Silencers

Circular duct silencers (attenuators) for spiral ducting systems, available in diameters of 100, 125, 150, 200, 250, 315 and 400mm, with longer 900mm versions on selected sizes for greater attenuation. A silencer drops into the duct run like a length of duct and absorbs fan and airflow noise before it reaches the rooms — or the neighbours.

Where to fit a duct silencer

The usual position is directly on the fan, on the side where noise matters most: between an inline fan and the supply grilles to quieten a living space, or on the discharge of an extract fan to protect the outside world. Larger installations often use one each side of the fan. Matching the silencer diameter to the duct keeps installation simple — its male ends push straight into spiral duct like any other spiral fitting. Where a bigger silencer than the duct is preferred, fit a reducer each end.

Choosing between lengths: the standard body suits most domestic and light commercial fans, while the 900mm-long versions give extra attenuation for noise-sensitive installations such as bedrooms, studios and offices. Stocked sizes ordered by 3pm are despatched for next-day delivery.