External coating for buried or immerged pipelines

The transport of petroleum products, whether in the form of a liquid or a gas, is a major industrial challenge. Indeed, the places where oil and gas are produced and consumed can be several thousands of kilometres apart from one another. One transportation method is the use of oil and gas tankers. Nevertheless, the most common way is to use buried pipelines. The same goes for the transport of other fluids such as oxygen, hydrogen and drinking water.

Such infrastructures are made of steel for the most part, so it is thus necessary to implement protective measures to guarantee their integrity over time, particularly by combating degradation phenomena such as corrosion.

This area is closely linked to safety, environmental protection, and also structural operating and maintenance costs.

Corrosion protection is provided through the combination of two methods: cathodic protection (active protection) and the use of anti-corrosion coatings (passive protection). Methods for monitoring cathodic protection have been known and understood for many years. Anti-corrosion coatings need to be selected with care and applied in accordance with standards and specifications, whether in the factory or directly on the site where the pipeline is being constructed and operated.

The aim of this article is to present the different types of materials and systems used as anti-corrosion coatings in the context of transport pipelines, along with points requiring extra care, relating either to the application or to the ageing of those products.

At the end of the article, the reader will find a glossary of important terms and a table of acronyms used in this article.