Vol 11 No 3 (2019)
Noise discomfort is one of the important unpleasant physical parameters in open-plan offices. This study was aimed to investigate the status of noise pollution and its effects on subjective fatigue and noise annoyance among bank staffs. The equivalent sound pressure level (Lpeq.T) of 100 bank employees was determined during the working time. Moreover, the sound pressure level (SPL) in client waiting areas and in the outer area of the studied banks was measured. For evaluating the mental fatigue, the standard Multidimensional Fatigue Inventory (MFI) questionnaire was used. Noise Annoyance Scale (NAS) questionnaire was also applied to study workplace noise annoyance and the subjective impressions of noise intensity. The mean Lpeq.T in the staff workstations, client waiting areas, and the outside area of the studied banks were determined 78.72, 61.14, and 81.32 dB (A), respectively. The mean values of the preferred noise criterion (PNC) and speech interference level (SIL) indices were 58.22 and 70.25, respectively. The results revealed that the feeling of mental fatigue and noise annoyance among bank employees were significantly affected by the Lpeq.T, level (r=0.84 and 0.90, respectively). The findings indicated that the background noise in open-plan offices increased the PNC and SIL indices which can increase the mental discomfort of staff and decrease their job performance in cognitive tasks. Reflective and rigid surfaces increased the SPL scale in the interior area of banks, and therefore it is necessary to modify the internal surfaces in these open-plan offices.
Investigating the Effect of Shape on Acoustic Performance of Micro Perforated Absorber at Low Frequencies
Nowadays, micro-perforated absorbers are one of the structures that are widely used nowadays. The sound absorption mechanism is performed by viscous energy losses in the cavities on the plate. This paper examined the effect of the surface shape on the micro perforated absorber performance at low frequencies (less than 500 Hz). The three-dimensional finite element method was used to predict the absorption coefficient of this group of adsorbents. Also, the results obtained from the shaped absorbers were compared with the flat micro perforated absorbers. After validating the numerical results, six different designs were defined as the surface shape of the micro perforated plates in the COMSOL Multiphysics, Ver. 5.3a software. The results reflected the fact that the factor of the surface shape can be used as a contributing factor in some frequencies. In general, the dented or concave shapes provide better outcomes than other flat designs and shapes and the convex or outward shapes bring the weakest results.
How are Organizations Complying with Health and Safety Regulations? A Content Analysis of Committee for Technical Protection and Health at Work Minutes
The main aim of Occupational Health and Safety (OHS) regulations is providing safe conditions at workplaces. A literature review was indicated that no study has been reported on the implementation and enforcement of the regulation of committee for technical protection and health at work (CTPHW) in Iran. Therefore, this study was conducted to assess how workplaces fulfill the requirements of the CTPHW regulation and prioritization of OHS issues in CTPHW’ decisions using content analysis of CTPHW’ minutes. In this study, 817 minutes for duration of 2011-2016 were assessed in Iran. The content analysis was used to assess the available documents. The findings of this study indicated that the committees gave more priority to safety issues than others. Administrative control measures were suggested as more prevalent safety measures than engineering measures and personal proactive equipment (PPEs). The qualitative analysis of the data indicated that the minutes of the companies differed in terms of the quality of the writing, assessed OHS problems, and the decisions taken about OHS. The majority of the companies did not fulfill the requirements of the CTPHW regulation in an appropriate manner. This study was concluded that the OHS authorities may help to fulfill the requirements of the CTPHW’ regulation and promote OHS status in the companies by training and encouragement.
Effectiveness of a Social Cognitive Theory Intervention on Promoting Personal Protective Equipment (PPEs) Use among Iranian Aluminum Company Workers
Workers in industrial workplaces are at increased risk of developing, occupational hazards, work-related accidents, and diseases. Personal Protective Equipment use (PPE) may protect the user against accident or safety risks in the working environment. Educational interventions may improve knowledge and practice related to prevention, but little is known about their knowledge and exposure prevention. This study was aimed to determine the effect of educational intervention based on social cognitive theory (SCT) on knowledge and (PPEs) use among Iranian workers of Aluminum Company (IRALCO). This parallel randomized trial was conducted in a sample of 188 workers who were randomly assigned as the intervention (n=94) and a control (n=94) groups. The intervention group received an educational intervention of six sessions lasting 45-60 minutes augmented with the electronic-learning whereas; the control group attended a routine education program of the company. A researcher-made questionnaire based on SCT constructs and a practice/checklist was used to collect data at baseline and six months after the intervention. Mann-Whitney Test and Wilcoxon Signed Ranks Test analysis were used for data analysis using SPSS version 24.0. P<0.05 was considered statistically significant. After the intervention, knowledge, practices (checklist) items, and all SCT constructs (except emotional adaptability (P= 0.077) revealed significant differences in the intervention group (P≤0.001) whereas in the control group were no significant differences (P>0.05). This study indicated that the application of educational intervention based on SCT constructs can reflect a positive impact on knowledge and appropriate use of PPEs to reduce occupational-related injuries. This theory is a recommended method to improve workers’ personal protective behaviors.
Risk Assessment of the Controlling Methods to Prevent the Harmful Environmental Effects from Fire and Explosion: A Case Study
Oil and gas production is an inherently hazardous activity due to the large volume of flammable and explosive hydrocarbons stored or processed in a facility. Therefore, formal risk assessments are necessary for various phases of the asset life cycle because they help personnel identify, evaluate, and control the hazards that could result in loss of life, injury, pollution, property damage, or business disruption. The aim of this study was to assess the risk of fire and explosion (F&E) in the Gas Treating Unit of a gas refinery using the DOW’S fire and explosion index in order to examine the influence of the controlling methods. Accordingly, the important processes of the subunits in the Gas Treating Unit were identified based on the important influential parameters such as process pressure, temperature, and material value. In the next step, the most important parameters affecting the fire and explosion index were calculated for each subunit. In each case, the corresponding control methods were identified and their effects were investigated. The results revealed that 5 subunits out of the 5 studied had a severe risk of fire and explosion. The feed gas K.O DRUM (Knock-out Drum) was the most critical subunit of the Gas Treating Unit, given an F & E index value of 235.62. According to the research findings, the controlling methods could reduce the F&E index but not less than 98.7.
Today traffic accidents are remembered as a major problem that threatens public health and safety. Iran is a country that has a high traffic accidents rate among the countries. The aim of this study was studying of taxi drivers’ safety culture in Tabriz city. This study was a descriptive-analytical study. The participants were the taxi drivers of Tabriz city. According to the results of a pilot study sample size estimated 120. The samples were selected in the clusters and randomly. The data collected through driver behavior questionnaire (DBQ) and were analyzed using independent t test, Pearson correlation and ANOVA. The results showed that there is a significant relationship between the number of hours worked per week and the incident. Also, there is a significant relationship between the observance of speed limits and driving time per week (p < 0.05). Given that the average behavior score of safety in the study was carried out 89/5 can be concluded that the safety of Tabriz taxi drivers is desirable.
Investigating the Circadian Rhythm Type and its Relation to the Problems Caused by Shift work: a Case Study-Workers in one of Iran’s Iron-Ore Mines
Nowadays, shift work systems are a very common work schedule in developed and industrialized societies. The human body needs to adapt itself to different cycles of sleep and awakening. These will predispose persons to various physical, psychological, and social problems. This study was aimed to investigate the circadian rhythm type among workers in one of Iran’s iron-ore mines. Furthermore, the relationship between the circadian rhythm amplitude and stability was also evaluated. In the present cross-sectional study, 356 persons were investigated who were working in their daily shift work in an iron-ore mine. The samples were collected randomly and for data collection, the standard questionnaires of “Survey of Shift Workers” (SOS) and “Determination Checklist of Circadian” (CTI) were used. Data were analyzed using SPSS software version 11. ANOVA, T-test, and Chi-square tests were applied. According to the research objectives, 356 participants, 75.2% (268 persons) were shift-workers, and 24.8% (88 persons) were fixed-shift workers. The average age of the shift workers was 35.22 ± 5.40 year-olds. In addition, the most frequent reason for choosing a night-shift for the shift workers was organizational constraints (57%). The results showed that working based on shift work schedule had a significant effect on individual activities (p = 0.034) and family life (p = 0.0001) compared to fixed-shift workers. It was also found that among inflexible individuals, problems such as digestive and psychological problems were less specified than shift workers. Shift-workers with stable circadian rhythms showed more flexibility to the sudden changes occurring in their inner rhythm and relatively had less shift-working issues. On the contrary, those who had rigid circadian rhythm, they were resistant to sudden changes. Consequently, these individuals were susceptible to problems caused by shift work. Stability (FR) and amplitude (LV) variables of circadian rhythms can be used as predictive indicators for employment and help to select appropriate individuals for the shift work system to prevent the occurrence of shift-working problems.
Modern systems have four basic components: hardware, software, organizational, and human. With the development of new technologies and systems, the hardware and software reliability has increased dramatically during the past decades, while in many cases the human reliability has remained either unchanged or even deteriorated over the same period as the result of complexity of systems. Human interactions are an important factor during the design, installation, production and operation, and maintenance phases of a product or system. The capacity of human beings to make mistakes and errors has been recognized since the beginning of recorded history. The new view on human error is that you can see the human error as the symptom of deeper trouble, in this case, human error is not a cause of failure. Human error is the effect, or symptom, of deeper trouble inside a system. It is not fair, logical and professionally ethical and sound for experts in the field of human factors and safety to say that human is recognized as the cause of as the matter of fact it is the failure of design and operation team and those who were unable to predict and mitigate source of human failure. This paper review was examined and summarized the history, significance, concepts, contributing factors, and all invented analytical methods and procedures in a systematic human reliability assessment (HRA). Furthermore, available human reliability data banks were introduced and elaborated. The challenges and issues in the field of human reliability field were later highlighted and emphasized. Lastly, the expected directions for future works by researchers and practitioners were suggested.