It’s official! The U.S. Green Building Council (USGBC) has transitioned from Leadership in Energy and Environmental Design (LEED) version 2009 to LEED version 4 (v4), requiring any project that has started after October 31, 2016 to be certified under LEED v4. So why are we as acoustical consultants excited about this? Well, the change from LEED 2009 to LEED v4 introduces new credits that can be achieved through acoustic design in numerous project types in addition to the previously eligible LEED for Schools and Hospitals. In addition to this, the criteria set forth in LEED 2009 for Schools has been modified to enhance acoustical conditions in core learning spaces to provide a better learning environment for students. Read on to learn more about LEED v4.
LEED v4 brings opportunities to obtain credits towards certification with acoustical design in multiple project types including offices, multifamily dwellings, retail, data centers, warehouses and distribution centers, as well as hospitality. These projects can be categorized as BD+C, which are new construction or major renovation projects, or ID+C, which are interior fit-out projects. The BD+C projects can receive one credit for acoustics while the ID+C projects can obtain two. To get these credits, specific spaces must meet acoustical criteria set by USGBC as well as ASHRAE, ASA, ANSI, and CEN.
To obtain the acoustical credit in an office fit-out for example, wall assemblies around confidential spaces such as offices and conference rooms must meet minimum Sound Transmission Class (STC) ratings. In addition to the wall assemblies, reverberation time criteria must be met in employee work spaces by incorporating acoustical finishes to enhance speech intelligibility and improve speech privacy. Another requirement to gain the LEED credit is control of the HVAC background noise; mechanical systems must meet specific Noise Criteria (NC) ratings so that the sound from the systems is not too loud in critical spaces. Finally, sound masking and sound reinforcement systems must be incorporated as occupancy, space uses, and size requires. While this may seem like a lot of requirements for one or two points, modifications to basic construction can typically meet the criteria.
In addition to the new opportunities for LEED credits in commercial, industrial and residential buildings, modifications to the prerequisites for schools have been made in the transition between LEED 2009 and LEED v4. In LEED v4, the prerequisite criteria for background sound level due to mechanical equipment is more stringent with a maximum of 40 dBA in core learning spaces versus 45 dBA in LEED 2009. For the additional acoustical credit that can be achieved in schools, this criteria has been lowered as well, from 40 dBA to 35 dBA. While this may seem like a drawback, the quieter design criterion will increase the signal to noise ratio in the classroom, which will allow students to better understand the teacher.
These LEED v4 changes are a win for all. Healthy environments encourage healthy behaviors.
Oh – and Happy Earth Day!