Carthage College, Siebert Chapel

The Carthage College Siebert Chapel’s 3,000-square-foot atrium spaces are currently being used as teaching spaces and speech communication is critical for learning in these areas. The facilities team at the College received multiple complaints from staff that HVAC background noise levels are high in these spaces, making it difficult to hear conversations. Carthage College requested that RTM visit the site, observe the noise issue, and provide recommendations for reducing noise levels and improving speech intelligibility.

After visiting the site, it was apparent that the noise was primarily being caused by excessive airflow and turbulence from the supply diffuser in the atrium spaces. The original drawings show that duct sizing is smaller than optimal, there are excessive duct turns, and the balancing damper is located directly adjacent to the supply diffuser. The combination of these factors is causing significant restrictions to the air flow, resulting in high noise levels. To reduce these levels, RTM recommended a combination of treatments, including removing the diffusers and balancing dampers (if possible) or moving the balancing dampers further away from the diffusers, reducing supply velocity at the air handling unit (AHU), and increasing supply duct pathways where possible.