Home / Application Guides / Article 26 Either of Two Methods Used to Measure Air Velocity To measure air velocity, connect a Series 2000 Magnehelic® Differential Pressure Gage, Series 2-5000 Minihelic® II Differential Pressure Gage, or Series 100 AV Durablock® Inclined Manometer to a Series 160 Stainless Steel Pitot Tube in the air stream as shown. The alternative method at right requires only a static tap plus a simple tube in center of duct to pick up total pressure. The differential pressure reading on the gage or manometer is velocity pressure, which may be converted to air velocity by calculation or reference to conversion chart. Where air density is known, the gage manometer can also be calibrated directly in velocity units. If you need an alarm or control function to maintain a preset air velocity limit, install a Series A3000 Photohelic® Switch/Gage. Stainless steel Pitot tubes are made in numerous lengths and configurations to serve in the smallest to the largest duct size.