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| Case Histories |
Plastic Hot Water Tank Valve
Specimen: Plastic Hot Water Tank Valve
Material: White Polymeric Plastic
Background: The plastic hot water tank drain valve
was originally installed in a hot water tank located in
a residential home. The tank leaked into the home
and caused approx. $50,000 worth of damage.
Service Life: The water heater would have been in
service for less than 5 years
Findings: The valve was poorly installed and had
been over-tightened past the “as-manufactured”
length of the threads. This action abusively “tapped”
further threads in the body of the valve, resulting in
undue stresses on the valve, and displaced the plastic
of the valve body, creating a “mushroomed” ridge
of plastic around the circumference of the valve. This
initiated cracking in the valve which led to the failure
of the valve and water damage to the residence. |
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