Acoustic Results of Application of Large Diameter Flexible Piping Connections on High Pressure Centrifugal Pumps

This paper discusses a brief case study related to a high rise building mechanical system. Sound sensitive spaces on floors above and below a mid-level mechanical room were plagued by high levels of tonal noise caused by the operation of a pair of large, high-pressure centrifugal pumps. Due to the operating pressure, large size, and chemical composition of the circulating fluid, elastomeric flex piping connections were initially omitted from the installation, and braided steel connectors were provided instead. The pumps are vibration isolated on concrete inertia bases, and all connected piping and conduit are isolated on spring and neoprene hangers. Upon startup of the pumps, high levels of airborne sound in the mechanical room were audible and disturbing to occupants in spaces above and below. After some investigation, custom elastomeric flexible connectors were sourced and installed on the pumps, resulting in significantly reduced sound transmission to neighboring spaces. In this paper, we present before and after data for airborne noise and slab vibration for this installation.