very efficiently transmitted through the generally stiff, metallic and therefore resonant structures. One common way of overcoming the considerable nuisance this can cause for the occupants is by absorbing the vibration and actually converting it to heat using viscoelastic polymer materials, typically based on polyurethanes or acrylics. Over the past 20 years, Swedish Acoustic Products -- Swedac -- has built a track record in overcoming noise and vibration problems using this basic technology. Goran Falk, the company's technical director, claims it is possible to reduce noise levels by 50-70% with the right choice of materials and their effective application. "Although we have a range of standard products, the skill comes in knowing how best to use them. One also has to keep an open mind about modifying existing products or designing completely new solutions when the conditions require it," he says. Falk believes that sound and vibration suppression should be an integral element of the design of the structure as a whole and not an 'add-on'. For this reason, Swedac offers sound-damping engineering consultancy to ship and offshore platform designers and builders. The company has supplied over 200,000 m2 of sound-damping deck coverings over the past 15 years. These generally consist of a trowel-applied liquid polymer, which, when dry, is overlaid with an SBR latex concrete. If speed of application is an issue, the liquid-applied polymer can be replaced with an adhesively-bonded polymer sheet. Where the requirements are more stringent, for example, in laboratory areas, the company can offer a 'floating floor'. This comprises proprietary sound-damping PVP (plate/viscoelastic polymer/plate) laminate plates laid on top of 50mm of mineral wool (140-150 Kg/m3). The sound-damping plates, which were conceived by Swedac, consist of two layers of steel or aluminium, each 2 or 3 mm thick, separated by a thin layer of viscoelastic polymer. While the...