weather tires them up and reduces their productivity Followed by 26.4% of people feel the effect of heat on their health but that does not reduce their labor productivity 8.8% of workers did not feel any effect of heat (Fig 3.7) 8.80% impact to health status and reduce the productivity impact to health status and not reduce the productivity 26.40% 58.80% not impact Figure 3.7 Answer of impact of heat stress to working productivity 41 However, with these results of impact, only 2.9% of workers wanted to change jobs and found new jobs 17.6% of workers wanted to change jobs but they could not change and had another choices With 23.5% people feeling that being a construction worker is the only option they could not change and 55% of the workers had a different opinion, they feel satisfied with the current job and did have any idea of changing it (Fig 3.8) 2.90% workers want to change and find a new job 17.60% workers want to change but can not change 55.00% 23.50% workers not want to change and can not change job workers have other opinions Figure 3.8 Answer of workers about their changing job intention Based on the results of the questionnaire, it is possible to clearly see the favorable time to begin the study of heat stress assessment with construction workers It can be clearly seen that it takes more time to track and learn more about their heat related symptoms in the right time Construction workers are generally well-off people, so they not yet have a proper assessment of their health damaged to the job in hot weather conditions and the lack of support from other facilities Although the responses are subjective, the consistency of the opinions in the majority of questions has opened the way for further research and provides more information on the construction workers 42 CHAPTER CONCLUSIONS AND RECOMMENDATIONS 4.1 Conclusions To accomplish the objectives of the study, the study carried out two periods of data collection at two construction sites in Hanoi The results are shown in three main parts:  Universal Thermal Climate Index (UTCI) in constructions in Hanoi is calculated During the first period in University of Commerce Dormitory, the temperature was quite low so heat stress index in location (UTCI) was below 26 from 23 rd January to 27th January, the last three days from 28th to 30th January had cold stress At the second construction sites (Le Trong Tan, Ha Dong), the first day (23rd January) had light heat stress, with UTCI reaching 27.69 Similar to the first location, the last three days were slight cold stress The second periods of the study, which took place in late March (27th March to 10th April), the methodology were changed: measuring only on sunny days and gathering at University of Commerce site From the 27th March to 2th April, UTCI was in the range of moderate heat stress (from 26 to 32) 27th March and 2nd April were two days with the highest UTCI at 27.82 and 27.48  UTCI and WBGT had negative correlation (this result was against the theory) although UTCI have positive relation with temperature in these sites As a result, UTCI seems to be more suitable to assess heat stress in these locations  The relationship between UTCI and construction workers health status is built up During the first period, on the days of cold stress, the blood pressure of workers build up slightly to 139.17 -140.17 / 90.83 43 In the second location, the blood pressure of the workers in this area increased to 140/95 and the heart rate reached the fastest rate on the day with moderate heat stress During the second period, 2nd April – the highest UTCI day was also the day when the employee's health profile was noticeable In addition, the questionnaire also provided related information including the hottest months, the hottest time in day and the heat related symptoms April – June were the hottest months, in this period, 11h -14h was the hottest time that probably causes heat stress symptoms 4.2 Recommendations  This study was conducted during the cold seasons in Hanoi, as a consequece, the results of heat index were lower than the standard of heat stress index This study as well as its methodology should be implemented under hot weather, such as the hottest months from April to June  The collected data can spread out to have more variation Data can be collected in other construction sites to ensure the diversity of data  Respondents should be investigated more personal information in detailed to analyze deeply their 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Lack of acclimatization Loss of body fluid from sweating Heat Sharp pains in muscles of arms, Heavy sweating causing loss of salt cramps legs or abdominal muscles May Drinking large amounts of. .. characteristics of workplace which is highly heat exposure Among them, the number of construction workers increases significantly in Hanoi because of the city infrastructure development In addition, according