What coating must steel pipe or conduit have to be resistant to corrosion?

The correct answer is galvanized. Galvanization is a process that involves coating steel with a layer of zinc to provide protection against rust and corrosion. This protective coating helps extend the life of steel pipes or conduits, especially when they are exposed to moisture or harsh environments. The zinc acts as a sacrificial element; even if the galvanized layer is scratched, the exposed steel remains protected as long as any exposed zinc is present.

Other coatings, such as paint or enamel, can provide a barrier but may not be as durable or effective as galvanization when exposed to various environmental stresses. Copper-coating is not typically used for corrosion protection in steel pipes or conduits, as it serves different applications and may not offer the same level of protection against rusting scenarios. Thus, for maximum corrosion resistance in steel pipe or conduit, galvanization is the preferred choice.