Online Ductulator
Fume Cupboard Duct Velocity Calculator
Duct Velocity: 0 m/s
Friction Loss: 0 Pa/m
BS EN 14175-3:2003
“Air velocities within the ducts should not exceed 7.5 m/s and where the noise level requirement is low, the air velocity should not exceed:
a) 5.0 m/s for single unit systems and branches to fume cupboards on multiple unit systems;
b) 5.5 m/s for main ducts within buildings;
c) 6.0 m/s for external ducts.
Air velocities exceeding 6.0 m/s may be necessary for fume cupboards intended for handling large quantities of aerosol or dust, in order to minimize the accumulation of deposits at bends and joints.”
This calculator helps you determine the air velocity in round PVC ducts used in fume cupboard systems. Either:
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Enter the Air Volume directly
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Input the Sash Width, Sash Height, and Face Velocity to calculate the Air Volume.
It then uses the specified Duct Diameter to compute the resulting Air Velocity. This tool is essential for ensuring compliance with safety standards and optimizing ventilation performance.
BS EN 14175-6 recommends a duct velocity of 7 m/s.
Friction loss per m needs to be used to aid selecting a suitable fan. This calculator uses the following assumptions:
- Temperature – 20°C
- Air Density – 1.2 kg/m³
- Friction Factor – 0.02 (This is a characteristic of smooth PVC duct)
