Sound is a far more common physiological stressor than most people realise.
Hard to identify noises at high or prolonged levels are rare in nature. However, poor acoustics in offices, even at low levels, leads to ‘blurred’ sounds, raised voices, distraction, and thus increased measurable levels of stress hormones. Artificial noises generated by lifts, office equipment and so on tend to cause the body to continuously tense and relax.
Poor sound design often means straining to hear your telephone call whilst being over-aware of what’s being said on the other side of the office. A series of hard flat surfaces (office walls and ceilings ) bounces sound waves into a series of chaotic reflections that are hard to interpret.
The acoustic problems in many modern offices are due to the fact that they are steel frame concrete and glass boxes with a 99% sound reflective capability. Adding the reflectivity of other hard surfaces in the office, makes acoustic resonance a major problem in most offices. It can take over one second for the echo of a sound to decay. This means that in a 10 metre wide office one pulse of sound can be reflected back and forth 30 times before it dies.
Suspended ceilings and plenum floors can exacerbate the problem by making the floor and ceiling void act as a sounding box. The bitumen backing of a carpet also acts as a sound reflector. Even foam-backed carpets only absorb impact sounds. Open cell polyurethane foam backing can create other problems by delaminating and or absorbing spillages. The combination of suitably dense pile and an integrated closed cell polyvinyl backing can produce an acceptable sound absorbent surface. Since floor and ceiling are the two largest potential sound reflective surfaces even a modest increase in sound absorption or reduction in the NRC (Noise Reduction Coefficient) can have a significant effect. This can be effected by sound absorbent ceiling tiles and carpeting. Carpeting needs to be of continuous filament construction to avoid delamination and have anti static,anti fungal and anti microbial properties. Vertical sound absorbing panels also help to reduce sound reverbration levels to those found in nature.
It is not just the volume of sound that can cause stress. It is the pattern of the frequency. A major source of muscle tension is machine generated sounds, which are tuned out by the conscious mind but interpreted as a potential threat by the sub conscious mind, which governs the fight or flight hormones.