Journal of Health and Safety at Work

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Introduction: Mercury, in different form can induce adverse effects on various organs especially central nervous system. The aim of this study was to determine concentration of mercury in inhalation and urine of the exposed worker and to investigate the prevalence of probable neurobehavioral disorders.
 

Material and Method: The present case-control study was conducted among workers of a unit in a petroleum industry. The study population consisted of 52 workers as case and 63 workers as control groups. The mercury concentration in air and urine was measured according to NIOSH 6009 standard and using the cold vapor atomic absorption spectrophotometer (CV-AAS). Demographic data and neurobehavioral disorders were collected using a self-reported questionnaire. Pearson correlation coefficient, multiple regression tests and SPSS v24 were used to analyze the data.
 

Result:  Air concentration of mercury was 0.062 ± 0.0014 mg/m3  which was higher than the recommended threshold by NIOSH and ACGIH. In addition, there was a significant difference between urinary concentration of mercury in the case (37.73 ± 13.01 µg/g cratinine) and control (5.93 ± 4.76 µg/g cratinine) groups (p=0.03 6). Based on the multivariate logistic regression model, significant relationships were found between memory loss, sleep disturbance, and urine mercurial concentrations and, between memory loss, moody, muscle weakness and air mercurial concentration.
 

Conclusion: The values of Hg in blood and urine workers who worked in investigated unit were significantly higher than recommended threshold values. In addition, the Hg concentration in urine was related to some of neurobehavioral disorders.

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Introduction: Nowadays, accidents are regarded as a main risk factor for both human and economic of countries. The triggerring cause of most accident is human error. In the healthcare setting, human errors can lead to injuries and even death of patients and damage the reputation of healthcare staff. Human errors in healthcares can occur during various activities including diagnosis of a disease, drug administration, and also during the use of various appliances. Therefore, it is of critical importance to identify these errors and assess their risks.  Accordingly, the main aim of the present study was to identify and assess human errors possible to occur during the use of the ventilator device in neonatal units of  educational hospitals of Hamedan University of Medical Sciences.  
Material and Methods: This qualitative study was conducted using PUEA technique in 2017. The required data associated with the function and operation of the ventilator were gathered by investingating documents, observing the operater while using it, and interviewing with the operator. Hierarchical task analysis (HTA) was used for determining the main tasks and subtasks performed for operating the device. The identified errors were categorized into seven groups, namely planning, functional, checking, retrieval, communication, and selection errors. The PUEA method was utilized in exploring the causes of errors, the possibility of error recovery, and associated risks.
Results: Functional error was the most prevalent one (72.7 %), whereas communication error was the least prevalent one (3.03 %).  Omission and commission were the most frequent functional error. Moreover, 42.2 percent of errors had roots in lapse and slip and 12.1 percent were of knowledge-based type. Moreover, it was impossible for 79.7 percent of errors to be recovered. About 54.53 percent of errors had severe or catastrophic consequences.
Conclusion: As the risk of accidents occurring in healthcare organizations is unacceptable, it is a necessity to identify these errors and evaluate their risks. As it is costly to replace the purchased devices with less error prone devices, human error analysis should be performed in the design phase and before purchasing the devices. Moreover, errors with an unacceptable risk should be controlled based on their probable causes.

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Introduction: Natural materials are more efficient and attractive than synthetic materials. In this study, the sound absorption behavior by natural kenaf composite and Micro-Perforated Panel (MPP) at low and medium frequency region was investigated.
Material and Methods: Initially, the results of kenaf fibers with a thickness of 10 mm were validated by the Finite Element Method (FEM) based on COMSOL Multiphysics 5.3a. The studied combined panel is consisting kenaf fibers with micro-perforated plates and an air layer. This study examined the varying arrangement of the behind layers of the MPP, the different thickness of the layers, and the structural parameters of MPP. The structure with the best absorption coefficient was chosen for the following stage and was considered constant at each stage.
Results: The arrangement of composite layers indicated a strong direct effect on the sound absorption performance; as we discovered that kenaf fibers behind MPP led to better performance in frequencies below 2500 Hz. In addition to the chamber depth behind the MPP, the material and macroscopic properties of the layers, at the same depth, are also important determinants of the exact point of the resonant frequency. Furthermore, configurations in which air layer depth is more than the absorption layer, with the same diameter (hole) and depth (chamber), maximum resonant absorption peak is achieved.
Conclusion: Low-frequency sounds can be successfully dissipated by combining MP plates with kenaf fibers as reinforcing absorber in combined panel. In general, choosing the optimum structural parameters (Composite panel according to structure A with 0.5 mm hole diameter and 2% perforation percentage) allows a significant absorption at a specific frequency range. In this context, the use of numerical estimation to assess the sound absorption behavior can be meticulously substituted the difficult methods and laboratory costs.

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Introduction: Fire safety in healthcare centers is crucial due to the limited evacuation capacity of the occupants and the necessity of not disrupting the operation in these centers. In this study, the fire risk of a public hospital was evaluated using the Fire Risk Assessment Method for Engineering (FRAME). Additionally, the factors affecting fire safety in the hospital were analyzed quantitavely, and fire control strategies were presented. 
Material and Methods: First, the fire risk assessment checklist was filled in all the hospital departments. Then, the values of the factors affecting fire safety were obtained. In the next step, the fire risk for the building, occupants and activities were estimated using Excel software-FRAME. Finally, control strategies and intervention measures were presented based on the value of these factors. 
Results: In the hospital under study, 22% of the departments posed an undesirable fire risk to the building and its property. On the other hand, 90% of the departments had risk levels that were undesirable for the occupants. The results of the initial risk (R0) showed that a balance between potential fire risk and risk acceptance can be established by implementing manual fire extinguishing systems and automatic detectors in all departments. 
Conclusion: ased on the condition of the hospital studied, a balance between potential fire risk level and risk acceptance level was not established. Therefore, there is a need for fire control measures, especially fire safety measures for the occupants. The results of this study can be useful for readers and experts in interpreting fire risk assessments and presenting detailed control measures based on the risk assessment and the value of the parameters.