To measure the acoustic characteristics of existing schools and estimate the impact of meeting the 2002 ANSI standard S12.60 (Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools), the Arlington, VA-based Air-Conditioning and Refrigeration Institute commissioned a study. Armstrong, Torseth, Skold & Rydeen Inc. (ATS&R), a Minneapolis-based architectural/engineering firm was retained to complete the study. Sixteen schools (primarily in Minnesota) were evaluated, along with four types of HVAC systems:
- Water source heat pumps, wall- and ceiling-mounted units.
- Central system air-handling units (including package rooftop units) remotely located from classrooms.
- Central chiller systems, 2-pipe and 4-pipe fan coil units (unit ventilators).
- Central chiller systems, desiccant-based cooling, fan-powered boxes with positive displacement diffusers.
According to ARI, the findings revealed that meeting the ANSI S12.60 standard required care in the application of HVAC equipment - including system selection, duct work, vibration control, and the location of air-handling equipment. Additionally, the costs of compliance are steep (between 4 and 19 percent for classroom areas) and must be considered during the planning and design stages. Findings reported in the executive summary also included the following:
- Partition walls that did not meet the standard failed mainly because of poor construction quality. Closer supervision during construction will be necessary to achieve the expected design.
- Almost all classrooms met the Standard for Reverberation Times, although meeting the standard did not guarantee an acoustically acceptable room. Diffusion, as well as reverberation control, was observed to be necessary to achieve an acoustically acceptable classroom.
- Virtually none of the schools being built today will pass the Impact Isolation Class (IIC) portion of the standard.
To review Executive Summary: ARI Classroom Acoustical Study, visit (http://www.ari.org/er/documents/ARI_clsrm_exc_sum.pdf).