Subsea flowlines and risers experience fatigue cycles due to thermal and/or pressure transients or vortex induced vibration (VIV). Tests were performed under constant stress intensity factor (K) levels, in a mildly sour environment and in seawater under cathodic protection to understand the difference in the CRG.
This report assesses (1) the rate of corrosion of bare steel with and without cathodic protection, and (2) the effectiveness of various commercially avail able coating systems in preventing corrosion of steel piles in seawater. Eighteen coatings and four sacrificial anodes were tested on 24 sets (three piles per set) of ASTM A 36 or ASTM 690 steel H-piles exposed for 5 years at Buzzards Bay, Massachusetts. Performance ratings were established for the following coatings: organic, organic over metal-filled, organic over metal filled with cathodic protection, metallic organic over metallic, and organic with cathodic protection. It is concluded that sacrificial anodes of zinc and aluminum effectively reduced the corrosion rate of bare carbon steel (ASTM 36) piles in the immersed zone from 0.076-0.102 mm/yr (3-4 mils/yr) to zero, and the coating performing best was coal tar epoxy over zinc-rich primer.
On an increasingly frequent basis, pipeline operators are using risk-based decision making to prioritize cross-company expenditures. Due to the long-term mitigation benefits of Cathodic Protection (CP), when planning external corrosion mitigation activities, pipeline operators typically prioritize mitigation of deeper anomalies for integrity expenditures due to their higher Probability of Failure (PoF). However, anomalies that are not receiving adequate CP or those experiencing electrical interference may remain unaddressed using this rationale. This paper presents both a qualitative and semi-quantitative approach to support the quantification of the risk reduction benefits gained from external corrosion prevention on pipelines. This can help in the efficient prioritization of both pro-active and re-active integrity repair activities. Supporting examples are also discussed to help explain the intended use of the methodology and the interpretation of the results.
Impressed current cathodic protection (ICCP) is one corrosion management approach adopted by the Port of Newcastle (PoN) for their reinforced concrete wharves. The Port’s West Basin 3 wharf, has ICCP systems installed to select substructure concrete elements (beams). The West Basin 3 ICCP system to the front beam soffit section was installed in 1998 (rear beam soffit sections having been protected from 2014). Other ICCP systems have also been installed by the PoN during the period 2002 to 2005 for the West Basin Wharf 4, East Basin (1 & 2) wharves and the Kooragang K2 wharf. This paper provides background to the different ICCP systems utilized and details performance results for the West Basin 3 front beam ICCP system dating back more than 20 years. Monitoring results are presented and discussed. Performance assessment to protection criteria is undertaken and the CP system maintenance requirements are summarized.
Wax coating systems are designed to provide underground pipes with protection against corrosive environments. This standard recommended practice covers surface preparation, material requirements, application, and handling of hot- and cold-applied wax and component wrappers and wax-tape coating systems for the protection of underground pipe, fittings, and valves. This standard is intended for use by corrosion control personnel, design engineers, project managers, purchasers, and construction engineers and managers.