In the past, various acoustical methods for measuring noise level reduction have been used to ensure that acoustical treatments met the FAA’s noise reduction requirements. The recent issuance of the FAA’s Program Guidance Letter 12-09, Eligibility and Justification Requirements for Noise Insulation Projects, has required a re-examination of the methods used to determine whether existing interior noise levels are greater or less than 45 dB. Although the criteria for the design of dwelling modifications are fairly well-defined, there is no industry standard to guide measurement procedures to confirm a dwelling’s eligibility, which can result in inconsistencies when implementing airport sound insulation programs. Research is needed to gain a better understanding of the factors that lead to differences among measurement methods and to understand and minimize inaccuracies in estimating interior noise levels.
The objectives of this research are to: (1) identify and evaluate the accuracy of noise level reduction (NLR) measurement methods for noncompatible structures; (2) propose procedures to minimize the measurement inaccuracies of each method; and (3) develop a matrix to help program sponsors identify the most appropriate methodology for determining interior noise levels for their airport sound insulation program.