Conventional steel acoustic enclosures can reduce noise significantly but can sometimes restrict access. Careful design of the doors and how the product enters the enclosure can often overcome this. However, it can be difficult to define the exact access requirements for some machinery.
A company producing air-conditioning systems had two high-speed automatic presses generating A-weighted noise levels of up to 93 dB. The company wished to reduce the noise radiated to adjacent areas but needed to maintain all-round access.
The solution was to install a PVC strip enclosure around each machine. This consisted of a steel framework, approximately 7 m long x 7 m wide x 3 m high, from which 4 mm thick strips of clear PVC plastic were hung. The roof of the enclosure was made of a 75 mm thick acoustic tiled ceiling laid into a self-supporting grid system, and overlaid with PVC sheet.
Each strip was 400 mm wide with the fixing arranged so that each one overlapped its neighbours by 50%, effectively doubling the thickness of the enclosure wall. The strips were secured at the top into double aluminium tracks allowing sections to slide open, enabling product and personnel access at any point. The transparency of the enclosure was also considered to be an important safety feature by the company.
About £5000 (1995)
A noise reduction of about 10 dB.
Photographs courtesy of Dunham-Bush Limited. Enclosure supplied by Mainline Industrial Products Limited.