Essentially sound absorption deals with the reverberation of sound within a space.
Sound will dissipate as it travels but reflects in a similar way to light, so once a sound, for example someone’s voice, reaches a wall, floor or ceiling, some of that sound will be reflected back into the space. Softer materials will absorb some of this energy, which will help prevent an echo and maintain sound clarity.
Different materials will react differently when sound contacts them, as a general rule a solid, dense material will reflect more sound back into an area than a softer one. As sound is reflected in much the same way as light, an environment such as an old hospital corridor (with all the walls, floor and ceiling being comprised of hard, solid materials) the sound will reflect off each surface, gradually dissipating. This can result in an ‘echoey’ environment and is obviously not acceptable in many areas that a suspended ceiling is required in.
There are numerous solutions to the problem; often a combination of which are implemented and can include rafts, wall panels, carpets and even free standing structures, although research has shown that ceilings have the biggest impact on the acoustic quality of open plan offices.
Ceiling tiles vary greatly in composition and pattern and by extension their acoustic performances are diverse. Many common tiles also have pinhole perforations on their face, which increase a tiles ability to absorb sound.
Each tile has a rating to demonstrate how good a sound absorber it is, measured in alpha waves: this rating is between 0.0 (no sound absorption) and 1.0 (100% sound absorption) but for ease of comparison, manufacturers tend to categorise tiles into 5 classes. These classes are denoted by letters – ranging from ‘A’ (best sound absorbers) to ‘E’ (poorest sound absorbers).
|Absorption Class||Guideline Rating||Absorption
|A||Outstanding||0.90; 0.95; 1.00||Call centres||CIS ROCA – Rockfon Alaksa|
|B||Excellent||0.80; 0.85||Classrooms, open-plan offices||CIS ROCX – Rockfon Artic|
|C||Good||0.60; 0.65; 0.70; 0.75||Standard office||CIS FF – Armstrong Fine Fissured
CIS SPIN 180 – Treetex Spintone 180
|D||Standard||0.30; 0.35; 0.40; 0.45; 0.50; 0.55||Private office||CIS SAH – Treetex Sahara Perforated
CIS DUS – Armstrong Dune Supreme
|E||Poor||0.15; 0.20; 0.25||Low acoustic criteria|
|0.00; 0.05; 0.10||No acoustic criteria|
Each tile on our website has a Sound absorption rating measured in alpha waves and NRC (Noise Reduction Coefficient) which represents the same property via a different unit.