International Journal of Occupational Hygiene
Year:2013 | Volume:5 | Issue:3|Papers Count:8

Sound power is considered as an excellent measure for evaluating the efficiency of noise controls as well as for comparing noise sources in workrooms. This parameter can be determined by sound pressure or intensity based methods in real conditions of workrooms. This paper aims empirically to compare these in situ methods in relation to a typical industrial machine located in workroom in terms of accuracy, applicability. Determination of sound power of a typical model of noisy embroidery machine located in enclosed workroom was performed in the interested frequency range of 125 Hz to 4000 Hz. Field measurement of sound power was conducted using the BSWA sound analyzer according to ISO 9614 and ISO 3746, respectively. The results showed SWL spectrum of the source was relatively high with flat noise spectrum. Operation speed was one of the most important features which could influence the noise of embroidery machine. In regard to uncertainty values, the sound power spectra, obtained using the two methods, showed acceptable agreement from the viewpoint of applicability. The higher value for pressure methods can be due to fluctuations in background noise and method limitations. Direct measurement of reverberation time compared with approximate method could improve the accuracy of the pressure method. Hence, pressure method can be employed by occupational health experts as an alternative to intensity method. Due to its direct and more accurate measurements, intensity method is considered to be a more preferred technique in order to describe any noise sources and to evaluate noise controls at sources.

In today’s world of advanced technology, "nothing is safe" and the fear from painful disasters caused by job accidents always exists. Therefore, hospital preparation for probable accidents, such as fire, and providing safety for both the staff and the patients in these situations are vital necessities. This study aimed to evaluate the fire safety status and level of fire-awareness in the hospitals of Shiraz University of Medical Sciences, Shiraz, Iran. This cross–sectional study was conducted in two parts.1) Reviewing the fire-safety status in the hospitals of the university and 2) Evaluating the level of fire awareness among the hospital personnel. In evaluating the level of fire awareness, 520 subjects were selected among Radiology, Pharmacy, Laboratory, And Nursing stations staff. The fire-safety status was assessed using a checklist including 54 questions evaluating fire-safety and emergency exit pathways. In addition, a questionnaire including 12 questions was used in order to evaluate the level of fire awareness. The results revealed maximum and minimum fire-safety status in Namazi Hospital (mean=20.36) and Shooshtari Hospital (mean=16), respectively. In addition, the highest and the lowest levels of fire awareness were found in Qotbeddin Hospital (mean=5.85) and Sina Hospital (mean=3.35), respectively. Level of fire-awareness of the study population had association with educational level and job tenure.

The safety of hydrogen generation facilities is the main concern in their process operation. This study was conducted to identify the hazards and evaluate the risks of a hydrogen generation plant. For this purpose, PrHA (Process Hazard Analysis) was applied for hazard identification while LOPA (Layer of Protection Analysis) was used for risk assessment. The study was conducted in the hydrogen production unit of Behshahr Industrial Complex, Iran in 2011 and 2012. In the process of risk assessment, the records of the accidents and plant flow diagrams were studied. Then, the knowledge of the experts and operators were used through brainstorming prior to the application of LOPA technique. LOPA standard template was applied using PHA-Pro6 software. The initiating events, consequences, independent protection layers and probability of failure were determined for 16 scenarios in 7 nodes. The results showed that without the application of IPLs, the risks of 2 scenarios needed immediate action, 9 scenarios required action at next opportunity and 5 scenarios were operational. The application of IPLs would significantly decrease the risks. The study concluded that LOPA has sufficient credibility for semi quantitative risk as sessment of high potentially hazardous plants.

A laboratory stirred tank bioreactor with six single and dual-impeller configurations was tested to obtain the optimum operating conditions for future biological processes. Six impeller combinations consisting of three basic impeller types, namely Rushton turbine (RT), pitched 4blade (P4B) and pitched 2blade (P2B) downward flow were investigated in 1.77 L bioreactor working volume. Power consumption and gas hold-up measurements were taken over a range of 100-1000 rpm of stirring speed and 1-5 Lmin-1 of air flow rates, for all the six combinations consisting of any single and dual impellers. Using predicted data some empirical correlations were derived which present relations in estimation of power consumption in stirred tanks with various impeller configurations. Electrical measurement method was use to determine the power drown in the stirred bioreactor. Gas hold-up increased with an increase in stirring speed and superficial gas velocity for all the impellers employed. The number and type of impellers in stirred bioreactor had considerable influence on gas hold-up behavior of the stirred bioreactor. Besides, Rushton turbine-dual Impeller gave comparably maximum gas hold-up, but at significantly higher power consumption levels. The proposed correlations offered good agreement with the experimental data.

Safety signs in the workplace are effective in the controlling of workplace hazards. Correct interpretation of signs is vital, preventing injury and saving lives. This study seeks to assess the perception of workplace safety signs and determine effective personal factors in comprehension. The current analytical-descriptive study was carried out in 2012 on 166 factory workers in 4 factories at the Khoramdasht and Bumehen industrial areas. Data was gathered using ISO 9186 and Demographic Information questionnaires. Stratified–random method was used for sampling and data were analyzed with Kendal statistical test using SPSS 16. General perception of safety signs was 69.22% with a standard deviation of 20.32%. Out of the 11 signs studied, the "eye protection must be worn" and "hand protection must be worn" signs had the highest effective perception and the "wear face shield" had the lowest. Results show a positive relationship between sign perception and factors such as age, experience and safety sign training (p£0.05). However a meaningful relationship between sign perception and gender was not observed. Acceptable perception of signs was 72.72% based on ISO 3864 and only 9% based on ANSI Z5353. Results show overall safety sign perception within the studied samples was low and few signs actually reach the perception limits. The contribution of personal factors on sign perception can be reduced by educating the work force on workplace safety signs.

Researchers suggested that the individual fit test be conducted to estimate the protection effectiveness of workers’ hearing protection device (HPD) while working. Practically, it is convenient to conduct single, instead of multiple, fit test measurement. This study examined if a single trial of earplug fit test can represent multiple performances. Additionally, it investigated how much noise exposure was due to the miners’ failure to wear earplugs at work. A total of 11 subjects from 3 coal mines in West Virginia in 2009 were each repeatedly fit tested using the microphone-in-real-ear technique on their earplugs. For each miner values of noise reduction (NR) were determined. The same fit tested miners each wore the earplugs doing his normal full-shift work. The real-time noise doses were determined continuously using the two dosimeters, one at the shoulder and the other under the earplug for determining potential exposure dose and the dose the ear actually received. Most subjects’ noise reduction values varied over a range of more than 10 dBA, suggesting that subjects should be fit tested with multiple donnings. Failure to wear the earplug was an important factor in determining the miners’ noise exposure, accounting for 64.6% of their doses at ear on average and ranging from 33.3 to 93.4% across these subjects. Nearly half (45.5%) of the coal miners might not receive adequate protection with their earplugs.35.2% of miners never wore any hearing protectors in the high noise environment and were in very high risk of hearing loss. Thus, an important portion of miners were exposed to excessive noise although the earplugs were provided.

Safety climate received substantial attention due to its potential for explaining variation in safety-related outcomes. Aim of present study was to determine degree of safety climate related to incidents reporting rate and its dimensions among workers’ Isfahan Steel Company. A self-administered anonymous was distributed to 189 workers. The survey included demographic factors, incidents reporting rate and its components (physical symptoms, psychological symptoms and accidents) and the safety climate Questionnaire. The data were analyzed by multivariate (MANOVA) and correlation techniques. The results showed that: 1) there was internal significant correlation between safety climate with incident reporting rate as well as with its two components namely physical symptoms and psychological symptoms; 2) there wasn’t a significant relationship between safety climate and accident; 2) In multivariate analysis, safety climate respectively about 6%, 7% and 11% of the variance of variables of incidents reporting rate, physical and psychological symptoms significantly predicted (p<0.05). The results of this study suggest that promoting the perception of safety climate can be important to prevent the development of work-related diseases and to promote workers health.

Exposure to toluene can be associate with genotoxicity, neurological dysfunction, reproductive toxicity, and etc. Biomonitoring of hippuric acid (HA) is used for a long time as an occupational exposure index to toluene. The aim of this study was to explore efficiency of HA as a biomarker of exposure to low level of toluene for Iranian Petroleum Depot workers in 2011. Personal monitoring to toluene exposure for 45 workers (exposed group) and 32 staff (control group) were done according to the NIOSH Method No.1501, and simultaneous biological monitoring were conducted as urinary HA for all subjects. Pre and post shift urine samples were collected for analysis of HA by the NIOSH method No.8300 and urinary HA concentrations were corrected with creatinine content. Personal exposure of petroleum loading operators to toluene was 0.78±0.37ppm (Mean±SE). There was no statistical significant difference between urinary HA of exposed and control groups (staff). There was no statistical correlation between occupational exposure to toluene and internal exposure in term of HA. Occupational exposures to toluene were less than TLV in petroleum products loading operators. Due to exposure with low levels of toluene concentrations, however the content of urinary HA in gasoline operators were higher than BEI (Biological Exposure Index), but of no significant relationship between airborne concentrations of toluene and levels of HA in urine in all exposed groups. In conclusion, urinary HA is not appropriate biomarker of low level exposure to toluene.