storae tank

[Samingme755]

hi,
can anyone explain to me this sentence meaning
corrosin allowance shall be add on all the surfaces of welded internal part exposed to medium
thanks

 

[Geoff13]

In this case medium means the product stored in the tank.

 

[Samingme755]

Thanks but I need more explanation

 

[JStephen]

They should specify a thickness of corrosion allowance.
Surfaces with just one side to the product will have thickness increased by that amount (shell and bottom)
Surfaces with both sides exposed to the product will have thickness increased by double that amount (submerged structural, nozzle neck extensions, etc.)
Typically, the tank codes will specify how that is to be added, how that additional weight is figured, etc.
In some cases, it is added to the calculated thickness only, in some cases to the minimum thickness as well.
In some cases, dead load resisting wind and seismic overturn will be as-built dead load, in other cases, corroded dead load.
The ASME vessel code and API-650 handle corrosion allowance in different ways.

 

[IFRs]

Add the specified corrosion allowance to everything that will get wet with product - things like the inside of the tank shell, all sides of the fixed roof support columns, shell nozzle pipes, the underside of the floating roof, etc.

 

[Samingme755]

Add the specified corrosion allowance to everything that will get wet with product - things like the inside of the tank shell, all sides of the fixed roof support columns, shell nozzle pipes, the underside of the floating roof, etc.

thanks that was helpful