Flexible acoustic screening material
The problem
In mining and similar industries, high noise levels can be emitted from equipment such as pumps, local ventilation fans or hand-operated tools. Noise reduction can be complicated as these types of equipment have to be quickly relocated as work moves. In addition, conventional rigid acoustic enclosures may not fit into the confined work space.
The solution
In such cases, the only practicable alternative is to surround the source (and the operator of hand-held tools) with an acoustic screen. The material used for the screening has to be:
- heavy enough to provide a reasonable transmission loss;
- flexible enough to mould itself to the contours of any confined space;
- portable;
- capable of meeting underground safety requirements such as anti-static and fire retardancy;
- reasonably robust.
One material developed for this purpose consists of a 5 kg/m2thin lead sheet, bonded to a 25 mm thick glass fibre mat and encased in a heavy-duty, quilted plastic cover. The material can be made up as individual curtains with metal reinforced eyelets along the top edge and industrial grade 'Velcro' strips along the side edges. The acoustic screen can then be made up by hanging the curtains on the wire hooks on a pre-strung cable or free-standing frame, and sealing them together with the edge strips.
Acoustic screen
The cost
£45 per square metre for the material. (1995)
The result
A noise reduction of 10 dB.
Source
Information supplied by The Noise Control Centre.