Noise Control - Rectangular Duct Attenuators - RS / RT Series

  Download PDF

 

Download pdf file
Rectangular Duct Attenuators (RS/RT Series)

Features

These notes apply to RS and RT type attenuators
Construction
The units are rigidly constructed and consist of a galvanised sheet metal casing containing a series of centre and side splitters. The casing is provided with Pittsburgh corner seams. End flanges have a red oxide finish and are not drilled as standard unless ordered with matching flanges. The splitters are filled with nonhygroscopic and incombustible material.
This material is covered with a gauze scrim and then further covered with galvanised perforated sheet metal. Where attenuators are exposed to the weather, all infill material shall be lined with an impervious film to prevent ingress on moisture. See page G-6 for selections from our Q-Seal range.
Standard attenuators are suitable for duct pressures up to 1kPa.
Attenuators suitable for higher pressures, or manufactured from special materials such as stainless steel or aluminium, are available on request. In addition special finishes such as epoxy coating can be provided.

Insertion Loss
The values quoted in the tables are defined as static insertion loss as defined in BS4718:1971, Methods of Test for Attenuators for Air Distribution System. Insertion losses greater than 50dB are not reported as their achievement in practice is difficult. The performance data is based on Australian-sourced and manufactured materials.

Insertion Loss
The values quoted in the tables are defined as static insertion loss as defined in BS4718:1971, Methods of Test for Attenuators for Air Distribution System.
Insertion losses greater than 50dB are not reported as their achievement in practice is difficult.
The performance data is based on Australian-sourced and manufactured materials.

Suggested Specification
Attenuators shall be as manufactured by Elta Fans and shall have the performance as scheduled. The casing shall be manufactured from high quality galvanised mild steel sheet with Pittsburgh corner seams. Mild steel end flanges shall be provided pop-riveted and sealed to the case. These shall be finished with zinc-rich primer or hotdipped galvanised after fabrication if requested.
Acoustic splitters shall have a semicircular inlet fairing with tapered discharge profile to minimise pressure drop and regenerated noise, similar to Q-Tech RT series. Where nominated, straight splitter attenuators can be used similar to Q-Tech RS series. Airways shall be straight and parallel. The infill material shall be either rockwool or fibreglass as specified by the manufacturer. The infill material shall be covered with a gauze scrim to prevent erosion of the fibres, then encased in galvanised perforated sheet metal Where attenuators are exposed to the weather they shall be of the Q-Seal type. All infill materials shall be lined with an impervious film to prevent the ingress of moisture. The infill material when tested in accordance with AS1530.3:1989 shall have the following indices:-
Ignitability 0
Spread of flame 0
Heat evolved 0
Smoke developed 0

 

Performance

Performance