Corrosion Allowance—Not Always a Simple Concept

An identified corrosion allowance, which is a specified value, is easy to use and is helpful in judging corrosion acceptability. A computed corrosion allowance can provide for greater depths of corrosion to be allowable. This article describes the use of a computed corrosion allowance, provides sample equations, and identifies applicable codes that provide guidance in computing a corrosion allowance.