Technical Booklet G Resistance to the Passage of Sound·Page 72·3.42
Enclosure construction for ducts and pipes
Ducts and pipes passing through separating floors must be enclosed with material of at least 15 kg/m² mass per unit area, and either lined or wrapped with 25 mm unfaced mineral fibre.
The enclosure should be constructed of material having a mass per unit area of at least 15 kg/m2. Either line the enclosure or wrap the duct or pipe within the enclosure with 25 mm unfaced mineral fibre.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet G - Resistance to the Passage of Sound.pdf