What are Quality Acoustics? Washington Administrative Code 246-366-110 Criteria for High Performance Schools (CHPS) Washington ANSI S12.60-2002 There are several codes and standards that specify criteria for quality acoustics in schools.  These include Washington   Administrative Code 246-366-110, which has established     Wing Luke Elementary Architects BCRA/Tsang acceptable noise levels within classrooms and instruction areas to be limited to a Noise Criteria (NC) 35.  Noise levels are required to not exceed 55 dB(A) during an hourly average and should not exceed an hourly maximum value of 75 dB(A) during the time of day the school is in session.  Actual background noise at any student location within a classroom shall not exceed 45 dB(A) for thirty seconds or more. In addition, several T and guidelines have been published which recognize the importance of acoustics for schools, including CHPS Washington (see below) and ANSI/ASA S12.60-2002. What are the new CHPS Washington Schools Criteria? •       CHPS is an all-encompassing definition of a high performance school in the state of Washington. Government agencies may require meeting these criteria for participation in sponsored programs. •       Points are awarded for improved acoustical performance. Districts and designers are strongly encouraged to move beyond the CHPS prerequisites to achieve greatly improved acoustic environments in all classrooms. How can improved Acoustical Performance criteria be met? •       Reaching NC 35 maximum unoccupied background noise levels for classrooms; an improvement over IEQ Prerequisite 3 of an NC 50 maximum. Both require maintaining a 0.6-second maximum reverberation times (RT60). •       Classrooms reducing the unoccupied background noise levels by and additional 5 NC (an NC30 maximum) maintaining a 0.6 second maximum unoccupied RT60 How can noise from exterior and interior sources be eliminated?
			Interior Room Acoustics and Reverberant Noise Sound absorption is necessary to reduce reverberant noise in areas where students gather and speech intelligibility is necessary. By adding sound-absorbing materials to a space, the reverberant sound is reduced, and occupants will hear considerably less noise. If a room has no absorptive treatments, occupants hear direct sound energy as well as reflected sound energy from the ceiling, floor, and walls. By designing absorptive materials for walls we can reduce overall noise levels to within CHPS and Washington Code standards. Sound Isolation Architectural acoustic recommendations are necessary to reduce sound transmission between spaces, provide impact insulation from footfalls and reduce sound from environmental sources and mechanical equipment, Specific wall, window, and floor/ceiling types need to be designed for effective sound isolation. Details on ducting penetrations, light fixtures, and electrical junction boxes are recommended. Environmental noise mitigation recommendations are based on sound data as well as predicted noise levels. Mechanical Noise Control The evaluation of noise from HVAC systems is applicable to all learning areas and administrative spaces. Predictions based on supply, intake, and radiated noise of HVAC units from the location of the equipment provide a starting point for recommendations to achieve the desired Noise Criteria.