You can see the E variable in the lower portion of the equation.Įxample 3. This is a hint at the fact that this formulas hide the E variable, because it is 1 for de-seamed tanks as by default in new tanks. Which are the minimum thicknesses for each shell course for the design and the hydrostatic test condition if the tank wasn´t completely de-seamed?Į = 0,85 according to Table 4.2 of API 653, given that the tank wasn´t completely de-seamed. Product stored is vehicle gasoline at 60☏ (G = 0,739), CA is 3mm, and the diameter of the tank is 15,6m. A tank built in 1970 is dismantled and later reconstructed using A283 Gr C steel plates for the shell. Using the formula to calculate the minimum thickness for the design condition, we have:Įxample 2. Which are the minimum thicknesses for the first shell course for the design and the hydrostatic test condition?Į = 1 beacuse the tank is completely de-seamed Product stored is Texas Crude Oil at 60☏ (G= 0,918), CA is 1/8″, and the diameter of the tank is 28,6m. A tank is completely de-seamed and the reconstructed using A283 Gr C steel plates for the shell.

St is the allowable stress for the hydrostatic test condition (Mpa and psi) PRACTICE EXERCISESĮxample 1. Sd is the allowable stress for the design condition (Mpa and psi) G is the design specific gravity of the liquid to be stored, as specified by the PurchaserĬA is the corrosion allowance (mm and inches) The Purchaser, restricted by an internal floating roof, or controlled to allow for seismic wave action. = is the height from the bottom of the course under consideration to the top of the shell including the topĪngle, if any to the bottom of any overflow that limits the tank filling height or to any other level specified by Tt is the hydrostatic test shell thickness (mm and inches)ĭ is the nominal tank diameter (m and ft) Td is the shell design thickness (mm and inches) In United States Customary System (USC) units The minimum thickness of the shell of a reconstructed tank, is given by the following formulas found in Formulas for the calculation of Minimum Thickness for Reconstructed Tank Shells We have seen an advance to this issue in the article we had on calculating joint efficiencies, but we will have a further look to the formulas that appear there. The inspector should be able to:Ĭ) Calculate “ td”, design shell thickness (API-650, 5.6.3.2, for tanks of 200 foot diameter and smaller)ĭ) Calculate “ tt”, hydrostatic test shell thickness (API-650, 5.6.3.2) The inspector should be able to determine the minimum thickness of the shell of a reconstructed tank. The book of knowledge says this about reconstructed tanks: Today we will make some practice exercises on determining thicknesses for reconstructed tanks Last time we saw the basics of shell calculations for reconstructed tanks.

Api 650 tank design calculation excel