Hello All,
API 653 section 9.4 states that the shell can be repaired by 'deposition of weld metal'.
My query is that if weld deposition repairs are carried out on the shell, what rules should be used with regards to minimum weld spacing requirements?
I would typically use the guidance shown...
Hello All,
I hope everyone is well and staying safe during these strange and difficult times.
Just wanted some opinions regarding some terminology used in ANNEX F of API 650 13th Edition...
The formula given to determine the Maximum Design Pressure (clause F.4.1) states that the value of 'A'...
Hello All,
I am looking at a tank that was built in 1973. The tank is 180ft Dia x 74ft High. Design code is API 650 'App D'.
The original drawings show that the shell material is OX522 D and OX522 C?
I am not familiar with this particular grade of steel and am struggling to find any info on...
Hi all,
I have been asked to carry out checks for roof frangibility and venting requirements on some existing tanks. However the tanks have had internal floating covers installed with half a dozen circulation vents fitted around the perimeter of the tank roof.
Am i therefore correct in saying...
Hello all,
I have an existing tank originally constructed in 1980 and the client now wishes to store a product with a higher SG value in the tank. All other design parameters such as pressure, temperature, corrosion allowance etc. will remain the same.
The original design SG value is assumed...
Hello all,
With regards to the 3 uplift criteria in section 5.11.2.1 ( API 650 12th Edition Addendum 2 ).
For the value of MDL is it acceptable to include the weight of the shell insulation if the tank is lagged?
Similarly can we also include the weight of any roof insulation in the value for...
Hello All,
API 653 Fig 9.13 gives details for "tombstone" shaped patch plates in the critical zone and states the max dimension for these patches along the shell of the tank is 24 inches. It also gives minimum distance requirements between 2 tombstone type patches.
I was just wondering what is...
Hello all,
I am going through the sample problem in Annex P and familiarising myself with the formulas, methodology etc...
I noticed that Figures P.2(a-l) are applicable if L/2a = 1.0 or L/2a = 1.5
My query is that if you have an L/2a value greater than 1.5 ( lets say 4.0 for e.g ) would you...
Hello all,
I have a client who wishes to change the product in their existing tank to a new one with a much higher specific gravity.
I have ran the relevant shell thickness calculations using the newer/higher SG value and the existing shell thicknesses for the lower 3 tiers of the tank are not...
Hello All,
I am looking at an Elevated Temperature Tank (Annex M) and was wondering if API 650 12th Edition has any restrictions with regards to which steel grades can be used for the tank floor, shell and roof plates.
I.e. For tanks operating at elevated temperatures can you use any of the...
Dear All,
My understanding of the API 650 code is that Radiography is only required for the Annular Plate Joints ( if the tank has annulars ).
For Butt welded floor plates I believe the NDE criteria is the same for that of lap welded floor plates e.g A Vacuum Box Test and Visual Examination...
Hello All,
Looking in API 650 12th Edition Addendum 1.....
Appendix F Clause F.4.2 shows a formula with the term 'DLS' which is defined as "nominal weight of the shell and any framing ( but not roof plates ) supported by the shell and roof".
I am not clear on what is meant by the term...
Hello all,
Looking at API 650 12th Edition............The uplift criteria for unanchored tanks has yet again been changed.
Clause 5.11.2.1 states that Unanchored tanks need to satisfy criteria:
1) 0.6Mw + Mpi < Mdl/1.5 + Mdlr
2) Mw + Fp(Mpi) < (Mdl + Mf )/2 + Mdlr
3) Mws + Fp(Mpi) < Mdl/1.5 +...
Hello all,
I am looking at Annex C External floating roofs in API 650 - 12th Edition.
Clause C.3.4.1 (a) states that floating roofs shall have sufficient buoyancy to remain afloat with 250mm of rain fall over the full horizontal tank area. i.e. total volume of rainwater in m³ = 0.25 x Pi*D²/4...
Is anyone familiar with Appendix K of the tank design standard BS EN 14015 regarding design rules for frangible roof to shell joints? I have found a few queries in this section of the code and would like anyones opinon on the subject........
For some reason it only addresses frangibility for...
Hello all,
I am currently trying to working out the external surface pressure on a circular storage tank ( 15m dia x 12m High ) using the formula....
pe = qs x Cpe x Ca (cl 2.1.3.1 in BS6399-2)
I have obtained values for qs and ca however I am not sure what value to use for Cpe.
Looking at...
Hello All,
Looking in Roark 7th Edition on page 449 for 'Circular plates under distributed load producing large deflections'....
Case no 3 for fixed and held shows a value K4 = 1.73 ( at edge ). However in previous 5th and 6th editions of Roarks stress and strain the value of K4 = 0.476...
Hello All,
I would like to get clarification on a couple of things regarding shell to bottom welds..........
1) Clause 5.1.5.7 - Are the fillet weld sizes shown in the table referring to 'Leg length' or 'Throat thickness'?
My original understanding was that the table specifies the minimum Leg...
Hello All,
Looking at the method of using patch repair plates on the tank shell.........
In API 653 clause 9.3.1.7 it clearly states the maximum size of lapped patch plates is 48inches in height and 72 inches in length.
It also states in clause 9.3.1.10 that patch repair plates shall not be...
Hello All,
I have the latest copy of API 650 11th Edition, June 2007, Addendum 1 Nov 2008.
I am designing a cone roof tank that is atmospheric and have a few queries with regards to the formula for working out MF and Liquid weight WL.
In the Code clause 5.11.2 states that unanchored tanks...
