Sunday, September 28, 2008

SP0169 updates and voting!

There are several points that must be questioned and answered before this document goes to ballot. At this time, I am not sure they will be answered before the first ballot is sent to the voters.

Those of you who want to vote on this document must pay attention to the new voting process for NACE document approval. Request a copy of the Technical Committee Publications Manual for all the details.

1. Be sure you are a member of the STG 35 group. This can be accomplished over the internet by going to the NACE International website and following the process for becoming a member of that STG group. You should then receive a copy of the ballot when sent out for vote. We are not sure when the draft will be sent out for vote, but some think it will be before the end of the year.
2. Once you receive the ballot, you must indicate on the ballot what group you are voting in. Some of these groups are:
a. End user
b. Consultant
c. Manufacturer/producer
d. Not sure of the other groups, but I think there are 7 categories
3. It is important to understand that the group you vote in is very critical. If more than 50% of the votes are from one group, NACE has to find more voters to fill in so that the majority voters are from more than one group. Of course the problem is that these (fill in) voters may not be knowledgeable of the document and the concerns that may exist. Since many votes will be from end-users, that group could easily be over 50% of the total votes. If you can legitimately be in another group, please sign up as so. Fro example, if you are an end user, but your job function is a consultant to the field techs, then I think you could sign up as a consultant.
4. If you do not vote on the first ballot you will not be able to vote on any further revisions or re-ballots of this particular version.
5. If you vote negative you must provide the committee with a perceived technical inaccuracy or omission or address points dealing with perceived ambiguity or lack of clarity.

The negative must be accompanied by a written comment with a technical explanation and justification statement. A suggested revision or an action that serves to resolve the negative should also be included. Without these the committee does not have to consider the negative.

As you can see it is rather complicated, but the first thing is to be sure you are member of the STG 35 group before the ballot comes out. Please let me know if I can help with any of these issues above.

DISCUSSION OF CTW MEETING – Draft Version #1e – July 2008

The import issues that come out this meeting from my perspective are:

There are several definitions the need to be corrected/changed.

Section #4 has some changes in wording that was worked on by the committee.

Section #5 addresses pipeline coatings and has not been completely revised. A representative from a rock shield company as well as myself have provide comments that have not been totally or correctly inserted at the time of this revision, but is being worked on.

Section # 6 has several issues, but here are the two big ones as far as I am concerned:

6.2.12. The two fundamental polarization criteria in this section have been proven empirically to reduce
the average corrosion rate of steel to less than 25 μm/y (1 mil/y) in soils and natural waters in the field
at ambient temperatures.3,4,5 Situations may exist in which a single criterion for evaluating the
effectiveness of CP may not be satisfactory for all conditions. A single criterion for evaluating the
effectiveness of CP may not be satisfactory for all locations along a structure.

The problem with this section is how does one apply this to a pipeline? How does one prove an average corrosion rate of less than 1 mil per year or less? Of course you can by installing coupons that measure the corrosion rate, but how does that really relate to a pipeline that travels through all kinds of terrains and situations with various coating conditions, etc? Coupons are great tools, but do not provide all the answers to these questions. We will continue to have external corrosion as long as we have coatings and other shielding effects along with interference (AC and DC).

This statement is used in the ISO document and perhaps some others, but the 25 µm/y (1 mil/y) is not a reasonable value for determining corrosion control on external surfaces of pipelines and most other structures. It may be a good definition for some purposes, but is not practical for pipelines. A negative (cathodic) voltage of at least 850 mV as measured with respect to a
saturated copper/copper sulfate reference electrode. This potential may be either a direct
measurement of the polarized potential, or a current applied potential corrected for voltage
(IR) drops other than those across the structure/electrolyte boundary.

This criterion would no longer allow the owner to consider IR drop, but force you to only use a polarized potential, because the current applied “ON” potential must now be “corrected” for IR drops. How else can you correct it without using an instant off? The language does not leave much for consideration and use of other methods to prove what you are doing works. Of course, I am still waiting on an answer for the questions I have asked about why we do not have external corrosion on pipelines that use non-shielding coatings such as FBE and an “ON” -850 mV even with out considering IR drop. Most of us know why but this does not “fit” what we are being told must be done to protect our pipelines. Those of you who have this evidence must be putting it together to show the committee and prove the point that we do not need to have more stringent criterion. We need to continue to use the tools we have and better train our corrosion control employees how to recognize the problems that may need more work or investigation and apply the necessary control methods as needed.

Each section and part must be read and examined for accuracy. Remember the document presents procedures and practices for achieving effective control of external corrosion on buried or submerged metallic piping systems. In all NACE SPO’s the Forward says “This standard represents minimum requirements…”. The purposed version is far beyond minimum requirements. If passed as is it will represent the maximum requirements!

Please comment so we can all learn and work together to develop the best possible document that is practical and economical for companies around the world to use for effective external corrosion control on pipelines!