125-900-50 round silencer NRF (50mm insulation), ETS NORD

The ETS NORD NRF 125-900-50 round silencer offers superior noise attenuation for 125 mm ducts, with an extended 900 mm length for maximum sound absorption. It features 50 mm mineral wool insulation, a perforated galvanised steel inner tube, and a durable outer casing.
A protective fabric layer prevents insulation fibres from entering the airflow.
Engineered to airtightness class D and fitted with a rubber gasket, it reduces air leakage and pressure drops, improving system efficiency. This silencer is ideal for HVAC applications where low noise levels are essential—residential homes, offices, restaurants, and commercial buildings.
Its longer design delivers enhanced attenuation across a wide frequency range, effectively reducing fan noise, duct regeneration noise, and terminal unit noise. Simple to install without adhesives or solvents, the NRF 125-900-50 is a top choice for quiet, energy-efficient ventilation systems.

Technical Information:
Connection diameter (d) Ø (mm): 125
Diameter “d1” (mm): 225
Length “L” (mm): 900
Insulation thickness (mm): 50
Weight (kg): 6.2
Fire resistance class: EI15, EI60
Material: Galvanised steel sheet, mineral wool

For greater noise reduction, multiple silencers can be installed in series.
The most effective noise reduction is achieved when the silencer is installed directly behind the fan or a duct elbow.