Why this ducting earns its place
Square flanges are the core connectors in extraction systems — they join duct segments together and handle transitions between different parts of your run. The 350 mm Combisteel flange sits in the middle of the ducting range, making it the workhorse size for most commercial kitchens.
A 350 mm duct moves substantial air volumes without excessive velocity, which keeps noise down and efficiency up. This flange provides the rigid junction point where two pieces meet. It holds its shape under the static pressures of kitchen extraction, and the flange itself gives you a solid mounting surface for bolts or clamps that keep the connection airtight.
In most kitchens, you'll use 350 mm and 400 mm ductwork as your main run sizes. This flange handles the connections throughout — at bends, at drop points to individual appliances, where sections step down to smaller ducts, or at the transition into your filter or external outlet. Proper flange installation means minimal air leakage and extraction that actually does the job.
