Testing and Commisioning AHU Tunnels

There are a number of ways of measuring air speed in a duct.

• The simplest one is the pitot tube and the manometer, by which the difference in pressure between the static streamline high pressure port and the low pressure port can be used to evaluate the speed of the air impinging on the high pressure port. Disruption to a duct of that size by introducing and using a device of that type would be minimal.
• The next more complicated one is a style of rotating blade that is driven by the air flow and spins in relation to the speed. The turn rate is picked up by a sensor and converted to a velocity reading that is displayed on the instrument.

AHU is air handling unit?

What instrument did you use?

An anemometer used to get an average would do,electronic or the type mentioned earlier,and then the maths.

Was your instrument calibrated?Firstly,ensure the figure is reliable.

It appears the velocity is low. Please check the recommended air velocity to be maintained in a.c areas .Generally velocity measurement of air is carried out by revolving vane anemometer. If you want direct measurement you can use hot wire anemometer. Manaomter, inclined manometer, pitot tube etc are some more air flow measuring instruments.

How were the measurements taken?

What is the current air velocity measurement?

Does the power measurement of the fan motor support the air volume supplied to the tunnel?

What is the pressure difference across the fan(s)? Does this match the design documents or is there a higher than expected pressure difference?

Dear Mirza

i am an iranian engineer active in subway tunnel ventilation.

we may exchange our experiences.

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