Listen to this!

John Spicer, technical sales manager for Armstrong Ceilings, advises seven things architects may not necessarily know about specifying ceilings

Ceilings are capable of so much more than just disguising a soffit or void. They can optimise acoustics and occupant well-being in general, help save energy by reducing a building’s reliance on artificial light, and contribute towards clients’ sustainability targets.

They have evolved from standard white mineral tiles into a kaleidoscope of colours, materials such as metal and wood, and shapes such as round and oval canopies, even curved mineral baffles and wall panels:

1 – Acoustically, any room will have an optimum reverberation time (RT) requirement depending upon its use and size and whether the main activity is speech or music based. Providing too much sound absorption, and hence having a very low RT, can be just as acoustically damaging and undesirable as having insufficient sound absorption when an excessively long reverberation time will result. Office workers improve their focus on tasks by 48 per cent when speech privacy is improved.

2 – You can calculate the reverberation time of space by using a mathematical model based upon the “Sabine” formula which takes into account the significant surfaces of a room, their respective sound absorption coefficients and the room dimensions. An acoustic module available from some manufacturers enables a simple indicative calculation to be made. Once the total sound absorption present in a room (from both planar surfaces and objects) has been calculated, an estimate can be made of the room’s probable reverberation time. The installation of clouds, canopies and baffles in a reverberant space can significantly reduce the reverberation time and contribute to the reduction in background noise.

3 – The increased use of concrete thermal slabs as heat sinks rules out wall-to-wall ceilings. But not having an acoustic ceiling will mean higher reverberation times and unacceptable noise levels. The installation of canopies and baffles in a reverberant space, in sufficient numbers and layout to satisfy both technical and aesthetic considerations, can significantly reduce the reverberation time and contribute to the reduction in background noise and occupants’ comfort and well-being.

4 – According to a 2006 Brinjac Engineering study on the environmental effect of high-light reflectance ceilings, the use of a 90 per cent light reflectance ceiling tile combined with indirect lighting can provide cost savings of up to 20 per cent, equating to as much as an 11 per cent reduction of the energy buildings use, compared with a standard 75 per cent light reflectance tile. Canopies installed over an individual working place can improve the light reflection over that space and provide improved user comfort without affecting other areas.

5 – It is now possible to calculate (according to ISO 14021) exactly what degree of recycled content a ceiling tile comprises, and recycling schemes such as those for the off-cuts from new installations and end-of-life tiles from refurb- ishment and strip out projects, both of which divert waste from landfill, will increase this ratio exponentially. Some ceiling tiles comprise more than 70 per cent recycled material and some ceil- ing systems are capable of achieving an Ecopoints rating of 0.16.

6 – Standard ceiling tiles can not only be used to hide or integrate service elements such as lighting fixtures, loudspeakers, air diffusers, chilled beams and sprinkler systems, but provide minimal grid visibility for a clean and monolithic ceiling finish. The system can also be integrated into canopies to offer design solutions for thermal mass and is flexible enough to allow the re-configuring of room layouts and service element positions without moving ceiling panels.

7 – Fire resistance in a suspended ceiling can only be achieved by a combined tile and grid system as there is no such thing as a fire resistant tile or a fire resistant grid. Depending upon national legislation, the type of structure to be protected (steel, wood or mezzanine) and a manufacturer’s product offer, ceiling systems can typically provide at least 30 and more than 60 minutes’ protection. Full details of the ceiling type and construction, protected structure and tested time are given in fire reports available from the manufacturer.

Far from perhaps being perceived as the poor relation of a new-build, fit-out or refurbishment, they are now capable of delivering stunning aesthetics that also meet onerous acoustic, thermal and sustainability requirements.