The architect or acoustics consultant calculates the volume of all classrooms and core learning spaces to determine the appropriate compliance path for RT. If a space is less than 20,000 ft3, follow Case 1 and design with proper NRC rated material. If a space is equal to or greater than 20,000 ft3, then follow Case 2 with calculations.

For Core and Shell projects where the FTE or transient visitors are not known, the appendix of the Building Design and Construction Reference Guide includes default FTE numbers based on square footage.

All Cases

Hiring an acoustics consultant will add a cost, but can be a worthwhile investment in achieving this prerequisite. Hire a consultant as early as possible in order to incorporate recommendations cost-effectively.

Include acoustic performance goals early in the design process to help keep this prerequisite cost-effective. Waiting to include acoustical strategies until after the building and mechanical systems have been designed can add significant cost to the redesign due to changes such as supply silencers, return silencers, duct layout reworking, lined ducts or flexible ducts, diffusers, lined sound boots, or double gypsum layers on fan-powered boxes. These strategies could be minimized or eliminated with early incorporation of acoustical goals.

For projects attempting EQc9 and those running RT calculations, an acoustics consultant is recommended. The consultant will also help verify that the mechanical engineer is running the background noise calculations correctly and understands the requirements.

Although reverberation time measurements can be taken after construction to show prerequisite compliance, this is a risky path because a redesign might be the only way to attain the prerequisite and could prevent LEED certification.

The FTE occupancy number you use here must be consistent with the FTE occupancy numbers used in all other LEED credits, including:

WEc2: Innovative Wastewater Technologies
WEc3: Water Use Reduction
SSc4.2: Alternative Transportation—Bicycle Storage and Changing Rooms
SSc4.3: Alternative Transportation—Low Emitting & Fuel Efficient Vehicles
SSc4.4: Alternative Transportation—Parking Capacity

The reverberation time compliance path depends on the size of the classrooms and core learning spaces. Rooms smaller than 20,000 ft3 will not have to run any calculations and will find it much easier to meet the prerequisite requirements. All classrooms and core learning spaces must meet the prerequisite requirements. Core learning spaces include band rooms, gyms, labs, libraries and more. It does not include cafeterias.

Determine the numbers and types of occupants in the building. The water use calculation is based on occupant use and the number of full-time equivalent (FTE) occupants, including employees and visitors, not the number of water fixtures installed.