David Kroon

Advanced Corrosion Protection Solutions for Ductile Iron Pipe

The results of a two-year study of corrosion and corrosion protection characteristics of ductile iron pipe are presented. Included are field and laboratory evaluations related to short term and long term polarization rates under varying conditions, corrosion rate reduction and corresponding cathodic current criterion, and the corrosion protection benefits of the traditional standard asphaltic shop coating. This information was then analyzed in conjunction with an extensive database from 1,379 physical inspections of buried iron water lines. The result of the study is a risk-based corrosion protection design strategy for buried ductile iron pipelines.

Ductile Iron Pipe: Proven Synergistic Corrosion Protection

This paper presents case histories where polyethylene encasement and cathodic protection have been used together to effectively control external corrosion of ductile iron pipelines in very corrosive soils. This practical and cost effective strategy capitalizes on the synergistic effects of these two established corrosion control techniques. Pipeline designs dating back to at least the 1970s for over 300 miles of construction have included this corrosion control methodology. The case histories include both impressed current and galvanic current protection. Non-invasive surface electrical potential measurements and record reviews were used to determine locations for excavations to inspect the condition of the pipe and polyethylene encasement.