You may assume that good acoustical performance is standard practice and will be delivered by the architect and mechanical engineer, but baseline designs often don’t meet the minimum acoustic requirements of LEED. To achieve this prerequisite you may need the help of an acoustics consultant, especially when project team members don’t have specific experience with acoustical performance. However, the architect or mechanical engineer can perform many of the needed calculations.

Keep background noise out of learning spaces

This prerequisite is intended to keep background noise out of learning spaces and prevent sound generated within a space from reverberating. Although this is a requirement of LEED for Schools projects, other projects can earn an innovation credit by meeting these or similarly appropriate requirements.

Background noise may come from a variety of sources: traffic on nearby streets, mechanical equipment, sounds from adjacent classrooms or multi-purpose spaces, and more. Isolating classrooms from these sounds usually involves a variety of different strategies, including selecting quiet mechanical equipment, locating classrooms away from noisy exterior and interior spaces, avoiding placing fans and mechanical systems directly above classrooms, insulating ducts, and using low-velocity air delivery or displacement ventilation.

Absorb reverberation

Reverberation within a classroom is caused by hard surfaces that reflect sound waves instead of absorbing them. To mitigate reverberation, install acoustically absorptive materials on the ceiling, walls, and floors; and use smaller classroom sizes. Ceiling heights over 10 feet will make it harder to meet requirements.

Good acoustical design can be cost-effective in any project as long as acoustics are considered early in design. Waiting until the design is set can lead to additional costs and needless frustration if  you end up having to redesign mechanical systems or the building envelope. Having the entire design team focused on acoustics, including stakeholders such as school board members, the principal, or teachers, will help ensure a consistent focus throughout the project, and will help the project surmount obstacles that may arise.

Also consider IEQc9

When setting project goals, consider both this prerequisite and IEQc9: Enhanced Acoustical Performance, which is a step up. For IEQc9, project teams are required to have a Background Noise Level of 40dBA, whereas the prerequisite only requires 45dBA. The credit also requires project teams to meet Sound Transmission Class (STC) ratings as outlined in ANSI S12.60-2002 whereas the prerequisite does not require projects to meet any STC rating. The biggest difference here is that the STC calculations typically require an acoustics consultant.