ارزیابی استرس گرمایی در شاغلین کارگاه‌های قنادی بر اساس شاخص‌های wbgt و di (مطالعه موردی شهر ایلام)

زمینه و هدف: شرایط جوی نامناسب از جمله عوامل زیان‌آوری هستند که اکثر شاغلین در محیط‌های کاری مخصوصاً محیط‌هایی که هم فرایند کار و هم شرایط جوی منطقه نامناسب است، با آن سروکار دارند. بطور کلی کارگران شاغل در قنادی‌ها مخصوصاً در فصل تابستان با استرس گرمایی بالایی مواجهه دارند. بنظر می‌رسد مواجهه با گرمای بیش از حد علاوه بر اینکه با اختلال در سیستم فیزیولوژی و سلامتی افراد سبب ایجاد بیماری‌ها و عوارض متعددی می‌گردد، راندمان و بازده کاری را نیز تحت تاثیر قرار می‌دهد. این مطالعه با هدف تعیین میزان استرس گرمایی در شاغلین کارگاه‌های قنادی در شهرستان ایلام انجام گرفت. روش بررسی: این مطالعه به‌صورت توصیفی تحلیلی در تابستان 1396 بر روی 104 نفر از کارگران شاغل در 35 کارگاه قنادی انجام گرفت. تعداد نمونه‌ی پژوهش بر اساس روش سرشماری انتخاب گردید. اندازه‌گیری متغیرهای مورد مطالعه در گرم‌ترین ساعات روزکاری (ساعات 10 الی 14) و برای هر کارگر تنها یک‌بار و آن هم در بدترین ایستگاه کاری (نزدیک ترین ایستگاه به منبع گرما) انجام گرفت. ارزیابی استرس گرمایی با استفاده از شاخص wbgt (بر اساس استاندارد iso7243 ) و شاخص di صورت گرفت. همزمان با اینکه پارامترهای محیطی مورد سنجش قرار گرفتند، دمای دهانی کارگران توسط یک دماسنج پزشکی دیجیتال اندازه‌گیری گردید. در نهایت تجزیه و تحلیل داده‌های جمع‌آوری شده با استفاده از نرم‌افزار spss 22 و آزمون‌های آماری کولموگروف اسمیرنوف، من ویت‌نی، کروسکال والیس، آنالیز واریانس یک‌طرفه و همبستگی پیرسون انجام گرفت.یافته‌ها: یافته‌های این مطالعه نشان داد که میانگین شاخص wbgt بر حسب شغل در مشاغل فر، پهن‌کن، مخلوط‌کن و نظافت و بسته‌بندی به ترتیب 3.96 ± 33.66، 3.05 ± 29.58، 3.61 ± 31.73، 2.44 ± 29.87 و همچنین بر حسب فر (محصول) در فر گردان (شیرینی تر و خشک)، فر طبقه‌ای (کیک‌و نان فنتزی) و فر کوره‌ای (باقلوا و کعک) به‌ترتیب 3.86 ± 30.94، 3.89 ± 34.14 و 2.91 ± 32.2 می‌باشد که این نتایج نشان می‌دهد میزان استرس گرمایی در بخش کار با دستگاه فر و محصول کیک و نان فانتزی (فر طبقه‌ای) بیشتر از بقیه بخش‌ها بوده است. آزمون همبستگی پیرسون‌ نشان داد که هیچگونه همبستگی معنی‌داری بین دمای دهانی با شاخص‌ها و متغیرهای مورد مطالعه وجود ندارد (0.05p) به‌طوریکه میانگین این متغیر در زنان با میانگین 0.27 ± 36.7 بیشتر از مردان با میانگین 0.84 ± 36.42 بود. نتایج مطالعه حاضر نشان داد که 85.6 % از افراد مورد مطالعه از لحاظ شاخص احساس ناراحتی (di) در حیطه شدید قرار گرفتند.نتیجه‌گیری: طبق نتایج، تقریباً کلیه‌ی شاغلین کارگاه‌های قنادی در معرض استرس گرمایی می‌باشند اما کارگران شاغل در زیرگروه‌های شغلی فر و مخلوط‌کن، فر طبقه‌ای (محصولات کیک و نان فانتزی) و فر کوره‌ای (محصولات باقلوا و کعک) و همچنین جنس مونث در معرض استرس گرمایی بالاتری قرار دارند و بنابراین در زمان اتخاذ اقدامات کنترلی اولویت با چنین افرادی می‌باشد. بنابراین اعمال راهکارهای کنترلی از قبیل استفاد از عایق‌های حرارتی، برقراری سیستم تهویه مطبوع و غیره ضروری و الزامی می‌باشد.

The Assessment of Heat stress in the employees of the confectionery workshops based on WBGT and DI Indexes (A case study of Ilam city)

Background and Objective: Inappropriate atmospheric conditions are harmful factors that cause particular problems in certain seasons (summer or winter). The occupation of confectionery in the regions like Ilam causes severe problems due to the heat generated by the nature of the work (synthetic heatgenerating processes) and the heat resulting from the climatic conditions in the region. Exposure to excessive heat, in addition to disrupting the physiology and health of the individuals that may cause many diseases and complications, also affects their efficiency and safety. One of the indices of heat stress is the WBGT index, confirmed by various national and international organizations and institutions as the standard method for measuring heat stress. WBGT index engages important environmental factors directly or indirectly in its computational structure. The Discomfort Index (DI) has been recommended for more than four decades along with the WBGT index for the evaluation of warm environments. Today, the oral temperature is used to determine the heat stress and strain. In addition, oral temperature is one of the important parameters for the validation of indices. Therefore, in order to prevent the occurrence of heat stress complications in occupational environments, a study was conducted to determine the amount of heat stress in the employees of confectionery workshops in Ilam city, so as to identify the factors affecting the heat stress of workers and to provide recommendations for the reduction of these risk factors and to create a healthy working environment.Methods: This descriptiveanalytical study was carried out on 104 workers in 35 confectionary workshops in summer of 2017. The sample size was selected based on census method. Prior to the study, the workers were monitored through medical records and interviews, and, two of them did not qualify for inclusion in the study. Measurement of the study variables was performed at the hottest work hours (10 to 14), once for each worker, in the worst workstation (nearest to the heat source). In the present study, four groups of occupations, i.e. workers of oven, mixer, flattener, cleaning and packaging, three types of ovens, i.e. layered, winch and furnace, and three productions of wet and dry pastry, cake and French bread, Baghlava and Ka rsquo;ak. Assessment of heat stress was performed by the WBGT (based on ISO7243 standard) and the DI indices. Metabolism and activity of workers were calculated according to the ACGIH standard. Also, the working pattern was 75% of the work25% of the rest, and according to ISO 9920, the clothing insulation coefficient in WBGT calculations was 0.6 clo. Along with the environmental parameters such as dry bulb temperature, natural wet bulb temperature, globe bulb temperature, relative humidity and dew point temperature, the oral temperature of the workers was measured by a digital medical thermometer. Finally, data analysis was performed using SPSS v.22 and statistical tests of KolmogorovSmirnov, MannWhitney, KruskalWallis, oneway ANOVA and Pearson correlation were performed.Results: Findings of this study showed that the mean of WBGT index in the workers of oven, mixer, flattener, cleaning and packaging was 33.66 ±3.96, 29.58 ±3.05, 31.73 ±3.61 and 29.87 ±2.4. Also, this index was 30.94 ±3.86, 34.14 ±3.89, and 32.2 ±2.91 for the winch (wet and dry pastry), layered (cake and French bread), and furnace (Baghlava and Ka rsquo;ak) ovens (products). These results show that the amount of heat stress in working with the oven and the cake and French bread product (layered oven) was more than others. Kruskal Wallis tests and one way ANOVA showed a significant difference between the mean of WBGT and DI indices with job variables, type of oven and products (p <0.05). A 95% confidence interval was observed in terms of the WBGT index between the subgroups of the oven and flattener, oven and cleaning and packing, layered oven and winch oven, and French bread and the wet and dry pastry. However, in terms of the DI index, this difference was found between the subgroups of the oven and cleaning and packing, oven and mixer with flattener, layered oven and winch oven, and French bread and the wet and dry pastry. Pearson correlation test showed that there was no significant correlation between oral temperature and indices and variables (p<0.05). Based on the results of this study, the mean of WBGT index at the heights of head, waist and ankle was 32.54 ±5.01, 31.54 ±3.86 and 30.49 ±3.12, respectively. Also, according to Kruskal Wallis statistical tests and one way ANOVA, there was a significant difference in WBGT index and dry bulb temperature, natural wet bulb temperature, globe bulb temperature and relative humidity at the heights of head, waist and ankle (P <0.05). The results of the MannWhitney test indicated that there was a significant difference between the gender variable and the oral temperature (p <0.05), with the mean of this variable was higher in women (36.7 ±0.27) than men (36.42 ±0.84). The results of this study showed that 85.6% of the subjects had a ldquo;severe rdquo; discomfort index (DI), and regarding the WBGT index, 14.4% and 85.6% were lower and higher than the threshold, respectively.Conclusion: According to the results, almost all of the workers in the confectionary workshops are exposed to heat stress, but subgroups of oven, mixer, layered oven (cake and French bread), furnace oven (Baghlava and Ka rsquo;ak) and the females were exposed to higher stress. So, these subjects have a priority when adopting control measures. It is recommended that measures such as preemployment examinations, preparation of proper drinks, training the workers, reduction of working time, using thermal shields, using air conditioning system, and paying particular attention to reducing the wet temperature and relative humidity of the workplace are taken to minimize the exposure to heat and the resulting diseases.