Circular Acoustic Attenuators

Circular Acoustic Attenuators

Technical description

Function

The circular attenuators are specifically designed to reduce duct borne noise generated by axial or centrifugal fans, dampers or any other source of noise within a ventilation system. They are also recommended for use in the reduction of noise caused by generators, compressors or other similar rotating equipment. The wide flexibility in the choice of materials permit the attenuators to be installed in a variety of situations. They are suitable for ventilated areas, and are recommended for use in corrosive conditions, heavy and light industrial atmospheres, shipping and offshore installations. Special consideration is given to the design of all units which are to be used in environments of high humidity, pollution or high temperatures. Although the attenuators are primarily designed for operation close to atmospheric pressure, they may be designed for pressures up to 20 bar. All silencers are engineered to achieve a maximum insertion loss with a minimum pressure drop.

Construction

Description & Construction

  1. Infill: The infill is inorganic mineral wool or glass fiber rigid slabs with a glass fiber tissue face to limit fiber erosion. The fiber is inert, vermin, rot and moisture proof, non-combustible and does not support bacteriological growth, packed to a density of not less than 45 kg/m³. The infill has been tested for fire and has a Class spread of flame (as measured to BS476: Part 7: 1971).
  2. Sizes: Attenuators may be supplied in sections for site assembly by others as required, or as advised by HSE. Nuts, bolts and washers to be supplied by others
  3. Acoustic Performance: The attenuators have been tested in accordance with BS4718 1971 by an independent consultant. The test procedure eliminates effects due to end reflection, directivity, flanking transmission, standing waves and test chamber sound absorption.
Dimensions Frequency
Dia Length 63 125 250 500 1k 2k 4k 8k
310 300 1 3 5 9 13 10 8 7
350 300 2 3 5 9 13 10 8 7
400 600 2 3 5 9 13 10 8 7
450 600 2 3 5 10 13 10 8 7
500 600 2 3 6 10 14 10 8 7
560 600 2 4 6 10 14 10 8 7
630 600 3 4 7 13 14 9 8 6
710 900 3 4 8 14 14 9 7 6
800 900 3 4 8 14 13 9 7 6
900 1150 3 4 9 14 13 8 7 6
1000 1150 3 4 9 14 12 8 7 6
1250 1150 3 4 10 13 12 8 6 6
1400 1150 3 5 10 13 11 8 5 5
1600 1800 4 6 11 13 10 7 5 5
1800 1800 4 6 11 13 10 6 5 5
2000 1800 4 6 11 13 9 6 5 5