Project Description

HVAC upgrade brings color, character, and nearly silent draft-free cooling to popular community space.

The gymnasium at the Alleluia Community School in Augusta, GA was originally built in 1951 (then owned by Richmond County Board of Education and known as Fleming School), long before air conditioning of gyms was typical. In addition to basketball and volleyball, the space is used for various community meetings, services, and conferences. Because of the multiple uses for the space, air distribution and sound generation were much more of a concern than in a typical gym system.

The original design was based on using 28″ diameter fabric duct to match the metal supply ducts from the RTUs.

Knowing that noise in the space was a major concern, we evaluated the distribution system sound generation using our Air Tailor software and found that using 28″ diameter fabric duct would result in an NC-40 – a little more noise in the space than ideal for non-sports events. This allowed us to recommend a slight increase in the duct diameter to 34″ to reduce the inlet velocity, thereby reducing sound generation in the space to NC-35 for an extremely quiet environment regardless of space usage. Director of Projects for HIPP Engineering & Consulting in Augusta, GA, Bob Harmon is also a member of The Alleluia Community and took the lead on system design.

Working closely with David Archer from Holden/Mingledorff’s in Savannah, GA, Bob incorporated two 15-ton Carrier Gas-Pack RTUs, inlet silencers and return elbows from Vibro-Acoustics, and, of course, fabric duct diffusers from Prihoda to create an economical, efficient, ultra-quiet system for conditioning the space for its many uses.

The straight runs of duct presented no design challenges, but our Air Tailor software confirmed the proper design and system parameters, and also provided the ability to customize the air distribution from the duct diffusers to optimize cooling in the entire space.

The original design was based on using 28″ diameter fabric duct to match the metal supply ducts from the RTUs.

Knowing that noise in the space was a major concern, we evaluated the distribution system sound generation using our Air Tailor software and found that using 28″ diameter fabric duct would result in an NC-40 – a little more noise in the space than ideal for non-sports events. This allowed us to recommend a slight increase in the duct diameter to 34″ to reduce the inlet velocity, thereby reducing sound generation in the space to NC-35 for an extremely quiet environment regardless of space usage.

The single cable suspension and internal support rings provided for simple installation, and an effective air distribution system that looks – and sounds – the same whether there is airflow through the ducts or not. We even made them red to match the school colors.

The final system provides exceptionally even, draft-free cooling to the entire gym and is practically silent. Another engineer who visited the job with us noted that even with the system running, we could hear the hum of the ballasts in the fluorescent ceiling lights.

We appreciate being a part of this project and hope the Alleluia Community enjoys many years of comfortable use of their gym – and, except for those cool red ducts, never even notices the system.

Project Partners:

Owner: The Alleluia Community School (Augusta, GA)
Engineer: Robert D. Harmon, PE, Director of Projects, HIPP Engineering & Consulting (Augusta, GA)
Equipment Supplier: David Archer, Holden/Mingledorff’s (Savannah, GA)
Equipment Setting & Ductwork: Quality Plus Services (New Ellenton, SC)
Ductwork Insulation: Morris Insulation & Environmental (Augusta, GA)
Medium & Low Voltage Controls: Tom Jackson Electric (Augusta, GA)
Roof-Top Units: Carrier Corp
Noise Control: Vibro-Acoustics
Fabric Duct Diffusers: Prihoda North America