Determination of Forces Required to Open Valves
Authors: Saif Al-Qaisia, Fereydoun Aghazadehb, Laura Ikumab
Abstract: The objectives of this study are: (1) to determine the effects of handwheel height and angle on valve-operators’ torque production; (2) to recommend maximum acceptable torque (MAT) limits for valve systems that will not exceed operators’ capabilities; and (3) to review and summarize the literature concerning the effects of handwheel height and angle on valve-operators. A total of 60 participants were recruited for this study, including 30 males and 30 females. The handwheel heights included knee, elbow, shoulder, and overhead levels. The handwheel angles included 0o, 45o, and 90o. At each height-angle combination, maximum isometric torque exertions on a handwheel were measured. MAT limits were computed using the 5th percentile torque strength values of the female participants. Depending on the height and angle of the handwheel, the average maximum torque exertions ranged from 51.6 Nm (found at overhead 0o) to 74.9 Nm (found at overhead 45o). The MAT limits ranged between 13.7 Nm and 24.1 Nm, depending on the height and angle of the handwheel. The results of similar studies in the literature and the current research are summarized and compared in one table.
Keywords: handwheel height, handwheel angle, valve-operation, maximum torque production
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