Why this ducting earns its place
Square flanges are the joints that connect ductwork. The 250 mm Combisteel flange is one of the smaller sizes — designed for lower-volume extraction runs in compact kitchens, snack bars, or as secondary branches off a larger main duct.
A 250 mm duct is right for applications where cooking intensity is light or where you're extracting from a single appliance. The flange provides a solid, airtight bolted joint between duct sections. It holds its shape under the modest static pressures of kitchen extraction and keeps air leakage to a minimum when properly installed.
In practice, 250 mm ductwork often works as part of a tiered system: small branch ducts (like this 250 mm) carry air from individual appliances or low-intensity zones, then step up to 300 mm, 350 mm or 400 mm as they feed into the main extraction run. This flange handles the connections wherever 250 mm duct meets 250 mm duct — at bends, joins, or drop points.
