4.How do I calculate airflow (m³/min) and static pre
Designing an efficient dust collection system is a science. If your airflow is too low, dust settles in the ducts and causes blockages. If the static pressure is miscalculated, the fan will operate off its performance curve, wasting massive amounts of electricity.
Here is the step-by-step engineering guide to calculating these two critical parameters.
1. Calculating Airflow
Airflow (often measured in CMM, m³/min, or CFM) is the total volume of air required to capture and convey the dust. To calculate it, you need two values:
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Velocity: The speed of the air (m/s). You must choose the correct velocity based on the dust type to prevent it from settling.
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Area: The cross-sectional area of your duct or hood opening
Recommended Conveying Velocities:
| Dust Type | Recommended Velocity (m/s) | Example Applications |
| Light/Fine Dust | 10–14 m/s | Welding fumes, fine powders |
| Medium/General Dust | 15–18 m/s | Wood dust, plastic chips, grain |
| Heavy/Abrasive Dust | 18–22 m/s | Metal grinding, sand, foundry dust |
2. Calculating Static Pressure
Static pressure is the total resistance the fan must overcome to move the required airflow through the system. It is usually measured in Pascals (Pa) or millimeters of water gauge (mmAq).
Total Static Pressure is the sum of three main resistance components:
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Hood Entry Loss: The resistance created when air is pulled into the extraction hood.
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Duct Friction & Equivalent Length Loss: As air travels through straight ducts, elbows, and Y-branches, friction slows it down. Every elbow has an "equivalent length" of straight duct that must be added to the calculation.
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Equipment Resistance: The pressure drop across the filter media (e.g., when the filter is loaded with dust) and other components like spark arrestors or cyclones.
3. Bridging Calculation with Real-World Performance
Calculations on paper must translate to reliable real-world operations. At YU-CHA, our systems are engineered and verified . This ensures that the theoretical system curve perfectly matches the fan's performance curve, delivering precise suction without energy waste.
Before finalizing your duct layout, always add a 10% to 20% safety margin to your static pressure calculations to account for future filter loading and minor duct modifications.