Steam Leak Survey
Steam and condensate return lines (see
figure 4) are almost always readily visible with infrared imaging,
even when no notable problems exist. This is due to the fact
that no matter how good the insulation, there is always heat loss from
the lines which makes its way to the surface. Problem areas are
generally quite evident, having brighter infrared signatures
that exceed the norm.
Steam line faults normally appear as an overheated line or as a large
hotspot in the form of a bulge or balloon along the line. Overheated
lines often occur when the steam line is located in a conduit or
tunnel. If there is a leak in the line, it will heat up the conduit
with escaping steam. If a steam line is buried directly in the ground
with an insulating jacket, a leak will usually saturate the
insulation, rendering it largelyineffective and begin to transfer heat
into the ground around the leak, producing the classic bulge or
balloon-like hot area straddling the line.
Some leaks may show up as an overheated manhole or vault cover.
Manholes or vaults that contain leaking steam system control apparatus
will often heat the covers to warmer than normal temperatures.
Figure 4) IR thermograph showing a leaking steam line
(highlighted in red).