100mm Round PVC Ducting Pipe

Frequently asked questions

What is 100mm round ducting?

100mm round ducting is rigid PVC duct with a 100mm diameter, also called 4 inch ducting. In the Domus range it is called EasiPipe 100. It suits bathroom, toilet and utility extract fans, standard cooker hoods and tumble dryer extract.

Is 100mm the same as 4 inch ducting?

Yes. 100mm is the metric size and 4 inch the imperial name for the same duct. Any fan, cooker hood or wall kit sold as 4 inch will fit 100mm ducting.

Rigid or flexible ducting?

Use rigid duct for the main run. It has lower resistance, makes air tight push fit joints and does not sag or collect grease and dust. Use flexible hose only for short final connections, ideally under 1m, pulled taut and clipped with a Jubilee clip.

How do I join 100mm duct?

Push the plain end of one length into the socket of the next, or use a straight connector to join two plain ends. Tape each joint with aluminium duct tape for an air tight seal, and support horizontal runs every 600 to 800mm so they do not sag.

Do I need to insulate the duct?

Yes, wherever the duct runs through a cold space such as an unheated loft. Warm moist air hitting a cold duct wall condenses inside and can drip back to the fan. Use Domus Thermal insulation shells on bends and wrap straight runs in duct insulation.

100mm round or 110 x 54mm flat?

They suit the same fans. Use 100mm round where there is room, as it is cheaper and has lower resistance. Use 110 x 54mm flat duct where depth is tight, such as above kitchen wall units or between joists.

How long can a 100mm duct run be?

It depends on the fan. Many 100mm extract fans allow around 6 to 12m of equivalent duct length. Each 90° bend adds about 1m and each 45° bend about 0.5m. If the run is too long, use fewer bends, step up to 125mm or choose a more powerful fan.