RE: Altitude correction for Air Samplers

["Joe Alvarez" <jalvarez@auxier.com>]

What type flow meter are you using?  The correction depends upon the flow meter.  For example, a roto-meter will read high with altitude.

Joe Alvarez
Auxier & Assoc
jalvarez@auxier.com
-----Original Message-----
From:	Paul R. Steinmeyer [SMTP:prstein@gyral.com]
Sent:	Friday, May 08, 1998 2:50 PM
To:	Multiple recipients of list
Subject:	Altitude correction for Air Samplers

Hello Radsafers;

I need to use a high-volume air sampler at an elevation of about 7500
feet above sea level.  (It was calibrated in Hebron, Connecticut, at an
elevation of about 450 feet above sea level).

Do I need to apply a correction factor?  I called the manufacturer, and
they gave me a "temperature and pressure correction" calculation,
similar to one I already use to correct for local temperature and
weather conditions.  Based on some previous Radsafe discussions, I don't

think this would be appropriate for correcting for altitude.

In thinking about it, it seems to me that the flow meter ought to be
"self correcting," since the less-dense air will have a proportionately
lesser effect on the flow meter.

Can any of you folks either confirm this or disabuse me and send me in
the right direction for the correct answer?

Thanks in advance,

Paul R. Steinmeyer
Health Physicist
Radiation Safety Associates, Inc.
prstein@radpro.com