Carbon steel wall thickness as per API 650
Carbon steel wall thickness as per API 650
(OP)
Dear All,
We are working on a project where there is are requirements to carry out preliminary design. I need some suggestion regarding wall thickness. As per the API 650, 5.6.1.1, the minimum plate thickness required for 36m diameter tank is 8mm. Now my question is does this 8mm includes corrosion allowance or I have to consider like 8+3 corrosion allowance = 11mm. Please advise. The tank dimensions are 36m dia x 15m height with 3mm corrosion allowance.
Regards
We are working on a project where there is are requirements to carry out preliminary design. I need some suggestion regarding wall thickness. As per the API 650, 5.6.1.1, the minimum plate thickness required for 36m diameter tank is 8mm. Now my question is does this 8mm includes corrosion allowance or I have to consider like 8+3 corrosion allowance = 11mm. Please advise. The tank dimensions are 36m dia x 15m height with 3mm corrosion allowance.
Regards





RE: Carbon steel wall thickness as per API 650
RE: Carbon steel wall thickness as per API 650
Please review Appendix K of API-650 ....
This Appendix contains Tables that will enable you to make reasonable estimates
MJCronin
Sr. Process Engineer
RE: Carbon steel wall thickness as per API 650
- Five course shell construction
- First Course 0.875 inch
- Second Course 0.750 inch
- Third Course 0.625 inch
- Fourth Course 0.500 inch
- Fifth Course 0.375 inch
let us know what your final estimate looks like..
Are there aditionsl tanks in your scope ??
Tell us more ...
MJCronin
Sr. Process Engineer
RE: Carbon steel wall thickness as per API 650
The specific question was on the interaction of specified minimum and corrosion allowance, and that was what I was responding to above.
RE: Carbon steel wall thickness as per API 650
Thanx for your replies.
Dear MJ Cronin,
As per the data;
product design stress bottom course=184MPa, upper course=196MPa
Minimum yield strength=250MPa
Minimum tensile strength=400MPa
Minimum hydro static stress=171MPa,
product - water,
my calculation shows as, including corrosion allowance of 3mm (0.118")
1st course-18mm (0.708")
2nd course-14mm (0.551")
3rd course-12mm (0.472")
4/5/6th course-11mm, (0.433")
RE: Carbon steel wall thickness as per API 650
For your case = Tank 36 (D)m x 15 (H)m
Assumptions:-
For the above mentioned assumptions the required thickness (Including corrosion allowance) will be:-
Regards,
MOHAMMED
RE: Carbon steel wall thickness as per API 650
RE: Carbon steel wall thickness as per API 650
The Operating condition (product design stress) which you have considered is 160MPa, whereas the Client has specified product design stress bottom course=184MPa, upper course=196MPa. Based on the Client's data I guess my calculations are correct. Please confirm if you can.
Regards
RE: Carbon steel wall thickness as per API 650
The the product design stress is based on the MOC for the shell plate, In my calculation i have selected material A36M for running the calculation. So please check API 650. Clause 5.6.2 & Table 5.2a. from that table you can get the Product design stress for your particular material.
Regards.