Medium Velocity Ductwork — Primary Distribution, Properly Built
Medium velocity ductwork is the workhorse of primary air distribution: risers and main runs carrying air from plant at higher speeds — typically in the 10–20 m/s range — before stepping down to quieter low velocity branches near occupied spaces. Running faster means smaller ducts where space is scarcest.
Where medium velocity ductwork earns its place
- Riser ductwork in multi-storey offices and residential blocks
- Primary supply and extract from air handling plant
- Distribution through congested service corridors
- Systems feeding VAV boxes and fan coil units before the low velocity stage
Why the pressure class matters
As velocity and pressure rise, leaks grow disproportionately. DW144's medium pressure classification exists precisely for this: heavier gauges, closer stiffening and sealed joints keep the system tight so the air you pay to move actually arrives.
One workshop for the whole system
Most buildings mix classes — medium velocity risers feeding low velocity floors, sometimes with high velocity sections at the plant. Every class comes off the same brake presses, so flanges line up and the package arrives compatible. Send your specification for a package price.
Frequently asked questions
What is medium velocity ductwork?
Ductwork designed for the middle band of air speeds — broadly 10–20 m/s — used for primary distribution and risers, built to the DW144 medium pressure classification with heavier gauges and sealed joints to suit the higher operating pressure.
When would a project use medium rather than low velocity duct?
When space is tighter than silence: risers, congested corridors and long primary runs where a full-size low velocity duct won't fit. Noise is managed by stepping down to low velocity before the air reaches occupied spaces — and we make those transitions to order.
Is medium velocity ductwork more expensive to run?
It uses more fan energy per metre than low velocity duct, which is why good designs use it only where the space saving justifies it. A tightly sealed system — built to the correct DW144 class — keeps that penalty to a minimum.
Can you deliver a mixed-class ductwork package?
Yes — low, medium and high velocity sections, with the transitions between them, all manufactured in-house and delivered together. Send your specification and drawings for a package price.