Claims personnel are often called to a building with a large loss caused by water leakage from under- ground water piping systems. Investigating the cause is an integral part of the claims adjustment
process since it bears on insurance coverage as well as potential
subrogation. The first step is finding the source of the water and
determining the nature of the leak.
Photographing the source and documenting the circumstances of the leakage are helpful for those who will be performing a
more detailed analysis of the problem.
The following case study illustrates a water leakage loss as a
result of a failed underground pipe. Figure 1 is a photograph of
a large industrial building that sustained a substantial water loss
from a failed four-inch water pipe near an exterior wall. The underground pipe was sufficiently close to the exterior wall that once
the leakage occurred, the water was able to enter the building,
causing significant water damage to the products and machinery.
Figure 2 is a view of the opening in the pipe that was the source
of the leakage. There was severe localized corrosion in the pipe
wall in this area. As shown in Figure 3, the corrosion was not
occurring along the entire length of the pipe underground. At
approximately five inches on each side of the hole, the wall of the
pipe was in good condition with no decrease in wall thickness
There was no active corrosion control in the form of DC voltage control or sacrificial anodes. There was no protective wrapping or coating on the iron pipe. This type of corrosive attack is
characteristic of electrical current flow to ground. It is not uncommon to use a piping system as a ground for electrical equipment in a plant. What happens is that the electrical current flows
along the pipe and may exit randomly at a location in the soil
which is conductive and at a lower voltage. This results in rapid
corrosion of the exterior of the pipe in a localized area, which
was the issue in this case.
Corrosion control on this particular piping system was lack-
ing. The designer of the piping system should have provided ad-
equate corrosion control. Typical methods of corrosion control
are external coatings, polymer wrap, cathodic protection and
The root cause of the loss is insufficient corrosion protection
of the pipe. Retaining the failed pipe, taking statements of the
insured’s personnel, documenting information regarding the loss
and obtaining an engineering failure analysis report will aid in a
successful recovery for the insurance adjuster’s client.
Charles C. Roberts, Jr., Ph.D., P.E., is president of C. Roberts
Consulting Engineers, Inc., which provides professional
engineering services in accident reconstruction, failure
analysis, fire causation, explosion analysis, and biomechanics.
He may be reached at firstname.lastname@example.org.