Laboratory measurements of air carbon arcing sound power levels.
NOISE-CON 2011. The 25th Conference of the Institute of Noise Control Engineering, July 25 - 27 2011, Portland, Oregon. Washington, DC: The Institute of Noise Control Engineering of the USA, 2011 Jul; :1-9
Investigative field reports show that air carbon arcing generates sound levels between 108 dB(A) and 120 dB(A) at the operator's ear. Sound levels above 115 dB(A) are in excess of the Mine Safety and Health Administration (MSHA) compliance limit, potentially resulting in hearing loss from short-term exposure. The National Institute for Occupational Safety and Health (NIOSH) is conducting research to understand the effects of air carbon arcing parameters on the noise produced, specifically to reduce hearing loss in the mining industry. Repeatable laboratory experiments have been conducted in an accredited reverberation chamber to measure the sound power levels generated by air carbon arcing. To reduce variability between gouges, air carbon arcing was performed using an automated machine with consistent sample material. Typical electrodes, 1.27 cm (1/2 in) and 0.95 cm (3/8 in) in diameter, were investigated. Amperage, air pressure, and gouging speed were measured. This paper will describe the measurement procedures and document the results obtained. The implications in terms of how the parameters affect the generated sound power will be discussed. The largest effects were seen by altering the amperage and air pressure settings. The highest sound power level measured was 130 dB(A), when gouging with a 1.27-cm electrode. The lowest sound power level observed was 116 dB(A), using a 0.95-cm electrode. Lowering current to the minimum effective setting had a larger effect than lowering the air pressure. However, lowering both current and air pressure to the minimum effective settings produced the lowest observed sound power levels.
Noise; Noise-levels; Noise-measurement; Sound; Hearing; Ears; Mining-equipment; Mining-industry; Permissible-limits; Exposure-assessment; Exposure-levels; Exposure-limits; Noise-induced-hearing-loss; Short-term-exposure; Machine-tools; Laboratory-testing; Exposure-chambers; Air-pressure; Electrical-measurement; Measurement-equipment; Power-generation; Pressure-testing; Machine-operators; Arc-welding; Cutting-tools; Arc-welders; Metalworking
R. E. Miller, National Institute for Occupational Safety and Health, Office of Mine Safety and Health Research, 315 E. Montgomery Ave., Spokane, WA 99207
NOISE-CON 2011. The 25th Conference of the Institute of Noise Control Engineering, July 25 - 27 2011, Portland, Oregon