Flexible Ducts

Flexible ventilation ducts bridge the points where a rigid duct does not fit: short connections to fans, hoods and air outlets, offsets in suspended ceilings or narrow shafts. The range includes flexible ducts from Blauberg and InoxAir along with matching connectors. They often connect units such as inline duct fans to the fixed duct network and decouple vibrations at the same time.

The versions

• Blauberg BlauFlex AF: aluminium foil laminated with polyester on a steel wire spiral, for residential, commercial and industrial ventilation.
• Blauberg BlauFlex in further versions such as AN, AM, PVC and the insulated Iso N.
• InoxAir aluminium flexible duct, single or double wall, and insulated as an acoustically damped Sono flexible duct.
• InoxAir flexible duct connectors (nipples) as well as duct and fitting connectors in galvanised steel.

Selection and installation

Choose the diameter to match the connection spigot. Insulated flexible ducts prevent condensation where warm and cold air meet, for example with outdoor air in heated rooms. Acoustically damped versions reduce noise between rooms, see our article on silencers in ventilation. Keep flexible ducts as short and straight as possible and free of kinks, because their ribbed inner surface causes more pressure loss than a smooth duct. For longer runs, rigid ducts from the ventilation ducts and fittings category are the better solution.

Frequently asked questions about flexible ducts

How do I attach a flexible duct to a spigot?

The flexible duct is pushed over the spigot or nipple and secured with a clamp. Additional sealing tape improves airtightness.

When do I need an insulated flexible duct?

When the duct runs through unheated areas or carries cold outdoor air, so that no condensation forms on the surface.

Can I shorten flexible ducts?

Yes, with a sharp knife or tin snips. The wire spiral is cut with side cutters.