20
OPERATION AND USE TIPS
S
HAPE OF THE
D
ETECTION
B
EAM AND
L
INE OF
S
IGHT
Another thing to consider is that the size of the beam can affect the reading
that the instrument gives, depending on the size of the plume.
Consider the picture to the right: the
green colored beam is roughly the
same size as the plume of gas, which
means that the instrument will be
reading only that plume. In the case
of the red beam, only half of it is
traveling through the plume, meaning
that the result on-screen is going to be
lower because part of what is being
analyzed is gas-free air.
What this means is that the distance
between the operator and the plume
can potentially affect the reading,
because the beam expands with
distance. Realistically, though, it is
unlikely to cause a noticeable effect
due to the gas plume naturally
dispersing over a (relatively) large
area. Where this might be more
noticeable is if the operator is far away
from a very small pinpoint leak. Most
of the beam will not be hitting the
plume, and will lower the reading.
In a real-
world scenario, a gas plume doesn’t have strictly defined edges like
this, and the operator obviousl
y won’t be aware of where it is to begin with.
However, what this illustrates is that technology of this nature makes it near-
impossible to get true quantitative results. There are simply too many
variables. Qualitative investigation and pinpointing is where it shines.
800
PPM
~400
PPM•M
800
PPM•M
1
M
E
T
E
R
Summary of Contents for GAS-TRAC LZ-30
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