An occupational noise exposure assessment of the Aberdeen Proving Ground bowling alley Abby Webster Mentored by Dr. Timothy A. Kluchinsky Jr. Introduction According to the Occupational Safety and Health Administration (OSHA) (2014), “Noise-related hearing loss has been listed as one of the most prevalent occupational health concerns in the United States for more than 25 years.” In many occupations, workers are exposed to high levels of noise for extended periods of time. These elevated noise levels can lead to noise induced hearing loss if preventive measures are not taken in time to mitigate the noise. Elevated levels of noise damage the cochlea, which is the inner part of the ear, leading to loss of hair cells. According to OSHA, the American Conference of Industrial Hygienists (ACGIH) (2014) states that workers should not be exposed to levels greater than 140 decibels Peak (dBP) for impulse noise and 85 dB A-weighted (dBA), or frequencies heard by the human ear, for steady state noise, based on an 8-hour time weighted average (TWA). Impulse noise is noise that comes in short bursts, and steady-state noise is continuous. The combination of noise sources within a bowling alley may cause elevated noise levels and therefore could be detrimental to bowling alley employees’ hearing. The Department of Defense (DoD) catalogues occupational exposures to employees in a database called Defense Occupational and Environmental Health Readiness System (DOEHRS). A specific aim of this study was to create an Aberdeen Proving Ground Bowling Alley shop in DOEHRS and populate it with exposure data and materials/methods used so that Industrial Hygienists performing future bowling alley exposure assessments will have baseline data for comparison purposes. It was expected that the TWA for an 8-hour work day would not exceed 85 dBA. Materials and Methods (continued) Results (continued) The dosimeters logged data each second. Peak values and averages from Dosimeter 3 are depicted on Graph 1. The data tables and graphs were retrieved using 3MTM DMS. The results of the occupational noise study show that for an 8-hour work day, the TWA was lower than the threshold limit value (TLV) of 85 dBA set by ACGIH for steady state noise for each of the 3 employees wearing a dosimeter during their shift. At certain locations within the bowling alley, the peak noise levels exceeded 140 dBP. This was found using a SLM (Figure 2). The loudest area within the bowling alley was at the end of the lanes where the pin setters are located, where a warning sign is posted. Workers are never in the pinsetter area while they are running, so they do not experience levels above 140 dBP. If anyone must be in this area while machines are running, they are required to wear hearing protection. Employee 1 had a TWA of 78.7 dBA; Employee 2 had a TWA of 68.6 dBA; Employee 3 had a TWA of 75.6 dBA. These values are all below the TLV of 85 dBA for steady-state noise. Noise Dosimeter Sound Level Meter Conclusions The initial hypothesis that the TWA for an 8-hour work day would not exceed 85 dBA is supported by the data collected in the study. Peak noise levels exceeded 140 dBP at certain locations within the bowling alley (such as at the end of the lanes where the pin setters are located); however, employees are not in this area when the pinsetters are running. Employee 2, who worked in the back room during his shift, had a TWA below the TLV. All 3 employees experienced similar noise exposure. These data will be entered into DOEHRS by Kirk Army Health Clinic. If active bowling alley operations increase, increased noise surveillance may be warranted for a future study. Figure 1: Pictured is the one of the 3MTM noise dosimeters used to capture the TWA for each employee. Figure 2: SLM measurements are being collected in the area of the bowling alley with pinsetters. The results showed that all three employees experienced similar exposure levels with TWAs below the ACGIH standard of 85 dBA for steady state noise. Therefore, one representative graph is shown below (Employee 3). Results Materials and Methods The assessment required the use of a Sound Level Meter (SLM) accompanied with Noise Dosimeters (ND). The SLM included a microphone, amplifier, and calibrator. The SLM output consisted of the instantaneous sound level. The ND is a small clip-on piece of equipment that records sound levels and outputs a TWA for an 8-hour work day. Graphs and data tables were created using 3MTM Detection Management Software (DMS). The first part of the procedure involved collecting data using a SLM at potentially noise hazardous areas within the bowling alley. Areas in which peak levels approached or exceeded ACGIH recommended standards were determined. Noise dosimeters were then placed on 3 different bowling alley employees during their entire shift (Figure 1). Dosimeter 1 was placed on Employee 1 working behind the shoe and food counter. Dosimeter 2 was placed on Employee 2 working in a small room behind the lanes near the pinsetters. Dosimeter 3 was placed on Employee 3 working as a cook. A dosimeter was clipped onto the lapel of each employee and set in run mode for the entire shift during a bowling league event. References Occupational Safety and Health Administration. (2014). Permissible Noise Exposures. Washington, DC: US Department of Labor. Retrieved from https://www.osha.gov/pls/oshaweb/ OSHA Annotated PELs. Permissible Exposure Limits – Annotated Tables. Retrieved from https://www.osha.gov/dsg/annotated-pels/ 3M. Noise dosimeter / wireless Edge™ 5 Quest Technologies. Retrieved from http://www.directindustry.com/prod/quest-technologies/noise-dosimeters-wireless- 31507-342262.html dB Acknowledgements I would like to thank my mentor, Dr. Timothy A. Kluchinsky Jr., for his help and encouragement with my project. I would also like to thank Mrs. Manuela Perez, Mr. Brett Huntington, Mr. Robert Batts, Mr. Tom Kaczorowski, Mr. Chuck Jokel, and Mrs. Yvonne Gabriel for their support and guidance throughout this process. They have all played a part in making this project possible by providing me with all the resources and knowledge I needed to complete this project. Date/Time Graph 1: Data log of the noise levels recorded every minute from Dosimeter 3. The green line (Peak Noise Level) indicates peak levels which are unweighted, maximum noise levels recorded per minute. The blue line (Average Noise Level) indicates the A-weighted average per minute. None of the values exceeded 140 dB during this employee’s shift.