It seems funny to me after reading thru most of the negative comments I have not really seen many changes that were made in the "New" revision.
One more thing I just dont understand. "Why" it is not important for the Members voting for this "not" to be required to leave comments why they are voting for it.
Unless.. most of the members voting for this are either vendors or contractors that would profit from this change.
Would you not think maybe NACE needs to do a study of leak history. Should we not look at the causes before we just go out and change the recommemded practies?
I can tell you the guys in the white trucks in the field know there is something wrong with this picture.
Monday, February 22, 2010
Sunday, February 21, 2010
Comments on TG 360 vote
I have to agree with Mauro on his comments. The problem I have with the 25 µm/y (1 mil/y) is that there will be no way to measure this corrosion rate on pipelines and other structures that we cathodically protect. As Mauro and I have pointed out coupons are not pipelines. Coupons are good tools when used properly, but are not the answer to this question. My issue is when does this become a requirement? If some (uneducated) regulator or other person (such as a lawyer or expert witness) asks you to prove you have protected your pipeline to this level, how are you going to answer them? We DO NOT need this in our SP0169 document. As a matter of fact the committee in 1990 even gave a really good answer as to why this should not be in the document when one of the members offered it as a way to determine adequate protection! What has changed?
The other thing that really bothers me is the use of “instant off”. Why would we want to use this term when we can not define it or measure it? At least the term polarized potential has a definition, even if there is no way to actually measure it accurately. There are too many times that we can not interrupt all current sources.
I will address these and a few more areas in my negative. I will post my negative response for those of you who need some guidance. Hopefully, I will have this done by next weekend. I will let you know when I have completed it and you may use any of it you like to help you with your wording.
Be sure you notify all who are on the voting list and have them vote. I am against the present form of the document, but do hope all of those who are on the list vote. I have learned very much from being active in this document and I hope the SP0169.com blog site has been and will continue to be helpful to all who are concerned about the revision of this document.
Polyguard has made an effort to provide this information so all can comment. I do not refuse comments that are reasonable and offer good information and discussion on this topic.
Another very interesting thing that has happened is the US Department of Transportation is now requiring the use of NON-SHIELDING coatings on pipelines if the operator wants to increase the maximum operating pressure from 72% to 80 %. As most of you know we at Polyguard have been promoting the use of non-shielding coatings for many years. Come by our booth at CORROSION 2010 and get some information on our Polyguard RD-6 coating system and other products.
Please let me know if you do not want to get this information and I will remove you from the list.
Thanks for supporting the blog site,
Richard Norsworthy
Polyguard Products
richnors@flash.net
The other thing that really bothers me is the use of “instant off”. Why would we want to use this term when we can not define it or measure it? At least the term polarized potential has a definition, even if there is no way to actually measure it accurately. There are too many times that we can not interrupt all current sources.
I will address these and a few more areas in my negative. I will post my negative response for those of you who need some guidance. Hopefully, I will have this done by next weekend. I will let you know when I have completed it and you may use any of it you like to help you with your wording.
Be sure you notify all who are on the voting list and have them vote. I am against the present form of the document, but do hope all of those who are on the list vote. I have learned very much from being active in this document and I hope the SP0169.com blog site has been and will continue to be helpful to all who are concerned about the revision of this document.
Polyguard has made an effort to provide this information so all can comment. I do not refuse comments that are reasonable and offer good information and discussion on this topic.
Another very interesting thing that has happened is the US Department of Transportation is now requiring the use of NON-SHIELDING coatings on pipelines if the operator wants to increase the maximum operating pressure from 72% to 80 %. As most of you know we at Polyguard have been promoting the use of non-shielding coatings for many years. Come by our booth at CORROSION 2010 and get some information on our Polyguard RD-6 coating system and other products.
Please let me know if you do not want to get this information and I will remove you from the list.
Thanks for supporting the blog site,
Richard Norsworthy
Polyguard Products
richnors@flash.net
Comments from Mauro Chaves Barreto
Richard,
Thanks for email below. It makes us thinking about this issue which is always an educational process. I usually agree on what you say, but this time I found something that I think you misunderstood. I do not think this draft asks anyone to measure corrosion rate. It just says that both criteria have empirical evidences to reduces corrosion rate down to 25µm/y. On the other hand, evidences that you reduced corrosion rate down to this level, does not mean that you comply to the statement. I say this because all corrosion rate measurement methods have flaws and coupons are not pipelines. Maybe a good comment to the negative is a better clarification about this issue.
Also, I think there is a big misunderstanding behind this long discussion in general. I think very low corrosion rate does not mean CP and immunity provided by CP is not always necessary for corrosion control. I can give you two practical examples about what I said:
- A pipeline operator wanted to assess pipeline integrity after 25 years operation. Their idea was to run a smart pig, but operational conditions did not allow them to do it at that time. They performed CIS and found a spread of 8 km without any potential shift. It happened because pipeline was in a rock trench that shielded CP current. They made several dig-ups and found no evidence of corrosion even with a deteriorated coating. My recommendation was to run smart pig and do nothing in case of no external corrosion is found.
- A consultant from our company inspected a very big heat exchanger in a power plant and recommended galvanic CP as the mitigation method. He designed the system without any way to measure potentials, since stationary reference electrodes were very difficult to install. Client asked how he can be sure that system was working properly and he just said that it can be done visually just stopping equipment after one year operation. It was done some weeks ago and system was just perfect.
So, my question is: why do we need to prove that any structure, including pipelines, have potentials that would reduce corrosion rates in almost all situations? If we can prove that corrosion rate is acceptable and under control, do we need to prove that we also have -0,85V ON or OFF or whatever? In the past, this discussion for pipelines would not make much sense, since there was no other way to “prove” low corrosion rate besides measuring pipe to soil potentials, but today we have smart pigs.
I will think better about how to incorporate these thoughts in my probable negative. I would appreciate your comments.
Mauro Chaves Barreto
IEC - Instalações e Engenharia de Corrosão Ltda.
Thanks for email below. It makes us thinking about this issue which is always an educational process. I usually agree on what you say, but this time I found something that I think you misunderstood. I do not think this draft asks anyone to measure corrosion rate. It just says that both criteria have empirical evidences to reduces corrosion rate down to 25µm/y. On the other hand, evidences that you reduced corrosion rate down to this level, does not mean that you comply to the statement. I say this because all corrosion rate measurement methods have flaws and coupons are not pipelines. Maybe a good comment to the negative is a better clarification about this issue.
Also, I think there is a big misunderstanding behind this long discussion in general. I think very low corrosion rate does not mean CP and immunity provided by CP is not always necessary for corrosion control. I can give you two practical examples about what I said:
- A pipeline operator wanted to assess pipeline integrity after 25 years operation. Their idea was to run a smart pig, but operational conditions did not allow them to do it at that time. They performed CIS and found a spread of 8 km without any potential shift. It happened because pipeline was in a rock trench that shielded CP current. They made several dig-ups and found no evidence of corrosion even with a deteriorated coating. My recommendation was to run smart pig and do nothing in case of no external corrosion is found.
- A consultant from our company inspected a very big heat exchanger in a power plant and recommended galvanic CP as the mitigation method. He designed the system without any way to measure potentials, since stationary reference electrodes were very difficult to install. Client asked how he can be sure that system was working properly and he just said that it can be done visually just stopping equipment after one year operation. It was done some weeks ago and system was just perfect.
So, my question is: why do we need to prove that any structure, including pipelines, have potentials that would reduce corrosion rates in almost all situations? If we can prove that corrosion rate is acceptable and under control, do we need to prove that we also have -0,85V ON or OFF or whatever? In the past, this discussion for pipelines would not make much sense, since there was no other way to “prove” low corrosion rate besides measuring pipe to soil potentials, but today we have smart pigs.
I will think better about how to incorporate these thoughts in my probable negative. I would appreciate your comments.
Mauro Chaves Barreto
IEC - Instalações e Engenharia de Corrosão Ltda.
Monday, February 8, 2010
Comments from Aynonomus
Richard,
I totally agree with you and I feel that 0.850 V "ON" criteria has proven to be good enough for many years...
But if they refuse to accept the 0.850 V "ON" criteria anymore for whatever reason, has anyone thought about just increasing the ON potential up to maybe 0.950 or even 1.000 V "ON" to add additional protection yet not requiring as much additional labor/expense?
This might be an acceptable option or also worth evaluating...
I totally agree with you and I feel that 0.850 V "ON" criteria has proven to be good enough for many years...
But if they refuse to accept the 0.850 V "ON" criteria anymore for whatever reason, has anyone thought about just increasing the ON potential up to maybe 0.950 or even 1.000 V "ON" to add additional protection yet not requiring as much additional labor/expense?
This might be an acceptable option or also worth evaluating...
Comments from Paul Nichols
Richard,
Of course you know there is nothing to prevent someone from using -850 mV On now, if the data is available to support that it is effective. SP0169 permits it, it just takes a bit of work, like collecting the data you ask for in your note. A combination of operator data on soil, coating and CP conditions, some ECDA and/or ILI data, plus the previous PRCI study would be sufficient to show if -850 On is effective. I think the same sort of, or substantially similar, data would be required anyway even in a revised SP0169; some data to show that the conditions are appropriate for -850 On and to show that it works.
Regards,
Paul
Paul Nichols
Senior Materials and Corrosion Engineer; Mechanical, Materials and Integrity - East
Projects and Engineering Services
Shell Projects and Technology
Of course you know there is nothing to prevent someone from using -850 mV On now, if the data is available to support that it is effective. SP0169 permits it, it just takes a bit of work, like collecting the data you ask for in your note. A combination of operator data on soil, coating and CP conditions, some ECDA and/or ILI data, plus the previous PRCI study would be sufficient to show if -850 On is effective. I think the same sort of, or substantially similar, data would be required anyway even in a revised SP0169; some data to show that the conditions are appropriate for -850 On and to show that it works.
Regards,
Paul
Paul Nichols
Senior Materials and Corrosion Engineer; Mechanical, Materials and Integrity - East
Projects and Engineering Services
Shell Projects and Technology
Sunday, February 7, 2010
Message from Jim Chmilar
Richard: I would like to thank you for your contribution in submitting comments for the STG 35 Ballot last August in the review of the TG 360 revision of SP0169-2007. I know you are aware that the ballot did not get the 2/3rd affirmative vote necessary to proceed and the document was sent back to the task group for revision. I believe that your comments along with the others have now been reviewed and discussed and revisions have been made during at least one of the SIX web-conference call meetings held by the task group members since CTW 2009 (in addition to many e-mail exchanges).
The task group is down to making the final revisions and we will hopefully be out for a four week ballot period during February with a ballot close before San Antonio so we can be discussing ballots results at the Tuesday March 16, 2010 TG 360 meeting.
I trust you will find your comments and views have been addressed in the ballot draft when it comes out. Be assured that if you have any comments or concerns about the document that your negative or affirmative vote will be addressed during Corrosion 2010 or following meeting(s) if necessary. Please consider that if you do submit a negative vote that you must provide a suggested resolution that can be printed in the document, a number of negative voters did not do this last time.
Thank you for your contribution to technical committee activities
Jim Chmilar
The task group is down to making the final revisions and we will hopefully be out for a four week ballot period during February with a ballot close before San Antonio so we can be discussing ballots results at the Tuesday March 16, 2010 TG 360 meeting.
I trust you will find your comments and views have been addressed in the ballot draft when it comes out. Be assured that if you have any comments or concerns about the document that your negative or affirmative vote will be addressed during Corrosion 2010 or following meeting(s) if necessary. Please consider that if you do submit a negative vote that you must provide a suggested resolution that can be printed in the document, a number of negative voters did not do this last time.
Thank you for your contribution to technical committee activities
Jim Chmilar
Comments from Jim Jenkins
Richard:
In addition to all of your comments, most of which I agree with, any potential measurement using a reference electrode where the absolute potential is to be determined needs to include the temperature of the reference electrode at the time of measurement. This is a bigger problem for the Cu/CuSO, than for the Ag/AgCl reference, but is a problem for both. In fact, I actually made the statement at an early RP-0169 revision meeting that "any absolute potential reading using a reference electrode where the temperature of the reference electrode is unknown is meaningless". I don't even think that using a reference electrode for potential rise or decay is valid unless the temperature of the reference electrode is known, or known not to change significantly during the measurement.
I hate zinc reference electrodes as I have found that the potential of even a freshly polished zinc reference can vary on soil by over 200 mV. It is closer for a freshly polished zinc reference in seawater ( about -1.05 V vs Ag/AgCl ) but the main problem in seawater is that the zinc always becomes more electropositive which indicates a more protected potential than would be measured when using a real reference electrode such as an Ag/AgCl. I am currently working on a project where using a zinc reference (even after I warned the owner that this is not satisfactory) to monitor a C.P. system has resulted in several millions of dollars of damage to a marine structure. Why risk structural integrity to save $ 100.00 on a reference electrode?
I plan to remain a voice in the wilderness on this and will continue to vote negative on SP-0169 until this is included. I have given my comments to NACE previously on this with my negative vote with no success.
Jim Jenkins
In addition to all of your comments, most of which I agree with, any potential measurement using a reference electrode where the absolute potential is to be determined needs to include the temperature of the reference electrode at the time of measurement. This is a bigger problem for the Cu/CuSO, than for the Ag/AgCl reference, but is a problem for both. In fact, I actually made the statement at an early RP-0169 revision meeting that "any absolute potential reading using a reference electrode where the temperature of the reference electrode is unknown is meaningless". I don't even think that using a reference electrode for potential rise or decay is valid unless the temperature of the reference electrode is known, or known not to change significantly during the measurement.
I hate zinc reference electrodes as I have found that the potential of even a freshly polished zinc reference can vary on soil by over 200 mV. It is closer for a freshly polished zinc reference in seawater ( about -1.05 V vs Ag/AgCl ) but the main problem in seawater is that the zinc always becomes more electropositive which indicates a more protected potential than would be measured when using a real reference electrode such as an Ag/AgCl. I am currently working on a project where using a zinc reference (even after I warned the owner that this is not satisfactory) to monitor a C.P. system has resulted in several millions of dollars of damage to a marine structure. Why risk structural integrity to save $ 100.00 on a reference electrode?
I plan to remain a voice in the wilderness on this and will continue to vote negative on SP-0169 until this is included. I have given my comments to NACE previously on this with my negative vote with no success.
Jim Jenkins
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