When it is needed
- The plant cannot reach rated load and the fan is suspected
- Pressure drop across the system has grown and nobody knows whether the fan or the duct is the cause
- Before an energy audit or a retrofit, to fix the baseline
- After a rotor change, a speed change or a duct modification, to confirm the result
- Acceptance testing of a new fan on a customer-specified standard
What we do
- Traverse the duct with a pitot tube or anemometer at a straight run upstream and downstream of the fan, following the plane and point count the standard calls for
- Record static and total pressure at inlet and outlet, speed with a tachometer, motor current and voltage, gas temperature and, where it matters, moisture and dust loading
- Reduce every reading to standard density so the result can be laid on the manufacturer's curve
- Plot the measured operating point against the fan curve and the system curve, and state where the fan is running: at the duty, to the left of it in stall, or to the right of it at high power
What you get
- A test report with the measured operating point, the reduced figures and the method used
- The fan curve with the measured point marked, so the gap between selection and reality is visible
- A statement of cause: fan, system or density
- Recommendations, which may be as small as a damper setting or as large as a rotor change
Standards: IS 4894, BS 848 Part I, or the customer's own test standard. The report states which was used.