Journal of Health and Safety at Work

Evaluation of pulmonary function of construction workers in Tehran city in 2017

Bahman Pourhassan

Introduction: Construction industry plays a major role in the economic development of all countries and among the various occupations, this industry is one of the most dangerous industries, particularly respiratory contaminants, around the world. The aim of this study was to evaluate the respiratory capacity of construction workers, working in different workshops in Tehran city and developing a regression model to examine the relationship between pulmonary capacities with the type of occupation, work experience and tobacco smoking.
Material and Method: This study was a cross-sectional descriptive study conducted among 628 construction workers in Tehran city in 2017. After data collection, data analyses were performed using statistical independent t-test, one way ANOVA and correlation tests by SPSS software version 22. Also, multiple backward regression was used to check the effect of independent variables on lung function.
Result: According to the results of this study, a significant relationship was found between age and work history with the pulmonary function indexes (FVC, FEV1, FEV1/FVC and FEF25-75%) (P-value<0.001). The average of FEV1/FVC% was significantly different among various occupational groups (p-value<0.001). In the analysis of the findings of the pulmonary function test in the exposed group a separate model was made using multiple linear regression for each of the pulmonary functions, and the independent variables including age, work experience, job type and cigarette addiction were entered into the model.
Conclusion: The present study showed a significant change in the pulmonary function parameters of the construction workers and the chance of pulmonary disorders might be high among these individuals.

Mental workload assessment among train drivers using ECG-related indices

Narmin Hassanzadeh-Rangi

Introduction: Driving a train is one of the high demand job due to high vigilance task requiring the ability to long periods monitor surrounding environment and recognizing signals. The aim of this study was to assess train drivers’ mental workload using heart rate (HR) and heart rate variability (HRV) indices.
Material and Method: An experimental design was conducted among 12 well-trained subjects to induce two different levels of mental demands in a metro simulator and to monitor mental workload levels while driving the train. The HR and HRV parameters were recorded and analysis using ECG signals.
Result: The HRV parameters including SDNNIX (p-value=0.01), RMSSD (p-value=0.00), %PNN50 (p-value=0.01), SDNN (p-value=0.07) and LF/HF Ratio (p-value=0.04) were significantly reduced in a normal operation task comparing to the abnormal one.
Conclusion: The HR and HRV (SDNN, SDNNIX, RMSSD, %PNN50 and LF/HF Ratio) were found to be sensitive to mental workload in metro train driving .It is recommended to include the HRV parameters for mental workload assessment of train drivers.

Hybrid approach for occupational hazard assessment in road construction projects

Mehran Amiri

Introduction: Safety at workplaces is an important issue, and lack of effective and efficient safety management methods based on scientific studies could cost the construction industry. An effective accident investigation and root causes analysis could prevent the occurrence of incidents at minimum cost and time.
Material and Method: First, major accidents in road construction projects were identified by interview and literature reviewing techniques. Then, fault tree was drawn for each main risks. In the next step, in order to calculate occurrence probability and severity of each accident type, a questionnaire was designed and distributed among the participants. Fuzzy logic was employed in calculations, due to the existence of uncertainty in linguistic variables. Fuzzy Fault Tree Analysis (FFTA) was used for calculating the occurrence probability, and importance of each criterion was determined using Fuzzy Analytical Hierarchical Process (FAHP) to calculate the severity of each accident. Finally, risk factors for each accident type was calculated and the risks were ranked accordingly.
Result: Accidents related to crusher and asphalt plant, traffic accidents, heat exhaustion and lack of hygiene and hit by machinery were identified as the most important risks among the eleven investigated accident types.
Conclusion: The findings in this research and also implementing effective safety management techniques, could be helpful on reduction of the probability of accidents root causes and to mitigate related risks.

Development of dispersive liquid-liquid micro-extraction procedure for trace determination of pesticide diazinon in urine samples

Seyed Jamaleddin Shahtaheri

Introduction: Measurement of pesticides in biological matrices is become a serious challenge for researchers due to their very low concentration in different matrices. The aim of this study was to develop a new sample preparation method with high accuracy and validity and short retention time for determination of diazinon.
Material and Method: Dispersive liquid-liquid micro-extraction technique coupled with high performance liquid chromatography equipped with ultra violet detector was developed for trace extraction and determination of diazinon pesticide in human urine samples. One variable at a time method was used to optimize parameters affecting the diazinon extraction. Different parameters such as extraction solvent, disperser solvent, and volume of the extraction solvent, volume of the disperser solvent, centrifugation time and speed, salt addition, and sample pH were studied and optimized.
Result: Findings showed that optimal levels of these variables for diazinon pesticide were 150 μl of carbon tetrachloride as extraction solvent, 1.5 ml of methanol as dispersive solvent, pH of 6, 5 minutes centrifuge time at speed of 4000 rpm , 0% (w/v) salt addition. Correlation coefficient was 0.9965 indicating the linearity of a wide range of concentrations of the toxin. LOD and LOQ was calculated less than 0.7 and 5 µg L-1 respectively. The relative standard deviation for six replicate experiments in intra-day and inter-day at tree selected concentrations (50, 200 and 1000 µg L-1) was less than 4% that indicates the accuracy and precision of the optimized method. Enrichment factor and extraction recovery for diazinon were 245 and 99% respectively.
Conclusion: According to the results, dispersive liquid-liquid micro-extraction procedure was successfully developed for the extraction of diazinon from human urine samples. Compared to other extraction techniques, the proposed procedure had some advantages such as shorter extraction time, better reproducibility, and higher enrichment factor.

Selection of the most suitable sound control method using fuzzy hierarchical technique

Seyed Medi Mousavi

Introduction: Noise is one of the most harmful industrial agents and there are different methods to control it. Fuzzy analytical hierarchy process is an appropriate technique for selecting the best choice among several control methods. Therefore, the aim of this study was the selection of the most suitable sound control method using fuzzy hierarchical analysis (FAHP) technique in a refinery plant.
Material and Method: The present study was a cross-sectional research in a refinery plant. After identifying the main sources of the noise in the studied palnt, five criteria and ten noise control methods were selected using a questionnaire and Delphi methods. Then, Fuzzy hierarchy analysis was applied for the selection of the best noise control alternative.
Result: The results showed that the performance with a final weight of 0.277 and the non-interference in the process with a final weight of 0.06 were most and least important criteria, respectively. Meanwhile, worker enclosure had highest score (0.207) of the control methods.
Conclusion: In general, the results showed that best criterion for selection of the suitable noise control method is performance. What’s more, based on the results, worker enclosure was selected as best noise control method in the refinery.

The validity and reliability of organizational resilience questionnaire (ORQ) in dealing with major accidents

Seyyed Shamsaddin Alizadeh

Introduction: Disasters, incidents and crises are complex and controversial issues for the industries and organizations. Organizational resilience is an effective goal that continuously helps the organization’s performance throughout business, disasters and critical situations. Therefore, the present study aimed to investigate the validity and reliability of organizational resilience questionnaire in dealing with major accidents.
Material and Method: The present study was a descriptive-analytic study. At first, the concept of organizational resilience and its dimensions were determined for the review. Then, for evaluating the content validity, the designed questionnaire was distributed among members of the expert’s panel and the Content Validity Index (CVI) and Content Validity Ratio (CVR) were calculated based on the comments. The reliability of the questionnaire was determined after completing it by 272 employees of the studied industries.
Result: The CVR was higher than the standard value (0.50) considering all items. Also, all dimensions of the questionnaire, except for the responsibility dimension the CVI’s were above 90%. Cronbach’s alpha coefficient for all questionnaire dimensions except for the responsibility dimension was higher than the acceptable value (0.70). This coefficient for the whole questionnaire was 0.967 indicating that this index was in excellent level.
Conclusion: The findings showed that the organizational resilience questionnaire in dealing with major accidents had an acceptable validity and reliability and in order to examine the organizational resilience in organizations, it could be used as a comprehensive, strong and reliable tool.

Risk assessment of heat stress using the AHP and TOPSIS methods in fuzzy environment- A case study in a foundry shop

Mohsen Omidvar

Introduction: Working in hot and harsh weather conditions can cause heat related diseases and in some cases, even can lead to death. Risk assessment of heat stress in these environments is of particular importance. As there are many factors that could affect the heat stress, therefore, an index should be applied that could properly reflect the effect of all of these factors.
Material and Method: Initially a five-member expert team was established. Then, the weight of each variable was determined by the fuzzy analytical hierarchy process (FAHP) method. In next step, five work stations of the casting process evaluated applying fuzzy TOPSIS (FTOPSIS) method and the risk of heat stress prioritized in these stations. Lastly, the Pearson’s correlation coefficient was used to determine correlation between the results of proposed method with WBGT index.
Result: The weights of three main variables including task characteristics, working environment, and worker characteristics was determined as 0.279, 0.526, and 0.195. The risk priority of the five work stations including, stocking, melting furnace, pouring and casting, polishing, and warehousing was established as S1= 4, S2= 2, S3= 1, S4= 3, and S5= 5. The Pearson’s correlation coefficient between the similarity index (CCi) and WBGT was 0.97.
Conclusion: From three main variables that can affect the heat stress, “Working Environment” has main impact in the risk assessment process; therefore, the most efforts must be focused on controlling this variable. The proposed method in this study has the capability of concurrent quantitative and qualitative assessment of factors that could affect the heat stress and can minimize the uncertainties in the risk assessment process relying upon the fuzzy sets.

Prioritizing strategies of skin exposure with chemical in a painting company using fuzzy analytical hierarchy process & Topsis

Hossein Molaei Far

Introduction: Skin disease caused by exposure to the chemicals is one of the major health-related problems in the workplaces. This study has done to prioritize the strategies for skin exposure with chemical in a painting company.
Material and Method: In this analytical cross-sectional study 7 criteria and 8 selection control methods were initially chosen by surveying the existing records and through the assessments of expert panel and checking the result of previous studies. Subsequently, control strategies were prioritized according to the criteria using Fuzzy Analytical Hierarchy process & Topsis.
Result: Results of the paired comparison showed that the safety of the control strategy (w=0.298) and it’s up to date (w=0.0138) were the most and least important criteria for skin control strategies. Among skin control strategies for chemical exposure, the highest and lowest importance were for training (w=0.817) and work-rest schedule (w=0.233), respectively.
Conclusion: In this study, training was determined as the best control strategies for skin chemical exposure in the studied painting company according to the investigated criteria. This decision-making process could be applied for promotion of the skin health among workers.