TSI / Airflow | Pitot tube | Telescopic

Contact Instrument Solutions

Available to buy of hire is the TSI / Airflow telescopic Pitot tube - extends to 980 mm maximum length


The Pitot static tube is a universally accepted means of establishing air velocity in ducts not fitted with permanent flow monitoring devices. When used with a high quality manometer the accuracy and dependability of results is far greater than with any non-fundamental method.


An important advantage of the telescopic pitot static tube is that it is only necessary to drill a few small access holes in the duct at the point where the flow measurement is to be made, and this feature makes the method the unquestioned choice for site work, where time and access is at a premium and a large number of in-duct measurements may have to be made at different points in the system.

By comparison with some other velocity indicating devices, the pitot static tube and manometer has a further advantage in that no flow of air passes through the instrument. This eliminates worries about pressure drop through the tubes to the indicating instrument, and for practical purposes there is no limit to the distance between the pitot tube and the manometer.

The shape of the nose, the size, number and position of the pressure holes etc, are all critical in determining the characteristics of the finished pitot tube and the modified ellipsoidal nose form used in TSI / Airflow tubes is recommended in BS ISO 3966 : 2008. This design was originally evolved by the U.K. National Physical Laboratory and is outstanding for its combination of high accuracy with insensitivity to errors in alignment. The calibration factor is very close to unity (0.997).


  • Durable and robust for on site conditions up to 100 °C
  • Air velocity/temperature calculator supplied
  • Telescopic probe with range 200 mm to 980 mm long
  • Carrying case supplied


  • Compatible with all micromanometers
  • Compact probe with maximum portability and high accuracy
  • Telescopic sections can be used as insertion depth markers
  • No limit to the distance between the pitot tube and the measurement device


  • HVAC commissioning
  • Process control lines
  • Combustion efficiency tests


Minimum overall length (compressed)      200 mm

Maximum overall length (extended)       980 mm

Maximum tube diameter      13 mm

Overall head length      64 mm

Head diameter       4 mm

Maximum working temperature      100 °C

Demonstration videos

TSI training video - How to set an instrument up do a duct traverse
TSI training video - How to perform a duct traverse

Support documents

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TSI Air velocity & volume application note.pdf TSI Air velocity & volume application note
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