Sound Trap Housing
ABC's patented Sound Trap housing is unique in the air movement industry. The Sound-Trap housing offers an alternative to conventional add-on silencers, which add considerable length to the unit. Unlike conventional silencers, the sound trap housing is also effective for reducing sound radiated from the fan housing. In addition, there is no additional static pressure loss created with the Sound Trap design.
ABC's Sound Trap housing increases the fan length only slightly to reduce sound transmitted from the inlet and outlet. The Sound Trap housing is available on all ABC vane axial fans.
U.S. Patent 4,508,486. Canadian Patent 1,209,974.
Construction Features
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A perforated steel inner liner directs sound waves into
sound absorbing material between the inner liner and
solid steel outer shell converting acoustical energy to
heat.
Two inches of sound absorbing fiberglass is sandwiched between the inner and outer shell. The fiberglass meets requirements of NFPA 90A and 90B, ASTM C 1071 Type I and TIMA Standard AHC-101. The liner meets all requirements for 25 flame spread or 50 smoke development when tested in accordance with ASTM-E84, UL-723 and NFPA-255.
Steel bands seal the insulated cavity against pressure loss.
Sound Trap housing provides no additional pressure drop when compared to standard vane axial housings.
Typical Sound Power Attenuation
ABC Sound Trap construction effectively reduces inlet and outlet sound power levels in each of the eight octave bands as shown below.
| Octave Band | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| dB Reduction | 0 | 3 | 7 | 10 | 10 | 7 | 7 | 1 |
External Silencers
ABC also offers conventional external silencers, when maximum sound attenuation of the inlet and outlet airstream is required. ABC’s external silencers utilize a heavy duty perforated steel inner liner construction with sound absorbing insulation, and lifting
lugs in the 12 o’clock position.