RE: Copper Tubing on the Intake of CAMs

[Dan Hoffman <dhoffman@pangea-group.com>]

I would use as small a diameter as would be compatible with the sampling
device to minimize particle fallout in the intake lines.

-----Original Message-----
From: Michael S Ford [mailto:MFORD@pantex.com]
Sent: Tuesday, October 31, 2000 10:40 AM
To: Multiple recipients of list
Subject: RE: Copper Tubing on the Intake of CAMs


Just a bit of sanity check....

We usually don't use sampling lines larger than one or two inches in
diameter for aerosol sampling.

For a one inch line, the volumetric flow associated with a transport
velocity of 3500 fpm is about 19 cfm.  For a two inch line, the volumetric
flow rate is about 76 cfm.  For a half inch line, about 5 cfm.  

I don't know of too many facilities with CAM sampling in the 20 to 80 cfm
range, aside from Savannah River which may or may not sample through tubing
with the impactor CAMs (comments folks?).

Metal tubing can presents problems, especially in high humidity environments
where the sample stream may traverse significant temperature changes (e.g.,
outdoor to indoor).

A very good person to consult specifically concerning line losses is Dr.
Andy McFarland at Texas A&M University.  Jeff Whicker at Los Alamos has
discussed whether you should even be using sampling tubes - he and his
colleagues at LANL have studied that issue extensively over the last several
years.  Lastly, the DOE has an Air Monitoring User's Group that meets
annually (at least) to discuss air monitoring challenges throughout the
complex.  You can find a description of the group at

http://www.lrri.org/amug.htm

'Hope this helps,
v/r
Michael


>>> dhoffman@pangea-group.com wrote 30 Oct 00 11:23:33 AM >>>
The length of the line is not as critical as its diameter and the number of
bends/elbows.  In general, unless you are dealing with a particularly large
or dense particle, a transport velocity of 3500 fpm should keep the
particulates suspended in the copper tubing, with minimal line losses.  This
transport velocity is used as a guideline in the air pollution control
industry.  I'm sure a reference could be found without too much effort. The
velocity in your system could easily be estimated and compared to this
value. 

Dan Hoffman CIH,CSP,CHMM
Pangea Group 
St. Louis

-----Original Message-----
From: Dave Biela [mailto:BielaD@wvnsco.com] 
Sent: Friday, October 27, 2000 8:46 AM
To: Multiple recipients of list
Subject: Copper Tuping on the Intake of CAMs


We use copper tubing on some of our CAM intakes.  We usually stay below 6
feet, but have had a few a little longer.  Some questions came up during a
recent audit and I am looking for data from other sites that may use tubing
on their CAMs.

1.  How long of lengths?
2.  Testing that may have been done (ex particle size, line loss etc.)
3.  Any written guidance that might be out there.

Please respond directly, my e-mail is changing, but I will still receive
messages at the current address for a few weeks.

BielaD@wvnsco.com 
716-942-4423

Thank You
Dave Biela
 
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