In 1998, MRA was selected by the City of St. Louis Airport Authority to provide architectural/engineering design services for a pilot noise mitigation project. The goal of the project was to remediate the effects of aircraft noise for homes surrounding Lambert-St. Louis International Airport. This pilot program was undertaken to evaluate the effectiveness of sound insulation for 60 residential homes that are located within an area exposed to aircraft noise (the 65-70 DNL noise contour), but outside the buyout area. As a result of the pilot study and the improvements made to the participating homes, a reduction in aircraft noise of an average of five to ten decibels was achieved.

In 2002, the MRA team was selected by the Airport Authority to provide design services for the expansion of the full-scale Residential Noise Mitigation Program which assessed and remediated aircraft-generated noise in over 1,250 homes in a significantly enlarged target area. Each home was surveyed and an initial inspection done to evaluate its structure, composition, and arrangement. A recording of noise levels was then performed in various areas of the home. From this information, a scope of work was developed outlining the recommended modifications. Once these modifications were complete, a second acoustical evaluation was performed in each home to ensure that the desired reductions in aircraft noise are realized.

Some typical modifications made to homes as a result of the noise mitigation program were: replacement of windows and doors, both primes and storms, addition of attic insulation, and various sound baffling techniques. The program also includes inspection for hazardous materials and environmental abatement, where required.

MRA worked closely with Airport Authority personnel to develop the organizational and procedural framework for this project. As part of that effort, MRA created a Homeowner’s Manual which clearly explains the Sound Insulation Treatment portion of the Program and helps to guide the Owner through the steps in the process.

The project scope included the community of Pasadena Hills as a historic district in the State of MO and is listed on the National Register. The designation recognizes the beautiful architecture and landscape design that characterizes this early 20th century neighborhood. MRA worked closely with Missouri’s Department of Natural Resources State Historic Preservation Office (SHPO), Pasadena Hills community representatives and airport officials to assure that the renovations made to homes in this district conformed to SHPO requirements and at the same time, achieved the Noise Mitigation Program goals.