Using the 100-mV Criterion for Protection of New Structures.

The 100-m V criterion, often used for buried structures in high-resistivity soils where corrosion potentials may be low, can be readily evaluated by comparing two potentials--"instant-off" and free corrosion. According to the relevant NACE standards, to assess 100-mV formation or decay, measuring instant-off potentials is a necessity. For new structures, an "instant-on" potential can be read after energizing. This article compares the results of instant-off and instant-on methods for buried piping in a petrochemical plant and in laboratory tests. [ABSTRACT FROM AUTHOR]