[ RadSafe ] Air Sample Pump Calibration

[Otto G. Raabe]

At 10:15 AM 12/16/2010, Harry Reynolds wrote:
>Can someone provide me with or point me to a guide document of some sort
>on the calibration of air sample pumps.
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Air sample airflow measure is a fundamental issue in air 
sampling  and is covered in many textbooks. For example, pages 
352-360 in "Aerosol Technology in Hazard Evaluation", Thomas T. 
Mercer, Academic Press 1973. For more details see 
http://www.nist.gov/calibrations/upload/sp250-49.pdf

The physical standard device for volumetric air flow sampling is a 
spirometer. However, for practical purposes a suitable precision 
volumetric laboratory-grade dry test meter with large face is the 
most dependable approach.  With each the total air flow is measured 
over a known time period to obtain the flow rate.  My pre-calibrated 
large-face precision dry gas meter came from American Meter 
http://www.elster-americanmeter.com/en/707.html

Calibrated dry gas meters come in various sizes such as 10L per 
revolution or 10 cubic feet per revolution. Samples must exceed 10 
revolutions to achieve accuracy of less than 1 %. In use it is 
essential that on side (inlet or outlet) be at ambient pressure (open 
to the air or set a ambient pressure).

Usually the dry gas meter its used to calibrate a secondary meter 
such as a spirometer or electronic flow meter, but a pressure drop 
correction is needed for air passing through a sample before it 
reaches the flow meter.


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Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
University of California
One Shields Avenue
Davis, CA 95616
E-Mail: ograabe at ucdavis.edu
Phone: (530) 752-7754   FAX: (530) 758-6140
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