Casella CEL Sampling heads for personal dust sampling - Manual (Page 13)

5. GAS & VAPOUR
5.1 Sorbent Tubes
5.1.1 Sorbent Tubes & Holders
Sorbent Sampling can be undertaken by
drawing air through sorbent that is
contained within a tube.
The sorbent will vary depending
on the contaminant that must be
captured. One of the best recognised
systems for this is charcoal. Tube sizes
also vary according to the suspected
concentration present. It is always better
to user a larger size rather than smaller,
otherwise saturation of the sorbent could
be possible.
Examples of sorbent tubes are
shown in Figure 9.
Typically, the sorbent tube is
mounted in a tube holder (Figures 10 and 11) that is clipped within 30 cm of
the subject’s nose and mouth. Usually, clipping to the OUTSIDE of a breast
pocket will be the most convenient.
An arrow on the sorbent tube glass indicates the correct flow
direction. The tube is inserted into the holder with the arrow pointing
upwards. A flexible tube passes over the subject’s shoulder to connect the
top of the holder to a sampling pump worn on the belt.
A wide selection of tubes and tube holders can be supplied. For
additional information, please refer to the
Air Quality catalog and contact the Casella
CEL Sales Department.
Gas & Vapour
Figure 9: Sorbent tubes
Flow
Direction
Figure 10: Small sorbent
tube holder Part No. P109023
Figure 11: Large sorbent tube
holder Part No. P109024
Flow
Direction Flow
Direction
Page 13 of 24
SAMPLING HEADS AND ACCESSORIES
Users Guide