API 650 larger diameter tanks decks

Large Low-Pressure Tanks Corrosion Allowance
In cases in which the rate of corrosion is closely predictable, additional metal thickness over and above that required for the initial operating conditions shall be provided and shall be at least equal to the expected corrosion loss during the desired life of the tank.
When corrosion effects are indeterminate before the tank is designed (although they are known to be inherent to some degree in the service for which the tank is to be used), and when corrosion is incidental, localized, or variable in rate and extent, the best judgement of the API 650 larger diameter tanks designer must be exercised in establishing reasonable maximum excess tank wall thicknesses. For all tanks that come under this classification, a minimum corrosion allowance of 1/16 in. shall be provided.

Under the same sealing effect, the internal API 650 larger diameter tanks floating roof API 650 tank can further reduce the evaporation loss compared with the external floating roof API 650 tank. This is due to the shielding of the fixed roof and the gas phase layer between the fixed roof and the inner floating plate, which has more significant heat insulation effect than the double disc floating roof of the API 650 larger diameter tanks external floating roof tank.

The preparatory work before the construction of the API 650 larger diameter tanks is directly related to the quality assurance, project progress, construction safety and other aspects of the entire oil tank project. Therefore, the preparation work before the API 650 larger diameter tanks construction should be paid attention to and planned. Before API 650 larger diameter tanks construction, you need to prepare conventional machinery, materials, and facilities, as well as the quality control of the project, such as the installation method of the API 650 larger diameter tanks, the welding method of the steel plate, and the inspection of the tank material. In addition, there is the most important item, construction safety protection.