Air flow meters measure air velocity, in meters per second (m/s) or feet per minute (ft/min). The measurements for air velocity must then be converted to air flow rate, in cubic meters per second (m 3/s) or cubic feet per minute (ft 3/min).
- Using an Alnor meter
- Using an air flow meter and a handmade air capture hood
The Alnor flow rate meter is a specialized instrument that can be used to directly measure air flow rate. It has an air capture hood, and is instrumented to measure air flow rate in m 3/s or ft 3/min. However, the Alnor meter is relatively expensive and lacks portability, even when folded.
A cost-effective and portable method to get reasonably accurate air flow rate measurements is to use a digital air flow meter that measures airflow velocity, and a handmade cardboard air capture hood. The accuracy of the measurements using the handmade air capture hood depends on the dimensions of the air hood, specifically the height, the placement of the air flow meter, and the air flow rates. Typically, measurements obtained using this method, with the height of the hood no less than 46 cm or 18 in, are accurate within 5-10% of those taken by a calibrated Alnor meter. A correction factor (CF) representing this discrepancy can be derived for a specific handmade air capture hood using an Alnor meter as calibration tool.
For detailed information on the recommended flow meter, the dimensions and fabrication of the hood, and the correction factor, contact your local Teradata Regional Technical Specialist (RTS), Teradata Customer Support, or Teradata Engineering.