Good day,
I am just looking for a little direction of which corrosion rates to use when calculating the remaining life of an API 653 tank bottom.
An example would be if you have a tank that has 2 soil side pits. The deepest pit of 0.150in after 10 years on a 0.250in nominal floor and a shallower pit of 0.050in. The maximum corrosion rate for this tank bottom would be 0.015in. If the client wants a 10 year interval and you use that corrosion rate you you would have to repair both pits to meet the MRT of 0.100in. Or at least that's the way I was thought it and most people I ask agree with that assessment.
I have a co-worker who disagrees and says that once the 0.150in pit is repaired your corrosion rate for the interval calculation drops and therefore you don't have to repair the second pit.
I was just looking for some insight on who is right, or are we both wrong?
I am just looking for a little direction of which corrosion rates to use when calculating the remaining life of an API 653 tank bottom.
An example would be if you have a tank that has 2 soil side pits. The deepest pit of 0.150in after 10 years on a 0.250in nominal floor and a shallower pit of 0.050in. The maximum corrosion rate for this tank bottom would be 0.015in. If the client wants a 10 year interval and you use that corrosion rate you you would have to repair both pits to meet the MRT of 0.100in. Or at least that's the way I was thought it and most people I ask agree with that assessment.
I have a co-worker who disagrees and says that once the 0.150in pit is repaired your corrosion rate for the interval calculation drops and therefore you don't have to repair the second pit.
I was just looking for some insight on who is right, or are we both wrong?
