Full welding of compartment plates
Full welding of compartment plates
(OP)
Hi All
Regarding API650 paragraph c.3.6, full welding of compartment plates along all edges is mandatory, I need to know that if welding of top edge of compartment plate is waived, capsizing of roof will be happend.(roof is double deck with ID=72m and area=4030m2,max. compartment area=56.5m2,roof liquid level=0.146m,total of compartment=50,Min compartment elevation=0.5m)
Thank you very much
Regarding API650 paragraph c.3.6, full welding of compartment plates along all edges is mandatory, I need to know that if welding of top edge of compartment plate is waived, capsizing of roof will be happend.(roof is double deck with ID=72m and area=4030m2,max. compartment area=56.5m2,roof liquid level=0.146m,total of compartment=50,Min compartment elevation=0.5m)
Thank you very much





RE: Full welding of compartment plates
RE: Full welding of compartment plates
I have never heard of a double deck capsizing, but I have heard of progressive sinking of roofs due to lack of welding along the top of a compartment plate. API-650 was revised about 15 or 20 years ago to require full welding of all compartment plates. If this is for a new tank you have to weld them fully. If it is existing roof you can evaluate the condition and decide a course of action. API-653 does not require upgrading of an exsiting roof to meet cureent requirements of API-650
Joe Tank
RE: Full welding of compartment plates
I have a question:If leakage is happend at one compartment,and the compartment is flooded, height of liquid will never reached to upper deck and flooding of adjacent compartments across the top of compartment bulkheah will never be happend. so how the tank will be sinked?
Thank you again
RE: Full welding of compartment plates
For shallow compartments it is possible for the compartment plate to be over-topped. Sometimes designers forget about heavy reactions due to rolling ladders. This causes further depression and may contribute to progressive flooding.
Joe Tank
RE: Full welding of compartment plates
Actually I dont get why you mentioned about rolling ladder,theres only on stairway outside of tank, but I dont understand the relation between compartments and stirway.
would you please explain me about this matter?
Thanks a lot
RE: Full welding of compartment plates
RE: Full welding of compartment plates
Thanks for your explanations,
Let me ask you something,we have four floating roof tanks,and our contractor has been finished erection of one roof without full welding of compartment, but I pushed them to perform it and they did it for 2 compartments and performing leaktest,I was there inside the compartment and we found theres leakage between upper deck plates that they are overlap.If we have to weld overlap plates to each other(inside lines)theres too much welding works, and maybe distortion is happend for upper deck(thk.=5mm), whats your opinion?
Thanks in advance
RE: Full welding of compartment plates
RE: Full welding of compartment plates
Thank you very much for your comments