High Velocity Ductwork — Maximum Air Through Minimum Space
High velocity ductwork moves air fast — above 20 m/s in some systems — squeezing maximum airflow through the smallest possible duct. It's the answer when riser space is measured in millimetres, and the traditional partner of VAV systems. At these pressures build quality is everything: we fabricate to the DW144 high pressure classification — the heaviest gauges, closest stiffening and fully sealed joints in the standard.
Where high velocity systems are specified
- VAV office systems — high pressure primaries to terminal boxes
- Deep risers in high-rise buildings where shaft space is critical
- Refurbishments threading new services through existing structure
- Process and industrial extract runs at high duty
Why circular duct dominates high velocity work
A round duct resists pressure evenly with no flat panels to drum, which is why spiral duct is the natural choice for high velocity primaries. We manufacture spiral tube and the full circular fittings range in-house, plus rectangular sections and transitions where the route demands them.
Tightness you can commission against
High pressure systems are routinely leakage-tested at commissioning. Every high velocity section leaves our workshop with sealed seams and protected ends, built to the classification your specification calls for. Send your drawings for a package price.
Frequently asked questions
What is high velocity ductwork?
Ductwork designed for the fastest air speeds in building ventilation — typically above 20 m/s — built to the DW144 high pressure classification. It delivers maximum airflow through minimum duct size, most commonly as the primary distribution of VAV systems.
Isn't high velocity ductwork noisy?
The duct itself must be built not to drum or leak — which is a fabrication quality issue — and the system design attenuates noise before air reaches occupied spaces, usually at VAV or terminal boxes. Our high pressure builds use the heavy gauges and stiffening the class demands.
Do you leakage-test high velocity ductwork?
Leakage testing is normally carried out at commissioning on the installed system. We fabricate to the DW144 high pressure class with fully sealed joints so the installed system can meet the leakage limits your specification sets.
Can you supply high velocity spiral and the fittings together?
Yes — spiral tube, bends, tees, reducers and the rectangular transitions where needed all come from the same workshop, made to match. Send your drawings for a package price.