This presentation looks at the BS and EN test standards for acoustic transmission, acoustic absorption, reaction to fire and fire resistance. It also clarifies various acoustic terminology, including Rw values Dnf, w values, Dnc, w values and DnT, W values and explains the fundamental differences between them. Included is an overview of methods of acoustic testing in both laboratory and site settings. Sound transmission paths via common ceiling voids, raised access floor voids and at partition abutment to durtain wall facades are explained. The presentation additionally highlights good design principles from an acoustic perspective for suspended ceilings and raised access floors, and also the potential performance limiting factors caused by other construction elements. There is focus on interfaces with curtain wall junctions for both New Build and refurbishment for interior fit-out projects as well as a view on the effects of workmanship on overall acoustic performance.