Technical Booklet G Resistance to the Passage of Sound·Page 100·4.44
Junctions with floor penetrations in conversions
Piped services and ducts passing through separating floors in conversions must be surrounded with sound absorbent material and enclosed in a duct above and below the floor, with joints sealed.
Piped services (excluding gas pipes) and ducts which pass through separating floors in conversions should be surrounded with sound absorbent material for their full height and enclosed in a duct above and below the floor.
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