When most people hear about the new Acoustic Standards in the LEED for Schools Rating System, their eyes start to glaze over like day-old Crispy Creams. With over thirty pages of detailed acoustical design criteria, the ANSI Standards are a force to be reckoned with. Today we will take a few moments to highlight the basic principles of acoustical design that will “LEED” to enhanced learning environments, happy school board officials, and of course…impressive LEED scores.

To create effective acoustical spaces for education, designers must observe criteria within three important measurements: reverberation times, STC ratings, and background noise levels.

Reverb Time is how long it takes for the sound to decay by 60 dB. In practical terms, it measures the sound absorption in a space. To meet the new LEED guidelines, core learning spaces can measure between 0.6 and 0.7 seconds depending on the room size.

The second design consideration is STC, or Sound Transmission Class. STC measures how much sound comes through a barrier (like a wall, ceiling, or floor.) For example, a student sitting at the back of the class can lose her concentration if she hears the voice of a teacher in the next classroom. LEED calls for most classrooms to have at least an STC 50 rating, and larger spaces to achieve a minimum STC 60. And the higher the number, the better the isolation.

The final element to control is the background noise level. This is always hard to isolate because the sounds come from everywhere. From environmental noise to the boiler system, background noise levels break students’ concentration levels and ultimately inhibit learning. The LEED guide calls for background noise levels not to exceed 45 dBA in most learning spaces.

You can download the Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools at the Acoustical Society of Amercia website. Just FYI, the site requires you to register and then “add to cart,” but the price is free.

Links:
ANSI S12.60 document: http://asastore.aip.org/shop.do?pID=109
LEED for Schools: http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1586
LEED for Schools Addendum, May 2008: http://www.usgbc.org/ShowFile.aspx?DocumentID=4061

Tags: Acoustic Consultant, Acoustic Engineer, Acoustical Consultant, K-12 Education, Sound Measurement, Sustainable

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