AST Aboveground Storage Tank Forum RSS Welcome the aboveground storage tank forum, a bulletin board dedicated to tanks, fuel tanks, plastic tanks, fuel storage tanks, and above ground storage tanks for engineers, tank operators, maintenance personnel, and technicians who work on or around these aboveground storage tanks (AST) and chemical plastic tanks. 3/30/2017 6:35:18 PM Earl at AST Aboveground Storage Tank Forum RSS 180 150 Re: Repair of the wall and floor - By: JGardiner [1848] Good afternoon<br /><br />I checked API-653, and didnt see an allowance/exception for weight. Using API-653 and the rules for repair Im not sure how much this could affect subsequent API calculations for design of tanks. Tank weight really isnt a big contributor to dead weight compared to fluid contents.<br /><br />Buckling in ASTs is due to global wind &amp; seismic response. Increasing tank weight slightly could have a limited reduction on anchorage demand wind and seismic. I would consider this negligible. <br /><br />For the roof, nominal thickness is the sum opf the design thickness + corrosion allowance. Can you say that smeared weight of your repairs is bounded by the corroded material weight? <br /><br />You could always do a finite element analysis to confirm <br /><br />JGardiner<br /><br /><br /><br /> Wed, 29 Mar 2017 11:13:00 -0300 Repair of the wall and floor - By: Brazil [201] The tank was repaired according to the rules of API 653 with repairs plates obeying the distances between welds, thicknesses of plates and formats of repairs. However the amount of plate repairs were a lot. Is there a limit to the amount of repairs to the wall and roof of the tank? Can these limits be calculated by the weight of the repairs? What percentage in weight can be adopted? Will there be structural interference if the repairs are concentrated in a single sector of the wall? Fri, 24 Mar 2017 21:58:00 -0300 Re: Seal Inspections - By: ADIEL HAR-SHOSHAN [93] If you are looking for the acceptance criteria to inspect primary and secondary seal in IFRT or EFRT you should look at 63.1063. Fri, 17 Mar 2017 01:21:00 -0300 Seal Inspections - By: Tankee [235] Out of curiosity, how does the Ka and Kb designations of tanks with the EPA affect their requirements for seal inspections? I see the separations and kind of understand that, but in 60.112b Standard for volatile organic compounds and 60.113b Testing and procedures, I cant find where they give direction for inspections as per the Ka or Kb separation. Seems to me that you have either an IFR or an EFR and they have ways that they must be examined, without ever mentioning Ka or Kb, unless Im missing it. <br />Anybody have any insight or can clarify any of this? Thu, 16 Mar 2017 17:52:00 -0300 Re: Temporary attachments on 9% Ni material - By: ITS [1678] Excellent response to your question by Valley Tank and right down to grinding the temporary weld attachment with nondestructive examination of the ground area using MT. Thu, 16 Mar 2017 08:45:00 -0300 Re: Temporary attachments on 9% Ni material - By: ValleyTank [1700] As long as you are using a qualified procedure for dis-similar welding such as this there is nothing code wise preventing you from using P1 as temp attachments just ensure the removal is clean and verified via MT. Tue, 14 Mar 2017 15:51:00 -0300 Re: API-653 - By: ValleyTank [1700] 1. Separate assemblies that are not being directly welded to the tank shell do not have to be qualified via ASME IX procedures.<br /><br />2. See table 4.1 in API 653 for yield and tensile stress for shells of the unknown condition. Tue, 14 Mar 2017 15:45:00 -0300 Temporary attachments on 9% Ni material - By: Patel [1177] Dear Experts,<br /><br />I would like to know whether temporary attachments of P1 CS material is allowed to be welded on the shell plates of P11 9% Ni material ? If not, kindly provide some code/standard reference please. Also suggest which alternative material can be used. Tue, 14 Mar 2017 05:42:00 -0300 Tank Foundation Settlement - By: ITS [1678] I was going to try to respond to a post by Mike in January of 2017 and thought others can help him if it was on the front page. I guess we will see. I will try but he has a tank in his factory and wanted to understand foundation settlement as well a find the optimum cosine curve.<br /><br />Mike, the optimum cosine cure for tank foundation settlement is a no curve at all, but a flat line. But in the real world it is more likely to be a bell curve after doing a best fit line. <br /><br />Work like this should be done by a professional as you know, Also, you should not expect deviations between the vendors, but you might get some. <br /><br />I can only assume you have a fixed roof tank because you are at a factory. Is this correct? Wed, 8 Mar 2017 15:58:00 -0300 Re: Sarc for settlement point B. - By: ITS [1678] Mike, I think moving your question to the front page is best. So, I started it for you titled Tank Settlement. Hope you dont mind. Wed, 8 Mar 2017 15:47:00 -0300 Re: API-653 - By: ITS [1678] The answer the first question you asked is as follows in my opinion that when welding a ladder or stair to the tank shell the weldments that are physically between the stair or ladder and the tank shell must have welds that have a WPS welding procedure specification that is qualified to the ASME B&amp;PV code Section 9 Welding the Brazing and the welder must be qualified WQR welders qualification record in the weld process being employed.<br /><br />That second question is much more difficult, for my approach would be to do a field hardness test and a field chemical analysis, but you may not have those readily available. That is how I would find the physicals and chemicals of the existing shell specification to find the suitable WPS. Sun, 5 Mar 2017 13:12:00 -0300 API-653 - By: ADIEL HAR-SHOSHAN [93] Can you please clarify the following :<br />1. Does Ladder &amp; Platform assemblies but not thier welding to tankk shell need WPS per ASME 9 or other?<br />2. What is the stress value to calculate the THK of a reinforcement plate when installing a new 6 nozzle in a unknown shell material?<br />Thanks<br /> Sat, 4 Mar 2017 04:12:00 -0300 Re: Intersting AST Analysis - By: ITS [1678] AST or Aboveground Storage Tanks are built or designed on the basis of the thin membrane stress theory as opposed to a ASME B&amp;PV Code which is not. API650 tanks are very flexible under extreme conditions and behave like a bladder. Dont know about the flying pickup truck or 380 mph winds. Fri, 17 Feb 2017 15:34:00 -0300 Intersting AST Analysis - By: JGardiner [1848] Greetings all,<br /><br />New to the forum but have been working with API-650 tanks, mostly in the commercial nuclear industry. Wanted to share an interesting project!<br /><br />In the nuclear industry ASTs are used to store water essential for the cooling of the reactor. We used finite element analysis to evaluate the tank subjected to winds of 360 mph and struck by a tornado missile. In this case an airborne pickup truck going 80 miles per hour. Its amazing how a thin metal tank and its energy-absorbing contents can withstand the impact and maintain its integrity..Definitely not an API-650 code case!<br /><br />Project Description<br />-<br /><br />Impact Video<br />-<br /><br />Look forward to great discussions on this forum!<br /><br />Jeff! Fri, 17 Feb 2017 08:21:00 -0300 Re: TANK JACKING SYSTEM - By: Dunedin [37] In my view Option 2 is the only viable method but best consult with specialist jacking contractor. Tue, 7 Feb 2017 01:37:00 -0300 TANK JACKING SYSTEM - By: KRISHNASWAMY [1139] A 54 M DIA COLUMN SUPPORTED ROOF TANK IS TO BE ERECTED USING TANK JACKING SYSTEM<br /><br />IT HAS 1 CENTRAL COLUMN AND 24 OUTER COLUMNS.<br /><br />WHAT US THE BEST METHOD FOR THE JACKING SYSTEM TO BE ADOPTED.AS SUGGESTED BELOW.<br /><br />1. ERECT ALL THE COLUMNS FIRST<br /><br />2 START ERECTING THE SHELL USING THE JACKING METHOD<br /><br />3 AFTER REACHING FULL HEIGHT, ERECT THE ROOF PLATES FROM SHELL TO COLUMN AND COMPLETE .<br /><br />ALTERNATIVELY<br /><br />1 ERECT THE TOP 2 SHELL COURSES.<br /><br />2. ERECT THE CENTRAL COLUMN AND THE SUPPORT COLUMNS EQUAL TO THE TOTAL HEIGHT OF THE SHELL ERECTED,<br /><br />3 COMPLETE THE ROOF PLATES ERECTION AND WELDING.<br /><br />4 INSTALL THE JACKS ON THE SHELL AND FOR EACH COLUMN AS PER TANK STABILITY CALCULATIONS.<br /><br />5. NOW LIFT/JACK UP THE TANK TOTALLY ALONG WITH THE COLUMNS TO REQUIRED HEIGHT FOR PLACING THE NEXT SHELL COURSE PLATE.<br /><br />6. ERECT THE SHELL PLATES AND COLUMNS OF EQUAL SECTIONS OF SHELL PLATES AND COMPLETE THE WELDING.<br /><br />7. REPEAT THE PROCESS TILL ALL THE SHELL PLATES ARE ERECTED <br /><br />EXPERTS ADVISE WELCOME <br /><br />THANKS IN ADVANCE.<br /><br />REGARDS Mon, 6 Feb 2017 09:30:00 -0300 Re: INSPECTION INTERVALS - By: ITS2 [1678] Longterm corrosion rate is critical, but so is short term corrosion rate of a tank floor. The next internal inspection and measurement of the tank floor is projected from those numbers. Problem with probable methodology is a level of confidence verses risk. A 100 percent measurement is best. A five year is typically associated with external inspection or in service inspection of tank. Thu, 2 Feb 2017 19:26:00 -0300 Re: INSPECTION INTERVALS - By: ITS [1678] Dont know if this can be answered to your satisfaction concerning aboveground storage tank inspection intervals. But my impression is the inspection interval review at 5 years is a generic inspection interval that is broadly based on AST inspection experience of the committee members, so no one falls between the cracks as reasonably as possible. As far as the consequences, the locale of the tank or jurisdiction the tank is located determines the consequences if any. Not all locales have laws or regulations and rules concerning this important tank inspection interval. Mon, 30 Jan 2017 13:27:00 -0300 INSPECTION INTERVALS - By: ADI HAR-SHOSHAN [93] 1. Api-653 Paragraph 6.4.2 : Can somebody please clarify why the review should take place within 5 years from january 2012? and if not what is the consiquence ?<br />2. Tank that their initial recorded internal inspection was 50 years after construction and the floor was inspected in probabillstic method , can the next internal inspection be determind on the basis of this long term corrosion rate? Fri, 27 Jan 2017 10:02:00 -0300 Re: Sarc for settlement point B. - By: MIKE [696] Hi<br /><br />I have same problem with a tank in my factory and I am trying to interpretate API 653 about settlement problems. How do you get the optimum cosene curve? By a computer? Thank you Fri, 27 Jan 2017 06:36:00 -0300