Fan ratings quote total pressure, which is the sum of static pressure — the energy available to overcome duct, filter and process resistance — and dynamic, or velocity, pressure, the energy in the moving airstream. Most system resistance calculations are based on static pressure, so confusing the two is a common cause of undersized fan selection.
To specify correctly, add up the static losses across your ducts, bends, filters and process equipment, then select a fan whose total-pressure curve comfortably covers that figure at your required flow. Our high-pressure 9-26 series, for example, reaches up to 7,610 Pa total pressure for high-resistance systems such as forging furnaces, while the 4-72 handles low-resistance ventilation up to 5,200 Pa.
