API 650 closed top welded storage tanks limitations

Allowable compressive stresses shall be in accordance with 5.5.4 except that for aluminum alloy plate the allowable compressive stresses shall be reduced by the ratio of the modulus of compressive elasticity to 29,000 for values of (t – c)/R less than 0.0175 and by the ratio of the minimum yield strength for the aluminum alloy in question to 30,000 for values of (t – c)/R equal to or greater than 0.0175 (see 5.5.2 for definitions). In all other equations in this standard API 650 closed top welded storage tanks where yield strength or modulus of elasticity is used, such as Equations 27 and 28, similar corrections shall be made for aluminum alloys.

If additional requirements are met, higher internal pressures are allowed. API 650 only covers tanks that support the whole bottom evenly and API 650 closed top welded storage tanks tanks in non-refrigerated service that have a maximum design temperature of 200 degrees F. It requires that you have a minimum material thickness of 3/16 inch.

Oil tank accessories are an important component of metal oil tanks. Common accessories of API 650 closed top welded storage tanks include manholes, light holes, oil measuring holes, breathing valves, safety valves, and fire extinguishers. The functions of these accessories are different. Some are to ensure the storage quality of various oil products, some are to ensure the normal operation of oil products receiving and dispatching, and some are to ensure the safety management of API 650 closed top welded storage tanks, etc.