Journal of Health and Safety at Work

Evaluating Morphological Characteristics and Filtration Performance of Electrospun Poly(Vinyl Alcohol)-Based Nanofiber Membranes for Capturing Particulate Matter

Farideh Golbabaei

Introduction: Polymer nanofiber filters have great potential for controlling particulate pollution due to their high filtration efficiency and low pressure drop. This study aimed to fabricate nanofiber membranes from a biodegradable polymer through solution electrospinning to address both health and environmental concerns, along with analyzing their morphological characteristics. The filtration performance of the prepared membranes was evaluated against different particle sizes under two air face velocities.
Material and Methods: The nanofiber membranes were fabricated from aqueous poly(vinyl alcohol) (PVA) solutions at various concentrations from 5 to 6 w/v% under different process parameters. The morphological characteristics of the nanofibers were examined using field-emission scanning electron microscopy (FE-SEM), while structural properties such as basis weight and thickness were measured to estimate porosity. Filtration performance, including efficiency and pressure drop, was evaluated at two standard air face velocities (2.5 and 5.3 cm/s) using a media test system. In addition, the quality factor of the prepared membranes was calculated.
Results: The electrospun nanofibers were uniform and bead-free, with the mean fiber diameters ranging from 106 to 151 nm. The filtration efficiencies were 95.72–99.92 % for sub-micron particles (0.3 and 0.5 µm), and 99.43–100 % for larger particles (1 and 3 µm). The pressure drop ranged from 67 to150 Pa at an air face velocity of 2.5 cm/s, and from 58 to150 Pa at an air face velocity of 5.3 cm/s.
Conclusion: The 6 wt.% PVA nanofiber membrane electrospun at 15 kV, 0.5 mL/h, and 15 cm produced thinner fibers (approximately 106 nm) and exhibited higher efficiency for 0.3 µm particles (99.89 % and 99.92 % at 2.5 and 5.3 cm/s air face velocities, respectively). For this membrane with thinner fibers, the pressure drop increased from 67 to 150 Pa with rising the air face velocity.

Experimental Validation of a Numerical Model for Predicting the Thermal Performance of a Liquid Cooling Garment

Iraj Alimohammadi

Introduction: Computer-based numerical simulation can serve as an effective approach for replicating system behavior over time. It enables the analysis of a system’s capabilities, capacities, and performance during the design phase—prior to physical implementation. Accordingly, simulation tools can be used for the design, modeling, evaluation, and visualization of heat transfer interactions among the components of a Liquid Cooling Garment (LCG) system. Therefore, the present study was conducted with the aim of designing and experimentally validating a numerical simulation model for a thermoelectric-based LCG.
Material and Methods: A new model of a liquid cooling garment (LCG) based on fluid circulation was developed using the Finite Element Method (FEM) in COMSOL Multiphysics software. To validate the simulated model, a physical prototype of the LCG with similar characteristics was designed, and human experiments were conducted under controlled environmental conditions. Finally, the findings obtained from the simulation and experimental results were compared.
Results: The results showed that the difference in microclimate temperature between the simulated predictions and the average experimental data ranged from 0.1 °C to 0.65 °C. Additionally, the deviation in coolant temperature within the piping system between the simulation and experimental data ranged from 0.1 to 0.6 °C. These findings indicate that the developed model demonstrates a satisfactory level of accuracy in predicting thermal parameters
Conclusion: The results suggest that the proposed model can serve as an effective tool in the design and evaluation process of wearable cooling systems before fabricating physical prototypes. Further studies are recommended to enhance the performance and precision of LCG simulation models.

Reliability Assessment of Gas Pressure Reduction Stations Based on Monte Carlo Markov Chain and Continuous-Time Markov Chain Methods: A Case Study of a City Gas Pressure Reduction Station

Rajabali Hokmabadi

Introduction: A gas pressure reduction station is an important facility in gas transmission systems. These systems consist of various sections, the reliability of each section affecting the station’s overall reliability. Therefore, this study aimed to assess the reliability of station sections using Markov chain Monte Carlo (MCMC) and the continuous-time Markov chain (CTMC) method.
Material and Methods: Equipment failure and repair rates were simulated using the MCMC method in WinBUGS14. Then, based on the failure and repair rates, the station reliability was evaluated using the CTMC. The results of the equipment failure rate simulation were validated using two criteria: MC Error and the Goleman-Rubin test. Also, the results of station reliability evaluation were validated using Reality Check and Partial Benchmark Exercise methods.
Results: Failures in the filtration and pressure reduction sections were more frequent than in other sections of the station. Therefore, these sections were considered the most critical sections in the reliability assessment. The posterior standard error was less than 0.01, indicating good convergence of the data for the parameter posterior distribution. The results of the Goleman-Rabin test showed values less than 1.2, indicating proper convergence of the chains. For all sections and stations, a systematic approach was determined using the Markov model. The results showed a strong correlation between the CTMC and the block diagram method (R2=0.9499).
Conclusion: The proposed approach combines failures of system components and can display multiple failures. It also accounts for time factors in its calculations and minimizes subjective expert evaluations.

The Effects of a Participatory Ergonomics Program on Musculoskeletal Disorders and General Health of Surgical Technologists: A Randomized Controlled Trial

Soheila Bakhtiari

Introduction: Surgical technologists encounter a challenging work environment, and therefore, they require well-organized workplaces and appropriate health-related training. This study aimed to determine the effect of a participatory ergonomics program on musculoskeletal disorders (MSDs) and general health among surgical technologists
Material and Methods: This single-blind randomized controlled trial was conducted in 2023-2024 in operating rooms of teaching hospitals in Isfahan, Iran. The study population comprised 88 surgical technologists meeting the inclusion criteria. One hospital was randomly selected as the intervention site, while the remaining hospitals served as the control group. Data were collected using a demographic questionnaire, the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ), and the 28-item General Health Questionnaire (GHQ-28). Initially, all participants in both groups completed baseline assessments. The intervention group received a participatory ergonomics program. Follow-up assessments were conducted at 3 and 6 months post-intervention in both groups. Data were analyzed using SPSS version 24 employing both descriptive and inferential statistical methods, with a significance level set at 0.05.
Results: Before the intervention, no significant differences were observed between the intervention and control groups in terms of mean scores for general health and MSDs (p=0.55). Three months post-intervention, a significant difference was found in the mean score of lower extremity MSDs between the groups (p=0.033). Six months post-intervention, a significant difference was observed in the mean score of Trunk region MSDs between the groups (p=0.038). Significant differences in mean general health scores were observed between the groups at 3 months (p=0.001) and 6 months (p=0.001) post-intervention, with the intervention group reporting better general health compared to the control group.
Conclusion: The implementation of a participatory ergonomics program can improve general health and reduce MSDs among surgical technologists.

Effect of Sound Absorber Design and Installation on Reverberation Time and Speech Quality in a Dental Clinic

Gholamreza Moradi

Introduction: Exposure to noise is one of the most common harmful factors in the dental profession that can have significant consequences. Unfavorable acoustic conditions of the environment can also worsen the conditions and lead to reduced speech clarity, auditory fatigue, and reduced quality of communication between the doctor and the patient. In this regard, designing effective acoustic interventions can play an important role in improving sound.
Material and Methods: This study was conducted in an academic dental clinic. After measuring the sound pressure level, reverberation time, and speech transmission index, the amount of rock wool absorber required was determined using the Sabin formula. The panels were structurally installed on the clinic walls, and after 24 hours, the sound pressure level, RT60, and STI were measured again, and appropriate statistical tests were used to determine the effect of the intervention.
Results: The results showed that the sound pressure level before and after the panel installation was significantly different and decreased after the intervention (p-value <0.05). The reverberation time at the dominant frequency of 2000 was 0.992 seconds before the intervention and reached 0.599 seconds after the intervention (p=0.027, z= 2.207). The speech transmission index in the center of the room improved from 0.64 and the “average” level to 0.85 and the “excellent” level, indicating an increase in speech clarity.
Conclusion: The acoustic intervention was able to bring the clinic’s acoustic indices closer to the recommended ranges. The significant reduction in reverberation time and sound pressure level along with the increase in the speech clarity index indicates the high efficiency of this intervention. Utilizing sound absorbers can be a low-cost and feasible solution to improve acoustic conditions and improve speech communication in dental treatment and educational environments.

Fire Growth and Smoke Transport Modeling Based on Risk Assessment in a High-Rise Hospital in Tehran

Mousa Jabbari

Introduction: Hospitals represent a critical fire safety challenge. The presence of patients with limited mobility, specialized staff, and invaluable infrastructure makes them seriously vulnerable. Further, toxic smoke inhalation, as a primary product of fire, is a leading cause of mortality. To address this concern, our study intended to conduct a comprehensive fire safety assessment of a teaching hospital in Tehran (2023-2024) by integrating risk assessment with numerical modeling.
Material and Methods: This study was conducted in a teaching hospital following three consecutive steps: risk assessment, fire scenario design, and fire and smoke modeling. First, vulnerable zones were identified using the FRAME method. Next, fire scenarios and control strategies were designed based on the identified risk factors and a review of the relevant literature. Ultimately, fire and smoke transport was modeled using the CFAST software to ascertain the performance of the proposed strategies.
Results: The risk assessment pinpointed two wards with unacceptably high occupant risk levels: the inpatient ward on the 10th floor, owing to a cluster of unsafe behaviors, and the basement warehouse, owing to improper storage and inadequate emergency exit access. Fire and smoke modeling was performed for these two zones, comparing the “current situation” against a proposed “risk control strategy.” The modeling results revealed that the control strategy positively affected key life safety indicators, significantly ameliorating the Fractional Effective Dose (FED) and Heat Release Rate (HRR).
Conclusion: According to this study, a fire risk assessment provides a clear and detailed perspective on a hospital building’s fire safety. Integrating the results of the FRAME assessment with CFAST simulations results in a comprehensive understanding of the facility’s safety status. These data can be utilized to design effective emergency plans and calculate the Required Safe Egress Time (RSET), thereby preventing life-threatening harm to occupants against toxic gases.

Analyzing the Impact of Climate Change on Heat Stress Levels among Workers in the National Steel Industry

Farideh Golbabaei

Introduction: Climate change is a major global challenge, strongly influencing the Wet Bulb Globe Temperature (WBGT) index and heat stress among steel industry workers. This study evaluates the impact of geographical location and climate change on occupational heat stress exposure in Iran’s steel sector.
Material and Methods: This qualitative-analytical study used data from the SABA system and the Iranian Occupational Heat Stress Atlas. Information on steel industries, their distribution, and production capacities across eight climate zones was extracted. WBGT measurements were collected in collaboration with industrial units in different zones. Data analysis was performed using ArcGIS and SPSS. The effects of climate change on heat stress were assessed for three future horizons: 2040, 2060, and 2080.
Results: The findings revealed that climate zones G1 (eastern, southeastern, and desert regions) and G4 (Persian Gulf coastal provinces including Hormozgan, Bushehr, Fars, and Khuzestan), which host the highest steel production capacities, are exposed to the highest levels of heat stress (WBGT index) and water resource scarcity. WBGT values in zones G4 and G6 (Gilan province) exceeded permissible limits, whereas zones G2 (including North Khorasan, Razavi Khorasan, Tehran, Alborz, Qazvin, Hamedan, Markazi, and Chaharmahal-Bakhtiari), G5 (Kurdistan, Kermanshah, Lorestan), and G7 (Ilam, Kohgiluyeh and Boyer-Ahmad) showed the lowest WBGT levels. Considering projected temperature increases in the three future horizons and the acceptable correlation coefficient (0.40) between annual daytime temperature and WBGT index per climate zone, predicted temperature changes may lead to increased WBGT levels, particularly in zones G3, G6, and G8.
Conclusion: Given climate projections and the spatial distribution of steel industries, it is essential to develop climate-responsive policies, implement sustainable water resource management, and reconsider the siting of steel production units. These measures can enhance the resilience of Iran’s steel industry against future climate change and mitigate occupational health and environmental risks.

Structural Equation Modeling of the Relationships Between Safety Climate, Self-Determined Safety Motivation, and Safety Behavior in a High-Risk Industry

Rasoul Azizian Shahrivar

Introduction: Workplace safety is a critical factor for organizational success and the protection of human capital. Safe behavior among employees is influenced by various psychological and organizational factors, including safety climate and safety motivation. Considering the importance of enhancing safety motivation and the lack of standardized indigenous tools in Iran, this study aimed to culturally adapt the Self-Determination Safety Motivation Scale (SDSM) and examine its mediating role in the relationship between safety climate and employees’ safe behavior at Kavir Steel Complex in Aran and Bidgol County.
Material and Methods: This analytical cross-sectional study was conducted in 2024 among 256 production line employees. Data were collected using the Safety Climate Questionnaire, the Safe Behavior Questionnaire, and the Persian-adapted SDSM. The adaptation process included forward–backward translation, content validity evaluation by experts, and confirmatory factor analysis. Data were analyzed using SPSS version 26 and structural equation modeling with SmartPLS version 4.
Results: The findings indicated that safety climate had a positive and significant effect on safe behavior (β = 0.608, p < 0.001), and safety motivation significantly mediated this relationship (β = 0.388, p < 0.001). It is noteworthy that the direct relationship between safety climate and safety motivation was significantly negative. The structural model explained approximately 42% of the variance in safety behavior (R² = 0.419), indicating satisfactory predictive power. Model fit indices (NFI = 0.91, SRMR = 0.06) demonstrated a satisfactory model fit. Convergent validity, discriminant validity, and construct reliability were all confirmed at acceptable levels.
Conclusion: The results highlight the importance of fostering a positive safety climate and strengthening employees’ intrinsic motivation in high-risk environments to reduce workplace accidents and promote organizational health. These findings can serve as a foundation for policy-making and training programs in the field of HSE.

Development and Fabrication of a Natural and Eco-Friendly Sound Absorber from Walnut Shell Waste: A Mathematical Modeling and Acoustic Performance Evaluation Approach

Mohammad Faridan

Introduction: Environmental and health concerns regarding synthetic sound absorbers necessitate natural, sustainable alternatives. Agricultural waste like walnut shells is promising due to its inherent porosity. This study evaluates the acoustic properties of walnut shell composites, investigating the influence of key design parameters like thickness and chopping level on sound absorption performance.
Material and Methods: Porous granular samples were fabricated from walnut shells at three chopping levels (minimally, moderately, finely) and four thicknesses (20, 40, 60, and 80 mm). The sound absorption coefficient was measured via the impedance tube method. Field Emission Scanning Electron Microscopy (FESEM) analyzed the material’s morphology, and results were validated with Slanted Slit (SS) and Non-uniform Pore Size Distribution (NUPSD) mathematical models.
Results: Both increased thickness and chopping level significantly enhanced sound absorption. For finely chopped samples, increasing thickness from 20 to 80 mm shifted the absorption peak from 2000 Hz to 630 Hz. At a constant 80 mm thickness, intensified chopping boosted the absorption coefficient at 630 Hz from 0.48 to 0.97. This improvement correlated directly with increased density, tortuosity, and airflow resistivity. Model predictions showed the best agreement for the most finely chopped samples.
Conclusion: Walnut shell waste, especially after intensive mechanical processing, is a highly effective and sustainable sound-absorbing material. The chopping process optimizes the acoustic structure by activating the material’s inherent micro-porosity, yielding excellent performance in the speech frequency range (500-2000 Hz). This material shows significant potential as a green alternative to synthetic absorbers for indoor noise control.

A Consequence Analysis of a Hydrogen Sulfide Gas Release using PHAST Software in the Sulfur Recovery Unit of Abadan Oil Refinery Company

Mohammad Reza Sardashti Birjandi

Introduction: Industrial units, such as oil refineries, face significant hazards due to the release of toxic and flammable gases. Hydrogen sulfide (H₂S), due to its high toxicity and environmental impact, is among the most dangerous pollutants. This study aimed to model and assess the consequences of H₂S release in the Sulfur Recovery Unit (SRU) of Abadan Refinery using PHAST software to support safety planning and risk reduction strategies.
Material and Methods: Consequence modeling was conducted using PHAST version 8.4. Process data, including temperature, pressure, flow rate, and feed composition, along with meteorological conditions (average temperature, relative humidity, and wind speed based on Pasquill stability classification), were used to define probable scenarios. Scenarios included partial pipeline rupture, variable leak flow, short pipe release, and catastrophic reactor tank rupture. Key damage criteria, including thermal radiation threshold, explosion overpressure, and toxic dose, were used to determine hazard zones.
Results: Thermal radiation up to 71.027 kW/m² can cause instant death within a 70-meter radius, while overpressure exceeding 0.206 bar can destroy equipment and structures up to 35 meters in summer conditions. The H₂S cloud can spread up to 120 meters downwind, causing immediate fatalities among exposed personnel. These findings identify high-risk zones in and around the SRU, emphasizing the need to relocate shelters, install gas monitoring systems, and provide protective equipment. Results are limited to the defined scenarios and PHAST assumptions.
Conclusion: Due to the lack of risk assessment studies in early phases and during operation, identifying safe points and high-risk zones, along with prioritizing risk reduction, is essential to ensure workplace and public safety. Comprehensive risk assessment, including probability analysis (using software such as SAFETI) and application of advanced models (CFD and AI-based methods), is recommended for future research.

Prevalence of Diabetes Among Individuals Exposed to Occupational Noise: A Systematic Review and Meta-Analysis

Shadi Naderyan Fe’li

Introduction: Occupational noise is considered as an emerging risk factor for type 2 diabetes. Although previous studies have mainly examined the auditory outcomes of noise exposure and estimated the relative risk of diabetes, there is insufficient evidence to estimate the prevalence of type 2 diabetes in Workers exposed to occupational noise. The present study aimed to conduct a systematic review and meta-analysis of the pooled prevalence of type 2 diabetes in workers exposed to occupational noise.
Material and Methods: In this systematic review and meta-analysis, the Web of Science, Scopus, Medline (PubMed) databases and Google Scholar engine were searched up to May 2025. The quality of studies was assessed using the Newcastle-Ottawa scale. The pooled prevalence was estimated using the DerSimonian and Laird random effects model, and heterogeneity was assessed using the I² index. The pooled prevalence was reported in subgroups based on the method of diabetes diagnosis and type of study.
Results: Out of 1,193 initially identified studies, 14 studies with a total of 94,975 participants were included in the systematic review and meta-analysis. The pooled prevalence of type 2 diabetes among individuals exposed to occupational noise was estimated at 5.91% (95% CI: 4.85%–6.98%). Significant statistical heterogeneity was observed among studies (I² = 98%, p < 0.001). The subgroup analysis indicated that the prevalence of diabetes in studies based on clinical or paraclinical diagnostics was higher than in studies based on self-report (7.31% and 3.73%, respectively). Moreover, the prevalence of diabetes in cross-sectional studies was higher than in cohort studies (6.45% and 5.67%, respectively).
Conclusion: The findings indicated a moderate prevalence of diabetes among people exposed to occupational noise. This prevalence was based on preliminary studies with an acceptable level of quality. The findings highlight the importance of recognizing metabolic consequences of occupational noise exposure alongside its well-known auditory effects.

Barriers of Risk Management in East Azerbaijan Industries: A Qualitative Study

Seyed Shamseddin Alizadeh

Introduction: Occupational diseases and workplace accidents have significant financial impacts on industries, communities, and nations each year. Risk assessment is considered an effective tool for managing these issues; however, many organizations fail to implement it successfully. This study explores this challenge from the perspective of Health, Safety, and Environment (HSE) officers.
Material and Methods: In this study, 30 Semi-structured individual interviews were conducted with HSE officers. Inductive content analysis was used for analyzing interviews. After analyzing the interviews, the codes in the interviews were categorized. To ensure credibility and transferability, participant checking and consultations with experts in the field of risk assessment were conducted.
Results: After analyzing the interviews, seven main categories were identified, each comprising several sub-categories. The main categories included: Resources, Technical Knowledge, Legal and Regulatory Barriers, Cultural Issues, Absence of Risk-Based Thinking in the Organization, Individual Issues, and Lack of Interaction and Communication.
Conclusion: This study revealed that seven major barriers hinder the implementation of risk management systems and the execution of risk assessments in the industries of East Azerbaijan Province. These obstacles can directly affect the identification, analysis, and control of risks, ultimately reducing the effectiveness of occupational health and safety processes. Therefore, to conduct effective risk assessments and enhance safety levels in industrial environments, it is essential for policymakers, industry managers, and regulatory bodies to accurately identify and analyze these barriers and develop appropriate solutions to address them. Moreover, designing and implementing educational programs, restructuring management systems, and strengthening interactions between regulatory organizations and industries can contribute to improving risk assessment processes and safety management in this sector.