How do I measure air flow inside a duct?
How do I measure air flow inside a duct?
(OP)
Friends, can you suggest what portable instrument is suitable for measuring air-flow rate in a duct?
Somebody tells me that a single point measurement in the centre of the duct is not a correct figure because the air speed is not uniform in a duct.
For an old duct, I can foresee problem because of few constraint,eg:
1. If I put my hand(which carries the measuring instrument) into the air duct, I cannot close the opening anymore.
2. If I have a small probe that can insert through a small hole, I can't make multiple measurements in order to get average value(unless I make many holes on the duct wall).
Somebody tells me that a single point measurement in the centre of the duct is not a correct figure because the air speed is not uniform in a duct.
For an old duct, I can foresee problem because of few constraint,eg:
1. If I put my hand(which carries the measuring instrument) into the air duct, I cannot close the opening anymore.
2. If I have a small probe that can insert through a small hole, I can't make multiple measurements in order to get average value(unless I make many holes on the duct wall).





RE: How do I measure air flow inside a duct?
http://www.flowmeterdirectory.com/flowmeter_artc/flowmeter_artc_02111201.html
RE: How do I measure air flow inside a duct?
I will try to read and see if it can help me.
RE: How do I measure air flow inside a duct?
RE: How do I measure air flow inside a duct?
I know that ASHRAE textbooks have a proceedure for taking the measurement, but I don't have them on me right now to verify which one.
RE: How do I measure air flow inside a duct?
Or use an anenometer at the outlet
If this is the only duct off a heater, use temp rise calculation to get airflow.
RE: How do I measure air flow inside a duct?
There are lots of portable air flow/velocity tools out there. A company called Dwyer Instruments carries a few models (www.dwyer-inst.com) of anemometer type devices that are easy to use and digital.
KevinF
RE: How do I measure air flow inside a duct?
Drapes