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How big a tank can you get a transportation permit for? We regulary build tanks 24' to 30' (7.3m - 9.1m) in diameter in the shop (Canada).

Section 5.7.6.1.a states that manholes are excluded from having to meet the requirements of B16.5.

Would you use the bearing plate as backing for your full pen weld on the annular ring?

Hi All, I have a 215' Diameter tank that has a annular ring and an annular bearing plate. Is it necessary to grind the welds flush between the 2 annular rings? Thanks for your input.

Does API 653 allow you to reference the As-built code of construction for a replacement nozzle? If the tank is an older tank, you might be able to get away from the PWHT by refering to the edition of API 650 that the tank was built to.

You are correct. This was corrected in the 11th ed Addendum 2.

This design method comes from the Structural Engineering Handbook by Gaylord, Gaylord and Stallmeyer. They give formulas for the maximum thrust, moment and the expected stress in the ring beam.

Unfortunatly no. The material is not in the bottom course and no nozzles were installed in it.

Has anyone ever recertified material to Grade 250? The way I read API 650, Grade 250 steel is a method of reclassifying steel from a foreign mill for use in API 650. My question is why is there so few restrictions on it? As per Table 4-2 the steel has to meet a few strength requirements and...

Hi All, I have recently come across an issue with G40.21-38W material and I was wondering if anyone else has come across this problem and what steps they took. On 2 seperate tanks I have recently worked on I have received material specified as 38W on the MTR. However on closer inspection it...

Check out Appendix I for spacing requiments of the beams on the skid and the required floor thickness of the tank.

Section 7.5.1 states that the purpose of the tolerances provided in 7.5.2-7.5.7 are for apperance and for the proper functioning of the floating roof. The shell could be out of round but still be structurally sound. Of course it is good practice to build any tank within the roundness...

API 650's roundness limitation would not be suitable for this type of deformation. The roundness limitation in API 650 is for the smooth operation of floating roofs. It is has no bearing on a structural deformation.

This is a limit on the maximmum thickness for the roof. It doesn't mean that a 1/2" thick roof will be sufficient for all tank sizes. If your calculations say you need a thickner roof you should use a different type of roof (umbrella, dome, structurally supported).

The joint efficiency you end up using should contain 2 factors. 1. The joint efficiency of the weld as determined by your destructive testing and 2. The joint efficiency due to the reliability of the weld. API 620 would suggest that you use a joint efficiency of 0.85 for a double welded butt...

ASME Sect VIII UG-34-c-2 gives some guidance on thickness requirements for non-circular openings. You could look to see if they give anything on reinforcement as well.

Depending in the size of your tank you could reference API12F. That is the only API code that I know of that allows the use of rectangular manways. This would only be suitable for tanks with low shell stresses (The maximum liquid head that 12F applies is 25') API 12F is not a design guide, it...

Hi All, I am trying to resolve a descepancy I have come across several times with small API 650 tanks. The tank in this example is a 3000bbl tank (23.5'D x 40'H). Per the main body there are 2 checks for overturning: 5.11.2 item 1 This formula can be rearranged to find the maximum pressure...

Does anyone know why API 620 is so much more conservative on their joint design then AISC ASD? For 38W material a single lap weld would have an allowable stress of: API 620 S_allowable = 16,500psi x 0.35 = 5,775 psi AISC (table J2.5) S-allowable = 60,000psi x 0.3 x 0.707 = 12,726 psi

As I feared... I had designed the tank to have a double lap weld for the outer 3rd of the tank to roof to increase the joint efficiency to 0.70. I just found out they didn't do the back weld on the roof and now the tank has been coated. Sigh...