Noise by definition is an unwanted sound. Sounds in the office come from a wide variety of sources from the click of keys on a keyboard to a pen dropping on a desk, voices and computer fans, heating and ventilation equipment, we all know the sounds there are.
With the increase in the amount of open offices, the effect can too easily be an increase in noise levels, and that affects productivity.
Too little background noise can result in poor privacy in conversations. There is a balance which will give enough noise to allow a degree of privacy but not enough to greatly affect productivity. Research by Kjellberg and Ladstrom in 1994 suggests a level of 45dBA-50dBA for an open office.
Inconsistent noise such as laughter, loud chatter vending machines and some office machinery can be loud enough to break concentration so staff need to be considerate and the office design needs to be such that noise producing equipment is isolated without being remote.
Sound travels through the air at approximately 750mph (332m/sec) so any sound will reach everyone in an office within a second of being produced. Sound can also be transmitted via objects such as floors, beams and walls when it will travel slower.
The different measures that can be taken against the sounds produced are to absorb or isolate it, in some cases it can be diffused. The characteristics of different materials mean they lend themselves to different applications.
Ceilings have the greatest effect of the sound quality in an open plan office. They can be sound absorbing and/or sound insulating, depending on the materials they are made of. Your office design needs to take into account whether to use the building soffit or a suspended ceiling.
Other services such as power conduits and ventilation tubes will need to be insulated against sound to avoid transmitting in to other areas.
A classic suspended ceiling, if made of light materials will naturally be a better sound absorber as the lighter materials used here have a better absorption rating. While here, it is worth mentioning that a material’s sound absorbing properties is rated from A-E with A being the best, so it depends on which tile specification is used. Also Where services pass through, attention should be paid, bagged or roll insulation can be used to minimise this.
Walls offer much less opportunity for sound absorption, they are broken up by doors, windows, storage cabinets and office machinery. Their contribution to noise control is more to do with insulation of sound, typical construction will normally be two layers of plasterboard and acoustic roll.
The exception to this may be in a pod or privacy booth where glass may be used which will insulate most of the sound but much of the privacy will be provided by the normal background noise. For ultimate sound isolation, the partitions need to pass through the suspended ceiling to the building soffit.
Raised access floors need careful management with attention paid to where services pass through, beneath partitions to continue the division downwards as well as where the floor meets the walls.
Floor coverings, although as large an area as the ceiling, do not typically proved as much absorption. Commercial carpet tile is often used which has a low absorption rating and the floor is hidden by desks, seating, storage and other equipment. Acoustic backed carpet tiles can make more difference. Hard tiles or wooden floors, though with great aesthetic value reflect noise and hard shoes make a lot of noise, stilettos should be banned here!