400-900-50 round silencer NRF (50mm insulation), ETS NORD

ETS NORD NRF 400-900-50 – round duct silencer with 50 mm mineral wool insulation
the ETS NORD NRF 400-900-50 is a high-performance round silencer designed for large-diameter 400 mm ventilation ducts, delivering maximum noise reduction without compromising airflow efficiency.
Engineered for demanding HVAC applications, this silencer features a 50 mm thick mineral wool sound absorption layer, a perforated galvanised steel inner tube, and a durable galvanized outer shell. Between the inner tube and insulation, a protective fabric lining prevents mineral fibre particles from entering the duct system, ensuring clean and safe airflow.

Technical information:
Connection diameter (d) Ø (mm): 400
Diameter “d1” (mm): 500
Length “L” (mm): 900
Insulation thickness (mm): 50
Weight (kg): 18.3
Fire resistance class: EI15, E60
Material: Galvanised steel sheet, mineral wool,

Key features and benefits
– Maximum noise attenuation – the 900 mm length and 50 mm mineral wool insulation provide superior sound suppression across a wide frequency range.
– Durable construction – perforated inner tube and robust galvanized steel casing resist corrosion and wear in long-term operation.
– Airtight sealing – factory-fitted rubber gasket ensures a secure, leak-free connection, reducing air leakage and pressure drop.
– Low airflow resistance – maintains optimal ventilation system performance while effectively dampening fan noise, regeneration sounds, and terminal unit noise.
– Quick installation – Simple to mount without adhesives or solvents, making it ideal for new installations or retrofits.
– Versatile applications – suitable for commercial buildings, industrial facilities, offices, and large residential HVAC systems.