Rectangular Duct Silencer


The SLC and SRC rectangular duct silencers reduce the noise
level in ventilation and A/C systems. This silencer type is usually
installed between a fan and an air supply or exhaust duct,
and upstream of air supply vents.
All silencers are made of a housing and inner baffles. The
housing is made from galvanized steel sheet and its ends are
framed with steel sheet angles.
All baffles inside the silencer have a round breast at one end
and comprise a galvanized steel frame with a sound-insulating
insert which absorbs the acoustic energy from the air flow.
The sound-insulating insert is a set of non-flammable mineral
wool panels. The outer surface of the sound-insulating insert
is lined with a special abrasion-resistant textile to protect the
mineral wool from wear and tear. The mineral wool panels
are finished with a glass fibre lining in black; this lining is
suitable for systems with a maximum air flow rate of 20 m/s.
The maximum heat medium temperature is 250°C. The product
is non-flammable.

Silencers are applied for noise absorption during the operation of the fan spread along the ducting systems. Suitable for installation into round ducts. The silencer will reduces the noise level in the air duct.
The SIL consists of a polypropylene inner duct, thermally and acoustically insulated with a glass wool layer and provided with an aluminium laminate outer jacket. Both ends are taped to create ready-made connections.
NEN 13180 Fulfils all the requirements and are classified as specified within NEN 13180: “Ventilation for buildings – Ductwork – Dimensions and mechanical requirements for flexible ducts”


You will want to attach your silencer just after the fan in the extract duct run, to soak up any noise generated by the motor. Ideally it will be connected with a fast clamp to ensure a nicely sealed, air tight connection. Then simply connect your ducting as your normal and run it to the usual place.

Bear in mind that the acoustic foam will slightly reduce the air flow rates throughout your system. It will not be by much, but there will be a small drop in the overall airflow rates.

Also worth considering if noise is a concern is to make sure that your ducting is pulled as straight and as tightly as possible. Not only will this reduce any extra noise generated from turbulence in the ducting, it will also help to improve the overall air flow rates.


Z275 galvanized steel sheet

0.8 to 1.0 mm thick aluminium sheet

1.4301 stainless steel sheet

1.4404 stainless steel sheet

Other stainless steel sheet grades: please submit a request

for quotation to determine manufacturability.

Number of baffles:

Silencer with 1 baffle: 2
half-baffles at the duct sides
Silencer with 2 baffles: 1 full baffle + 2
half-baffles at the duct sides
Silencer with 3 baffles: 2 full baffles + 2 half-baffles at the

duct sides

Silencer with 5 baffles: 4 full baffles + 2 half-baffles at the

duct sides


Mineral wool: rock or glass wool; other insulators, e.g.

expanded PVC or as supplied by the customer.

Baffle thickness: 40 mm to 300 mm with type N3 lining or

type G9 washable lining.

Mineral wool density: 40 to 100 kg/m
The baffle front breast is curved to reduce the air flow

turbulence and pressure loss.


PQ frames: see the standard dimensions of square ducts.
versions are available on request.

Front-to-back baffles: stops 1 to 3 cm before the PQ angle

at the edge.


    Scope of interests

    Speed ControlEXTRACTION FANPartsSilencerDucts CustomaidFresh Air FanElectric-MotorAntivibration Chassis


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