When we discuss acoustics and ceilings, we tend to reference two core values: NRC and CAC.


NRC (Noise Reduction Coefficient) is a number that shows how much noise our ceiling tiles are tested to absorb, with a higher number having better absorption.

Without sound absorbing materials in a room, sound simply bounces around from one surface to the next, resulting in reverberation – or what we all perceive as noise.

That noise can be a mixture of voices, printers, phones ringing, air conditioners – all bouncing around together resulting in an unnecessary and uncomfortable distraction for those trying their best to work, learn or heal in the space.

If you have a busy open plan, its best to choose a ceiling tile with a high NRC (acoustic absorption) rating. We recommend an NRC rating of 0.70 to 0.90 depending on how many hard surfaces (such as hard flooring) and people are in the space.

If there are closed rooms, then a ceiling tile designed to both absorb sound & prevent it traveling to the adjacent area is recommended.

That’s where CAC comes into play.


CAC – Ceiling Attenuation Class measures a ceiling tile’s ability to block (attenuate) sound transmission from one room to the next through the ceiling (when/where these rooms share a common plenum).

If you have a closed office environment, we recommend choosing a ceiling that offers:

  • An NRC rating of 0.60 or higher depending on how many hard surfaces are in the room.
  • A CAC rating of 35 to 40 depending on how the rooms will be utilised.

Example: A higher CAC of 40 or more might be required where there is a boardroom next to a kitchen/lunchroom where people congregate.

Contact us or an AMF distributor for more information.