Monday, November 10, 2008

API 650 11th Edition, Addendum 1

Can you believe it? It has been released! Addendum 1 to the 11th Edition of API-650 is now available! Now we can begin looking at what has changed. Since it has been indicated that there where a lot of editorial changes between the proof copy I had and the released copy, I will start over letting you know what changes have been made in the Addendum 1. We will also begin making revisions to our program to incorporate these changes into our ITSdesign program. The release date on the addendum is November. Therefore, the mandatory effective date will be May, 2009.

Thursday, October 30, 2008

API Inquiries

In the past one of the items at the API committee meetings has been the review of inquiries sent in by those of you who had questions concerning some aspect of the API-650, API-653, or API-620 codes. There have been some changes going on that has prevented this from happening or has reduced which inquiries would be reviewed at the committee meeting. After the last meeting I thought this had been worked out so that at this meeting inquiries would once again be considered. In fact the schedule has a time set aside for this. I had submitted several inquires last time and resubmitted them this time anticipating that I would have answers at this meeting. After requesting verification that my inquiries had been received by the right person, I received a reply that said API has changed their requirements once again on how inquiries are to be handled. I am not sure what all this entails but hope to have it explained at the meeting in November. What I do know is that some of the committees accepted this new process and are following it. However, the committee that would be reviewing the inquiries I submitted decided that instead of using the new process they simple would not review or answer inquiries. I do not now where this leaves us. We shall see.

Tuesday, October 28, 2008

Update on Addendum 1

I have been trying to find out when API-650 11th Edition Addendum 1 was going to be released. I finally got an answer back. They now say it will be released in "November or December". The way it has been going I would say it will be December. It appears that they are trying to clean up some of the typo errors that exist as well as adding the changes. I think they had a lot more of the committee checking over what they were putting into the addendum. In the process they made a lot of corrections which meant it had to go back to the editors and be revised and rechecked. Hopefully there will be very few errors they will need to be corrected after it is released. As far as Addendum 2, they have not indicated any date. Just that it will be next year. We may have a better idea when we get to the API meeting in a few weeks. I will keep you posted.

Thursday, October 16, 2008

API-650 11th Edition Addendum 1

It has been a while since I posted. I will be trying to correct this in the future. First, there have been many questions concerning when Addendum 1 to the 11th Edition will be released. We are all still asking that question. I have asked API and am waiting for a reply. It might be November but we shall see. At the April meeting we were told that Addendum 2 would be released by the end of this year. Who knows, maybe Addendum 2 will be released before Addendum 1! I will be attending the API committee meetings in early November. By then we should have some type of answer.

I have submitted a series of inquires to API to try to get answered at this next meeting in November. After the meeting I will let you know what the results are of these inquires.

With regard to our software, ITSdesign, we have made several revisions to the program. An addition was made to allow you to enter additional wind moments and wind shears. We have added IPE, IPN, and HEA beam shapes to our SI database. We have also corrected some beam weight problems in the SI database. With regard to seismic designs, we have added a checkbox for entering "Peak Ground Acceleration" and values for "Q" to accomodate seismic areas not covered by ASCE7. Other minor corrections have also been done.

In my next post I will comment on some more of the changes that supposedly are coming in Addendum 1.

Saturday, August 30, 2008

ITSdesign Additions

We have just released an update to our ITSdesign API-650 and AWWA D-100 tank design software. In this release we have added the ability to specify a maximum allowable stress for shell plates that is less than what is specified by the code. We also added a link to the USGS website for obtaining the seismic values needed. The biggest addition is that we added the ability to use channels and wide flanges as center and intermediate columns. The column can be either a single beam or it can be a composite beam. Drop down menus allow you to select which beam sections you want to use. Corrosion allowances can also be applied to the beam sections. In addition we have corrected a couple of printing errors. We are constantly working to add to and make corrections to our software.

Monday, July 28, 2008

New Revisions to ITSdesign

I have just posted a revision to ITSdesign. In this revision I added new data entries for shell and roof appurtenance weights in the corroded condition. This allows you to have a different weight for the new and corroded condition. I also added a new data entry for the percentage of the roof appurtenances that is transferred to the shell. For column supported roofs this allows you to specify how much of the weight is transferred to the shell for resistance to overturning. The appurtenace weights have also been added to the resistance to uplift when internal pressure is present. For wind girder required section modulus I have added the 'm' factor to account for increased loading per I also added to check whether Appendix F calculations need to performed based on the weight of the roof and appurtenances as compared to the uplift due to internal pressure.

For those who are using ITSdesign, see the Revision block for other minor revisions to ITSdesign. We continue to strive to make ITSdesign as accurate and complete as possible. Suggestions for additions and corrections are always welcome.

Thursday, July 17, 2008

API-650 Appendix J Material

I have been debating about what to do with the material requirements for an Appendix J tank. What is specified in J.2 is that the material must meet the requirements of Section 4. This would mean that if you use A36 material in a shop built tank with a design metal temperature of -10 degrees F, you would have to impact test the material. What is strange to me is that if I built that same tank to Appendix A the material does not have to be impact tested per A.2. I plan on presenting the question to the API committee at the next meeting. In the meantime, I have added a checkbox to the design page of our software where you can select to use the material limitations of Appendix A. Each user will have to determine whether their customer will allow them to use the material as specified in Appendix A instead of the requirements of Section 4.

We have made some additional modifications and corrections to ITSdesign. Be sure to read the revision notes to see what we have done.

API-650, 11th Edition, Addendum 1

I am continuing to review Addendum 1 to the 11th Edition of API-650. Here are some comments on what I have found so far.

1) There are many slight modifications in the values used for SI units. Places that used to specify 12.5 mm now use 13 mm. In the table for, they have revised the angle size slightly. In 5.5.1 they changed 172 MPa to be 171 MPa. In they changed the limit for using the 1-foot method for shell design to 61 m. Revised the angle size in and
2) In 5.2.1 (loadings) they revised the external pressures so that tanks with internal floating roofs with circulation vents do not require a minimum external pressure.
3) In 5.2.1 they also added loading requirements for internal floating roofs.
4) In they added additional rules when using a lower allowable stress material in the upper courses. You now can do an elastic analysis or the lower course must be no thinner than the required thickness for product design or hydrotest design of the upper course.
5) They have revised some of the tables for manway neck thicknesses, nozzle reinforcement, cover plate thicknesses, and flush cleanouts.
6) For intermediate wind girders, the shell course thickness is now to be based on the thinnest shell course which may not be the top shell course.
7) An expanded design for frangible roofs has been added.
8) now states that the purchaser can specify that lateral loads be imposed on the roof supporting columns.
9) has been revised to reduce the minimum thickness for roof support columns from 0.25" to 0.236".
10) has been revised to provide calculations for the maximum spacing of the roof rafters. It also set the maximum spacing at 84". These limits apply to both inner and outer rafters.
11) 5.11.2 has been revised to add a limit on the value of wL for the wind condition. It also now specifies that tb is in the corroded condition. A calculation of the minimum annular ring width for wind has been added.

This covers most of the changes I see in the design section (Section 5). Next time I will give you information on the changes to the various appendices and which new appendices have been added.

To keep our software, ITSdesign, current, we are already working on the revisions to incorporated these changes into ITSdesign.

Monday, July 7, 2008

API-650 11th Edition Addendum 1

Can you believe it! I have finally received a proof copy of Addendum 1 to the 11th Edition of API-650! Yes, Addendum 1 will be finally released in the next 4 to 6 weeks. I will be working my way through this addendum to see what changes have been made. It looks like Appendix E has been corrected. Also, duplex stainless, aluminum, and mixed material appendices have been added. There is a change in Appendix V on how loadings are calculated combined for wind and vacuum. It appears there are some minimum thicknesses that are changing slightly. There is also a change in the determination of the maximum spacing of rafters (both inner and outer). The calculations for anchor bolts has changed as well. Appendix F has revised formulas for calculating the internal pressure. Appendix S has specific requirements for the use of "seamed" stainless steel.

This is just a quick overview of what I see in my first glance through the addendum. I will be posting more on the specific changes as I begin a more complete reading of the addendum. Be sure to come back for more information.

Tuesday, May 20, 2008

3 Bay Rafters

I would like to annouce that we just released an update to ITSdesign that includes 3-bay rafter systems. This applies to API-650 and AWWA D-100 tanks. In this update we also corrected some calculations related to SI units including the change from using 0.785 as the factor for pressure in the anchorage calculations to using 785. This change may possibly appear in Addendum 1 when it is released (still no proof copy yet). We continue to expand the capabilities of ITSdesign in both US and SI units. Also, we continue to verify that it is up to the latest edition of the code. If you have not tried ITSdesign, you can download a trial copy at You will find the program easy to use. If you do have questions, we are here to answer them. You can contact us at or by calling 651-480-0258.

Friday, May 16, 2008

API-650 Table 5-21

I received a reply on my concern with the formulas in Table 5-21a for SI units and it is agreed that the formula is wrong when pressure is included in the calculations. They are now trying to determine what is the easiest and fastest way to make the corrections. In my program, ITSdesign, I will use the factor of 785 instead of 0.785 for the pressure. This revision will be included in the release I will do this weekend. There is a possibility this change could make it into Addendum 1 but I kind of doubt it. Maybe they will release an errata sometime soon after Addendum 1 is released. I have not seen the proof copy of Addendum 1 so am still wondering when it will end up being released. I will keep you informed on this.

Thursday, May 15, 2008

API-650 Table 5-21 Uplift Loads for Anchorage

After returning from the API committee meeting I began looking at revising ITSdesign to conform to the changes approved to Table 5-21, Uplift Loads for anchorage. I had reviewed the changes proposed and agree with the changes being made. However, as I began rewriting the program and checking the output, it appears to me that the factor in Table 5-21a (SI units) is wrong. In looking back at even the 10th Edition, Addendum 3, it has a value of 0.785 for the factor when working with pressure. However, the pressure is in kPa while the result is to be in N. When checking the units we are off by a factor of 1000. I have written a note to the person who handled the agenda item and requested a claification. I will let you know what his response is once I receive it. In the meantime, I am revising ITSdesign for the SI units to use a factor of 785 instead of 0.785. I will also be incorporating the changes as approved by the committee for the agenda item.

Monday, April 28, 2008

API meeting in New Orleans

I attended the API meetings in New Orleans. There were some things addressed. Here is a brief summary.

1) Addendum 1 to the 11th Edition of API-650 should be released by the end of May. The proof copy we received was incomplete and they have not resent the complete proof copy yet. I will let you know when that occurs.
2) All of the agenda items approved at last falls meeting and this spring meeting are supposed to be coming out in addendums by the end of the year.
3) Table 5-21 was revised to conform to the combination loadings. This should be in Addendum 2.
4) Self-supporting roof calculations are changing that would use the strength of the material. This could reduce the compression ring area when highe strength materials are used. This should be in Addendum 2.
5) Clarification of the API-620 references in F.7 are still being worked on.
6) Shell nozzles larger than 48" is still being worked on.
7) Several minor items were approved and several are being reworked or reballoted.

Inquiries that had been submitted for review were not considered due to some timing problems. Hopefully this will be resolved by the next meeting.

Not much came out of this meeting. I will keep you informed as to when Addendum 1 is ready to release.

Monday, April 14, 2008

API meeting

I am currently at the API meeting in New Orleans. The day has been very disappointing. I found out that Addendum 1 for API-650 now will probably not be released until at least June. In fact the draft I have is incomplete. When released it should include new appendices X and SC. We shall see.

The other disappointment was that they did not review design or fabrication inquiries. They were scheduled to take place. However, it seems that all those inquiries we sent to API staff never made it to the heads of the committees in time to be sent out to the other committee members to review. Therefore, none of them are being reviewed at this meeting.

We will see if tomorrow is any more productive. We will continue to add to and update ITSdesign. We will also keep you updated on what is happening here at the committee meetings.

Sunday, March 30, 2008

API-650 11th Edition Addendum 1

I have started reviewing a copy of the final draft of API-650 11th Edition Addendum 1. I have not seen a lot of major changes. I do see that they have corrected Appendix E and it appears that it is the same as Addendum 4 of the the 10th Edition including the errata. Other areas I will be reviewing as to the affect on designs are the definition of Pe, the definition of material thicknes in 5.3.5, changes to manholes and nozzles, changes in frangible roof designs, and a change in maximum rafter spacing. I will be reviewing these and will comment more after Addendum 1 is released by API.

I will also be attending the API committee meetings in New Orleans the middle of April. I will let you know if any important information comes out of that meeting.

We are continually updating, correcting, and adding to ITSdesign, our API-650 and AWWA D-100 design software. Changes to ITSdesign are automatically received by our users the next time they start ITSdesign on their computer. All updates are automatically downloaded from our internet site.

Wednesday, March 5, 2008

API-650 App. R

In API-650 11th Edition Appendix R, there is a factor of 0.40Pe (external pressure) or 0.40Pi (internal pressure) added to various loading conditions. This same factor is used when determining anchor bolt loads on anchored tanks due to wind or seismic. However, there is also a note that says that if the operating pressure divided by the design pressure is greater than 0.40, the purchaser should consider using a higher value than the 0.40. How many times do we see a operating pressure but no specified design pressure? Many times the purchaser only knows the pressure he wants for operating and specifies that as the design as well. If you just plug these values into the formulas given then you will be designing a tank for less than what the operating conditions will be. We probably do not want to increase the design pressure to 2 1/2 times the operating pressure if the purchaser has not specified this condition as this will greatly increase the thicknesses or cause a requirement for anchorage or stiffeners. However, care then needs to be taken to address these other conditions to make sure we are providing an adequate design. Towards this end, our ITSdesign software now incorporates a check for the ratio of the operating to the design pressure, flags this condition, and provides the option to increase the factor beyond the 0.40 value as needed.

Tuesday, February 26, 2008

Two span rafter system

A new version of ITSdesign has just been released. The new update now includes two span rafter systems for both API-650 11th Edition and AWWA D-100-05. The design includes inner and outer rafters, intermediate girders, center column, center column base plate, intermediate columns, and intermediate column base plate. You can choose different material grades for the girders than for the rafters allowing higher strength material for girders. A new "Loadings" report has been included to show the loadings on the columns and shell.

Look for more additions coming soon.

Tuesday, January 29, 2008


A correction to my previous post.

API-653 3rd Edition, Addendum 3 is currently under final review and will be released soon.

I apologize for the error.

Monday, January 28, 2008

ITSdesign Update

We are just releasing an update to ITSdesign. A couple of corrections have been made and a couple of additions. One addition is that we now have an export to an Excel spreadsheet. We are seeking comments as to whether the format we have will satisfy the needs of the users. You can comment here or email me at The other addition is adding tooltips to the entire program. If you place the cursor on an item you will get a note explaining the use of that particular item. Also, if it is yellowed, which indicates that an error has occured concerning that particular item, additional information will be displayed concerning the error. That way you do not need to click on the Code Errors tab to see the errors.

Other notes of interest:
API-620 11th Edition appears to be in final review and will be released soon
API-650 3rd Edition, Addendum 3, appears to be in final review and will be released soon
API-650 11th Edition, Addendum 1, has not been released for final review but is to be released soon and will be released shortly thereafter

We will be going to the API committe meetings in April and are getting ready to submit inquiries. If you have any inquiries you would like us to submit for you, contact us and we will see what we can do. Right now we are waiting to see what Addendum 1 changes are before we do the submission.

Wednesday, January 9, 2008

API-650 11th Edition now available

As of January 1, 2008, the API-650 11th Edition is now in effect. To meet this requirement we have revised ITSdesign to be in conformance with the new 11th edition. The updated version of ITSdesign is now available from our website at Those currently using the program will receive the updates the next time they open the program. In addition to updating to the 11th edition, we have also added the base plate designs for center columns to conform to paragraph

We have not revised the seismic portion of ITSdesign as what is in the 11th edition is incorrect and will be corrected in the soon to be released Addendum 1. As soon as that is released, we will revise the seismic to meet the Addendum 1 corrections.

Yes, there is an addendum scheduled to be released for API-650. The last word I received is that it would be released sometime in January. I will keep you informed as to when this does occur.