757 AIRPLANE WING MAJOR JIG FACTORY NOISE REDUCTION

摘要

The main technical lesson learned from this program was the fact that the riveter actuallyreceives noise reduction of significance. It was forecast that the only personnel that would realize any noticeable reduction in noise exposure would be those not riveting. This is dueto the fact that the riveter is exposed to all the direct noise from the panel they are rivetingand it was thought that the reflected noise would not be a big contributor. Anothertechnical lesson learned on this program was the fact that even though we tried to keepthe openings between the curtains at a minimum, such as at the floor and sides and evenover the top, we were able to achieve very good noise reductions. This seems to violatesome of the major rules ofacoustics with respect to always having tight seals around jointsetc. We believe that these rules still apply, however, in this case where the noise energylevel is so high, even though there are plenty of leaks through the barriers, considerablenoise reduction is achieved. If the leakage could be sealed better, perhaps more reductionwould be realized, but the high energy level still exists and will until some new technologycan be developed to actually reduce the noise at the source.