Abstract:

The Federal Aviation Administration’s (FAA) Airport Improvement Program (AIP) handbook outlines guidance for the funding of noise mitigation projects and the accuracy of existing noise reduction measurements of a structure. Prior research by the FAA to develop best practices for measuring the aircraft noise reduction of building façades resulted in the development of a new SAE Aerospace Recommended Practice (ARP) 6973, that provides additional details for application to practical situations. Like its predecessor, ASTM E966, the method requires the use of an outdoor loudspeaker. However, there are situations encountered in the field, such as areas with limited exterior space, where it is difficult to position a loudspeaker or to generate a uniform distribution of sound energy over the test façade.

To overcome these limitations, an alternative method for measuring noise reduction has been developed, with a loudspeaker placed inside the house and the noise reduction measured from the inside to the outside. This approach removes restrictions on the placement of an external loudspeaker. A feasibility study of such an indoor-to-outdoor test procedure for measuring noise reduction in buildings demonstrated the equivalence of the results with those of the standard outdoor-to-indoor method.

The goal of this project was to further develop the alternative indoor loudspeaker procedure with additional measurements in houses with special conditions, such as those with limited outdoor free space or attached porches, and to incorporate the methods into a revised version of SAE ARP 6973.