I have used a tedlar bag in the past to sample suspected hydrocarbon
vapours (recorded by a GA2000 as methane) It turned out to be diesel,
which a PID had failed to pick up.
-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of steve
wilson
Sent: 29 May 2009 12:16
To: [log in to unmask]
Subject: Re: Inert landfill gas/hydrocarbon
Clive
The usual gas meters used to measure methane and carbon dioxide are not
FIDs
- they use an infrared detection system.
Also I am not sure that you can use Gresham tubes for sampling
hydrocarbon
vapours (as opposed to methane, ethane, etc) - maybe one of the
hydrocarbon
experts can put me right on this one!
Steve Wilson, Technical Director
EPG Limited
Tel 07971 277869
www.epg-ltd.co.uk
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-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of Clive
Williams
Sent: 29 May 2009 10:59
To: [log in to unmask]
Subject: Re: Inert landfill gas/hydrocarbon
A PID may not pick up less volatile components of your hydrocarbon. If
the hotspot you mention was diesel or oil and is quite old the PID will
have little chance of finding anything. An FID might pick more up - your
gas meter is probably an FID, but calibrated to methane. A gresham
tube or tedlar bag sample submitted to the lab for a detailed
hydrocarbon suite should clear the matter up.
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