Projects complying with the credit requirements through the ANSI standard should also consider researching the design recommendations for HVAC in the 2007 HVAC Applications ASHRAE Handbook, Chapter 47. This handbook will provide you with useful information when designing HVAC systems for noise reduction.
Compliance with the ANSI standard requires projects to limit maximum allowable background noise levels from HVAC equipment based on section 4.3 of the ANSI standard and provide after construction measurements to verify compliance. Projects will have a better chance of meeting the measurement requirements by following these practices. (See the ANSI standard—and in particular Annex B—for full details.)
ASHRAE has guidelines on running the calculations without software, but these are fairly detailed measurements and a consultant will most likely be needed. See the Sample Background Noise Calculations in the Documentation Toolkit for more information.
The calculation for background noise level can be performed by a mechanical engineer if they are familiar with the calculations or have common software, such as the Trane Acoustics Program (TAP). (See Resources).
HVAC system layout also plays a large role in mitigating background noise from mechanical equipment. It is important to avoid placing fans and mechanical systems directly above classrooms and core learning spaces and insulating ducts. Projects may also want to consider displacement ventilation, which uses lower-velocity air and is quieter.
Isolating mechanical equipment and installing low-noise and low-velocity equipment, including fans and boxes, will help project teams meet the HVAC background noise level requirements.
Meet with the owner, teachers, or principal to review programmatic uses and layout of individual classrooms and core learning spaces. Doing so will help to inform both the school administrators and the design team of each other’s goals and intentions.
Depending on the extent of contamination and the strategy for remediation, efforts may not be complete until just before construction begins. The timeline will vary for each project.
