Evaluation of Different Pneumatic Pressure Levels and Tool Types for Reducing Hand-Arm Vibration and Dust Exposures at a Foundry

Abstract

Occupational exposures to hand-arm vibration and dust have been shown to have deleterious human health effects. Exposure to vibration from pneumatic tools can result in Hand-arm Vibration Syndrome (HAVS), which is a collection of vascular, sensorineural, and musculoskeletal disorders. Exposure to dust can result in a variety of adverse respiratory symptoms. The use of a low-frequency, high-magnitude sand rammer tool during mold-making processes at a foundry could result in significant exposure to these hazards, thus it is important to mitigate the associated risks in order to ensure worker safety. The goal of this study was to evaluate whether different pneumatic pressure levels and sand rammer types have an effect on reducing hand-arm vibration and dust exposures at a foundry. Vibration and dust measurements were obtained at three different pneumatic pressure levels (90 psi, 80 psi, 70 psi) and for three different sand rammer types (LM, SM, T). The primary concern of the study was reducing hand-arm vibration exposure. Measurements were taken in compliance with ISO 5349-1 resulting in frequency-weighted, root-mean-square (rms) acceleration values (m/s2). Significant differences in mean rms acceleration were observed across all pneumatic pressure levels and sand rammer types. At 90 psi the mean rms acceleration value was 25.53 m/s2, decreasing to 19.58 m/s2 at 80 psi, and further decreasing to 18.38 m/s2 at 70 psi. The mean rms acceleration values were 19.63 m/s2 for sand rammer LM, 21.46 m/s2 for SM, and 19.95 m/s2 for T. The results of this study indicate that reducing pneumatic pressure levels can reduce vibration exposure in the workplace when using low-frequency, high-magnitude tools. The results also indicate that the use of different sand rammer types produces differences in vibration exposure when tested across all pneumatic pressure levels. Dust measurements were taken concurrently with vibration measurements. The number of dust particles was counted for each pneumatic pressure level and sand rammer type. Overall, the mean particle count for the dust measurements was the highest at 90 psi (41,681) followed by 70 psi (33,514), and 80 psi (26,047). Sand rammer SM had the highest mean dust particle count at 35,732, followed by T at 34,460, and LM at 31, 382. The results indicate that lowering pneumatic pressure levels could potentially reduce dust exposure in the workplace when using a percussive tool such as a sand rammer. However, variability in the sampling conditions related to dust measurements weaken the association.