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Showing 2 results for Welding

Amir Aliabadi, Ghasem Hesam, Zahra Moradpoor,
Volume 2, Issue 4 (3-2015)
Abstract

Introduction: Welding is considered to be one of the main sources of occupational exposure to non ionizing radiations. The present study was conducted to examine the rate of occupational exposure to non-ionizing radiation in common welding processes.

Materials and Methods: In the present descriptive analytical study, occupational exposure to different types of non-ionizing radiations including electromagnetic fields with extremely low frequency and ultraviolet and infrared radiations were examined in five types of arc welding processes at the welding department of the technical and vocational training center of Malayer. Electric field intensities and magnetic field intensities were measured using the HOLADAY HI-3604 instrument and based on the ANSI/IEEE Std 644-1994 method. Ultraviolet and infrared radiation intensities were measured using Hagner-EC1 radiometer (made in Sweden).

Results: Electric field intensities and magnetic field intensities were lower than the exposure limits in the different types of welding processes examined. Nevertheless, the intensity of UV-B radiation exposure was higher than the exposure limits in the different types of welding processes examined, while UV-A radiation exposure was only higher than the exposure limits in arc welding. The results of measuring UV radiation intensities transmitted through protective goggles revealed the acceptable shade number of the lenses used. However, welders' clothing did not provide adequate protection. Moreover, the results showed that welders' infrared radiation exposure degree was much lower than the exposure limits.

Conclusion: The intensity of exposure to non-ionizing radiations was influenced by the type of welding process taken. Given the overexposure of welders to UV-B radiation in unshielded conditions, wearing clothes with an Ultraviolet Protection Factor of 50 is necessary for providing better protection.


Reza Tahmasebi, Majid Motamedzade, Sadaf Torkashvand, Mehrdad Anbarian, Maryam Farhadian,
Volume 5, Issue 4 (3-2018)
Abstract

Background: Many workers, especially welders, have awkward postures during their working hours. Evaluating such kind of postures is done with the aim of corrective actions. Therefore, the present study was conducted to evaluate the activity of welder's muscles in common welding postures working on gas transmission pipelines.
Methods: This cross-sectional descriptive-analytical study was performed on 15 welders of the Iranian Gas Transmission Co. After the required analysis, three postures that were most used working on the gas transmission pipelines were identified to evaluate muscle activity. The surface electromyography (EMG) activity of the erector spinae, biceps femoris, vastus medialis, gastrocnemius medialis, gastrocnemius lateralis, tibialis anterior, rectus abdominis, abdominal internal oblique, abdominal external oblique, and semitendinosus muscles are evaluated in three postures. They are analyzed based on the maximum voluntary contraction (MVC).
Results: The results indicated that the mean of muscle activity in the kneeling posture is significantly lower than two other postures (P<0.001). The mean activity of each muscle in different postures were compared and evaluated. The highest activity was related to the tibialis anterior, vastus medialis and biceps femoris. Abdominal muscles have the lowest activity.
Conclusion: The muscle activity of the welders in the evaluated postures was very high. Based on the findings of this study, the muscle activity was strongly affected by the type of posture and angle of the joints, so  the muscles’ activity in the kneeling posture was lower than the two other postures due to the suitable angle of joints and the direct transmission of body weight.


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