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. http://www.ast-forum.com 5/25/2013 7:07:43 AM http://www.ast-forum.com/images/earl_clear.gif http://www.ast-forum.com/ AST Aboveground Storage Tank Forum RSS 180 150 New one non-welded seam, leg supported, liquid mounted seal in service one welded seam, suspended, shoe with wiper being installed now http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Thu, 23 May 2013 18:38:00 -0300 Can you define new http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Thu, 23 May 2013 16:53:00 -0300 New aluminum IFR just hitting the market. http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Thu, 23 May 2013 08:31:00 -0300 Any examples of this type of IFR? Surely you do not mean a pan type but manufactured in Aluminum or Stainless Steel? http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Wed, 22 May 2013 10:26:00 -0300 Lay them out and weld the top,<br />Pick them up, support with skids, weld baskets, large heavy rocks, where the welder can get under it, back gouge and overhead it. You can do two welds at a time working 180 degrees across from each welder. Dont move it until the welders are finished with each back weld. Then pick it up, remove the support, set it down and go to the next weld. <br />If you move a section before both welders are finished it could fall on the other welder. http://www.ast-forum.com/ast_forum_tree.asp?master=15625 Tue, 21 May 2013 20:38:00 -0300 Why not go for an aluminum floating roof without any enclosed compartments no spaces to be contaminated with vapors , that has superior strength, better emissions, suspended or vapor tight legs and better seals? http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Tue, 21 May 2013 19:23:00 -0300 Has anyone had issues with tank bottoms due to rainwater getting in. Any pictures available?<br /><br />thanks. http://www.ast-forum.com/ast_forum_tree.asp?master=15626 Tue, 21 May 2013 11:55:00 -0300 can any one share how to carry out butt welding from both sides i.e. top as well as bottom of annular plates without backing strip for tanks concrete ring. http://www.ast-forum.com/ast_forum_tree.asp?master=15625 Tue, 21 May 2013 11:13:00 -0300 I believe you are right, silicon is not ideal for sealing in certain environmentsand it does not look good on a completed dome. You might want to check out the Ateco Dome which claims to have a polyurathane seal beneath the hub cap and this means that they do not use silicon. http://www.ast-forum.com/ast_forum_tree.asp?master=15595 Tue, 21 May 2013 10:42:00 -0300 Some very interesting advice from CNT, however I wonder if he could clarify a couple of points for me:<br /><br />he mentions that supporting an Al IFR can save on emissions?<br />he mentions avoiding full contact type - why?<br /><br />Thanks. http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Tue, 21 May 2013 01:59:00 -0300 Why would a IFR be needed in a 620 tank. A 620 tank holds pressure. A IFR needs vents to work. The vents would tend to defeat the pressure holding qualities required for a 620 tank. http://www.ast-forum.com/ast_forum_tree.asp?master=15621 Sun, 19 May 2013 23:28:00 -0300 Hi,<br /><br />Could you please confirm can Carbon steel internal floating roof can be used for API 620 tanks? <br /><br />For example for internal pressure 15 Psig/-4 H2o tank<br /><br /><br />Thank you,<br /><br /><br />Regards,<br />Sameer http://www.ast-forum.com/ast_forum_tree.asp?master=15621 Sat, 18 May 2013 10:26:00 -0300 Inline with what Tankee said, settlement of the tank will cause a lot bulging / out of roundness issues. It can also lead to buckles, dips, and bulges in the floor. If your tank is in bad shape, you should look at jacking and leveling it before addressing any shell issues. http://www.ast-forum.com/ast_forum_tree.asp?master=15604 Thu, 16 May 2013 16:09:00 -0300 Advantages/Disadvantages to both. Here are some things to consider.<br /><br />Compatibility with product stored. - you dont want the material to attack the roof.<br /><br />Overall cost. - A low end aluminum roof will be much less expensive than a steel roof, but wont last near as long. A high end aluminum roof can sometimes approach the cost of a steel roof.<br /><br />Longevity of service - There are some very good aluminum roofs out there, but carbon steel is still probably going to last longer. On the high end aluminum roofs, the service life will be very comparable to steel. The price might be as well. The cheaper the aluminum roof, the shorter the service life. A cheap aluminum roof will cause maintenance headaches down the road. How often will you be cycling the tank? If the tank will be pretty active, you will definitely want a good quality roof that can take the abuse. A good aluminum roof will cost money, but will also be able to take the abuse. A steel roof can take about anything.<br /><br />Emissions requirements - Some areas require seamless roofs. A steel roof will be seamless welded, meaning lower emissions. There are one or two aluminum roofs out there with welded seams, but they are expensive. On the other hand, you can cable/chain suspend an aluminum roof and eliminate the need for legs, thus reducing emissions that way. That also eliminates the need for entering the tank to change the roof setting safer.<br /><br />A steel roof is going to sit lower in the product and generally will have an overall bigger profile than an aluminum roof. That takes up potentially valuable storage space. It doesnt take long for that to add up to serious lost profit potential.<br /><br />If you opt for a steel roof, I highly recommend that you look at putting bulkhead compartments. Since it is an internal roof, they dont need to be covered like an external pontoon, but you will be well served to bulkhead the roof if you get a crack in a weld or a pinhole leak that would otherwise sink a simple pan roof.<br /><br />Personally, I would avoid most of the honeycomb style aluminum roofs in preference for pontoon style. http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Thu, 16 May 2013 16:04:00 -0300 I have a question about API 650 5.1.5.7 Shell to Bottom Fillet Welds.<br /><br />Our tanks Data is below.<br />Annular Plate thickness 20 mm<br />Shell Plate thickness 41 mm<br /><br />according to Fig. 5-3C leg length groove depth, <br />according to 5.1.5.7b leg length + groove depth 20 mm, <br />leg length10 mm, groove depth10 mm<br /><br />But, the manufacturer designed that the leg length+groove depth of oneside is 30 mm, the leg length+groove depth of other side is 10 mm. And the manufactruer will weld by full penetration. Is it permissible?<br /><br /><br /><br />5.1.5.7 Shell-to Bottom Fillet Welds<br />a. For bottom and annular plates with a nominal thickness 13 mm 1/2 in., and less, the attachment between the bottom edge of the lowest course shell plate and the bottom plate shall be a continuous fillet weld laid on each side of the shell plate. The size of each weld shall not be more than 13 mm 1/2 in. and shall not be less than the nominal thickness of the thinner of the two plates joined that is, the shell plate or the bottom plate immediately under the shell or less than the following values:<br /><br />Nominal Thickness of Shell Plate Minimum Size of Fillet Weld<br /> mm in. mm in.<br /> 5 0.1875 5 3/16<br /> 5 to 20 0.1875 to 0.75 6 1/4<br /> 20 to 32 0.75 to 1.25 8 5/16<br /> 32 to 45 1.25 to 1.75 10 3/8<br /><br />b. For annular plates with a nominal thickness greater than 13 mm 1/2 in., the attachment welds shall be sized so that either the legs of the fillet welds or the groove depth plus the leg of the fillet for a combined weld is of a size equal to the annular-plate thickness see Figure 5-3C, but shall not exceed the shell plate thickness. http://www.ast-forum.com/ast_forum_tree.asp?master=15617 Wed, 15 May 2013 04:29:00 -0300 Somebody help me here. What would be the circumstance to put a floating roof in a 620 tank? http://www.ast-forum.com/ast_forum_tree.asp?master=15614 Tue, 14 May 2013 17:09:00 -0300 Hi,<br /><br />Could you please advise me, what is the criteria for selection of material for internal floating roof. I mean we are working on 108 feet dia tank x 48 feet height tank and I received different opionion from vendor regarding material of IFR. So which is the best practice to select whether we should go ahead with Aluminum IFR or Carbon steel IFR?<br /><br />Tank information: Tank1: 108 ft dia x 48 ft Height<br /> Service : Paraxylene <br /> Operating Temp: 150 deg F<br /><br /><br /><br /> Tank2: 108 ft dia x 48 ft Height<br /> Service : Benzene <br /> Operating Temp: ATM<br /><br /><br />Thank you,<br /><br />Regards,<br />Sameer http://www.ast-forum.com/ast_forum_tree.asp?master=15615 Mon, 13 May 2013 06:54:00 -0300 Dear Elites,<br /><br />I am working on fixed dome roof internal floating roof tank, which is designed as per API 620 so our client asked us following parameters in detail design. <br /><br /><br />Vapour space design pressure 15 Psig/-4&#226;&#8364;&#157; H2o<br />Maximum operatin temperature 131 deg F<br />Design Temperature 180 deg F<br /><br /><br />My question is, in my understanding for internal flaoting roof tanks, internal pressure is not applicable so please clarify me or advise me in this matter.<br /><br /><br />Thank you,<br /><br />Regards,<br />Sameer <br /> http://www.ast-forum.com/ast_forum_tree.asp?master=15614 Sat, 11 May 2013 00:41:00 -0300 You dont unless you have roof vents for the internal floater http://www.ast-forum.com/ast_forum_tree.asp?master=15610 Wed, 8 May 2013 23:14:00 -0300 In my humble opinion, rim vents have always been a solution in search of a problem. Steel or aluminum, internal or external - I dont see the need for them. API 650 is silent on the need for rim vents. http://www.ast-forum.com/ast_forum_tree.asp?master=15610 Tue, 7 May 2013 21:12:00 -0300