125mm Diameter Branch – 90 Degree Curved Boot – 125mm

Our galvanised spiral ducting range runs from 80mm up to 1000mm diameter, with 24 standard sizes in between including 100mm, 150mm, 200mm, 250mm, 300mm and 400mm. Matching bends, T-pieces, Y-pieces, reducers, connectors and end caps are available across the same sizes. You can browse the range in metric or imperial sizes using the site’s shop-by-size categories, whichever convention your drawings use.

All of our spiral ducting is supplied in 3 metre lengths, in every diameter from 80mm to 1000mm. For shorter runs, the duct can be cut down on site with standard metal-cutting tools and joined using male connectors. For longer runs, simply join multiple 3m lengths together with connectors, sealing each joint as you go.

Spiral duct is sized by its internal diameter, so a 200mm spiral duct has a 200mm bore. Fittings such as bends, reducers and connectors are made with male ends that fit inside the duct, which is why a 200mm fitting slots straight into 200mm duct. When matching to an existing system, measure the inside of the duct rather than the outside.

Push the male end of the fitting into the duct, fix it with self-tapping tek screws, then seal the joint with duct sealant or foil duct tape for an airtight finish. We stock tek screws, duct sealant, foil tape and gasket tape alongside the ducting. Support horizontal runs with split rings or suspension rings from our bracketry range at regular intervals.

Spiral ducting is the most common rigid ductwork for dust extraction, fume control, general ventilation and air conditioning. The galvanised steel construction is sturdy and long-lasting, and the full fittings range — bends, branches, reducers, access doors, silencers and terminations such as jet cowls and weather hats — lets you build a complete system from stock parts.

Yes — spiral ducting and standard fittings are stock items with next-day availability on most sizes; the exact lead time is shown on every product page. Delivery is free on orders over £400 excluding VAT, which most ductwork orders of any size reach comfortably. If you need help working out a parts list for your run, call us on 0116 246 0031.