Metal Flange

A steel flange is the fixed point a ventilation system starts from. You screw it to a wall, a ceiling, a cabinet or the body of an extractor, and then slide the ducting over it. This version is galvanised steel and comes in 100 to 250 mm.

Why this is the wrong place to save money

Everything downstream hangs off it. Ducting under suction pulls on its connection, and a flange that flexes or tears takes the whole run with it. Galvanised steel does not deform under negative pressure and does not rust away in air sitting above sixty percent humidity for months.

The rim is flat and pre-drilled, so four screws onto a flat surface hold it. If a gap remains between the flange and the wall, seal it: air entering there has not passed your filter.

Choosing the size

Take the same size as your ducting and your fan. A flange one size down from the rest of the run throttles the system at exactly the point you can least do anything about, because it is screwed down.

Available sizes

Technical Specifications:

• Material: galvanised steel
• Use: wall flange and flange spigot for ventilation work
• Connection: flexible ducting or spiral pipe slides over the rim
• Fixing: screwed through the flat rim

Frequently asked questions

Are screws included?
No. Which screw you need depends on the surface, so you choose those yourself.

How do I secure the ducting to it?
Slide the ducting over the rim and fix it with a worm clamp. Aluminium tape around it makes the joint airtight.

Can it go outdoors?
Galvanised steel handles damp well, but permanent weather and rain call for a stainless or plastic version.