Complying with High Sound Isolation Requirements in Acoustics Standards when a Suspended Ceiling Extends Continuously Over Partial-Height Demising Walls

Résumé

An update is provided on an ongoing, multiyear, research program to develop lower cost, interior, building design approaches that comply with sound absorption and isolation criteria in acoustical standards, guidelines and rating systems.  An early phase showed the negative effects of noise flanking through typical lighting and air distribution penetrations in suspended ceilings on sound isolation when the demising walls stop at the ceiling height. A subsequent phase showed how optimal absorption and isolation levels can be achieved using lightweight, plenum barriers in combination with sound-absorptive, stone wool, ceilings. The current phase studied design approach and installation under worst case conditions ~ when the suspended acoustical ceiling runs continuously above the demising walls.  This is done when future relocation of the interior walls is anticipated.  In the past, this design approach typically did not comply with acoustic standards and resulted in unsatisfactory sound isolation. The findings of the current research phase show how high levels of sound isolation (STC 40-50+) can be achieved using 38 mm (1-1/2 inches) thick stone wool insulation as plenum barriers and standard, 16 mm (5/8 inch) thick, stone wool ceiling panels even when the ceiling grid runs continuously above the demising walls.