Polyline’s Fan Silencers are designed for the Underground Mining environment to provide ready inbuilt noise absorption.

High tech sound foam and sound barrier is critical to the fabrication process to lower noise volume.

An overall width of < 50mm is maintained, unlike conventional Rock Wall types (overall > 120mm). This means that the silencer outside diameter does not exceed the fan flange.

Silencers can be bolted end to end when mounting a fan in a restricted area such as a vent access wall. They are available in high visibility yellow.

Advantages of Polyline's Fan Silencers

Excellent in damp and salty environments, a superior to steel silencers

By using ‘closed cell’ foam and protective coating, we are able to produce a silencer which is impervious to moisture and dust, resulting in no maintenance.

This product can take severe impact and return to its original shape

Enables installation & removal an easier task to perform, especially in difficult locations

The overall diameter of the fan assembly is not increased by the silencer, preventing catch points in environments such as Underground Mining

With Polyline’s specialist fabrication capabilities in fan silencers, be sure to send us a message for a free estimate!

Polyduct Ventilation Fan Silencer close up
Polyduct Ventilation Fan Silencer
Fan Silencers
Polyduct Ventilation Fan Silencer
Stock CodeSilencer TypeLengthWeight
G001VH7131m –
G003HF 8041.2m
G004GAL 91.6m
G005ES 91.6m
G006HF 10041.6m
G008ABB 12201.6m
G009GAL 12.51.6m100kg
G010HF 12541.6m100kg
G011CC 1400Short 1.6m125kg
G012HF 1400Short 1.6m125kg
G013CC 1400Long 2m160kg
G014HF 1400Long 2m160kg
G015HF 1454Short 1.6m
G016HF 1454Long 2m

The following table details standard flange configurations that Polyline manufactures. Other configurations can be accommodated to suit your requirements.


Silencer Type‘A’ Case I.D.‘B’ Flange O.D.‘C’ Bolt P.C.D.‘D’ Hole Dia‘E’ No Holes
HF 8048048908411416
GAL 990410189602016
ES 9997111910602216
HF 10041005109310471416
ABB 12201232138512891820
GAL 12.51258140013302416
HF 12541260137013201820
CC 14001412155014902416
HF 14001400154214882216
HF 14541458160015301820
Vent Bag Adaptors
Polyduct Ventilation Bag adaptor

Vent Bag Adaptors are manufactured in various diameters and transitions as required.



Stock CodeSilencer TypeBag Adaptor Size
G030HF 804804-800
G031GAL 9900-915
G032GAL 9900-1067
G033ES 9900-915
G034ES 9900-1067
G035HF 10041004-1000
G036AF 12001200-1200
G037ABB 12201200-1200
G038GAL 12.51250-1200
G039HF 12541254-1200
G040CC 14001400-1400
G041HF 14001400-1400
G042HF 14541454-1400
Intake Cones
Polyduct Ventilation Intake Cones Intake Cones are manufactured in various diameters and transitions as required.
Stock Code Silencer Type
G017 700-762
G018 HF 804
G019 GAL 9
G020 ES 9
G021 HF 1004
G022 AF 1200
G023 ABB 1220
G024 GAL 12.5
G025 HF 1254
G026 CC 1400
G027 HF 1400
G028 HF 1454
Self-Regulating Fan Covers
Polyduct Ventilation Self regulating fan covers
Self regulating fan cover (fan on)

A simple configuration that bolts to the fan flange and automatically opens or closes with air flow from the fan.

Fan Silencer Test Results
Fan type tested: Twin 45 kW Howden
Silencer length: 1.8m each
Overall fan length: 4.9m (incl. intake/exhaust cones)
Silencer weight: Approx. 105kg (including bell and cone end fittings)
Average db(a) rating of fan unsilenced: 105.2db(a) at 1 metre (including line of sight at intake and exhaust)
Average db(a) rating silenced at 1 metre: 88.9 db(a) average (at 1 metre the reflective influences were negligible)
Average at 3 metres:  There was a significant reduction at 3 metres in the high 70 db(a). The amount reduced would be even greater in a free field condition whereas the actual test conditions included significant reflective surfaces (e.g. factory wall and plant machinery).
Noise level average reduction at 1 metre: 16.3 db(a) average decrease at 1 metre (inclusive of line of sight at intake and exhaust)

All tests were undertaken by Trevor Holland (Dip Mech Eng, Grad A.A.F.) from Industrial Noise Control Pty Ltd and duplicated using the same location and conditions.