API Std 650 storage tank workmanship

Deformation of the welding seam of the API Std 650 storage tank is a common quality problem during the actual use of the API Std 650 storage tank, which easily causes the tank body to leak and affects the safety of the oil storage tank. The welding seam deformation of the API Std 650 storage tank is mainly caused by the lack of reserved welding seam gap and irregular operation. The oil storage tank has not reserved the corresponding weld gap, resulting in deeper root removal during the front welding activity. The heat output of the weld will increase under the influence of a long time, and the deformation of the weld will gradually become serious.

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 Std 650 storage tank 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.

When API 650 storage tank is designed, when the design pressure is small F2 kPa, the impact of air pressure on the API Std 650 storage tank tank wall thickness is not considered in the tank wall design.