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1

Workplace hazards and safety practices in the small-scale industries

ElSharkawy Mahmoud Fathy

Production Engineering Archives

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2024

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Vol. 30, Iss. 2

241--250

EN

The small-scale industries are considered a major sector of economic investment in the world. Small-scale industries typically suffer from problems such as poor management systems, poor safety training, difficulties in complying with legislation, and absence of safety performance. This study aimed to measure the levels of heat stress and noise and assess the safety performance in small-scale industries. Twenty industrial workshops were selected representing four different types of small-scale industries (foundries, automotive repair, metal processing, and aluminium processing) in Alexandria, Egypt. Inside each selected workshop, both levels of heat stress and noise were measured by calibrated instruments. A pre-designed checklist evaluated the adequacy of the safety performance. Noise levels ranged between 86.4 ± 2.0 and 89.7 ± 2.7 dB exceeding the recommended value (85 dB). In the most studied workshops, the levels of heat stress were relatively high, especially in the foundries. Besides, the safety practices at all these workshops were poor or very poor. The most obvious safety problems included poor housekeeping, lack of PPEs, inadequate illumination, absence of emergency exits, and insufficient fire extinguishers. The results emphasize the responsibility of the local authorities to give more atten-tion and interest to this type of industry.

2

Heat Stress Analysis Using the Discomfort Index Method: Impact on Macro Environmental in Yogyakarta

Nurmaya E. M., Abidin A. U., Hasanah N. A. I., Asmara A. A.

Journal of Ecological Engineering

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2022

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Vol. 23, nr 1

286--295

EN

A growing urban development pattern can have both positive and negative impacts. One of them is the thermal discomfort in the form of heat stress. Heat stress is the maximum condition of the human body to receive the heat exposure to various activities. This study analyzed the thermal comfort in Yogyakarta City based on the Discomfort Index (DI) method. The DI method is commonly used in tropical climates using the parameters that include average air temperature and humidity. The data consists of secondary data obtained from Geophysics Station Gamping in 2004-2020 and Climatology Station Mlati in 2017-2020. The result of DI indicated that the highest value occurred in the wet moon climate type in April, with 25.63 °C. Therefore, the conditions showed that more than 50% of people in the city of Yogyakarta fall into an uncomfortable category with an average index of 24.97 °C, which can lead to heat stress. Environmental engineering can be employed to decrease the heat stress potential and improve the thermal comfort for Yogyakarta’s urban community, which is public and private open space, plant road shade vegetation, implement a green façade (vertical garden), as well as improve people’s living behavior and use appropriate clothing.

3

Ocena obciążenia cieplnego człowieka w środowisku gorącym poprzez wskaźnik WBGTeff wg zapisów normy PN-EN ISO 7243:2018-01

Młynarczyk Magdalena, Konarska Maria

Podstawy i Metody Oceny Środowiska Pracy

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2021

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Nr 1 (107)

5--14

PL

Ocena najwyższego dopuszczalnego obciążenia cieplnego organizmu w środowisku gorącym wyznaczana jest za pomocą wskaźnika WBGT. Nazwa wskaźnika WBGT pochodzi od nazw czujników wykorzystywanych do pomiarów przesiewowych parametrów środowiska: do pomiaru temperatury w stanie wilgotnym (temperatura wilgotnego termometru – Wet Bulb) oraz pomiaru temperatury poczernionej kuli (Globe Temperature). WBGT jako wskaźnik używany do oceny obciążenia cieplnego organizmu do 2017 r. był powiązany z wydatkiem energetycznym i przedstawiony w postaci tabel w polskim wydaniu normy PN-EN 27243:2005 (oraz PN-EN 27243:2005P). W 2017 r. normę zastąpiono dokumentem EN ISO 7243:2017, a w styczniu 2018 r. zostało zatwierdzone polskie tłumaczenie normy PN-EN ISO 7243:2018-01. W artykule zamieszczono opis metodyki prowadzenia badań wskaźnika WBGT zgodnie z zapisami PN-EN ISO 7243:2018-01. Zakres tematyczny artykułu obejmuje zagadnienia zdrowia oraz bezpieczeństwa środowiska pracy będące przedmiotem badań z zakresu nauk o zdrowiu oraz inżynierii środowiska.

EN

The assessment of maximum allowable heat load of a body in a hot environment is determined using the WBGT index. The name of the WBGT index is derived from the measurement of two parameters: natural wet-bulb temperature and black globe temperature. WBGT as an indicator used to assess the heat load (until 2017) was related to the metabolic heat production and placed in the form of tables in the Polish edition of Standard No. PN-EN 27243:2005 (and PN-EN 27243:2005P). In 2017, this standard was replaced by Standard No. EN ISO 7243:2017, and in January 2018, the Polish translation of Standard No. PN-EN ISO 7243:2018-01 was approved. This article describes the methodology of conducting WBGT research according to Standard No. PN-EN ISO 7243:2018-01. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

4

Modelling of contact geometry of tool and workpiece in grinding process with crossed axes of the tool and workpiece with circular profile

Kalchenko Volodimyr, Yeroshenko Andrij, Boyko Sergiy, Kalchenko Olga

Acta Mechanica et Automatica

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2021

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Vol. 15, no. 1

9--15

EN

A general model is developed, and on its basis, there are special models formulated of the grinding process with crossed axes of the tool and workpiece with a profile in the form of a circle arc. A new method of control of the grinding process is proposed, which will provide processing by equidistant curves, and the amount of cutting of a circle equal to the allowance. This will increase the productivity and quality of grinding. The presented method of grinding implements the processing with the spatial contact line of the tool and workpiece. When the axes are crossed, the contact line is stretched, which leads to an increase of the contact area and, accordingly, to a decrease of the temperature in the processing area. This allows processing of workpieces with more productive cutting conditions.

5

Investigating Indian summer heatwaves for 2017–2019 using reanalysis datasets

Hari Manoj, Tyagi Bhishma

Acta Geophysica

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2021

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Vol. 69, no. 4

1447--1464

EN

Heatwaves are characterized by an increase in temperature to extreme levels, which adversely distress the living organisms. India ranks second in terms of disaster mortality among the world countries, preponderantly by heatwave—infuenced by regional climatology. In this study, the Excess Heat Factor (EHF) index is used to detect the heatwave using the ERA-Interim reanalysis dataset over various states of India during the summer period (April–June of 2017–2019). EHF categorizes heat waves based on the severity, which is an intensity measure created by combining the measures of excess heat, long-term temperatures anomaly characteristics by each location’s unique climatology of heat by various thresholds. The heatwave events are analysed by combining the means of excess heat and heat stress, which has a strong aspect of EHF measure ments. Concerning the intensity of future heatwaves, EHF index helps to analyse the frequency and intensity of heatwave episodes and alert those community most exposed to heat related illness. One of the indices is derived from a climatological background to analyse the severity of heatwave over the Indian states. The analysis over India using the EHF index refected a substantial rate of increase in the intensity and the frequency of heatwaves in the successive years with an average EHF intensity (mean EHF for the analysis period) of ~ 41 °C2 , ~ 38 °C2 and ~ 39 °C2 , especially over the north–western states, eastern coastal states and central and southern states, respectively. The results of this study serve as a drive in the risk and vulnerability planning and assessment.

6

Effectiveness of a cooling jacket with reference to physiological responses in iron foundry workers

Shirish A., Kapadia V., Kumar S., Kumar S., Mishra S., Singh G.

International Journal of Occupational Safety and Ergonomics

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2016

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Vol. 22, No. 4

487--493

EN

Personal cooling garments (PCGs) have gained increased attention in recent years due to heat stress and strain in the working environment. The present study was conducted in hot environments of an iron foundry to evaluate the efficacy of a battery-operated PCG. Twenty-four workers were exposed to climatic conditions of 35.89 ± 1.25 °C, 35% relative humidity during 90-min work with PCG and habitual clothing (HC). Mean weighted skin temperature was significantly lower by 4.84 ± 1.05 °C compared with HC 0.38 ± 1.02 °C (p < 0.05). A statistically significant difference was also observed for 0.492 ± 0.26 g mean sweat loss in the PCG group compared with 0.775 ± 0.42 g in the HC group (p < 0.05). Heart rate, and back and chest skin temperatures were comparatively more reduced in the PCG group compared with the HC group. PCG provides a practical and economical way of alleviating the physiological effects of heat stress when environmental control is not feasible.

7

A Thermal Stress Treadmill Walk for Clinic Evaluation of Candidates for Hazardous Materials (HazMat) Duty

Raymond L. W., Barringer T. A.

International Journal of Occupational Safety and Ergonomics

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2014

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Vol. 20, No. 2

281--293

EN

U.S. guidance for examining hazmat workers recommends stress testing be considered when heat stress is expected. However, the most common stress test—Bruce protocol treadmill electrocardiography (BPTE) wearing gym clothes—creates little thermal stress. Objective. Evaluate a novel thermal stress treadmill walk (TSTW). Methods. Body temperatures and heart rates during BPTE in 93 current and potential hazmat workers wearing gym clothes were compared with later values in 35 of these subjects while they were wearing thermally-restrictive “sauna suits” during a 45-min TSTW. Physiological strain index (PSI) was calculated from temperature and heart rate changes and compared with PSI values from hazmat simulations and climatic chamber exercises. Results. Tympanic temperature (TT) rose 0.5 °C (SD 0.5) during BPTE lasting 12.4 min (SD 2.9). PSI reached 6.0 (SD 1.3). TT rose 1.0 °C (SD 0.5) during TSTW, p < .01. PSI averaged 6.6 (SD 1.9) in 29 subjects who completed TSTW, versus 5.7 (SD 5.7) in the 6 subjects who did not. Ingested thermistor temperatures increased more than did TT during TSTW, yielding PSI of 7.0 (SD 1.5), equal to PSI values from climatic chamber exercises, i.e., 7.0 (SD 1.0). Conclusion. TSTW increased body temperature and PSI in 29 of the 35 subjects who completed it to levels matching those of operational simulations in climatic chambers and during hazmat exercises. This TSTW may be useful for evaluating candidates for hazmat duty.

8

Evaluation of human thermal comfort and heat stress in an outdoor urban setting in summer under arid climatic conditions

Abdel-Ghany A. M., Al-Helal I. M., Shady M. R.

Environment Protection Engineering

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2014

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Vol. 40, nr 3

139--150

EN

Thermal sensation and heat stress potential were evaluated in summer in an outdoor arid environment. Such evaluation had never been made in arid regions. Various scales: the temperaturehumidity index (THI), physiological effective temperature (PET), universal thermal climatic index (UTCI) and standard effective temperature (SET*) were used for the evaluation. RayMan software model was used to estimate the PET and SET* and the UTCI-calculator was used for UTCI. The required air dry and wet bulb temperatures (Td, Tw), solar radiation flux (S0) and wind speed (V) were measured in summer (April 29–July 15). The results showed that: Persons are exposed to strong heat stress and would feel very hot most of the day time; and they are safe from heat stress risk and would feel comfortable most of the night time. Heat stress levels can be determined using the PET or UTCI scales; both are valid for arid environment and their results are almost similar; however, the THI cannot be used. SET* index specifically describes the thermal sensations and discomfort conditions along with summer days at any activity under arid conditions.

9

Wybrane elementy obciążenia cieplnego pracowników w ścianach eksploatacyjnych

Szlązak N., Obracaj D., Głuch B.

Górnictwo i Geologia

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2013

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T. 8, z. 3

143--158

PL

W artykule scharakteryzowano metodę obliczeń stresu cieplnego pracownika dla wyrobisk ścianowych w kopalniach węgla kamiennego. Na podstawie wyników pomiarów parametrów powietrza z wylotów wyrobisk ścianowych w wybranych kopalniach przeprowadzono ocenę obciążenia cieplnego standardowego górnika (waga, wzrost, wskaźnik BMI itp.). Przeprowadzono analizę wpływu izolacyjności odzieży oraz wydatku energetycznego na wartość ubytku wody z organizmu i temperaturę wewnętrzną pracownika. Na podstawie uzyskanych wyników wykazano istotność parametrów odzieży oraz ciężkości pracy w środowisku o trudnych warunkach klimatycznych.

EN

This article characterizes a calculation method for a worker’s heat stress in longwalls in coal mines. Heat strain of an average miner (weight, height, BMI index etc.) were estimated on the basis of the measurement results of air parameters in longwalls in selected mines. The influence of thermal insulation of clothing and a metabolic rate on an insensible water loss and worker’s core temperature were also examined. On the basis of the obtained results it was concluded that the parameters of clothing and how hard work in very hard climate conditions is play a significant role.

10

Effect of heat stress on biochemical parameters of hens

Havlicek Z., Slama P.

Proceedings of ECOpole

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2011

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Vol. 5, No. 1

57--60

EN

The objective of this paper was to evaluate the effects of high temperatures on biochemical parameters of hens. Heat stress generally causes a decrease in feed intake. The hypothesis that feed intake, egg production, egg quality measures, acid-base status (pH, pCO2, HCO3 –) of hens would be influenced by the high temperature period was tested. Twenty four Isa Brown hens at 60 weeks of age were used in this experiment and hens were randomly separated into 2 equal groups. Each group contains 12 hens. First control group was housed at 20.1÷21.2°C and 60÷65% relative humidity. Experimental group was housed for 2 weeks at 20.5°C and 60÷65% relative humidity in experimental box, and then exposed to 27°C and 60% for 4 week, and then allowed to recover for 2 week at 20.5°C and 60% relative humidity. All production parameters and egg quality were significantly affected by heat stress. Feed intake during first week heat period was significantly reduced (18%). In three next weeks, feed intake was increasing with reduction 14.5%, 8% and 9.5%, respectively. Blood pH values were significantly lower from 3rd week of exposure. Blood pH had these values: 1st week 7.372, 2nd week 7.371, 3rd week 7.380 and 4th week 7.289.

11

UTCI - nowe narzędzie badania warunków bioklimatycznych w różnych skalach czasowych i przestrzennych

Błażejczyk K., Broede P., Fiala D., Havenith G., Holmér I., Jendritzky G., Kampmann B.

Przegląd Geofizyczny

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2010

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Z. 1-2

5-19

PL

Spośród licznych wskaźników oceniających oddziaływanie środowiska atmosferycznego na człowieka tylko nieliczne mają bezpośrednie odniesienie do reakcji fizjologicznych zachodzących w organizmie. W ostatnich latach powstał kilka prostych i wielowęzłowych modeli bilansu cieplnego człowieka, które opisują złożone mechanizmy gospodarki cieplnej organizmu. Na bazie wielowęzłowego modelu Fiali powstał nowy wskaźnik oceniający obciążenia cieplne człowieka (UTCI). W artykule przedstawiono założenia i podstawy interpretacji wskaźnika oraz przykłady jego zastosowania w różnych skalach czasowych i przestrzennych.

EN

Starting from 1999, in the frame of International Society of Biometeorology special study group is working to develop new Universal Thermal Climate Index (UTCI). Since 2005 these efforts have been reinforced by the COST Action 730 of the European Science Foundation (ESF) in order to achieve significant progress in deriving such an index. The new UTCI index represents air temperature of the reference condition with the same physiological response as the actual condition. The index base on Fiala model that is one of the most advanced multi-node thermophysiological models. It includes the capability to predict both, whole body and local thermal effects. The model consists of two interacting thermoregulatory systems: the controlling active system and the controlled passive system. The passive system simulates the dynamic heat transfer phenomena that occur inside the body and at its surface. The active system is a model predicting the thermoregulatory reactions of the central nervous system. The assessment scale of UTCI base on the objective physiological reactions to environmental heat stress in wide range of weather and climates. As an example the index was applied to assess biothermal conditions it two patio-temporal scales: local and regional. The results show good representation of specific local and regional features of bioclimate. Thus, the index can be applicable in various research dealing with: bioclimatological assessments, bioclimatic mapping in all scales (from micro to macro), urban design, engineering of outdoor spaces, consultancy for where to live, outdoor recreation and climatotherapy, epidemiology and climate impact research.

12

Heat Gain From Thermal Radiation Through Protective Clothing With Different Insulation, Reflectivity and Vapour Permeability

Brode P., Kuklane K., Candas V., Den Hartog E. A., Griefahn B., Holmer I., Meinander H., Nocker W., Richards M., Havenith G.

International Journal of Occupational Safety and Ergonomics

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2010

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Vol. 16, No. 2

231--244

EN

The heat transferred through protective clothing under long wave radiation compared to a reference condition without radiant stress was determined in thermal manikin experiments. The influence of clothing insulation and reflectivity, and the interaction with wind and wet underclothing were considered. Garments with different outer materials and colours and additionally an aluminised reflective suit were combined with different number and types of dry and pre-wetted underwear layers. Under radiant stress, whole body heat loss decreased, i.e., heat gain occurred compared to the reference. This heat gain increased with radiation intensity, and decreased with air velocity and clothing insulation. Except for the reflective outer layer that showed only minimal heat gain over the whole range of radiation intensities, the influence of the outer garments’ material and colour was small with dry clothing. Wetting the underclothing for simulating sweat accumulation, however, caused differing effects with higher heat gain in less permeable garments.

13

Effect of Exercise and Heat-Load on Simple Reaction Time of University Students

Chandra A. M., Ghosh S., Barman S., Iqbal R., Sadhu N.

International Journal of Occupational Safety and Ergonomics

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2010

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Vol. 16, No. 4

497--505

EN

Visual and auditory simple reaction times for both right and left hands of young university male students were recorded with a simple reaction timer, before and after an exercise schedule without and with elevated temperatures in a climatic chamber. The results indicated a decrease in both visual and auditory reaction times after the exercise, but a marked increase in them was noticed when exercise was performed at elevated temperatures. The difference in reaction times in preferred and nonpreferred hands was negligible at rest, i.e., without any exercise and elevated temperature. However, the difference was significant when exercise was performed at elevated temperatures. Visual reaction time was longer than auditory reaction time in all conditions. The results suggest that in hot industries, increased temperature has a specific rather than general effect on cognitive processes, perception and attentiveness, leading to increased chances of human errors, fatal accidents and loss of productivity.

14

Analytical Study of the Heat Loss Attenuation by Clothing on Thermal Manikins Under Radiative Heat Loads

Den Hartog E. A., Havenith G.

International Journal of Occupational Safety and Ergonomics

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2010

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Vol. 16, No. 2

245--261

EN

For wearers of protective clothing in radiation environments there are no quantitative guidelines available for the effect of a radiative heat load on heat exchange. Under the European Union funded project ThermProtect an analytical effort was defined to address the issue of radiative heat load while wearing protective clothing. As within the ThermProtect project much information has become available from thermal manikin experiments in thermal radiation environments, these sets of experimental data are used to verify the analytical approach. The analytical approach provided a good prediction of the heat loss in the manikin experiments, 95% of the variance was explained by the model. The model has not yet been validated at high radiative heat loads and neglects some physical properties of the radiation emissivity. Still, the analytical approach provides a pragmatic approach and may be useful for practical implementation in protective clothing standards for moderate thermal radiation environments.

15

Numerical model of heat exchange between a worker body and the hot environment

Wacławik J.

Archives of Mining Sciences

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2010

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Vol. 55, no 3

573-588

EN

The subject of considerations enclosed in this paper is the mathematical model of the worker's body-environment heat exchange in mining working. At the low and moderate temperature and humidity of air the basic way of carrying away of heat from human body is convection. In the difficult climatic conditions the evaporation of sweat is of prevailing importance. Heat exchange between miner's body and his environment was calculated for transient state, when the temperature of body is changing. It has been assumed that the average skin temperature is a factor controlling convective, radiant and evaporative modes of heat exchange. The state of thermal stress is determined by accumulation of heat in worker's body and increase of core and rectal temperature. The second measure of thermal stress is maximum of sweat rates emitted during work and dehydration level. The heat balance of human body affords possibilities for estimation of these parameters.

PL

Przedmiotem pracy są zagadnienia standardów komfortu cieplnego pracownika, określone na podstawie bilansu cieplnego jego organizmu. Przy niskiej i umiarkowanej temperaturze i wilgotności powietrza oraz przy małym wydatku energetycznym ciepło z ciała pracownika odprowadzane jest do otoczenia przede wszystkim drogą konwekcji. W trudnych warunkach klimatycznych oraz przy wydatku energetycznym odpowiadającym pracy umiarkowanej lub ciężkiej dominującą rolę odgrywa parowanie potu. Stan obciążenia termicznego może być modelowany numerycznie metodami bilansu cieplnego ciała pracownika, sporządzanego dla nieustalonej wymiany ciepła z otoczeniem. Stan obciążenia (stresu) i napięcia cieplnego może być oceniany na podstawie akumulacji ciepła w ciele człowieka i wzrostu temperatury wewnętrznej ciała lub temperatury w rectum oraz maksymalnej ilość potu wydzielanej podczas pracy i stopnia odwodnienia organizmu.

16

Cooling Suits, Physiological Response, and Task Performance in Hot Environments for the Power Industry

Furtado A. L., Craig B. N., Chard J. T., Zaloom V. A., Chu H. W.

International Journal of Occupational Safety and Ergonomics

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2007

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Vol. 13, No. 3

227--239

EN

Heat stress on workers working outdoors in the power industry may result in fatigue and deterioration in task performance. This research collected and analyzed data on task performance of workers working indoors and outdoors with and without a cooling suit. The task performance was compared on the basis of heart rate, oxygen consumption, tympanic temperature, subjective responses, productivity, and error rates. Based on One-Way Analysis Of Variance (ANOVA) results, a significantly lower estimated working oxygen consumption was observed (p < .001) when the cooling suit was worn. The productivity was higher while workers wore the cooling suit as compared to no cooling suit (p = .011) whereas the error rates were significantly lower (p < .001). Also a significantly lower self-reported discomfort was observed in the neck and shoulders while working wearing the cooling suit (p = .004). This study concluded that wearing a cooling suit while working outdoors was associated with physiological benefits as well as improved task performance of the study participants.

17

Propozycja nowych przepisów do wyznaczania dopuszczalnych zmian temperatury czynnika roboczego w czasie nagrzewania i ochładzania grubościennych elementów ciśnieniowych

Taler J., Dzierwa P.

Archiwum Energetyki

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2007

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T. 37, nr 1-2

91-108

PL

W pracy przedstawiono cztery metody wyznaczania optymalnych przebiegów czasowych zmian temperatury czynnika podczas nagrzewania i ochładzania ciśnieniowych elementów konstrukcyjnych kotłów, tak aby naprężenia maksymalne wywołane ciśnieniem i różnicą temperatur nie przekraczały naprężeń dopuszczalnych. Optymalne zmiany temperatury czynnika w metodzie pierwszej wyznaczone zostały przy zastosowaniu dyskretnej postaci całki Duhamela z wykorzystaniem tzw. kroków przyszłościowych. Optymalne zmiany temperatury czynnika wynikające z metody pierwszej trudno jest zrealizować w praktyce. Metoda druga oparta jest na niemieckich przepisach kotłowych TRD - 301, które bazują na quasi-stacjonarnym rozkładzie pola temperatury w elemencie. Współczynniki koncentracji naprężeń cieplnych i pochodzących od ciśnienia przyjęto zgodnie z tymi przepisami. W trzecim sposobie współczynniki koncentracji naprężeń wyznaczono za pomocą trój- wymiarowej analizy pola naprężeń przy użyciu Metody Elementów Skończonych (MES). W ostatnich dwóch metodach nie dopuszcza się skokowych zmian temperatury czynnika. Z tego względu zaproponowano czwarty sposób optymalnego nagrzewania elementu. Na początku nagrzewania temperatura czynnika wzrasta skokowo. Dopuszczalną wartość skoku temperatury otrzymuje się z podzielenia naprężeń dopuszczalnych przez maksymalną wartość funkcji wpływu, która reprezentuje naprężenia obwodowe wywołane jednostkowym, skokowym wzrostem temperatury czynnika. Dalszy optymalny przebieg temperatury czynnika wyznaczony jest przy założeniu quasi-stacjonarnego pola temperatury i naprężeń w elemencie grubościennym.

EN

In this paper, four methods of determining the allowable rate of medium temperature changes during cooling and heating of thick-walled elements of steam boilers have been presented. In the first method, the optimal temperature changes were calculated using discrete form of Duhamel's integral in conjunction with future time steps. During optimal heating or cooling, the total stresses due to thermal and pressure loading do not exceed the allowable stresses. Optimum temperature changes obtained from the first method are difficult to accomplish in practice. In the second method, the optimum medium temperature changes are determined by using the German boiler code TRD-301, which is based on quasi-steady state temperature distribution inside the component. The concentration coefficients of stresses caused by pressure and thermal load are assumed in compliance with this code. In the third method, the stress concentration coefficients are determined from 3D-stress analyses using the Finite Element Method (FEM). Sudden step changes of medium temperature were not allowed in two last methods. Therefore, a new fourth technique for determining the optimum medium temperature changes was developed. At the beginning of the component heating, the fluid temperature is step-wise increased. The value of the allowed temperature jump is obtained from dividing of the allowed stress by the maximum value of the so called influence function which represents stresses caused by the unit step-wise temperature increase of the medium. Further temperature changes are determined under the assumption of the quasi-steady state of the temperature distribution in the thick-- walled component.

18

Test of Firefighter’s Turnout Gear in Hot and Humid Air Exposure

Holmer I., Kuklane K., Gao C.

International Journal of Occupational Safety and Ergonomics

|

2006

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Vol. 12, No. 3

297--305

EN

Five students of a rescue training school cycled at 50 W for 20 min at 20 oC before walking at 5 km/hr up to 30 min in a climatic chamber at 55 oC and 30% relative humidity. 4 different types of clothing ensembles differing in terms of thickness and thermal insulation value were tested on separate days. All subjects completed 28–30 min in light clothing, but quit after 20–27 min in 3 firefighter ensembles due to a rectal temperature of 39 oC or subjective fatigue. No difference in the evolution of mean skin or rectal temperature was seen for the 3 turnout ensembles. Sweat production amounted to about 1000 g in the turnout gears of which less than 20% evaporated. It was concluded that the small differences between the turnout gears in terms of design, thickness and insulation value had no effect on the resulting heat physiological strain for the given experimental conditions.

19

Ocena możliwości stosowania wentylacji naturalnej w budynkach dla drobiu przy wysokich temperaturach zewnętrznych - analiza teoretyczna

Kuczyński T., Gniazdowski J.

Problemy Inżynierii Rolniczej

|

2003

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R. 11, nr 4

105--112

PL

Przeprowadzono teoretyczną analizę skuteczności działania wentylacji naturalnej w warunkach wysokich temperatur w zależności od prędkości wiatru. Przedstawione w parcy wyniki badań symulacyjnych wskazują, że prawidłowo zaprojektowana wentylacja naturalna może w okresie letnich upałów zapewnić poprawne warunki termiczne w budynku dla brojlerów.

EN

Paper presented a theoretical analysis of natural ventilation efficiency in a broiler house at high ambient temperatures in the summertime. Continous wide ridge opening and large openings in two sidewalls of the building were provided for the airflow. The simulation aimed at evaluating the effect of various ambient temperatures and wind velocities on air exchange intensity and the difference between inside and outside air temperatures. Another simulation object was to broiler building. The results of study suggested that properly designed natural ventilation should provide desirable thermal conditions in a broiler house even at high summer temperatures. Along all the duration of high temperatures in summer, the microenvironment temperature inside naturally ventilated building is supposed to be even slightly lower than in a building with mechanical ventilation. Potential problem could arise in the periods of high air temperatures joined with windless conditions, particularly lasting for a few hours.

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Ocena możliwości stosowania wentylacji naturalnej w budynkach dla drobiu przy wysokich temperaturach zewnętrznych - badania empiryczne

Gniazdowski J., Kuczyński T.

Problemy Inżynierii Rolniczej

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2003

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R. 11, nr 4

113--120

PL

Zweryfikowano empirycznie wyniki analizy teoretycznej skuteczności działania wentylacji naturalnej w budynkach dla brojlerów w warumkach wysokich temperatur, a także porównano skuteczność działania wentylacji naturalnej do mechanicznej. Przedstawione w pracy wyniki badań generalnie potwierdzają, wyniki badań symulacyjnych i wskazują, że w okresie letnich upałów wentylacja naturalna zapewnia warunki termiczne porównywalne do tych, jakie są możliwe do uzyskania przez wentylację mechaniczną.

EN

Paper presents an attempt to empirical studying the efficiency of natural ventilation in broiler houses during high ambient temperatures in the summertime. Moreover, the study aimed at comparing the microenvironment in similar buildings with natural and mechanical ventilation, under similar weather and technological conditions. The effect of various ambient temperatures and wind velocities on differences between inside and outside temperature was also evaluated. Obtained results suggest that the natural ventilation should provide the proper thermal conditions in a broiler house at high air temperatures in the summer. Experimental data generally confirmed the results of simulation study indicating that well designed natural ventilation system should protect the birds against thermal stress to similar degree like mechanical ventilation.