Low Velocity Ductwork — Quiet Air for Occupied Spaces
Most of the ductwork in an occupied building is low velocity: comfort ventilation moving air gently — typically up to around 10 m/s — so occupants hear nothing and feel no draughts. We fabricate low velocity rectangular and spiral ductwork to the DW144 low pressure classification, made to your exact sizes and priced online in minutes.
Where low velocity systems are the right choice
- Office supply and extract distribution
- Schools, colleges and public buildings
- Retail units and restaurants
- Final connections from fan coil units and air handling units to grilles and diffusers
Matched to the rest of your system
Low velocity runs are usually the final, occupant-facing stage of a system that may start at medium or high velocity from the plant. We manufacture all three classes from the same workshop, with made-to-measure transitions between them.
Made to DW144, sealed as standard
Every section is fabricated to the DW144 specification with the correct sheet gauge, stiffening and oil-based mastic sealed seams for its size and class — delivered protected, ready to hang, anywhere in the UK.
Frequently asked questions
What counts as low velocity ductwork?
Comfort ventilation systems designed around gentle air speeds — typically up to about 10 m/s in main ducts and slower in branches — corresponding to the DW144 low pressure classification. It's the standard for occupied spaces where noise matters.
Why choose low velocity over a smaller, faster system?
Slower air means less noise, lower pressure drop, smaller fans and lower running costs for the life of the building. The trade-off is duct size, so the choice usually comes down to the space available in ceiling voids and risers.
Can you supply both the low velocity duct and the fittings?
Yes — straights, bends, reducers, transitions, plenum boxes and grille connections all come from the same workshop, made to match. You can price most parts online for an instant figure.
Do you make the transitions between low and higher velocity sections?
Yes. Reducers, tapers and rectangular-to-round transitions between any classes and sizes are made to order, so primary distribution steps down cleanly to the low velocity stage.