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Articles · FCWA Requires Corrosion
Protection
FCWA Requires Corrosion Protection
Fairfax County Water
Authority (FCWA) is now requiring that all new ductile iron pipe water mains
be corrosion protected. This is achieved by wrapping each pipe section with
4 mil. cross-laminated polyethylene wrap and placing it in a six inch
envelope of 21A select fill. The additional cost associated with this
treatment is $8-$12 per foot installed.
As an alternative, the
developer may submit a 10-point soil evaluation, as outlined in Appendix A
of the ANSI/AWWA C105/A21.5, certifying that polyethylene encasement is not
warranted. The test assigns point values to soil resistivity, pH, redox
potential, sulfides, and moisture. When the point total meets or exceeds 10,
protection is required. A qualified laboratory must perform the testing and
the results certified by an NACE International Corrosion Specialist.
The cost of performing the
evaluation will, obviously, vary by job size. We recently had a project with
approximately 10,000 LF of waterline, and the evaluation cost approximately
$10,000. We determined, however, that corrosion protection was not required,
thus resulting in a net savings to the developer of $90,000.
In many cases, this soil
evaluation can provide substantial savings to construction costs. Further
information can be found on the FCWA website at
http://www.fcwa.org/engineering/developers.htm. |
