By Kathi Mestayer
LEED, or Leadership in Energy and Environmental Design, is a green building certification program run by the U.S. Green Building Council. Its objective is for buildings to save money and resources and have a positive impact on the health of occupants, and promote renewable, clean energy.
This includes good acoustics. “Our 2009 ratings systems for schools and healthcare institutions cover sound because of the overwhelming evidence that it critically affects learning and healing environments,” says Larissa Oaks, the LEED Indoor Environmental Quality Specialist with the U.S. Green Building Council (USGBC).
Surveys by the Center for the Built Environment and other groups have shown that occupants of office buildings and other work environments rated “acoustic comfort” low, even when the air quality and temperature were deemed acceptable. Acoustic comfort is defined as conducive to speech intelligibility, speech privacy, and concentration where appropriate, with few distractions and annoyances.
Optimizing green design and good acoustics can be a balancing act. "The imperatives of green design—such as lower-energy consumption mechanical equipment and designs, harder-surfaced materials, reduction in use of full-height partitions, and more glass—resulted in spaces that achieved high marks for efficiency, and high LEED certification levels, while simultaneously not meeting the needs of the occupants acoustically," says Ethan Salter, a principal at Charles M. Salter Associates in San Francisco and a lead technical adviser for the LEED acoustics credits.
These credits specify measures to create (and ways to measure) sound isolation and speech privacy, and reduce background noise and external noise. For example, for school acoustics, limits apply for noise from HVAC (heating and cooling) systems and noise from adjacent spaces.
Limits are also set to minimize the effect of reverberation from hard surfaces, which makes speech harder to understand. Reverberant environments can degrade speech intelligibility and increase the “noisiness” of a space, with greater potential for distraction. To mitigate reverberation, designers can incorporate absorptive materials where possible; there are a number of new, sustainable material options that fit within the “green” framework.
As of this writing, LEED credits are in place for acoustical performance for healthcare facilities, classrooms, offices, and other workplaces. There is also a pilot credit for exterior noise control.
Take a closer look at an example of LEED acoustical credits here.