مجله مهندسی بهداشت حرفه ای
سال هفتم شماره 2 (تابستان 1399)

Workplace air quality is a very important factor in community health and is measured by measuring and evaluating airborne contaminants. One of these airborne pollutants is ammonia gas. Spray towers are important components of air pollution control. The aim of this study was to investigate the effects of using diluted sulfuric acid solution on the efficiency of ammonia removal in a spray tower.

In this study, the rate of ammonia removal from the air stream was measured using a spray tower in the laboratory, by changing the liquid pressure and nozzles and the inlet density. The volume of air flow used was 3737.82 l/min and the nozzle used was 20 microns in diameter, one, two and three, with dilute sulfuric acid solution. Data were analyzed by One-Way ANOVA and SPSS.21 software.

Increasing the number of nozzles and the spray pressure of the spray tower increased the spray removal efficiency and increasing the input load to the system reduces the elimination efficiency (P<0.05).

By increasing the number of nozzles and diluting the dilute sulfuric acid solution, it is possible to achieve proper performance in spray tower removal of ammonia gas.

Hospital personnel are exposed to anesthetic gases in various parts of health centers such as operating rooms and recovery rooms. Exposure to anesthetic gases can have serious effects on a personchr('39')s physical and mental health. The purpose of this study was to investigate the effect of demographic variables on the prevalence of neurotoxic symptoms in operating room personnel.

This was a cross-sectional study. Participants included 404 operating room personnel in western Iran. Euroquest questionnaire and demographic checklist were used for data collection. Data were analyzed by t-test, ANOVA and Pearson correlation at the significant level of 0.05.

The results of this study showed that the rate of neurotoxic symptoms in men was more than women and this difference was statistically significant but there was no significant difference between single and married employees and morning work and turnover in neurotoxic symptoms. Also, there was no significant correlation between age and experience of the subjects with neurotoxic symptoms.

Symptoms were higher in some demographic groups, so it is recommended to use appropriate training programs or management techniques such as job rotation in operating room personnel.

Medical laboratories face with different types of health, safety and environmental issues because of their sensitive functions. Hence, the management of the above issues is very important. The aim of present research is evaluating the process of managing health, safety and environment (HSE), in 37 public and private medical laboratories, and 148 employees in 8 cities of North Khorasan province, Iran.

We used a checklist (approved in the terms of validity and reliability) to assess the level of HSE management. SPSS and SMART-PLS softwares were used to analyze the data.

The results show that variables are good in the laboratories, but different aspects of HSE management in public labs are better than private ones, except the maintenance variable. Different dimensions of HSE management chr('39') awareness in different cities of the province are similar, except sewage variable.

Current laws and inspections of medical laboratories of North Khorasan province, following the guidelines and directives of the Ministry of Health and Medical Education, are very well evaluated and implemented.

Oxygen central is one of the vital parts of the hospital that is responsible for supplying oxygen. The occurrence of any defect can result in fatality and finansial damage. Therefore, effective risk analysis is very importance in preventing and mitigating such potential accidents.The purpose of this study was to analyze the scenarios of accidents in the oxygen central unit of the hospital using FTA and LOPA methods.

In the first step, probable errors in oxygen leakage were identified and then FTA was plotted and semi-quantitative LOPA method was used for risk analysis. Finally, control measures to reduce oxygen leakage were predicted.

Results

The results of the study show that the most important accident scenarios include oxygen Release, explosion and fire. The independent protective layers in the oxygen storage and production tanks are suitable. Use of IPLs can significantly reduce risk.  The most important cause of leakage in the patientchr('39')s room was due to the mask being removed from the respiratory area or the lack of fit with the patientchr('39')s face.

The results of this study showed that the independent protective layers in central oxygen are sufficient to prevent oxygen leakage. But it is also necessary to use an oxygen sensor in the patientchr('39')s room and alarms to increase the oxygen concentration to reduce the risk of oxygen leakage in the environment. It should also be periodic training to all employees and maneuver in the crisis management measures should be considered Hospital

Electrocutions have a low frequency and severe consequences. The purpose of this study was to analyze the parameters related to electrical accidents, and evaluation of electrical safety performance of small-scale industries.

This study was conducted in 2019 on 232 small-scale industries. Electrical accidents over a 7-year period were studied. The tools used included electrical accident report forms and a researcher-made checklist for evaluating the study industries based on electrical safety. Data were analyzed using Chi-square, Fisher and regression tests.

The incidence of electrocution in 125 small-scale industries without safety measures was approximately 10 times that of 107 industries have safety measures. poor housekeeping in the first and second groups was 79.5% and 75.0%, respectively. Perceptual error had the most role in the incidence of electrocution in the two study groups (64.1% and 50.0%, respectively). the rate of personal protective equipment training in the two groups was 3.2% and 44.0%, respectively. the rate of using these PPE in both groups was 5.6% and 55.1%, respectively. In addition, there was a significant difference between the two groups in terms of safety measures (P<0.05). the results of modeling the parameters affecting electrocution showed that electrical safety training had the highest correlation with other variables.

However, it has been found that electrical safety was poor in small-scale industries, so it is recommended to use practical electrical safety training as well as implementing safety systems such as earthing system and circuit breaker switches to help reduction of electrocution accidents.

Pulse jet systems are of interest due to their high filtration velocity,Theychr('39')re used as inlets from top and bottom. the purpose of this study was to compare the pressure drop and collection efficiency at the different inlet positions in a baghouse

In this experimental study, a pilot system was designed at 12ft/min permeability for MDF particles.For each inlet after several filtration-cleaning periods,pressure drop was measured by a manometer.Isokinetic sampling was also performed by Grimm1.108 monitor to determine the efficiency.To observe the behavior and Tyndall effect of particles, light and safety glass were used in one dimension of the baghouse

The mean pressure drop during the filtration-cleaning,the bottom inlet was 3CmWG, the top whit expansion inlet was 2.42CmWG,and the top flanged inlet was 2.57CmWG. but the particles settled on the expansion floor.The mean efficiency of top-expansion inlet was 99.995% and top-flanged 99.994%,significantly higher than the bottom inlet (99.974%).After several filtration-cleaning periods,The efficiency of  bottom inlet resulted 99.99%,top-expansion 99.97% and flanged 99.96%.There was no significant difference between the mean total efficiencies for different inlets.

The collection efficiencies were the same for baghouses with inlet from top and bottom.The pressure drop for baghouses with the top inlets was lower than the bottom inlet.It is recommended to use top inlets in case of predominantly fine particles with low density or in presence of a pre-separator,if  large particles,bottom inlet is recommended.Due to the slight difference of pressure drop and more functional limitation of the top inlet,bottom inlet in practice is preferred.

Reducing the consequences of the Covid 19 outbreak requires a systematic approach. The most effective way to prevent this disease is to cut off the virus transmission chain. In this letter, a systemic model for the management of the Covid 19 crisis is presented based on the bow-tie analysis model and the concept of Layers of Protection Analysis from the perspective of safety engineering. In this model, in order to reduce the patientchr('39')s entry into the hospitals, five layers of defense have been introduced to effectively manage the disease transmission chain. In addition to maintaining the health of citizens, the implementation of this model will improve the health of healthcare workers by reducing the burden of patient admission to hospitals.

Human error is the most common cause of crane transfer accidents in the construction industry. Operator errors are caused by a variety of factors during lifting operation by the crane (SLIM) (Success Likelihood Index Model), as a simple and effective way to detect human errors.

In this study, the SLIM method was used to evaluate and manage human errors in equipment displacement operations by tower cranes. After forming the team of experts, the effective PSFs in the crane management activities identified were identified. Then the rate and weight of these factors were determined. Finally, by calculating the total SLI, the probability of human error for each PSF was calculated.

First, four effective PSFs in tower crane guidance were identified by experts. Of the identified PSFs, training received the highest weight and the highest likelihood of success was calculated for the correct use of operating lever during displacement and discharge. By calculating the HEP based on the calculated SLIs, it was found that the mentioned activity had the highest HEP of 3×10-3

SLIM is an appropriate method for determining the probability of human error. Since reducing the likelihood of human error can lead to a reduction in the incidence of accidents, therefore, appropriate measures can be taken to effectively reduce the likelihood of human error and increase the fault tolerance power of tower crane operations.