Multi-family party wall design: A case study: Fid-Bau Portal

Multi-family party wall design: A case study

Hessler, G.F. jun.

Obtaining acoustical privacy between dwellings in a multi-family project is of paramount importance to the project owner and architect, as well as to future residents. Long-term success for a project in today's litigious environment cannot be assured without acceptable acoustical privacy between units. Recent home entertainment sound reproduction systems including three-loudspeaker sets with sub-woofer and five-loudspeaker home theater setups present new challenges for controlling the transmission of low frequency sound through party walls. The current sound transmission classification (STC) rating system alone is inadequate for controlling low frequency sound transmission between units. A simple supplemental music/mechanical transmission classification (MTC) rating is described and its use is recommended to specifically address the transmission of low frequency sounds. This paper describes a program for achieving high performance STC and MTC ratings using 'thin' drywall construction aided by an innovative preconstruction full scale mock-up test facility. The test facility was designed and constructed to duplicate project room sizes with real room-to-room sound transmission paths including those through the concrete floor and ceiling slabs. The critical importance of sound flanking paths is illustrated with comparative test results from the facility. Recommended minimum STC and MTC ratings are suggested to achieve acoustical privacy between dwelling units.