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2015SpringShotcreteEMag

Safety Shooter The Hidden Danger of Noise Shotcrete workers are subject to noise, much of which is at potentially dangerous decibel levels By Derek and Amanda L. Pay Hmanently damage. According to the Centers various real-world jobsites. Data was collected -They researched multiple environments designed to generate data on noise levels for-earing is one of the most important sensesthat we have, and one of the easiest to per for Disease Control and Prevention, “Occupa- using a noise dosimeter fitted to shotcrete tional hearing loss is one of the most common workers over the span of their exposure time. work-related illnesses in the United States. The unexpected results of these tests clearly Approximately 22 million U.S. workers are illustrate the acute need for hearing protection exposed to hazardous noise levels at work….An amongst shotcrete workers. estimated $242 million is spent annually on worker’s compensation for hearing loss dis- The Decibel ability.”1 The use of hearing protection is one of A unit of sound is measured by a decibel. A the most overlooked pieces of personal protec- decibel measures the loudness or intensity of a tive equipment (PPE). Shotcrete workers sound. Once sound hits the ear, bones behind the working without effective hearing protection are eardrum begin to vibrate within the middle portion exposed to potentially damaging noise levels. of the ear. The sound then travels to an area called How dangerous are these noise levels? Pre- the inner ear. Damage from noise exposure occurs vious studies regarding worker exposure rates in an area of the inner ear called the cochlea (refer have been derived from common construction to Fig. 1). The cochlea contains hairlike sensory job site exposure. Pump operators, finishers, receptor cells that transmit the acoustic message and especially nozzleman and blow pipe to the auditory nerve, which then sends it up to operators continuously use some of the loudest the brain. Damage occurring within the cochlea construction equipment in operation today. is permanent and is labeled sensorineural hearing Over the last 2 years, research on shotcrete loss. Unfortunately as of now, there is no known worker noise exposure rates was conducted by cure for sensorineural hearing loss. Derek Pay and his wife Amanda Pay, an audi- For this experiment, we were interested to ologist specializing in hearing conservation. know at what point in the workplace, and for what period of time, could our ears be exposed to such sound levels before nerve damage may occur. Noise level and exposure time are key factors for possible permanent hearing loss. The Occupational Safety and Health Admin- istration (OSHA) provides us with a table (refer to Table 1) using A-weighted sound levels that calculate decibel levels (listed on left side of table) and length of time (listed on right side of table in hours going down to seconds) that an ear can be exposed to before nerve damage may occur. This chart illustrates, as the intensity level of sound increases, safe exposure time decreases.2 The Experiment The experiment focused on three typical envi- Fig. 1: Anatomy of the ear ronments in which shotcrete workers may be 66 Shotcrete • Spring 2015


2015SpringShotcreteEMag
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