The Casavent SRD-90-50 is a 90mm diameter radial semi-rigid air duct supplied as a 50 metre coil, designed for higher-airflow MVHR (Mechanical Ventilation with Heat Recovery) and MEV radial ductwork installations in residential properties. Built with the same dual-layer HDPE construction as the smaller-diameter version in the range, it combines a corrugated outer layer for mechanical strength and flexibility with a smooth inner bore enriched with an antistatic and antimicrobial additive that reduces electrostatic tension and minimises dust accumulation.
Radial ductwork runs individual duct lengths from a central manifold or distribution box directly to each supply or extract point. The 90mm size is typically specified where higher air volumes are required per duct run, reducing the number of parallel runs needed for larger rooms or higher-capacity systems.
90mm
Outside Diameter
76mm
Internal Diameter
50m
Coil Length
330mm
Bending Radius
366N
Compression Strength
-25°C to +90°C
Service Temperature
System Component
This is a radial (semi-rigid) duct, not flexible insulated hose. It requires manifold/distribution boxes, plenums, flanges, lock rings and sealing rings (sold separately) to complete a working system.
Higher Airflow Capacity
The larger 90mm bore supports greater air volumes per duct run than the 75mm size, useful for larger rooms, kitchens, or higher-capacity MVHR/MEV systems where fewer, larger duct runs are preferred.
Antimicrobial & Antistatic Inner Bore
The smooth inner layer is enriched with a highly effective antistatic and antimicrobial additive that significantly reduces surface electrostatic tension, minimising the attraction and build-up of dust particles along the duct walls.
330mm Bending Radius
A defined 330mm bending radius allows the duct to form gradual bends through joists and service voids without kinking or restricting the internal bore.
Corrugated Outer Layer
The dual-layer HDPE construction gives the duct excellent mechanical strength and resistance to deformation, allowing it to withstand demanding operating conditions while remaining easy to handle and install.
Wide Service Temperature Range
Rated from -25°C to +90°C, the duct is suited to the temperature range typically encountered in loft voids, external walls, and ducted MVHR/MEV supply and extract runs.
Wide Mounting Flexibility
As a semi-rigid radial duct, it is designed for ceiling, floor, or wall mounting, giving installers more routing options than fully rigid ductwork through a building's fabric.
Compatible System Accessories
This duct connects to 90mm manifold boxes, plenums, round flanges, lock rings and sealing rings to form a complete radial system. These components are sold separately — check compatible accessories before ordering.
Product Overview
Brand
Casavent
Product Code
SRD-90-50
Description
Radial Semi-Rigid Ducting, Anti-Microbial & Anti-Static, 90mm x 50m Coil
Approx. 3 Pa (see manufacturer airflow/pressure chart)
Application
Use
Supply and exhaust ductwork for radial MVHR/MEV systems in residential premises
Installation
Ceiling, floor, or wall mounted; suspended ceilings and ceiling voids
Airflow & Pressure Performance
Pressure difference across the duct rises with airflow rate, as shown on the manufacturer's performance chart. The 90mm duct's larger bore gives it a lower pressure drop than the 75mm duct at the same airflow rate, which is the main practical advantage of stepping up a size on longer or higher-volume runs. Refer to the full chart for intermediate values when sizing a system.
What is the internal diameter of the 90mm duct?
The outside diameter is 90mm, with an internal bore diameter of 76mm.
What is the bending radius for this duct?
The bending radius for the 90mm duct is 330mm. Bending tighter than this can restrict airflow and stress the duct wall.
How does the 90mm duct compare to the 75mm duct?
The 90mm duct has a larger internal bore, giving it a lower pressure drop at the same airflow rate and making it better suited to longer runs or higher-volume supply/extract points. It has a slightly wider bending radius (330mm vs 290mm) and marginally lower compression strength (366N vs 394N) than the 75mm duct.
What does the antimicrobial and antistatic lining do?
The inner bore is treated with an additive that reduces surface electrostatic tension, which in turn minimises the attraction and build-up of dust particles inside the duct over time.
Can this duct be used for both supply and extract air?
Yes. This radial semi-rigid duct is suitable for both supply and exhaust/extract runs in residential MVHR and MEV systems.
What accessories do I need to complete a system with this duct?
A complete radial run typically needs a manifold or distribution box, a plenum or round flange with lock ring, and a sealing ring for an airtight connection, all sized for 90mm. These are sold separately.
What temperature range is the duct rated for?
The duct has a service temperature range of -25°C to +90°C, suitable for typical loft void, wall, and ducted MVHR/MEV installation conditions.
