The Airwise AWSR150X3 is a 150mm diameter, 3-metre length of semi-rigid aluminium ventilation duct. Semi-rigid duct bridges the gap between standard flexible foil duct and rigid PVC or galvanised pipe - it is considerably stronger and more crush-resistant than plain aluminium flex yet can be bent by hand to navigate joists, beams, and other building obstacles, holding the formed shape permanently. The smooth, seamless inner bore keeps pressure drop low, and the duct connects to both round and oval duct systems without specialist tools. Supplied compressed to approximately 0.6m, it extends to the full 3m on site.

About Airwise: A leading UK and Ireland ventilation products supplier based in Tetbury, Gloucestershire - known for quality, integrity, and competitive pricing across the full spectrum of ventilation ducting, valves, and accessories.

150mm

Internal Diameter

3m

Extended Length

0.6m

Compressed Length

Aluminium/Polyester

Construction

Hand-Bendable

Shape-Retaining

Semi-Rigid vs Standard Flex: Standard aluminium foil flex is lightweight but easily crushed and does not hold bends. Semi-rigid duct holds any bend formed by hand - making it suitable for installations where the duct passes through or behind structures that could compress plain flex, and for runs where the duct needs to hold a specific routing shape long-term.

Install at Full Extended Length: Always extend semi-rigid duct to close to its natural fully-extended length before fixing in position. A partially compressed section dramatically increases pressure drop and can reduce extract rates below Part F minimums. Avoid tight bends - minimum bend radius should equal the duct diameter.

Key Features

Stronger Than Standard Aluminium Flex

The aluminium/polyester laminated construction is significantly more rigid and crush-resistant than single-layer plain foil flexible duct - retaining its circular cross-section under normal installation loads and incidental contact after installation.

Hand-Formed Shape Retention

The semi-rigid body can be bent by hand to navigate around structural obstacles - joists, beams, wall plates, and purlins - holding the formed angle permanently for a stable, professional installation.

Smooth Seamless Inner Surface

The seamless inner bore reduces turbulence and keeps pressure drop lower than corrugated flexible duct over the same run length - supporting adequate extract rates in longer flexible sections.

Connects to Round and Oval Duct

Compatible with both standard 150mm round duct fittings and 220×90mm oval duct systems, making it versatile across mixed-format ventilation installations.

3m Compressed to 0.6m

Compresses to just 0.6m for easy transport through access hatches and loft ladders, extending to the full 3m on-site without tools.

Cut to Length Without Special Tools

Can be trimmed to any required length using tin snips, a hacksaw, or a utility knife - minimising waste and reducing on-site tool requirements.

Specifications

SKU	AWSR150X3
Brand	Airwise
Diameter	150 mm
Extended Length	3,000 mm (3 m)
Compressed Length	Approx. 600 mm
Construction Material	Aluminium / polyester laminate
Inner Surface	Smooth, seamless
Colour	Silver
Compatible Systems	150mm round duct, 220x90mm oval duct (with adaptor)
Typical Applications	Fan-to-duct connections, routing through joists and beams, short flexible runs in rigid duct systems, retrofit ceiling void installation

Frequently Asked Questions

When should I choose semi-rigid over standard flexible duct?

Use semi-rigid duct where the duct runs through a space where it might be compressed after installation — between joists, in loft floor spaces, or behind plasterboard. Standard foil flex collapses easily in these situations; semi-rigid maintains its shape and airway under light loads.

Is this duct insulated?

No — the AWSR150X3 is non-insulated. In cold loft spaces or unheated voids where condensation is a concern, either use insulated flex (AWFDI series) for short connection runs, or wrap the semi-rigid section with duct lagging tape after installation to provide a thermal barrier.

What is the maximum run length recommended?

Keep individual semi-rigid sections to a maximum of 3m (the full roll length). For longer runs, switch to rigid duct — semi-rigid adds more resistance per metre than rigid PVC or galvanised pipe, particularly through bends.

How do I secure semi-rigid duct to a fan spigot or duct fitting?

Use a 150mm worm drive duct clip tightened over the duct end on the spigot — minimum 40mm engagement. For MVHR airtight sealing, follow up with aluminium foil tape over the joint.

Can this duct be used in MVHR systems?

Yes, for short connection and routing sections. For the main distribution runs, use rigid duct for lowest resistance. Semi-rigid duct is ideal for the final connection from main duct to the MVHR unit spigot, or for navigating specific obstacles within a predominantly rigid system.

Ventilation | Extractor Fans, MVHR & Mechanical Extract Systems