Offshore Thread

Please use this topic thread to post comments and information that is applicable to the Offshore sub-committee of the U.S. Wind Energy Standards Group. Please see the first post in the “General Thread” for the contact list. Attached you will find the draft scope statement and the minutes from the first meeting. Please contact the sub-committee lead, Walt Musial,, if you have any questions or comments that you prefer not to post below.
Offshore_Minutes_281009.pdf (178 KB)
Scope statement AWEA Offshore Roadmapping-final draft.doc (68.5 KB)

Minutes April 22, 2010 & Draft - roles and responsibilities
DRAFT-roles and responsibilites v2.doc (30 KB)
Minutes April 22 2010.docx (22.2 KB)


I summarized the process that is being pursued
• Subcommittee authorized by SCC to develop a guideline
• Subcommittee recommendations for guideline to be submitted to SCC for review
• Based on SCC approval, draft guidelines to be sent to “affected parties” for review and comment
• SCC reviews and addresses comments; they may send comments back to Subcommittee for review and recommendations
• Once comments are satisfactorily addressed, SCC may adopt guidelines

If individuals (not as members of the Subcommittee) recommend that AWEA engage in additional activities to develop a standard (alone or in partnership with other organizations, like ASCE and TIA), they need to submit recommendations to the AWEA SCC for consideration of the new work item. The SCC will be able to respond to the recommendations at the time the recommendations are made.

Communication Protocol

I consider the current process for communication to and among the groups to be awkward at the very best. AWEA’s planned improvement to AWEA’s group management processes will not be immediately useful to standards groups as, at first at least, the service will be available only to AWEA members. Therefore I conferred with the leaders of the project teams then recommended to the subcommittee that we (the standards program) establish our own independent communication system through electronic discussion groups. The recommendation was accepted. Based on the approval of the group (again, subject to ratification by you), I have set up four Yahoo Groups:

• Large Turbine Guidelines
• Large Turbine Structures
• Large Turbine Electrical
• Large Turbine Off Shore

I’ll be finalizing the groups and running them by you and project team leaders before populating them with project team members. The members WILL need to respond to the invitation from Yahoo in order to participate in the groups. We can do targeted follow up in some members neglect to respond.

I also recommend establishing a separate information dissemination group – not a Yahoo Group – that would provide information to persons interested generically in standards development (I’m suggesting it would be broader than just folks interested in the large turbine guidelines). Persons participating in the Yahoo Groups (which would allow members to join only with your approval and concurrence of the project team leaders) would actively engage in developing the guidelines; the dissemination group would just receive information (one way) from the AWEA standards program.

Next Meeting

Based on the progress made at the meeting and the schedule for completing project team draft documents, the group agreed to meet in conjunction with the Off Shore Workshop that will be held in October in Atlantic City, NJ. The group preferred meeting on Monday, October 4, prior to the Tuesday – Thursday workshop, rather than on Friday. I will check on the proposed timing of the Workshop – it may not begin until Tuesday afternoon – and we can develop a meeting schedule accordingly.


We adjourned at 3:30 p.m.

John Dunlop
Senior Project Engineer
American Wind Energy Association email
612-377-3270 direct
612-590-5538 cell

Attached the scoping document generated at our first meeting in Colorado back in October as well as the minute from our last meeting in Dallas.
Scope statement AWEA Offshore Roadmapping-final draft (2).doc (64 KB)
Minutes 052710 offshore group.doc (48 KB)

5-27-2010 Attached minutes of the conference meeting for the offshore group
Minutes 052710 offshore group.doc (48 KB)

This is the outline for Offshore Group 2: Manufacturing, Installation, Qualification Testing current as of 8/16/2010.
Offshore Standards Group 2 Outline 2010-08-18.xlsx (16.8 KB)


In preparation for our call tomorrow, I realize that the notes that I had distributed regarding schedule were sent to the original distribution of the meeting date and not the updated distribution included here. For those of you that are seeing this e-mail thread for the first time, I apologize.

As a reminder to the others, we do have our normally scheduled call tomorrow morning at 8:00 am PST. There is not a lot of new material to review but there are a few strategic issues that I would like to discuss with the group. Specifically, I am struggling with the revised outline that is to follow the “wrapper” approach that we agreed to in June. The complexity here is not so much specific to ICE, but dealing with all of the “capacity side” parts of the requirement. I have some suggestions going forward that I will discuss tomorrow looking for feedback.



The following documents and information were provided by Rudy Hall of Keystone Engineering as a useful reference for the offshore road-mapping groups. The API RP 2A 22nd Ed is still under review and is only intended to be viewed by the AWEA road-mapping group as a reference. PLEASE DO NOT DISTRIBUTE. Also, since this document is currently in review, if you do find errors please contact Rudy Hall and he will pass them on to the editors (

API SC2 Strategy, Document & Organization Plan Oct, 2007.pdf (237 KB)
The first document (API SC2 Strategy, Document & Organization Plan Oct, 2007.pdf) outlines a strategy that was adopted in 2007 to merge API RP 2A and the associated API documents with the ISO Standard. The presentation provides a “map” of how the API documents will relate to the overall ISO Standard and the plan SC 2 is following to achieve this goal.

API Document Formatting and Style Manual.pdf (243 KB)
The second file (API Document Formatting and Style Manual.pdf)is manual explaining how to write or re-write API documents to ISO formatting and style. This is no easy task. It requires a lot of work and editing to achieve a document that will be accepted as an ISO Standard. If the Offshore Groups want to adopt this manual, we will need to purchase copies or get a release from API to use before widely distributing.

API RP 2A 22nd Edition Final Draft.pdf (2.64 MB)
The third document (API RP 2A 22nd Edition Final Draft.pdf) is the latest “DRAFT” of API RP 2A 22nd Edition in the new ISO format. The Offshore Groups may use this as a reference document under limited distribution. It should not be distributed outside the working Groups. Please report any typos or believed errors in this draft release to me (, so that I may forward same to the document editor. Please review “ 2 References” listed on pages 2-1 and 2-2. Some of the topics included in the 21st Edition have been moved to other API documents.

The following is provided via Rudy Hall of Keystone Engineering as a reference for the Offshore Standards Road-mapping group.

API RP 2A 1st Edition October 1969.pdf (1.77 MB)
The attachment (API RP 2A 1st Edition October 1969.pdf)is a copy of the original API RP 2A 1st Edition. Not many offshore engineers still practicing have read this document. It is included only to demonstrate that a 1st Edition does not need to be a large document. In fact it may be better to have a standard that simply directs the user to the appropriate reference standards and provides some “general words of wisdom” to keep the end users out of trouble. That was the original intent of RP 2A.

Large Turbine Compliance Guidelines Subcommittee - PLANNING MEETING SEPTEMBER 3


Here is a nice gift basket for your Labor Day weekend. Included are the minutes that Lars recorded from our last call, the original document outline, our contact list and an e-mail regarding the agenda for the AWEA meeting next month. Per our last discussion, I would like to have final comments on the main sections headings, included both on the minutes and on the outline spreadsheet, within the next 2 weeks. Don’t worry too much about the sub-sections that are shown on the spreadsheet; we will leave that up to the section leads to finalize and we can collect those comments later. I left that information on the spreadsheet since several of you had asked and I thought it would be helpful to recap the original logic as you consider any comments that you may have on the main sections. In conjunction with any comments that you may have, please also indicate your ability to contribute either as a lead author, contributor or reviewer in any of the sections identified. I know that it would be better to compile comments, adjust the sections as needed, and then ask for this identification but we need to short cut the process a bit. My hope is that we have the final sections and allocations of leads identified prior to our next call so that we can begin to have more topically focused discussions.

Lastly, please let me know if you intend to attend the meetings on Oct 5th in Atlantic City.


Please let me know your schedule for the overview guideline that you discussed during the call. Can you have that done by mid-week next week?

Everyone have a great holiday weekend!!


Dan Dolan, Principal
475 14th Street, Suite 400
Oakland, California 94612
Office: 510-836-3002
Direct: 510-285-2731

Please note the following issues and events relevant to the Subcommittee:

Name: SCC Chair Suzanne Meeker concurs that we should discontinue using the term “permitting” in the subcommittee name. Please use the current name of the subcommittee: Large Turbine Compliance Guidelines Subcommittee

Leadership: Sandy has resigned as the Subcommittee chair. Suzanne has accepted the recommendation to appoint Paul Veers as the new Subcommittee chair, and Paul has accepted.

Subcommittee Meeting: The next meeting of the Subcommittee will be on Tuesday, October 5, in Atlantic City, NJ from 9 a.m. to 5:30 p.m. We will have three separate rooms available throughout the day, each with AV equipment. The opening reception for the Off Shore Workshop will be held that day from 4 – 7 p.m. Information on the conference, logistics and lodging is available at:

Draft agenda for October 5 meeting:

9 Introductions, logistics, purpose
9:15 Overview of the project
9:30 Status reports by each Project Team Leader
10:30 Break
10:45 Project Teams meet separately
12 Lunch on your own
1:30 Reconvene Project Team meetings
3 Break
3:15 Reconvene Project Team meetings
4:30 Full Subcommittee meets to receive an update from Project Teams
5:30 Adjourn

Minutes 081710 draft.doc (84 KB)
structural reliability outline rev3.xlsx (52.5 KB)

[LgTurbineStructures] AWEA/ASCE Survey Key Questions for Discussion Today

Questions sent previously attached below for convenience.

Dear Kevin and team,

I believe you have the right list, in any event I am cc’ing the Yahoo group and anyone who didn’t receive 2 emails from me today should notify me.

Kevin et al.

You have done a good job at synthesizing this information. I encourage you all to review these results on your own and create an independent view of the same to be shared in our next meeting. The following are some of the comments and (seemingly obvious) questions I will have for you all next time.

Comment 1: I’m aware of the internationally-recognized stds. but survival wind speeds are a problem for otherwise appropriate turbines for this region (Class II/III) due to potential hurricane exposure.
Question 1: Does our Guide address this issue? How will it be addressed? Can anyone provide further input?
Comment 1 should be considered in conjunction with whether or not the document we are developing will require certification of the turbine, and therefore development of the system loads, per IEC. If so, certification per the IEC standard should include design for maximum wind speed in site-specific events like hurricanes if necessary, with design to include turbine active yaw, which is understood to reduce combination of peak wind load with static moment. Tornadoes may not be covered, however. Our loads section should identify that turbine manufacturer loads are produced per an existing standard (IEC) utilizing the proprietary knowledge required to define / determine the electromechanical and aerodynamic interactions of turbines with different wind conditions (drag coefficients, angle of attack of wind, etc). Local engineers will not be able to utilize only ASCE-7 (for example) without direct employ of turbine manufacturers as turbine loads in wind are not (as indicated) JUST dependent on wind.
I agree with Mr. Moller’s comments. IEC has a wind turbine class S design for extreme wind conditions. Unlike ASCE (or similar) codes, it considers fatigue life. Local Engineers following ASCE (or similar) will be gauging single-event survival (less stringent) without the benefit of proprietary knowledge and consistency. Comment 2: The IEC/EN standards are performance related and specifically state that they are only for protecting the multimillion dollar investment of the buyer = they have NOTHING to do with “safety”
Question 2: Is this true? What “safety” are they referring to? Doesn’t IEC 61400-1 state that structural, mechanical and electrical safety of these systems is covered by the same Standard?
The basis of the comment is not clear, plus we are not readily familiar with all aspects of IEC/EN.
IEC does direct that the “appropriate” personal safety be used during construction, erection, commissioning, service etc. It does not give specific safety guidelines as those vary from region to region – or state to state for that matter. Comment 3: Permitting is similar to other towers and stand-alone structures.
Comment 4: And this is not good for large vibrating structures
Question 3&4: If permitting of wind turbines is done as for towers and stand-alone structures, and this is not good for large “vibrating” structures, will our Guide provide the necessary interface of knowledge between standards for tower/stand-alone structures and “new” international Standards for wind turbines?
It is not clear what Comment 3 refers to, i.e. design and associated review, or some other aspect of permitting, however we must admit not being familiar with e.g. transmission or radio tower design standards. Relative to wind turbines, it is as simple as requiring adherence to an existing standard for the turbine / tower loads assessment, production of both ultimate strength and fatigue limit state design scenarios, and requiring thorough (e.g. complete load path for fatigue and ultimate) tower / foundation design for each. The loads are EVERYTHING; development of them is discussed above.
The comment is not clear to me either.
Comment 5: My staff is fully trained and certified to make the necessary code related decisions and observations. Our biggest trouble is with the owners, engineers, and contractors involved in these projects and their lack of understanding of the codes and their lack of plannign and coordination.
Question 5: Will our Guide provide enough information or help “owners, engineers, contractors” regarding their understanding of codes, planning and coordination? Do/Can/Should we provide solutions to all these?
Without knowing what area of code compliance review the respondent specializes it’s difficult to comment, however addressing the comment may be a local issue, something that the guide probably can’t address. The comment also sounds like whining.
This sounds like it comes form an AHJ who insists on enforcing building codes even when they don’t make sense. A note in the guide that these are not buildings or subject to are subject only to applicable codes would be helpful. Comment 6: Your qeustions seem geared to achieve a particular answer.
Question 6: Can somebody review our survey questions and see if they all seem geared towards a particular answer?
The questions seem fair.
Comment 8: Wind turbine structures are designed and permitted on aperformance based design for the entire installation as required by the statewide buildign code.
Question 7&8: If permits are issued based on review of Certified Structural Engineer and wind turbines are designed and permitted on performance-based design…. Are these structural engineers working for the manufacturer or all the independent structural engineers who provide review perform a “performance-based” analysis?
Comment 7 seems to say that the author is not familiar with the code classification (i.e. non-building) of turbines for structural permits and is satisfied knowing that a structural engineer is doing the review, which may not always be true. The definition of “performance-based” design for a given structure is highly dependent on criteria. Insofar as the code sets criteria for non-building structures related to strength it establishes performance requirements for turbine foundations – but this is less than half the story as dynamic stiffness and fatigue requirements are not covered in the code but are at the fore of criteria derived from turbine needs. The tower and foundation structural engineers have historically had to determine how to come to this without the benefit of US standards, often against their will.
These are typically independent engineers – the guide should be moot as to who hires them as this is a commercial matter,
Comment 9: If vetted through the ICC code review process
Question 9: Should our Guide be vetted through the ICC code process? What can we do better to create more trust in our consensus-based Guide developed under the AWEA/ASCE umbrella?
Does the ICC have a code review process for other than of their own codes? We have aligned the guideline with IEC, the body that has authored standards to which the turbines are often certified using defined wind classes and turbine operational states (=> loads) that also fall under IEC. Technical committee 88 of the IEC authors the relevant documents in wind … RG_ID:1282. By producing a document that marries the preeminent international standard (with its inherent reliability framework around loads pegged at 20-year life) to a standard or standards for structural design aimed at US compliance may very well provide the connection needed between the world of turbines (IEC) and the world of US building codes (IBC, ASCE, ACI, AISC, etc). Fatigue design requirements would need to be folded into this, however, and there is more available through reference to standards from other countries than US standards (unfortunately).
Question 10: What approval are they referring to? Really? Why?
The comment appears to be utilizing “approval” to replace “consensus” from the survey question [/color]“…consensus within the industry on code provisions, safety margins, and design life…” The comment also appears to not recognize that US engineers are preparing the guideline and that US codes are the basis of the guideline, supplemented by international codes as necessary.
Is he talking about certification (DNV, GL…)?

Kind regards and Thank you.

Last edited by Beverly.Cisneros on Thu Sep 16, 2010 2:47 pm, edited 1 time in total. Beverly.Cisneros

Posts: 47
Joined: Fri Apr 02, 2010 9:08 am
E-mail Beverly.Cisneros


It has been some time since our first meeting on that cold October day in Boulder and I have been remise at keeping everyone in the group up to date and the activity, albeit sparse, that has taken place this past winter. Recall that the main groups included, Offshore (Walt Musial), Electrical (Timothy Zgonena) and Structural (Rolando Vega) and that the Offshore group was further allocated into subgroups for: 1) Structural Reliability (which is the subject of this e-mail), 2) Manufacturing, Qualification Testing, Installation & Construction and 3) Safety of Equipment, Operation / Inspection, and Decommissioning.

We have developed the first draft of an outline for the structural design guideline which you will see attached here as an Excel spreadsheet. There has been similar content developed by the other groups and sub-groups and some discussion over the past several weeks on the consistency in approach amongst the various groups. There will be more discussion on the basic goals and architecture of the documents that are being developed by the groups, however, rather than wait for full resolution of these questions, I thought it best to begin at least some initial review of our outline. Please note the following when you review the spreadsheet;

• The main purpose of the document is to provide the MMS and state agencies with a regulatory basis for their licensing of offshore wind farms and would be adopted by the Code of Federal Regulations just as API RP2A is currently used for oil and gas.

• The secondary purpose of the document is to provide designers and engineers with guidance for designing OWTG support structures.

• The approach that I used was to identify the complete range of issues that a designer would need to address, regardless of whether or not these issues would be addressed directly within the document or through reference. Towards this end, the spreadsheet includes a column that identifies whether or not a section is new, taken from IEC, taken from API, etc.

• The means by which we use or refer to other codes and standards will require further discussion. However, it is clear that part of the function of this document will be to resolve inconsistencies and fill gaps that exist between any of the references (e.g., IEC and API) that we use. This in itself is a significant task.

• I have included some specific comments in the spreadsheet that provides more detail. You can add comments directly to the document this way or provide more general feedback in an e-mail.

Given that we are still discussing the overall approach, there may be some fundamental restructuring of this document. Therefore, please don’t spend a lot of time providing detailed comments and editorial suggestions. At this stage it would be most helpful to hear comments on the following basic topics:

• Given the secondary purpose of the document (above), do you see any specific technical areas that are missing or superfluous? What should be added or removed?
• What are your thoughts regarding the means by which we refer to or include other standards? Do we need to have a “complete” document that provides specific pointers to other guidelines or can we get by with a general guideline that makes a general reference to IEC and API, for example, and then let the designer work out the details?
• How would you prioritize these sections?

It would be very helpful to know if you have a specific interest in contributing to any of these sections. Again, we would hope that much of this material would be included through reference to other codes and standards, so there may be little to write for some sections, but we will still need member of the team to work out the references. It would be great if we could have your comments back by Monday the 22th.

Lastly, I would like to propose (it was actually Lars who suggested it) a monthly call to discuss the issues presented in this e-mail and the attached document and our progress toward the end goal. Would everyone support this? I would suggest that we hold a call during the middle of either the first or second week of each month, but perhaps we should hold our first call sooner. Please let me know your suggestions.

Group 1 – Structural Reliability
**Dan Dolan
Mort Andersen
John Cushing
Sid Falk
Jason Jonkman
Lance Manuel
Walt Musial
Marty Pollack
Frank Puskar
Lars Samuelsson
Arvind Shah
Ron Young


Dan Dolan, Principal


Here is the Canadian guideline that was requested during this morning’s call.


Canadian 61400 wind turbine design requirements.pdf (2.89 MB)

Reconfirmation: Large Turbine Compliance Subcommittee to meet in Atlantic City, next Tuesday, October 5
Members of the AWEA Large Turbine Compliance Subcommittee, Project Teams and Working Groups (via bcc):

Please be assured that the meeting of the Subcommittee and all the subdivisions will occur on Tuesday, October 5, in Atlantic City. I understand that some of you may not have received that confirmation earlier, and I apologize. The “good” news is that we are very close to making significant improvements in the communication system we use at AWEA for our standards program, which will significantly improve communication capabilities.

The meeting be at the Atlantic City Convention Center (, room 404, and will last all day on Tuesday the 5th, 9 a.m. – 5 p.m. A copy of the meeting agenda is attached. Lunch will be on your own at nearby restaurants.

The meeting is being held the day before the AWEA Off Shore Conference and Exposition. You are welcome to attend the conference and use the designated lodging for conference attendees, but it is not necessary to register for the conference in order to attend the meeting. Conference and lodging information is available at Group rate rooms are still available (as of last night) at Caesar’s (the “overflow” facility) AND the word today is that the Sheraton has had a few cancellations, so you may be able to secure the conference group rate there as well.

Please drop me a quick line if you plan to be at the meeting or to request any further information.


PS: Please excuse the multiple messages.
Large Turbine Subcommittee Meeting 2010 October 05 agenda.docx (15.1 KB)

All, new procedure guidelines from AWEA. It would be good to read this before Tuesday’s meeting.


Here is the AWEA standards review process, which after the meeting today, will likely be adopted for these guidelines. Please send this out to your groups and expect that it will be discussed in the plenary in Atlantic City. I think the agenda will come to you from John Dunlop.

Walt Musial
National Renewable Energy Laboratory
AWEA Standards Development Procedures Final 2007 July.doc (116 KB)

All, please find attached the minutes of the last call with the scope document and agenda for next Tuesday’s meeting.
Minutes 092010 draft.doc (63 KB)

All, attached are the minutes recorded by Qing at our meetings in Atlantic City. Thanks Qing.
Draft AWEA Meeting Minutes 2010-10-05 Offshore-Reliability SubGroup.doc (52 KB)
IEC Outline and Assignments.xlsx (13.4 KB)