ABSORBING NOISE

Wanganui Chronicle, Volume 72, Issue 90, 16 April 1929, Page 10

ABSORBING NOISE

QUIET IN OFFICES NEW USE FOR SEAWEED. LONDON, Fob. 5. London offices arc being made toler- ! able to work in by moans of a certain ! kind of seaweed. This is a little- : known industry developed since the war, mainly by an officer of the Royal Engineers. Board rooms, rooms and halls in hospitals and big schools, courthouses, and council chambers have been improved out of recognition in the matter of noise and echoes by this method, and the most striking example is the lofty banking hall of the Midland Bank' at their new headquarters in Cheapsido. Simplicity of System. Actually the sound expert does not come in contact with the. public at all, a s it is through architects that the system is installed, and this architect said that ho should, whenever possible, specify a sound-absorption system for .al city buildings, as the advantages -n reducing noise, and therefore the strain on working staffs, was undeniable The system seems simplicity itself, and not the least novel part is that it depends mainly upon the use as an absorbent packing of walls and ceilings with a seaweed gathered off the coasts of Nova Scotia Why seaweed should be transported the whole way across the Atlantic to make life more peaceful in the heart of London when there is plenty of seaweed of sorts around our coasts was explained. This eel grass, as it is called, is fireproof, non-vermin-ous and sound absorbent, and it grows to perfection only whore it is washed by frosh and salt water. If it is gathered from a sandv shore it is full of impurities, but off the Nova Scotian coasts it has ideal conditions and a rocky shore. As a result an industry has grown up there supplving America and England, and one London firm alone imports 50.000 square feet a. month. Tt comes over in the form of mats and is fixed to tlu* flat spaces of eoilings or along walls; thin wood battens are then nailed over it and upon this is stretched canvas which can be treated to suit any decorative scheme required. Sound-Absorbing Plaster. It is essential to avoid hard reflecting surfaces, hence the need for canvas. and whore it is not considerd advantageous to use the seaweed quilt, a special sound-absorbing plaster has been developed through the Department of Scientific and Industrial Research, while an artificial stone, also sound-absorbent, has also been qvolvod for this specialised work. Those materials act like a sponge; in fact their virtue lies in their porosity. Of course, more is involved than merely covering any flat surface haphazard and such study has been given to acoustics. Many experiments have shown that an average room will perpetuate a sound for from four to eight, seconds, and council chambers and lofty rooms not occupied by many people or crowded with furniture arc particularly had offenders in this respect. A reduction of the echo to about two seconds is usually neces-,