Development of a ‘‘quiet by design’’ approach to reduced-noise gas flow systems for experimental research facilities at NASA Lewis Research Center

Abstract

At the NASA Lewis Research Center, occupational and community noise exposures associated with experimental research in aircraft and space propulsion are managed via a hearing conservation program that prohibits unprotected exposure to A-weighted noise levels above 85 dB. In support of hearing conservation goals, a ‘‘buy quiet’’ program requires project designers and engineers who purchase equipment expected to generate A-weighted noise emission levels above 80 dB to consider noise emissions along with other performance criteria. A Guide to Specifying Equipment Noise Emission Levels provides the means to effecitvely pursue this approach. A recently implemented ‘‘quiet by design’’ initiative complements this program and provides design guidance for new facilities, systems, and equipment designed in-house rather than purchased from an outside vendor. A Reduced-Noise Gas Flow Systems Design Guide serves as a companion to the earlier document and covers design practices for reducing noise emission and methods of estimating noise emission from piping and atmospheric vents associated with gas flow systems. A computer spreadsheet guides the user through the design process from noise emission specification through predictive equations and selection of noise control elements, greatly facilitating the development of noise control strategies for new experimental research facilities and the associated servives required for their operation.