Circular silencers are installed in the duct work between spaces, which must provide noise reduction of air tolerated noise to at least match the sound transmission loss of the separating structure.

Outer Casing: Outer casings of standard circular silencers shall be made of lock former quality, galvanized steel, Type G90 (316/304 stainless steel, aluminum), in the following gauges:

OUTSIDE DIA. METAL GAUGE- (0-10”w.g+)
300-650mm: 22ga
675-1500mm: 18ga
1525-2100mm: 16ga

Inner Casing: Constructed of 0.7mm perforated pre galvanized sheet steel

Acoustic Infill: Filler material, except for reactive (no media) silencers shall be inorganic glass fiber of a proper density to obtain the specified acoustic performance and be packed under not less than 5% compression to eliminate voids due to vibration and settling. Material shall be inert, vermin and moisture proof.

End Connections: Tapped end ring inserts are standard, alternative connections, and would be spigot or rolled angle flanges.

Performance: A central pod is fitted, constructed from 0.7mm perforated pre-galvanized sheet steel with conical, domed or flat ends as appropriate constructed from pre galvanized sheet steel.