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Safety Shooter exposed. In each environment, the nozzleman was Table 1: OSHA Noise Exposure Computation, Table G-16A fitted to a Q­200 noise dosimeter device manu- A-weighted Reference A-weighted Reference factured by Quest Technologies (refer to Fig. 2(a) sound level, duration, sound level, duration, and (b)). The probe was placed near his ear for L (decibel) T (hour) L (decibel) T (hour) the duration of his work day. The device is 80 32 106 0.87 designed to measure and record data on the exact sound pressure levels and decibel levels reach- 81 27.9 107 0.76 ing the worker’s ear. 82 24.3 108 0.66 The first test environment was a jobsite 83 21.1 109 0.57 including a soil nail tieback wall in an open 84 18.4 110 0.5 area with a maximum height of 65 ft (20 m) while in a man basket. The device displayed 85 16 111 0.44 data for the 8-hour work day. Collected data 86 13.9 112 0.38 revealed that the nozzleman was subjected to 87 12.1 113 0.33 an average of 93 decibels. According to Table 1, 88 10.6 114 0.29 at 93 decibels constant noise, ears are safe for only 5.3 hours before permanent hearing loss 89 9.2 115 0.25 can occur. 90 8 116 0.22 The second environment was an indoor seismic 91 7.0 117 0.19 retrofit project. This project consisted of tight 92 6.1 118 0.16 working conditions creating a less-than-ideal acoustic environment. The nozzleman was on the 93 5.3 119 0.14 job for 10 hours and exposed to an average of 94 4.6 120 0.125 95 decibels. The device recorded an exposure 95 4 121 0.11 level of more than double the allotted safe lis- 96 3.5 122 0.095 tening time of 4 hours. The final environment involved an outdoor 97 3.0 123 0.082 residential swimming pool. The nozzleman 98 2.6 124 0.072 worked for 10 hours with an average exposure 99 2.3 125 0.063 level of 92 decibels. Again, the device recorded 100 2 126 0.054 levels that are considered safe for only 6.1 hours. During the experiment, sound levels were also 101 1.7 127 0.047 measured in the same manner for a pump oper- 102 1.5 128 0.041 ator. With all three environments, the same pump 103 1.3 129 0.036 was used and the pump operator was subject to 104 1.1 130 0.031 a shocking average of 104 decibels with occa- sional peaks of up to 110 decibels when standing 105 1 — — at the controls. The operator was at an extremely high risk for hearing damage given the amount of time of his exposure. With his average of 104 decibel exposure, in only 1.1 hours perma- nent nerve damage may begin to occur. Results of this study conclusively prove that shotcrete workers are in very real danger of serious and permanent hearing loss. The solution to keeping our ears safe and conserving our hearing can be as simple as wearing effective protection designed for the expected exposure rate. The importance of wearing effective hearing protection during working hours cannot be overemphasized. The National Institute for Occupational Safety and Health (NIOSH) rec- ommends using hearing protectors in all situa- tions where dangerous noise exposure cannot be controlled or eliminated. Fig. 2(a): Dosimeter ear probe Fig. 2(b): Dosimeter Shotcrete • Spring 2015 67


2015SpringShotcreteEMag
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