New Form INC

6.0 flanking transmission

Flanking transmission occurs when all airborne sound travels around dividing elements between two occupancies. The degree to which flanking transmission occurs depends on the floor / wall junction details and the quality of construction. Values of sound insulation given in this document assume that the surrounding elements have the same or better insulation values, and care must be taken to eliminate any possible bridging of acoustic insulation.

The following measures can be taken to reduce flanking transmission in structures incorporating composite floors:

Ensure that all gaps between the composite floor and separating walls are sealed. Dense mineral wool can be utilized and edges sealed.
Care must be taken to make sure that internal columns do not bridge the separating wall.
Construct ceiling spaces so that secondary / primary beams do not come in direct contact with plasterboard ceilings.
When structural beams come below ceiling lines, box beams with mineral wool and two layers of plasterboard lining. Take care that linings do not strut off or contact the steel beam concerned.
Prohibit the used of exposed steel beams in internal spaces.
Avoid any air paths through separating elements. Seal junctions at service openings.
Check that where two layers of plasterboard are used that joints are staggered from one layer to the next.

Where boarding is used on the floor, ensure that a 5mm gap occurs between skirting’s and flooring. Ensure that wall linings finish above finished floor and that any gaps are sealed with acoustic sealant.