Response to Gummow Article

RESPONSE TO BOB GUMMOW ARTICLE IN PIPELINE AND GAS JOURNAL
November 2010
R. A. (Bob) Gummow has written a very good article “Examining The Controversy Surrounding The -850 mV CP Criteria” that is published in the November 2010 Pipeline and Gas Journal. As usual Bob does a very good job of making his points while barely mentioning some well-known “facts” that do not quite fit his theory and experience. For this reason I would like to provide comments on some of his statements that may concern some in the pipeline and CP industry.
I agree with much of what is addressed in the article. The discussion is mainly about the controversy between using an “ON” -850 mV and the “polarized” -850 mV criterions. The discussion below will be about specific statements and where I believe we “MUST” discuss each side of the debate if we are to actually learn and achieve a better understanding of the proper ways to use these criteria as separate items in the NACE International SP0169 document. Even though some say there is confusion when there are two criterions using the -850 mV as the base number, most of the end users do not have this problem. When allowed to consider their specific system and what criterion actually provides the most economical and efficient process for evaluating the cathodic protection effectiveness for their system, while at the same time providing a safe environment for the pipeline and surrounding communities is the critical issue.
Statements are made that if the CP levels are such that a polarized -850 mV (or more negative potential) or proof of at least 100 mV of polarization would result in (most cases) a corrosion rate of less than 1 mil per year (mpy). This rate of corrosion has been established in several tests using coupons and no one is questioning this fact, but it is something to keep in mind while reading this response. Just how we are going to measure this on a pipeline has not been totally addresses yet.
One of the issues with using the “ON” -850 mV criterion is that of considering IR drops in the soil. There is no doubt that we can see a difference in the “ON” and instant Off potentials. Whether this difference is truly a problem is debatable. One of the problems is that we cannot easily measure the so called “instant off” or polarized potential. That is a discussion for another time.
Assuming that we can measure the instant Off effectively (mostly we try to measure it consistently), then we can subtract the instant Off from the “ON” and that value is the IR drop that is the assumed culprit. It is interesting that this is called an “error” in the “ON” potential. This is not an “error”. It is simply part of the “ON” potential. Whether it should be considered as a problem or not is up to those responsible for interpreting these potentials using their knowledge and experiences on that particular pipeline system according to all the information available, not just CP potentials. This is sound engineering practice. Forcing all to use a polarized potential because of a few tests on coupons, is not sound engineering practice.
The companies that use the “ON” potential as one of their criterion do not try to protect an entire pipeline system at an “ON” -850 mV, but use this “ON” potential as a warning sign that the protection at that site and the surrounding area needs further testing or additional CP. I have yet to see a pipeline system that could be protected at one specific potential for its entirety. It is absurd to even bring this up when discussing the “ON” -850 mV potential criterion, yet this is one argument against using it. Bob has to admit that “likely” when using this criterion the 100 mV of polarization is met or exceeded, therefore since the “ON” potentials are typically much more negative than the -850 mV, these companies are indeed considering IR drop in these potentials. The 5th paragraph under “The -850 mV cse Current Applied Criterion” addresses this fact.
Another interesting statement is when discussing the paper by Mr. Holtsbaum. In the caption under Figure 1, he states “IR Drop versus On Potentials to Illustrate a Dangerous Use of a Constant IR Drop Factor, in this case 100 mV.” I do not think the use of “Dangerous” is called for here, but if you are trying to convince folks that do not know, that you are right then you use such words to get their attention. The statement was perfectly fine without the word “Dangerous”. Had these potentials actually been allowed to depolarize there would have likely been at least 100 mV of polarization which would have proven that these potentials were not dangerous, just not complete. Since I do have copy of Mr. Holtsbaum’s paper, I do not know if this testing was performed or published in this paper.
The last sentence of the ON criterion section says, “Because of the extreme range of the IR drop on coated pipelines, the level of CP cannot be determined by the “ON” potential alone.” This statement could be interpreted to mean that using only any “ON” criterion will result in many pipeline failures. This has not been proven to be true. Yes, there have been pipeline failures on coated pipelines which use this “ON” criterion (also the polarized and 100 mV of polarization criteria), but if we could go back and actually find the root cause of the problem, we would find that most of these failures occurred because of disbonded and CP shielding pipeline coatings, interference or other shielding issues. If this statement were true, then why would companies with FBE coated pipelines not also experience these same external corrosion failure problems? Again, there have been a few external corrosion problems on FBE coated pipelines, but nearly all can be explained as AC or DC interference or shielding from other objects placed in the ditch.
From the time I started in the pipeline industry (1980) and before companies were using an “ON” -850 mV criterion for protection of most of their pipelines. Those coated with FBE starting in 1960 did not and still do not have the same external corrosion problems as those pipes coated with other coating types. This is still true today. This has been proven out through the use of many ILI tools over the last 25 years, as well as ECDA. This points out that if using non-shielding pipeline coatings such as FBE even with an “ON” -850 mV criterion, companies will rarely have external corrosion caused from inadequate CP. This particular issue is conveniently ignored by those who propose that only a polarized -850 mV criterion is the only -850 mV criterion that can be used successfully.
For the most part everyone agrees with the fact that use of the polarized -850 mV criterion would result in more polarization and in some cases would certainly be a better choice. Of course, we must also understand that there can be problems when using this criterion just like when using the “ON” -850 mV. These facts are also conveniently left out of this article, but should be part of any discussion of this topic.
In the section on the comparison of the two -850 mV criterion, the statement is made that there have been no studies made where the current applied (ON) -850 mV potential was held at -850 mV on coated pipe in order to determine what the expected corrosion rate would be. First there is no company I know of that would attempt to do that in real life. As mention before, this NOT the way the “ON” criterion has been used or should be used. A much better test would be to see how many times 100 mV of polarization cannot be attained when the “ON” potential is a -850 mV or more negative on coated pipelines. This would really be useful information. There are a few instances where 100 mV may not be reached, but these are rare because with well coated pipe (assuming no CP shielding) CP current only has to protect the very few bare areas (holidays) and will easily find these. Polarization of these areas takes minimal current allowing current to move on to other openings. Compared to a bare structure that meets the 100 mV of polarization criterion, the well coated pipeline will require considerably less current than an uncoated pipeline. Most of the uncoated pipelines will never reach a polarized -850 mV criterion or the “ON” -850 mV criterion so the 100 mV of polarization is the only choice.
The push of this article seems to be to prepare everyone for the use of a statement in the SP0169 revision that states that if the polarized -850 mV or 100 mV of polarization criterions are used then there will be 1 mil or less corrosion rate. I think most basically agree with this concept if these criteria are used (and current can actually reach the pipe steel), but this is not a statement that should be placed in the SP0169 since there is no way to actually measure this in the field. If a statement like this is used in the SP0169, it must be well explained as to its intent, but I would still be concerned about the problems that could develop if lawyers and expert witnesses start using such statements to try to win law suits against pipeline companies. This is a discussion for another time.
Mark Mateer’s report is used to back up the theory that if everyone would use the polarized -850 mV criterion then we would have less external corrosion problems than if we use the “ON” -850 mV criterion. This may or may not be, but there are several issues that must be addressed before such assumptions can be made. I agree this is a very comprehensive report since it covers a 50 year time frame, but many other issues were not addressed in this article such as:
1. Again there is no discussion of the root cause of corrosion on these pipelines. There is no discussion of coating types, condition or if the coatings were shielding or non-shielding.
2. Even though the criterion used for the mid portion of the pipeline life was -850 mV “ON”, we are not given whether this criterion was properly applied or not.
3. What happened during the period of time when the polarized -850 mV criterion was used that may have also influenced the results beyond that of simply applying more CP?
a. As companies began to learn more about CP, coatings and reasons for external corrosion, they applied more CP and performed more detailed surveys to find areas of coating damage and repaired these areas. The same can be said from the beginning of CP on these pipeline systems until use of the “ON” -850 mV criterion.
b. The use of ILI tools also started at this time which also helped find and correct corrosion problems along with recoating programs and pipe replacements.
c. There were (probably) more and better coated pipelines laid during this 16 year period, which would sway the results. Only if the same pipelines were carried throughout the entire survey could this be reliable data.
d. More training and certification courses were offered during this time from NACE, companies and other organizations providing a much more knowledgeable and experienced work force.
e. During this time corrosion control becomes much more important in these companies and governments, which forced significant changes in the industry with large budgets and more attention paid to corrosion control efforts.
f. I would suspect that nearly every company could show similar results even if they were using an “ON” -850 mV criterion throughout the same time frame because of the reasons mentioned, not just because of using a polarized potential criterion.
Distribution companies are referenced as needing to change to the polarized potential criterion to eliminate their corrosion problems. Of course, the issue here is that most distribution companies do not have a reasonable way of performing the required testing to determine a polarized potential because most of these systems are protected with galvanic anodes that do not have access to install interrupters. Also, many systems have short segments of steel mixed with plastic pipe so electrical continuity is a problem. I have been told all they have to do is install coupons to determine what the polarized potential would be on these systems. Coupons are good tools when used properly, but are not the total answer and the cost of installing, reading and maintain these would be significant with limited improved results. Distribution companies have significantly more problems than transmission pipeline companies.
In the Summary the statement “the claim that the -850 mV current applied potential is as effective in controlling as the -850 mV polarized potential criterion is not borne out in the published literature”, is another statement that could use some discussion. Even though there have been several papers and presentations made to contrary, these are typically ignored.
The first sentence of the second paragraph under the Summary section is another bit of misinformation. I do not know a single company that only relies only on external corrosion failures to determine their external corrosion control program. It is interesting that in Mark Mateer’s article, these companies continued to have external corrosion “failures” even though they switched to a polarized potential criterion. Apparently they had corrosion rates over 1 mil per year! Are Bob and everyone else supporting this issue ready to tell us that there will be no external corrosion problems (at least less than 1 mil per year) if all switch to a polarized -850 mV criterion? I do not think so.
What we need is to continue to educate those who are responsible for corrosion control programs around the world that there are many parts to an external corrosion control program, not just CP and criteria. SP0169 is a critical document to our industry. Let’s do it right by making it flexible enough that companies can use the processes available to control the external corrosion on their systems. Those companies and their workers understand these systems better than anyone else, so all we have to do is continue to education these folks so they have a well-rounded understanding of all these processes and let them make the decision on what is best for their companies.
Another issue that needs to addressed is that of some in NACE teaching that only a polarized potential or 100 mV of polarization are acceptable criteria. If the -850 mV current applied criterion is listed it should also be taught as acceptable as long as it properly applied. Until and if the “ON” criterion is removed from the SP0169, it should be taught as a viable criterion when properly used.
As much as I have said, I want to be perfectly clear that I do respect Mr. Gummow. He is a very intelligent person and truly dedicated to what his experiences and knowledge has given him. I have had the opportunity to teach with him many times and he is a great instructor. Each time I get to teach with him, I learn and will always be grateful for the opportunity. Even though we have differences in opinions, as long as we all learn from and challenge each other we will all improve our knowledge and abilities.

Richard Norsworthy
Polyguard Products, Inc.

How Instant is Instant

For thosw of you who are concerned about the process of taking accurate "so called" instnat off potentials, the is a very good article in the Journal of Corrosion Sceince and Engineering that helps to explain the issues surrounding this problem.

Please go to the www.jcse.org and search around until you find a copy. It is a very good paper that should be in stack of references, etc.

Once again the Paper is "How Instant is Instant" by B.W.Cherry.

ISSN 1466-8858 Volume 9 Paper 6 - How Instant is Instant? B.W.Cherry Department of Materials Engineering, Monash University, Victoria 3800, Australia.

You will have to register, but the process is easy and worth your time! There are many other articles that are available from the JCSE that will be of interest to us "Rust Idiots".

Thanks,

Richard

Results of SP0169 vote 9-22-2010

For results of the most recent vote results go to the NACE website under committees, then look for the "On Line Balloting" and click on it. It will ask you for your login information and password. Then the TCC Balloting Home screen will be there. Chose the "Results" and go to page 11. Under the TG 360 be sure to take the one that dated 9-22-2010.

There you can see all the information on how many votes were cast, number and percentages of affirmatives, negatives and abstains. The breakdown of each group and category that voted, etc. This version got 87% affirmative!

Since this version has passed the 66 2/3 needed for it to move forward, now the committee will have to address the negatives and comments. If technical changes are made, then only those sections will have to be reballoted.

Hopefully, this will get the document on the way to being approved. Once approved, the next battle will be the Test method committee and making sure it is all correctly done there! Please stay dilligent and be sure you get on the voting/balloting list for the revision of the test method!

I want to thank all for your support and effort as this document is now moving forward, but is not there yet! We must be sure nothing is slipped in with no one paying attention!

Polyguard has chosen to continue the SP0169.com blog site through out this process.

Thank you,

Richard Norsworthy

Comments with Richard's affirmative vote

Comments to TG 360 Committee – Ballot August 2010

Definitions:

Coating: (1) A liquid, liquefiable, or mastic composition that, after application to a surface, is converted into a solid protective, decorative, or functional adherent film; (2) (in a more general sense) a thin layer of solid material on a surface that provides improved protective, decorative, or functional properties. For the purposes of this standard, “Coating” is defined as an electrically insulating material applied to the surface of a metallic structure that provides an adherent film which protects a metallic structure from the surrounding electrolyte.

Reason for change: Not all coatings are “thin”. Not sure how you would define “thin”.

6.2.1.4.9 When operating pressure and conditions are conducive to high pH stress corrosion cracking, the use of polarized potentials in the cracking range relative to the temperature indicated in Figure 1 is not advised.56

This table concerns me since many times the SCC happens under disbonded coatings and that is not affected by the polarized potential measurements outside of the coating. Could there be precautionary statement to cover these situations?

6.4.3 In situations in which the temperature of the reference electrode is below 15 °C (59 °F) and above 35 °C (95 °F), refer to Table 2.

This table is very confusing to most folks and will cause many problems. Why is there not a difference when the temperature is between 15º C and 35º C? Now when you are out of these ranges we have to calculate these differences. We have already thoroughly confused the industry with reference cell conversions that change continually according to which course they are taking at the time. Is this really a serious problem? If so, why has it not been in the document before? Do we really need this?

Thanks for all the hard work and effort!

Richard Norsworthy
Polyguard Products, Inc.
214-912-9072

Richard Norsworthy's comments on August 2010 version

At this time I believe this is a copy that I will vote affirmative. There are some areas that need help, but this is the most reasonable version I have seen. There are some excellent changes and improvements in the overall document.

Please take time to review the document and vote as you feel neccessary, but please vote. If you vote affirmative, you can provide comments for the areas that still need some improvements or changes. This does not force the committee to change anything, but they should and I believe will address any comments.

I have not had time to provide my comments yet, but will later.

Even if this version passes, we will continue the SP0169.com blog because the TM0497 now has to begin the revision to accomodate this revision.

Thanks,

Richard
Polyguard Products, Inc.

William Tessier comments

“The still small voice in your head must be the final arbiter when there is a conflict of duty.” –Mahatmas Gandhi

The recent discussions and debates concerning the -0.850mv “On” or “Instant Off” necessitate the need for additional dialogue among all members of the NACE family. With this brief article, I hope to encourage members throughout NACE, regardless of the position held, to let their thoughts and concerns be known as well as describe my own position.
Over forty years ago, NACE had developed a Standard Practice to offer direction for corrosion professionals around the world in determining the success of their corrosion control efforts. This Practice has also provided guidance to the U.S. federal government and other entities in their rulemaking efforts as well.
I have not aware of any compelling reasons to modify the Practice. It was created, I believe, to offer a guideline, not a de facto law of physics to say corrosion was or was not occurring. Many of us can recite numerous occasions where, despite adequate cathodic protection according to the Practice, corrosion has occurred. Perhaps equally so, narratives are abundant stating the absence of corrosion when these parameters are not met. As with any scientific theory, the status quo needs to be accepted until, and if, unequivocal evidence is given to dispute it.
Regardless of the NACE members’ propensity towards one theory or the other, one point is clear. That point is to investigate thoroughly, and mitigate to the best of their ability, any system or structure under their responsibility. The "letter" of the law must be followed consciously; the “spirit” of the law must be approached with integrity, dignity and personal conviction. This is the reason for the quote above. We need to comply with the laws that govern our industry but it is imperative to rectify any situation that is identified as having a corrosive environ whether that situation does or does not meet the “magic” -0.850 mv “On” or “Off”.
We, as corrosion control professionals and NACE members, have the ethical obligation to determine that if a system or structure is in a corrosive environment, proper prompt remedial action is taken. As leaders in a very challenging field, we must take this occasion presented from NACE and examine the different aspect of this Practice and comment accordingly. Having been acquainted with other industry specific Associations and realizing that it seldom happens; I would like members to take moment to appreciate this gift of empowerment that NACE and the Committee has bestowed upon us. Together, we will remain the principle voice in the continuous struggle to protect our environment, our communities and our assets from the devastating effects of corrosion.
My statements are not intended to discourage debate but to promote a discussion where we, as dedicated corrosion control professionals, can arrive at an acceptable solution. I propose NACE and the associated Committee, according to the established bylaws, to vote among the Committee members for acceptance or rejection of the proposed revision. If, however, the vote does not achieve a two thirds (super) majority, perhaps a vote from all NACE members can be incorporated. The process of the solicitation and receipt of votes should be relatively brief, possibly two months, and any revisions accepted or rejected according to a simple majority. If irrefutable evidence introduced in the future is vetted and accepted by a simple majority of NACE members, then, like the U.S. Constitution, the Standard can, and should be, amended.
I would like to thank everyone for allowing me the opportunity to convey my opinions on this very important topic.
Regards,
William Tessier –NACE Senior Corrosion Technologist
NACE Internal Corrosion Technologist

Removal of the copy of the past SP0169 revision

I was asked by NACE to remove the posted copy of the last version of the SP0169. Apparently, there is some clause that I did not read or pay any attention to. My fault and I gladly removed it.

My feeling was that those who are not on the voting ballot list should be able to see and comment on the document. I think you can go through the NACE web site under committees and eventually see a copy. If not contact the folks at NACE for help.

Also, the efforts of all of you who have commented on the recent attempt to stale the document from going to vote apparently helped some on the TG 360 committee to change their mind and vote for the current version. Maybe we did help the process to go forward!

Thanks again for all the help. I will comment on my thoughts later.

Richard

Comments from George Fernandez

Richard,
I have indirectly been involved with the new stance of what criteria we should follow to ensure our pipeline is cathodically protected and safe. I have been in the business for about 26 years and I don’t know everything about corrosion that I should but I do know something about pipelines in general and especially the pipeline I’m in charge of. Our group takes care of about 1900 miles of crude oil pipeline with some old and some new systems within that asset. Part of this asset is over 55 years old and we have never had a “corrosion leak” on any of our systems – knock on wood”. I am not going into the chemical and or engineering design of what corrosion is all about because we can make this letter longer than it should be. I will agree things have changed throughout the years and we have learned through experience what works and what doesn’t work. I agree with Tom Laundrie’s comment that regulations have increased, company standards have improved, companies have developed Integrity Management Plans which are auditable by PHMSA, running smart tools, doing close interval surveys, DCVG, digs, other testing, I can go on and on. Each company/technician know their systems. I work with many peers in the industry and we learn from each other, work together to improve our systems, and strive to make sure we are doing what is right for our respective system. As a regulated system, we strive to follow all regulatory requirements and we have done a pretty good job.
I would just like to say that the committee is trying to set a criteria that will have to be followed by the industry and I just don’t think it is fair across the board. We take IR drop into consideration because it’s another level of satisfaction that we feel is necessary. Is it necessary for all, probably not due to the fact that each environment is different. Other methods of testing and requirements can be done to ensure our safety and the safety of others. The present and existing criteria is doing its job. In my case the criteria is working well.
I commend the TEG 360 committee with their efforts but I think they need to look at what their peers are saying. The committee has spent enormous amount of time on this effort and it is time to look each other in the face and say if this is the right thing to do with what has gone on in the past few years.
Again, I have learned from very notable corrosion experts and I have followed their leads. With that said, we have refined the world of corrosion and NACE has been a big part of our success. Let’s keep doing what is right and let the people in the industry do what is working for them.

Thank You

George Fernandez

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

Comment from Joe Pikas

And Now the Rest of the Story – SP0169
NACE Central Area Conference, Corpus Christi, TX – 10-17-10

From the NACE Beginning
Let’s start with the history behind this legendary first standard produced by NACE in January, 1969. No let’s start a lot earlier in 1943 when NACE was formed in Houston, TX. Why 1943 in the middle of World War II and why Houston, TX. We could all agree that chemicals produced, pipelines serving the war effort, the Gulf environment above and below ground, operating temperatures, lack of industry standards, and did I mention the number of leaks and failures which brought this group together. “The perfect storm or the perfect venue; take your choice. Even during this massive war effort and the hiring of over 50,000 engineers, technicians and laborers to build atomic facilities to produce plutonium around the country; there were a number of smart guys who decided it was the time to start a corrosion society in this time of distress in our country. It was truly amazing that this occurred.
War is over and no standards?
What happened to NACE from 1943 to 1969? What happened to your “I Like Ike” political buttons as he fell asleep at the wheel and played golf in the early 50’s? NACE held annual conferences almost every year except during the early beginning due to the war effort. Where did all the smart guys go or do for a quarter of a century? Were we still celebrating the big ONE? What about the Korean conflict. We built the Little & Big Inch pipelines from the Gulf Coast to the Northeast only to be followed by many other others, by the way which are still in existence. Why 1969, we were still celebrating largest hippie gathering in Woodstock, NY? What more leaks and failures? Where were the standards? Were NACE and IKE on the same agenda? No wonder the flower power people took over.
Yes it took an act of Congress called the “Pipeline Safety Act” to get the wheels in motion. Was Congress finally doing their job? NACE is finally called to the rescue and to produce a standard by an organization called the Department of Transportation – Office of Pipeline Safety - Wow. How good can it get?
It’s Time to Start Your Engines
With a little nudge from DOT in preparing the Pipeline Safety Act for natural gas lines and certain companies like Transco and Tennessee Gas experiencing SCC failures back in the 60’s, NACE was encouraged to come up with a set of criteria for cathodic protection in a standard. A group of industry leaders including one of my old bosses Sal Bellasai were on the original committee to write this standard. Using their experiences and what worked in the field, they came up with a set of (field) criteria consisting of:
• -850 mV with the protective current applied (IR drop considered)
• 100 mV of polarization
• 300 mV shift
• Net protective current
• E-Log-I
Did these criteria complement each other? Yes. Did they oppose each other? Yes How can that be?
However, today, we have 3 criteria consisting of:
• -850 mV with the protective current applied (IR must be considered)
• -850 mV polarized
• 100 mV of polarization
Yes they also compliment and oppose each other just as the five criteria. But now we deleted 3 and added another -850 criterion (dueling criteria). How can that be? It goes back to the NACE Las Vegas Conference and what goes on in Vegas stays in Vegas. As you know the fight never ended back in the 60’s or the mid 90’s i.e. similar to the Korean Conflict. But somehow we were able to compromise and come up with solution after years of infighting. I cannot put this in words how this came about, but it resulted in some backdoor political compromises in the Frank Sinatra room. Just like Frank’s NY, NY; NACE makes it to Broadway with dueling -850s.
If each of these supposed criterion can oppose each other, then there must be other factors that are influencing the results. Yes, we all heard of shielding, disbondment, AC and DC interference, MIC, temperature, age, type and condition of coating, corrosive soil and electrolytes and other environmental factors. Then one must postulate that none of these criterion has an confidence level since most of the unknowns were not taken into consideration as shown in these limited number of examples.

1. A pipeline in NC exhibited a -1400 mV ON and -1100 mV OFF with several hundred millivolts of polarization yet continued to experience leaks. The coating was a single wrap of cold applied tape with minimal primer, experienced soil stress, experienced poor application and the pipe was pre-70 ERW. Yet the operator concluded and continued to state that the line was fully protected even after each of the leaks occurred.
a. Did the operator meet the criteria for cathodic protection, Yes? Was the line protected, No.?

2. A pipeline in AL exhibited a -1300 mV ON and -1050 mV OFF with several hundred millivolts of polarization, yet a catastrophic failure occurred 2 months after a close interval survey was taken. The coating was a coal tar enamel over the ditch application, experienced soil stress, never had CP for the first 5 to 6 years, was in a low spot with poor drainage and had a history of SCC. This operator continued to show that the line was fully protected even though there was a history of SCC and no CP for five years. Everyone thought that it was SCC; however, the failure was attributed to MIC.
a. Did the operator meet the criteria for cathodic protection, Yes? Was the line protected, No.?

3. A pipeline in North TX exhibited -1200 mV ON and -1000 mV OFF with several hundred millivolts of polarization, yet they were experiencing leaks in less than 10 years of operation. The coating was FBE, with hot applied sleeves, soil stress and poor drainage. The choice of sleeves was poor along with some application issues, but the weak link was wrinkling due to soil stresses.
a. Did the operator meet the criteria for cathodic protection, Yes? Was the line protected, No.?

4. A new pipeline in Gulf region of TX exhibited structure to electrolyte potentials of -1400 mV ON and -1100 mV OFF with several hundred millivolts of polarization, yet the operator was experiencing indications from the in-line-inspection results of pitting. The line and joints were coated with FBE and installation of the pipe was excellent. The coating was inspected in several areas and there was some minor pinholes, minor blisters with high pH and everything appeared to be in accordance to industry standards. Why the pitting? It was near an AC high voltage line. This line was in a rights of way with many other pipelines, but they were not experiencing this issue. The soil resistivity was in the order of 250 ohm cm and it only takes several volts of AC to start AC corrosion on a FBE coated line.
a. Did the operator meet the criteria for cathodic protection, Yes? Was the line protected, No.?

5. Conversely, let’s take a pipeline in South Texas where the structure to electrolyte potentials of -750 mV ON and -600 mV OFF. The coating was an asphalt enamel and was in poor condition and current requirements were extremely high. Everything about this line was as bad as it gets including some rock in the backfill. A direct examination revealed minor corrosion of less than 30 mils. Did I fail to mention the static potential was -250 mV and this line had several hundred millivolts of polarization, it was a dry environment and was 55 years old?
a. Did the operator meet the criteria for cathodic protection, Not in accordance to PHMSA? Was the line protected, Yes
b. It experienced less than 1 mil of pitting per year. Did it look and smell bad, Yes. However, the pipe had integrity, with little or no corrosion.
I can give hundreds more if not thousands of everyday examples of how pipelines operate with similar problems Criteria were designed to be guidelines not harden rigid rules. Why, because there are too many factors and unknowns that should be taken into consideration but are not. Basic tribal knowledge about the pipeline and its environment needs to be known. It is like driving your car in the rain with bald tires. We cannot use a criterion such as the dual -850s without knowing what is underneath the ground like the conditions of the tires. Does the pipe have any tread (coating) left. Has anyone kicked the tires or bent over to look in the ditch to see what is going on. There are companies who refuse to look deep into their systems and come to understand that shielding, MIC, interference; aged coating systems, corrosive soils, etc. are the issues and not the criteria. Then they make the bold statement, we are just going to move to -850 mV polarized criterion to make the material suppliers, contractors and others happy. What they don’t understand is that problem will not be solved. A lot of investment but little improvement in safety.
The SP0169 committee needs to recognize that these field guidelines called criteria are only as good as they fully understand the factors that really impact the integrity of the pipeline. If integrity issues are not part of the criteria, then how could we protect these lines? Any criterion will work as long as the tribal knowledge exists about the pipeline and its environment.
Recommendations:
• Get away from the simple single criterion values or numbers
• Set up system consisting of Confidence Factors (CF) or Risk Assessment (RA) Weighting
o A factor of 1.0 would be a verified laboratory test of a pipe specimen with a specific environment.
o Example of Factors that would influence readings – You the operator would set the weighting factors based on experience, environment, history for the specific pipe segment or plant setting:
 Type, condition and age of coating
 Isolated or grounded to power neutral or plant
 When CP was first applied (within 1 year, 2 years, etc.)
 How many lines in rights of way (1, 5, 25, 100, 150, etc.)
• Bonded, separation distance, stacked, etc.
 Number bonds and current drain to foreign lines
 Current Density to protect pipeline(s) for a specific coating, pipe diameter, length, etc.
 AC/DC interference issues
 Shorted to ground neutral, plant piping, casings etc.
 Type of CP – Impressed, Galvanic, etc.
 Environmental – resistivity, corrosivity, pH, temperature, MIC, etc.
 Plant environments
• Grounding
• Mixed metals such as copper, galvanized and stainless
• Other nearby structures
o Conduit, Rebar, Tubing, Piping Runs, etc.
 History of leaks or failures
 Other – specific to this pipe segment or plant piping
• Get Out of Jail Free Card to offset Confidence or Risk Factors
o Pigging runs with little or no corrosion
o Other technologies such as guided wave with no corrosion
o Direct Examinations at areas of concern that validated structure to electrolyte readings
• Fully understand the integrity of the pipeline system and integrate this tribal knowledge with Corrosion Control Activities and
o History
o Construction and installation
 Inspection records
 Hydro test
o Coatings (Line pipe , Girth welds and fabrication piping)
 Type
 Condition
o CP levels
o Type of Pipe, WT, SMYS, Toughness, etc.
o Operations
 Temperatures
 Pigging Operations(Smart and Cleaning)
 Patrolling Activities
 Excavations
o Get out of the chair and get back in the ditch and really find out what is going on - involvement
o Let’s end the conflict and polarize the pipe not each other.
o No excuses, just old fashioned progress
PS
Did I fail to mention that DOT did not reference the original NACE RP0169 into the Pipeline Safety Regulations 49 CFR 192 Gas Regulations Appendix A back in 1970? ASME, API, ASTM and others were referenced but not NACE. However, DOT did create an Appendix D to Part 192 “Criteria for Cathodic Protection and Determination of Measurements”. The criteria were taken from then RP0169 along with the accepted measurement practices but no mention of NACE.
Does any know why?
If you were not at the NACE Central Area Panel Discussion in Corpus Christi, TX, the answer is that this was NACE’s first document after 26 years in existence with a little government prodding to get NACE to produce RP0169. However, it was not without controversy even at that time (IR drop is nothing new). Now we now understand this situation due to the many variables that are encountered in the right of way or the plant environment to achieve an indirect measurement to meet one of the criteria. In addition, API, ASME, ASTM was already established and had credibility, whereas NACE was finally taking their first baby step to establish standards. We have come a long way by the number of standards produced.
Note:
The above does not represent the view of any of my present or past employers (either operators or corrosion engineering companies), clients, or peers within the industry. These view points are based my 44 years of experience and findings on the many pipelines that I worked, studied and analyzed throughout the USA and the world.
Thank you,


Joe Pikas
Mobile - 832 758-0009
E-mail - jpikas@schiffassociates.com

Criteria in Crisis

CRITERIA IN CRISIS

From all that I can gather from the TG 360 committee, there is apparently a stalemate on the committee. This is very disappointing. From what I have heard, the problem is still the refusal of some on the committee to allow the use of the “ON” -850 mV criterion in the new document. They simply want to completely do away with this criterion, no matter what others have presented, proven or experienced.

The plan was to have another vote before CTW so the results could be discussed, etc. Now it appears this is not going to happen. Why? I am sure Jim will explain it to us and we will know what they are planning for the future.

I feel that there is a movement by some to stall the document in an attempt to force NACE to withdraw the SP0169 altogether and force the use of the ISO standard onto the world. The SP0169 is the first document every published by NACE and it will be an injustice to NACE and NACE membership to allow this to happen! This standard has been and is still used around the world today as the referenced industry standard in nearly all the others that are used. Do we as NACE want to allow this to go away or do we stand up and start the process in a direction to get it resolved?

What is amazing to me is the fact that the straw poll from this summer showed that almost 80% of those who voted in the poll would vote yes for the SP0169 if they would just leave the criterion as stated in the SP0169-2007, yet some on the committee are bound and determined to force their views or else. NACE documents are compromise documents that allow all who want to vote and comment to do so. I do not know of any standards that everyone totally agrees with.

The time has come for all who are interested in this document to take a stance! We have a choice:

1. Let it die and start using the ISO standard ( which I do not agree with and will explain later)
2. Force the committee to bring the document to vote with SP0169-2007 wording for criteria
3. Disband the TG 360 and start over
4. Replace some on the committee and move forward

#1
The problem with the ISO standards is that they are developed by a few folks and voted on and controlled by a select committee. Most of us would never get to voice an opinion or vote on these documents. NACE at least allows anyone to vote (if you sign up on the voting ballot list) and then to provide input and comments to defend your position. As with most things in life, this is not a perfect system, but I think offers a much better way of producing a document that is the best overall for our industry. When only a few select folks (who may have certain agendas) are allowed to produce these standards we are limited to their views and experiences only. If they are elitist in attitude, then the rest of us do not count.

#2
I think we need take the SP0169 – 2007 version of the criteria with most of the other changes and allow it to go to vote. Why did they even do the Straw Poll if they are not going to use the information! Folks have become accustom too this version of the criteria and are willing to move forward. There are those who insist that we no longer have an “ON” criterion in the SP0169, therefore they are right and everyone else is wrong.

#3
Maybe it is time to disband the committee that we now have and start over. Apparently, there are those who will not compromise and refuse to allow the document to go forward unless they get their way. I think most of us have been willing to listen, learn and in some case compromise to move the document forward. I am not the expert on laws of NACE committees, but something must be done to break this stalemate.

#4
Maybe it is time for Jim Chmilar to replace some on the committee to allow the document to go forward. Certainly these folks will vote negative if the document passes with the criteria as in the 2007 version, but if we can get the 66 2/3 vote, then we can at least move forward and address the negatives and try to get these resolved.

I also believe that some are hoping that we get tired and just give up. Please do not do this! This is too critical of a standard for us to allow to die or to not get the best document possible. Keep up the work and the commitment to providing the industry with a NACE document that will for all to us and provide efficient, effective and economical external corrosion control to our pipelines around the world!

I strongly encourage all to who are concerned as I am with this issue to please e-mail those at NACE and those on the committee with your thoughts and concerns. I am providing e-mails for the ones that you should contact. Some of these may not be on the committee any more, but this is the list that is posted on the NACE website. I will also include those at NACE that are important in the resolving this issue.

If you have any say in this process, no matter how you voted or even if you voted, please forward you comments and concerns to the committee and NACE! Pass this along to others in your company, who may need the information, want to comment or have clout to help this document along!

NACE contacts

Linda.Goldberg@nace.org
daniela.matthews@nace.org

Technology Coordinator
Ernest Klechka - eklechka@schiffassociates.com

STG 35 Chair
Steve Biagiotti, Jr. – sbiagiotti@structint.com
STG 35 Vice Chair
Roy Fultineer - rfultineer@eQt.com

If any of you know of others who need to be contacted please pass the information along to the rest of us. I will post this information on SP0169.com blog site for all to have access too.

There are a few of the TG 360 committee members that I do not have e-mail addresses for at this time. If any of you have contact e-mails for these folks please pass these along.

Name Title Member Since
Mark Brogger
Member 9/24/2007
James Chmilar jimchm@telus.net
Chair 10/17/2006
Robert Gummow bgummow@correng.com
Member 10/17/2006
Kimberly-Joy Harris kimberly.harris@enbridge.com
Member 10/18/2006
Gerald Holton Jr jerry@spc-net.com
Member 7/14/2008
Naeem Khan
Member 10/18/2006
David Kroon
Member 10/17/2006
Mark Lauber mlauber@lacledegas.com
Member 10/18/2006
Joseph Mataich joseph.mataich@dot.gov
Member 8/20/2007
Matt Matlas
Member 1/7/2010
David McQuilling David.McQuilling@sug.com
Member 1/7/2010
Richard Mielke, P.E. rmielke@nwpipe.com
Member 12/11/2007
Norman Moriber norm.moriber@mears.net
Member 10/17/2006
Richard Newell rnewell@wsscwater.com
Member 1/7/2010
Paul Nichols paul.r.nichols@shell.com
Member 10/17/2006
Frank Perry
Member 10/18/2006
Marcel Roche marcel.roche@orange.fr
Member 10/18/2006
Travis Sera tsera@semprautilities.com
Vice Chair 7/14/2008
Neil Thompson Neil.Thompson@dnv.com
Member 10/18/2006
Robert Vail
Member 10/17/2006
Brian Wyatt
Member 10/17/2006

This has become an urgent matter that needs to be addressed. Please post your thoughts on the blog site for all to view as well as e-mailing them to those on the committee and NACE. I urge all to do so. We need reasons and comments from all sides so we can arrive at the best overall document possible for our industry and that takes everyone’s input.

Thanks for the participation and time. DO NOT GIVE UP ON THIS PROCESS OR THE DOCUMENT. I hope the committee can move forward with our help and comments.

Richard Norsworthy
Polyguard Products, Inc.

TG 360 Straw Poll - Final Results

Original source of information was taken from the TG 360 Straw Poll.pdf file that can be found on the NACE International website (Proposed Revision to NACE SP0169 -2007). Under the “SUMMARY AND STATUS” heading, click on the bullet that says “Straw Poll for Section 6.”

Version 1 (CORROSION 2010)

A cathodic voltage of –850 mV or more negative across the structure to electrolyte boundary as measured with respect to a saturated copper/copper sulfate (CSE)reference electrode.

COMMENTS

Version 1 is the only technically corrrect version of the 850 criterion. Versions 2,3 and 4 do not eliminate the ambiguity between current-applied and polarized potential critera that the committee was charged to accomplish. Version 5 is better than versions 2, 3 and 4 but it is still technically incorrect because you can not correct for voltage drops by "Determining whether or not there is physical evidence of corrosion".

Version 1: What is the definition of Cathodic Voltage? This term does not appear in the SP0169 versions I have.

1. Fails to address IR drop.

Version 1 is from 1969, and is no longer valid for modern pipelines given our understanding of sources of measurement error with well coated pipeliens.

The remaining versions are more or less acceptable, but the wording requires the CP practitioner to 'correct' or 'consider' IR drops. I think this is a messier way to treat the criteria issue, as 'correction' implies some mathematical treatment, and 'consideration' is subject to interpretation.

While I agree Version 1 is technically correct and simple, I think more information is necessary such as in versions 4 and 5.

V1 –agree

Version 1 - cannot measure the potential reasonably as stated.

Version1, is inpractical.

Version 2 (Committee E-mail Suggestion)

(1) A structure-to-electrolyte potential measured with the cathodic protection current applied. The current-applied potential criterion value shall be established by the owner through sound engineering practice and supported by empirical evidence that demonstrates the corrosion control objective of the owner is achieved.
(2) A negative polarized potential (see definition in Section 2) of at least 850 mV relative to a saturated copper/copper sulfate reference electrode.

COMMENTS

Version 2: Just the (2)

2. (1) Fails to address IR drop.
2. (2) Is an excellent criteria and scientifically defensible.

Version 2 is most agreeable to me because it allows virtually any empirically supported CP criterion to be used - and it places the burden of proof on the owner. This is consistent with CSA OCC-1.

I really like Ver.2. It is concise and well written. However I can see some pipelines owners/operators trying to abuse of criterion #1.Maybe NACE should emphasize that the owner shall used proper skilled and trained personnel in the CP area. And that the effectiveness of the current-applied potential criterion value selected will be owner responsibility only.

Should have been maybe added to the choices. I hate to be like the ones that vote yes but i want some changes made. Version #2 and #3 are not bad but could not vote for them as they are written. Thanks for going the extra mile to make it right. I would like to be alble to support it this time.

V2,3,4 – disagree

Version 2 - This is a start, but needs more information for ON. Why would the polarized not have to meet the corrosion control objectives of the owner?

Version 2 would be a nightmare to comply and enforce.

Version 2, To what detail the Empirical evidence needs to be supported? Sometimes a collection of all data, ie, leak survey, cp reads and history, all taken together will suffice. The devil is in the detail.

In version 2 the use of empirical evidence is too broad and therefore is not as helpful/informative as the other options.

Version 3 (RP0169-1969)

(1) A negative (cathodic) voltage of at least 0.85 volt as measured between the structure surface and a saturated copper-copper sulfate half cell contacting the electrolyte. Determination of this voltage is to be made with the protective current applied. The Corrosion Engineer shall consider voltage (IR) drops other than those across the structure-electrolyte boundary for valid interpretation of the voltage measurement.

(2) A negative polarized potential (see definition in Section 2) of at least 850 mV relative to a saturated copper/copper sulfate reference electrode.

COMMENTS

3. (1) Better but not scientifically defensible.

Version 3 would have been my top selection but I do not like that they have used the title "Corrosion Engineer". It should read "Responsible Corrosion Person". I do not like that they specified that a Corrosion Engineer should make the determination. I have met several Corrosion Engineers that I was amazed how little they understood about CP. Conversely, I have met many Corrosion Technicians that put these engineers to shame. I would vote yes on version 3 if the term "Corrosion Engineer" were replaced with "Responsible Corrosion Person" or something similar.

Since Corrosion Engineer is capitalized in the wording I presume that means NACE certified corrosion engineer.

Sentence 2 of version 3 contains the destination of a Corrosion Engineer as the one to consider voltage drop. Is that on purpose or are other professionals able to "consider" voltage drop?

I would vote for version 3 and strongly agree with it if the destination of "Corrosion Engineer" was changed to reflect field personnel. This seems to say that a person with even as high as a CP3 certification is not qualified to consider voltage drop and we must consult a corrosion engineer to get IR drop measurements.

Version 3 - Rephrase to take corrosion engineer out. There is no definition for this professional in many countries. A technician or any other qualified person can make this consideration. 3 and 4 with affirmative with comments.

V3 could be improved by deleting the second sentence and add "with IR drop considered" to the end of the first sentence.

Version 3 - Does not give guidance as to ways to consider IR drop.

Version 4 (SP0169-2007)

(1) A negative (cathodic) voltage of at least 0.85 volt as measured between the structure surface and a saturated copper-copper sulfate half cell contacting the electrolyte. Determination of this voltage is to be made with the protective current applied. The Corrosion Engineer shall consider voltage (IR) drops other than those across the structure-electrolyte boundary for valid interpretation of the voltage measurement. NOTE: Consideration is understood to mean the application of sound engineering practice in determining the significance of voltage drops by methods such as:
• Measuring or calculating the voltage drop(s);
• Reviewing the historical performance of the CP system;
• Evaluating the physical and electrical characteristics of the pipe and its environment; and
• Determining whether or not there is physical evidence of corrosion.

(2) A negative polarized potential (see definition in Section 2) of at least 850 mV relative to a saturated copper/copper sulfate reference electrode.

COMMENTS

Version 4: Just the (2)

Version 4 appears to leave Section 6 of the SP 0169 standard as is. I am in favor of this not only for the referenced criteria but for the section as a whole. Please see my detailed response for all the issues of concern within Section 6 provided during the last round of voting.

I like Version 4 but prefer using the .850 volt designation instead of 850 mV.

As no criteria can or should be an "absolute" for all situations, NACE should provide the best practical advice for an owner/operator to follow. I believe Version 4 accomplishes this and allows for good engineering practice to evaluate many highly variable environmental and field specific situations.

4. (1) Fails to define "considered" at all and thus is not scientifically defensible.

I feel that both the "CP On" and the "Polarized potential" should be in there own statements. I also like that in the Version 4 some guideance is given in "what must be considered for valid voltage drops"

Please consider the physical and electrical characteristics of the pipes coating in version #4.

In Version #4, bullet #3 the word pipe needs to be changed to structure.

In version 4 the integrity of application of the On criterion puts the emphasis squarely on the company's procedure. The proper aplication of a proper procedure is the key to any criterion, CP is no exception.

Version 4 I agree with the following reservation. With the current IMP regulations in the U.S. there is much useful data with regards to corrosion coming from metal loss smart pig runs. We should take advantage of this information when making decisions regarding "physical evidence of corrosion". I would suggest this data can be used to fulfill this caveat in Version 4.

Version 4 is a soft option for poorly designed systems. It is possible as it specifically draws the users attention to the issues required for consideration.

Version 4 - I would remove "Reviewing the historical performance of the CP system". This will be interpretated as a leak detection criteria that is really dangerous.

I would prefer to leave the criteria section the same as the current version - I believe that is V4.

Version 4 appears to leave Section 6 of the SP 0169 standard as is. I am in favor of this not only for the referenced criteria but for the section as a whole.

Version 4 - This version gives some guidance as to how to consider IR drop

Version 4 of the criteria represents no change from the existing standard SP0169 with regard to the -0.850 V criteria and I am in agreement with leaving Section 6 as currently written.

As stated above, cosideration of cathodic protection is already appropriately addressed in the existing standard. Version 4 appears to make no chage to the existing standard.

There should be a maybe. With some enhancement I could vote yes for version 2. Version 4 I could compromise and vote yes for it. Thanks for asking!

Version 4 appears to provide the broadest range of options, and provides detail regarding the interpretation of the work consider. It also recognizes the application of the polarized criteria.

Versions 4 and 5 are the most informative in my opinon.

Version 4 best represents my view.

Version 5 (current draft)

A cathodic voltage of –850 mV or more negative as measured with respect to a saturated copper/copper sulfate (CSE) reference electrode. This potential may be either a direct measurement of the instant-off potential, or a current-applied potential. Interpretation of a current-applied measurement requires correction for voltage drops in the earth or metallic paths.

NOTE: Correction is understood to mean the application of sound engineering practice in the determination of the magnitude and significance of voltage drops by methods such as:

• Measuring or calculating the voltage drop(s); or
• Determining whether or not there is physical evidence of corrosion.

COMMENTS

Version 5: What is the definition of Cathodic Voltage?

5. First bullet: A scientific method of "calculating the voltage drop(s)" must be provided. Second bullet: There is no practical method of "Determining whether or not there is physical evidence of corrosion".

Version 5 would be better if instant-off was changed to polarized.

To much can be miss understood with the On and Off criteria in version 5. Regulators can go off in a tangent and require the Off potential.

Version 5 would be "neutral" & "yes" if "correction" was changed to "consideration".

We've got to stay with the word "considered" and stay away from "corrected". No way on Version 5.

Version 5 - Correction means off potential. There is no other way. "Determining whether or not there is physical evidence of corrosion" does not mean correction. Ohmic drop can be big, but soil corrosion rate is negligible.

V5 - neutral

Version 5 - basically the same as the polarized potential since you must "correct" for IR drop.

I favour somewhere between versions 4 and 5 such as version 5 with the 4 points itemized in version 4. The other 3 versions can only be valid if they have been validated at leats once using my modification of version 5 suggested above. That being said then version 5 is the most acceptable. In version 5 we do not feel we can support the term corrected at this time.

Other Comments (General):

Part of your problem is wording. How many ways can you basically say the same thing. It seems you are just word-smithing to cover all the bases. Say it one way and let that be it - don't confuse people. For instance the first sentence in item (1) for each version. Look at the different ways you say the same thing.

This doesnt seem like a fair poll. Did everyone on the TG agree with this, or just a few individuals?

need to omit having two criteria that both say 850 is the magic number but each 850 is defined differental, this can not be correct. Just state control is achieved at some degree of polarization depending on environmental conditions... (period)

I agree with all so interpret the rankings as 1 = least prefer to 5 = most prefer

IN GENERAL: there is not even one of the proposals strongly asking for the negative polarized potentials as only possibility (of course including also the 100 mV of cathodic polarization). This will be the criterion that I will vote for. Meanwhile we are giving the chance for interpretations of the measured values beyond the simple measurement, people can use these
interpretations to their convinience.

Can only do the first part, not the second part.
Voltage applied - can do.
Voltage off - no can do

All of the above criteria are meaningless unless the temperature of the reference electrode is specified.

Guidance for correction of the reference electrode potential given elsewhere in previous drafts gave method for this correction but did not give a temperature that the potentials should be corrected to.

Why not simply define "polarzed potential" as:

Polarized Potential = A pipe-to-soil potential (excluding all IR or other possible sources of error in the measurement) more negative than -850 mV CSE.

Then the criteria becomes:

Protection is determined by demonstrating a polarized potential of more negative than -850 mV CSE.

Note that I used one choice for each ranking and didn't repeat any of them.

It seems to me that potential readings are essentially a conservative way of being reasonably confident about the structural integrity of a pipe without seeing it or otherwise testing it. It seems there should be an alternative such as sufficient visual inspection or testing that adequately proves there is no damage of sufficient size to compromise the structural integrity of the pipe before the next inspection or test. This alternative would say that any level of cathodic protection, or even leaving off cp, is adequate since service life can be safely
anticipated.

Over the years, on pipeline systems that I maintain, I have come to find that as long as there are no foreign cathodically protected structures in the near vicinity that the negative 850 millivolt "on potential" will result in a greater than 100 millivolt shift in cathodic protection current. This has been substantiated with many miles of close interval survey data. I have maintained lines in several of the western states and this has been true on all that I have been in charge of. Foreign cathodically protected structures nearby to my structures have been a concern due to interferance and groundbed gradients.

I strongly disagree with all statements as presented and believe the move should be made completely away from voltage potential measurements for "protective criteria". We all understand that -850 mV does not work in all cases and in fact we should be further focusing on applied current to prove that in fact we are protecting a structure. In the past voltage potential was an easy available way to prvide some proof that current might flow to the structure (emphasis on the might) and was in no way meant to be what it is today. Methods of measuring current (not voltage) must be included in criteria today. Once it can be demonstrated that current is in fact flowing to the structure, then a voltage potential measurement can be useful in montioring the situation. A voltage potential by itself can mean nothing at times without knowing about the current flow.

I'm not sure why the negative comments aren't being looked at. This seems like a way to push through a change that isn't wanted. Can you please add teh poll question: Do you feel additional requirements to SP0169 are being pushed by people who would profit from the changes? Do you feel this is right?

Please see my detailed response provided in the last round of voting that details the rationale for the negative response. I would vote affirmatively only if all the issues identified in my negative response were addressed appropriately. Version 4 of the criteria represents no change from the existing standard approved SP0169 standard with regard to the -0.850 V criteria and I am in agreement with leaving Section 6 as is.

Any criteria that is published must be based in the scientific method. Otherwise, failures will result and damage infrastructure, lives, and the reputation of NACE and our engineers.

Alterntaly why not adopt criteria given in ISO 15589-1 that is

(a) Protection potential applies at the metal/electrolyte interface, i.e. a potential which is free from the IR drop in the corrosive environment (IR-free potential)

(b) Prtoection potential is dependent on soil type / resistivity, as follows:
anerobic conditions or < -950 mV high resisitivty soils (10 to 100 kohm.cm) -750 mV very high resisitivty soils (> 100 kohm.cm) -650 mV

As you mentioned the wording of the above can be changed. So actually an affirmative volt depends on the wording. The no's on this questions is a maybe depending on the wording, but you did not give that choise.

My company, one of the largest energy transmission companies in North America, will continue to use the -850 polarized OFF potential regardless of how weakened the standard becomes through the lobbying efforts of certain individuals.

In canada, we are entitled to use alternate criteria where we can demonstrate the objective of corrosion prevention has been achieved (but we need to support it empirically).

To reiterate my position, voltage potential by itself should not be allowed as a criteria. One must prove out the current flow in the system and that it is in fact enough current to the steel to be cathodically protective. Until that occurs, voltage potential is only a hopeful way of measuring what might occur. I know some may think this is radical but today's technology (along with older technology) allows one to measure direct current on a pipeline (both through direct measurements and measurements from above the ground without touching the pipeline). Until NACE members recognize the failure of a voltage only criteria, we will not make progress in our world of cathodic protection. We must start measuring current again to prove if a structure is cathodically protection.

The format and content of this poll is a waste of time. If SurveyMonkey and hence NACE thinks that this survey "Surveys Made Simple" then this is all monkey business and belongs in a zoo. And, we need to rethink about NACE leadership qualifications and where it is taking us. This poll is worthless.

It is my opinion that the existing version of Section 6 of SP 0169 adequately addresses cathodic protection measurement and interpretation.

While I am not sure that we need to eliminate current applied measurements, I think the format presented actually would encourage that.

Update to SP0169 Revision July 7, 2010

Another vote likely in August 2010!!

Another version of the SP0169 is in the works. I think everyone is hopeful for resolution of the key issues on this document so we can move forward. The committee is working to address many of the negatives and comments from the last vote. Even though they do not have to resolve the negatives (because the ballot failed), they are trying to see where the main issues are and how they might resolve them before the next vote.

I have no idea of where they are at this time or what changes have been made, but it is time we get this document out to our members and others that need this standard around the world.

Those on the voting list did receive a poll recently addressing the criteria section and what would be acceptable to them as far as the criteria section. I was hoping the committee would release these results to see how the voters responded. Since this is the critical issue for most voters, it would be nice to know where the committee is focusing their changes, if any, in this section before the balloting process. As far as I can tell there is nothing on the NACE website under the TG 360 committee that addresses the recent poll.

The last word I had was that another version of the revision will be out for vote in August 2010. To vote, you will have had to signed up on the original voting ballot list which was in July 2009. If you are not on this list you can not vote, but you can make your views known by posting them on the SP0169.com blog site and by passing them along to those who are voting, especially those in your company. That way others who will be voting can get information from anyone who posts their views on the blog in order to help them make a more informed decision.

It has been interesting to me that those who favor changes to the criteria section rarely post their concerns, reasons and information on the topic. Why not allow everyone to get as much information as possible so they can reason the best choices for this document. We learn from every ones comments derived from their experiences, knowledge and education. Those who chose not to inform others of their views on this subject are not allowing for an open forum to discuss these very important and critical issues. Please provide you insight into these issues no matter where your experiences have taken you.

Get ready for another ballot soon! And please vote if you are on the balloting list! Take some time to read the document and comment as you see places that may need some changes or improvements. You can choose to vote for or against or abstain. If voting for this version you do not have comment, but are welcome to. If you vote against the document, you must give the committee valid reasons why you voted negative. You will need to define the particular section and give reasoning why you voted negative on that part, as well as giving a valid resolution to the committee. This is where the information mentioned above becomes very important.

The committee has spent many long hours and much effort in this matter and like the rest of us is tired of the battle, but in order to give the industry the best possible document, we have to keep working together! Do not give up! And do not just give in to get it over with. Compromise is the only way we will get this document out, but it must happen on both sides.

Thanks for the support of the SP0169.com blog site. Please continue to provide comments and any other information (especially case histories) that will help with this effort!

Richard Norsworthy
Polyguard Products, Inc.

Anonymous comments

I, like many others, are weary of the battle between those for and against the -0.850V "ON" criteria (yes yes with reference to a CuCuSO4 reference cell).

I do lean towards the science side of the debate, but also recognize that a lab is not the same as in the field, and practical measures are required in the field.

IMHO, a -0.85V "ON" criteria specifically for galvanic anode CP systems in soils above some soil resistivity (pick a number based on science 2000? 5000? ohm-cm)will protect the pipe. The amount of current an anode can generate would not be able to produce a significant IR drop, hence by default "considers" those drops other than those across the electrolye boundary.

Providing a sound basis that allows the operator to use the -0.85V "ON" criteria addresses the concerns I hear at the meetings. It provides the operator a safe criteria, supported by sound science, and give a valid/supported stance to take with a regulator. Most importantly, it provides for a procedure that can be performed cost effectively, repeatably, correlates with the historical data.

This is no different than what I hear others say they do. It just documents the process, brings some consensus and consistancy to the approach, and moves us forward on this standard.

Why is this important to some many operators? The practical issue, as I see it, are associated with trying to measure an "instant off" value on a pipeline that is protected by galvanic anodes that are cad welded to the pipeline. This is very imparactical to interrupt. Even if they the anodes came up into a test station, just the vast numbers of anodes involved make it an impractical test procedure to perform (how many interrupters would it take?). In many cases, we wouldn't even be allowed to dig down just to break the anode wire connection.

Besides the impractical nature, it is not warranted in these low current situations.

I propose a study to establish some norms for when the -0.85 ON criteria would be acceptable. Tables could be generated that might correlate soil resistivity, "typical" anode current flow, and "expected" IR drops associated with those currents. This should meet the concerns of most folks. Guidance could be provided if an operators system were outside of those norms.

Of course this is not 100% iron clad. There could be scenarios where interference could be involved, thus the "ON" reading might not be real, but this is no less true of any CP system, even with "instant off" readings. No criteria eliminates the need for knowledgeable CP personnel to monitor and interpret the results.

Standards of any kind do not lend themselves to performing a task in the most precise way, but takes complicated processes and builds in enough of a safety factor that it becomes a practical rule book to use in most cases. We always depend on knowledgeable folks to know when the "rules" or standards are applicable for a given situation.

Straw Poll

Comments on Straw Poll concering criteria for SP0169

The recent straw poll sent by the TG 360 committee gives you a chance to provide the committee with your thoughts and potential compromises. They have provided 5 versions to choose. Also, you are to rank each one as to whether you strongly agree to strongly disagree. Then you are asked if you would vote yes or no on each version.

The 100 mV polarization criterion would be common to each version so is not included.

Here is what I think:

Version 1

A cathodic voltage of -850 mV or more negative across the structure to electrolyte boundary as measured with respect to a saturated copper/copper sulfate (CSE) reference electrode.

MY COMMENTS: (Disagree)

The major problem with this version is that there is no “real” way to perform this in the field. Theoretically, this is what we are trying to accomplish, but in the real world, I do not think we can do it with enough consistent accuracy to be viable. The cost of performing these type surveys can be high and the extra cost does not provide much value for amount it could cost. Therefore, I could not agree with this being the only criterion besides the 100 mV.

Interpretation of the way to measure the potentials in this criterion would lead to much confusion and possible problems that could be a major issue for those trying to use such a criterion. The test method committee for TM-0497 would have to come up the ways to measure this version and that may take longer than revising the SP0169!

Version 2

(1) A structure-to-electrolyte potential measured with the cathodic protection current applied. The current-applied potential criterion value shall be established by the owner through sound engineering practice and support by empirical evidence that demonstrates the corrosion control objective of the owner is achieved.

(2) A negative polarized potential of at least 850 mV relative to a saturated copper/copper sulfate reference electrode.

MY COMMENTS: (Has potential, but needs some re-wording)

I like much about this version, but am concerned about the definitions of “empirical evidence” and “objective of the owner”. If these are defined satisfactorily in the document, then possibly I could “strongly agree” with this version. At this time I would say it is a definite “maybe”.

This would leave it up to the owner to determine what “ON” potential they will use at each test site. This could be determined by several methods that should be spelled out in the test method document.

Also, why is it important to establish “by the owner through sound engineering practice and support by empirical evidence that demonstrates the corrosion control objective of the owner is achieved” for the “ON” potential, but if you take an “instant off” you do not have to meet the owner’s objective? Seems like every criterion should meet the owner’s objectives and if we mention it in one we need to mention it in all or make a generic statement as such in the document and not apply it to each separate criterion.

Version 3

(1) A negative (cathodic) voltage of at least 0.85 volt as measured between the structure surface and a saturated copper-copper sulfate half cell contacting the electrolyte. Determination of this voltage is to be made with the protective current applied. The Corrosion Engineer shall consider voltage (IR) drops other than those across the structure-electrolyte boundary for valid interpretation of the voltage drop.
(2) A negative polarized potential of at least 850 mV relative to a saturated copper/copper sulfate reference electrode.

MY COMMENTS (Disagree at this time)

This was almost good. Had they not included the wording “Corrosion Engineer” and “shall consider”. Not sure how we define a corrosion engineer these days. Not even sure we can get a corrosion engineering degree as such in most places around the world. There are “degreed engineers” that work in the discipline of corrosion, but not many who actually have a degree in corrosion. There are also more of us working corrosion that do not have an engineering degree than those with one. So how do we define that?

I know “must” is used in Version 4, but at least they allow for some ways of considering the voltage drops.

Version 4

(1) A negative (cathodic) potential of at least 850 mV with the CP applied. This potential is measured with respect to a saturated copper/copper sulfate reference electrode contacting the electrolyte. Voltage drops other than those across the structure to-electrolyte boundary must be considered for valid interpretation of this voltage measurement.

NOTE: Consideration is understood to mean the application of sound engineering practice in determining the significance of voltage drops by methods such as:

- Measuring or calculating the voltage drop(s);
- Reviewing the historical performance of the CP system;
- Evaluating the physical and electrical characteristics of the pipe and its environment; and
- Determining whether or not there is physical evidence of corrosion.

(2) A negative polarized potential of at least 850 mV relative to a saturated copper/copper sulfate reference electrode.

MY COMMENTS (Agree overall)

These are the same two criterion in the SP-0169 – 2007 and is the same as has been used since 1992 (I believe). We have been able to make this work and I can vote for the document (if a few other areas are corrected) with the criteria as is at present.

I personally could do without the “must” before “be considered” and would prefer “should”, but can live with “must” as a compromise.

Version 5

A cathodic voltage of – 850 mV or more negative as measured with respect to a saturated copper/copper sulfate (CSE) reference electrode. This potential may be either a direct measurement of the instant off potentials, or a current applied potential. Interpretation of a current applied measurement requires correction for voltage drops in the earth or metallic paths.

Note: Correction is understood to mean the application of sound engineering practice in the determination of the magnitude and significance of the voltage drops by methods such as:

- Measuring or calculating the voltage drop(s); or
- Determining whether or not there is physical evidence of corrosion.

MY COMMENTS: (Strongly disagree)

This is the same criterion that was in the most recent revision. The term “correction” concerns many because it means you must determine the “instant off” for each reading when using an “ON” reading. The term “with current applied” is useless, because you have to “correct” for voltage drop by doing an “instant off”. Even though it does give some help with “evidence of corrosion” statement, I could not support this criterion.

FINAL COMMENTS:

Only those on the voting list got the opportunity to vote in this straw poll, but I encourage all those who have interest and want to express their opinion please do so through contacting the TG 360 committee or you can voice it through the blog site. You may have the best wording of the criteria so let us know.

I do hope the committee will take our words and comments as constructive and work to get us a document that gives the industry a valuable tool that can be used reasonably in the field to provide us with the data needed to determine when we have achieved the goal of providing adequate external corrosion control to the industries pipelines around the world. We will never reach 100%, but we can get very close and keep the effort affordable and reasonable. There have been many improvements and updates in the document, now let us compromise and move forward.

Again, I want to thank the committee and everyone else for hard work and effort. Though we may disagree at times, we all want the same thing. This is a critical document to the industry and we all want the best standard possible to provides guidance to the pipeline industry around the world.

I think this is a great opportunity to provide input to the committee. Please respond to best of your knowledge. You do not have to agree or disagree with me or the committee, but we do need to resolve this standard and get it out.

Thanks for your help and time,

Richard Norsworthy

Comments to the TG 360 committee

Comments to the TG 360 committee:

As the struggle continues to revise this document we must work together and respect each persons experience, knowledge and education. Each of us has formed different opinions of what we think should be in the document. Since the main problem is with the CP criteria, I will focus on that today.

Norm Moriber has an article in May addition of Materials Performance that discusses some of the issues surrounding the revision of the SP0169. I do agree with Norm on many of the topics he has discussed in this article. First, I know that the committee and many other NACE members have worked very hard to resolve these problems. There have been some significant changes in the last revision that updates many of the references. Significant information has been added about pipeline coatings and mechanical damage protection (rock shields, etc.). I personally think they have too many references that confuse the coating tables, etc.

Most of the concern is with the fact that the document no longer has a separate criterion that states the use of an “ON” -850 mV or more negative potential as a viable option. The word “consider” is the word that is at issue with the committee in the 2007 and earlier versions. “Consider” can be defined in different ways and this seems to be the road block.

Yet the committee still uses “consideration” throughout the most recent document. Here are a few areas where “consideration” is still used in last revision:

6.2.3.1.3 Criteria that have been shown to successfully control corrosion through empirical
evidence on specific piping systems may continue to be used on those piping systems or others
with the same characteristics. These criteria include –850 mV on with consideration for
voltage drops other than those across the structure-to-electrolyte boundary, other current applied
criteria, net current flow, 300 mV shift, or E log I.

6.2.3.2 Special Conditions
6.2.3.2.1 The amount of cathodic polarization maintained on a metallic surface may be affected
by changes in electrolyte conditions, CP system or structure configuration changes, and changes
in influencing sources of AC or DC currents. These factors should be considered when tests are
performed to verify compliance with the CP criteria.

6.2.3.2.5 In uniformly high-resistivity well-drained soil, instant-off potentials less negative than
–850 mV CSE may be sufficient. Note: ISO 15589-1 offers the following for consideration:
–750 mV where soil resistivity is between 10,000 Ω.cm and 100,000 Ω.cm, and –650 mV where soil resistivity is greater than 100,000 Ωm.

6.3 Other Considerations

It is interesting that most on the committee does not think we should use “consider” or its derivatives, yet the committee has chosen to use it several times in Section 6! In 6.2.3.1.3 it is used similar to the use in SP0169 – 2007 version. Why can we not just use it in the criteria section as in the 2007 version and move on?

I and others think that if the committee would simply leave the 6.2.2.1.1 as written in the 2007 version, the document would pass (with some cleaning up and elimination of so much extra stuff). Here is the wording in the 2007 version:

6.2.2.1.1 A negative (cathodic) potential of at least 850 mV with the CP applied. This potential is measured with respect to a saturated copper/copper sulfate reference electrode contacting the electrolyte. Voltage drops other than those across the structure to-electrolyte boundary must be considered for valid interpretation of this voltage measurement.

NOTE: Consideration is understood to mean the application of sound engineering practice in determining the significance of voltage drops by methods such as:

6.2.2.1.1.1 Measuring or calculating the voltage drop(s);
6.2.2.1.1.2 Reviewing the historical performance of the CP system;
6.2.2.1.1.3 Evaluating the physical and electrical characteristics of the pipe and its environment; and
6.2.2.1.1.4 Determining whether or not there is physical evidence of corrosion.

In this version the document has provided some guidance in to what they mean by “consider” which most folks can interpret without a problem. The way a company interprets “consider” should be clearly spelled out in each company’s procedure manual. It is their responsibility. The SP0169 is a standard to guide them, not dictate to them.

The referenced article mentions the potential of the STG 35 committee recommending the withdrawal of the SP0169 from NACE Standard Practices. This would be a great miss-justice to the membership of NACE. This was the first recommended practice NACE every published. We are the experts! Some on the committee would prefer this since most companies would then resort to the ISO standard for CP, which would give them what they want. For those of you who do not understand the ISO process, these documents are not voted on by members as in NACE. These are decided by a committee of folks from various countries that are given direction by those in that discipline, therefore not everyone has an opportunity to vote or even voice an opinion in all cases.

Whether this is a scare tactic by some on the committee or not, I am not sure, but it seems there are some who think these tactics will result in members voting for the standard whether it is correct or not just to be sure we keep the SP0169 in NACE.

We, the voting pool, the committee and NACE membership, must work together to complete this document in a manner that gives us the best document for the world’s corrosion control industry. As we move forward with this critical document, as with all NACE Standards, there must be compromise on both sides of the controversy.

I am asking the committee to please consider the keeping the 6.2.2.1.1 as stated in the SP0169-2007. This would likely resolve the issue and allow the document to move forward. Since the committee has used the term “consideration and considered” in basically the same manner in the last attempted revision, there is no reason not to use it again. This is a compromise that we should all be able to live with!

As Norm points out, PLEASE VOTE if you are on the balloting list. Also, do not vote for or against any NACE document without studying, questioning and understanding the various parts as much as possible before making your decision. Never feel intimidated by those in the industry that “know” more than you. Each person has a different level of expertise and knowledge. Yours is as valuable in the process as everyone else’s. Ask for help and clarification when needed. This is the way we all learn and helps us to produce the best SP0169 document ever published!

Any comments are welcome to the blog site. Even Norm’s! I will be fair and print all suggestions to the committee that are constructive comments and information. This is not a forum to bash anyone, but is one to allow free expression and ideas, especially for those who feel intimidated in front of the committee.

I want to thank every one who has supported the SP0169.com blog site. Polyguard Products, Inc. has allowed me time and provided the resources to support this process. Please let me or some one at Polyguard know if there is any way we can help you with any pipeline coating or corrosion control issues. Please visit our website at polyguardproducts.com.

Thank you,

Richard Norsworthy
NACE Corrosion Specialist # 4037