A Typical Case Study of School Sound Insulation

摘要

In order to mitigate noise due to aircraft operations associated with ManchesterAirport, the Federal Aviation Administration (FAA) and the City of Manchester sponsoreda sound-insulation program at Green Acres Elementary School. Based on the 2003noise contours, the school will be exposed to a DNL of approximately 65 dB. Noise levelreduction (NLR) measurements showed that the existing NLR was between 24 and25 dB in three classrooms. The resulting estimated interior 2003 DNL (based on thepre-modification construction) in the classrooms was 40 to 41 dB, whereas the estimated2003 loudest hour average noise level during school hours ranged from 36 to 47 dB(based on five weekdays of on-site measurements).The sound insulation modifications included replacing windows and aluminumwall panels with acoustically-rated units, installing acoustical doors, installing upgradedventilation, and installing new acoustical ceiling tiles. The NLR after sound insulationwas 29 to 31 dB.This paper summarizes the designs, construction process, ventilation systemdesign, and acoustical test results. Although the ANSI Standard (S12.60-2002) was notpublished until after the design process was complete, the resulting indoor noise levelsdue to aircraft and the new ventilation system are compared to the ANSI criteria.