A perforated liner sheet is often specified when there is a requirement to reduce the levels of reflected sound inside the building. This will improve the sound quality and clarity inside the building and reduce the overall noise levels. The perforations in the liner sheet allow the airborne noise to more easily penetrate the cladding. This effectively reduces the airborne sound reduction index. The liner sheet can be either fully perforated or the perforated area can be limited to the profile troughs.
The size, pattern and total area of perforation can vary between different systems. Increasing the level of perforation will generally reduce the airborne sound reduction index and increase the sound absorption coefficient. Coverworld’s standard perforated pattern is an R3T5, this means that the holes are 3mm in diameter in a triangular pattern at 5mm pitch.