Tom Laundrie's comments

How did Nace let this mess get this far? Let's go back to basics. Since when is any Nace document 100% technically correct. Engineering is applied science. We take scientific principles we learn in a controlled environment, such as a lab, and apply them as best we can to the "real" world environment.

I believe we learned in the lab a long time ago, that all we need to minimize corrosion is a shift of 100 millivolts. Reading Potentials of -0.85 volts On or Off is simply a shortcut that has worked for us in 99% of the cases. In other words, the -0.85 Volt Off Criteria just has a bigger safety factor built in to it than the -0.85 Volt On Criteria, taking reading errors into account. It is economical and they have proven to work by digging up the pipes and examining them. From what I keep hearing, almost all of the corrosion or problems found have been due to Interference or Shielding under disbonded tape or coatings. This is not going to change. In fact by insisting on a -0.85 volt Off Criteria, there will be a type of "current wars" and incidences of Interference damage will only increase. There may be even more disbonding, and thus more corrosion due to Shielding. Insisting on a -0.85 Volt Off Criteria will lead to more problems; not less.

With the emergence of ECDA programs in more and more companies, we should be gathering the data from all of these Direct Assessments and comparing them to the CP readings that have been taken and the Criteria that was used. This is empirical data that is just as useful as theoretical data.

The Nace Committee working on this document has a cancer in it, in the form of obstinance; and it is time that Nace cuts it out and lets the body heal.

Thank you,
Tom Laundrie
Sr. Materials Engineering Specialist
NACE Cathodic Protection Specialist