API 650 carbon and low-alloy steel tanks corrosion allowances

The quality inspection department is responsible for the inspection management of raw materials and finished products, and the quality inspection and acceptance of products and raw materials. Strictly abide by the company's management system, conscientiously exercise the management power given by the company, and put an end to all ultra vires; be responsible for the inspection of all kinds of raw materials entering the company, and put forward quality problems and handling opinions.

The cost of mechanical cleaning for vertical storage tank, API 650 carbon and low-alloy steel tanks is low, almost all oil can be recovered, and the quality of recovered oil is high. The cost of manual cleaning for vertical storage tank, API 650 carbon and low-alloy steel tanks is high, the oil can not be recovered completely, and the quality of recovered oil is low. The mechanical cleaning of API 650 carbon and low-alloy steel tanks adopts fully enclosed operation, and separates oil, water and oil sand. There is no direct discharge of oily sewage and waste gas, which will not pollute the environment.

In this project, the area of tank wall used is of the same construction, material, and geometry as that described in F.1.3.1 except that the thickness of the plate is 3/8 in. The wall is stressed in the same manner as is described in F.1.3.1. A corrosion allowance of 1/16 in. is required. The computed (meridional) tensile stress, stc, in the net thickness after deduction of the corrosion allowance is 8000 lbf/in.2.
The problem in this example is to find the maximum allowable (latitudinal) compressive stress value for the given conditions, in conformance with the provisions of API 620 tank standard 5.5.4.5.
Solution: As determined from Table 5-1, the maximum allowable tensile stress value, Sts, for ASTM A285, Grade C, steel plate in simple tension is 16,500 lbf/in.2. Since the compressive stress is latitudinal, the governing value of R in this situation is R1, or 75 in.