What kind of coating or coating protection is commonly specified for steel pipelines exposed to soil?

• A. External protective coating (e.g., epoxy) with corrosion protection; concrete encasement if required.
• B. Internal lining only; no external protection.
• C. Concrete encasement always required.
• D. External coating is optional and not protective.

Answer: (A)

Steel pipelines buried in soil must have a protective external barrier to keep moisture and soil chemicals from corroding the steel. An external coating, such as epoxy, is a common and effective first line of defense, and projects often pair that coating with additional corrosion protection strategies. In many cases, concrete encasement is added when the design calls for extra physical or environmental protection, or when conditions require more robust protection than coating alone provides.

Relying on an internal lining only protects the inside of the pipe and does nothing to shield the exterior surface from soil contact. Concrete encasement is not universally required; it depends on the specific project conditions. Calling external coating optional would ignore its primary purpose of preventing exterior corrosion.