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henever steel is exposed to atmosphere
or soil, corrosion can occur. Corrosion of
pipelines is not limited to high-pressure
natural gas pipelines, or hazardous and
volatile liquids pipelines. All pipelines constructed of steel
are susceptible to corrosion. This includes water pipelines,
concrete cylinder pipelines, and ductile iron pipelines.
Owners and operators of pipelines utilise external
coating systems and cathodic protection (CP) to mitigate
corrosion. These solutions can work extremely well to
protect pipelines and steel structures. However, activities
such as improper backfill during construction or excavation,
third-party damage, soil stress, and interference from
foreign CP systems can circumvent and even nullify
the protective effects of good coating and CP systems.
Corrosion, when left unmonitored, can grow and lead to
pipeline leaks or ruptures.
In the US, the Pipeline and Hazardous Materials Safety
Administration (PHMSA) governs pipeline operators
in maintaining the integrity of their pipelines in high
consequence areas (HCAs). It will also soon dictate
regulations in moderate consequence areas (MCAs). The
external corrosion direct assessment (ECDA) process was
developed by the National Association of Corrosion
Engineers (NACE) and is a PHMSA-approved pipeline
Marlane Rodriguez and Keith Nevils, Corrpro, USA, discuss the adaptation of
regulated processes for use on unregulated pipelines to evaluate external corrosion
threats.
Taking a new approach
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