Hello all,
Looking at API 650 12th Edition............The uplift criteria for unanchored tanks has yet again been changed.
Clause 5.11.2.1 states that Unanchored tanks need to satisfy criteria:
1) 0.6Mw + Mpi < Mdl/1.5 + Mdlr
2) Mw + Fp(Mpi) < (Mdl + Mf )/2 + Mdlr
3) Mws + Fp(Mpi) < Mdl/1.5 + Mdlr
Clause 5.11.2.2 then follows on to say that unanchored tanks with supported cone roofs (i.e. where the roof plates are resting on and supported by an internal roof structure ) shall satisfy the following criteria:
Mws + Fp(Mpi) < Mdl/1.5 + Mdlr...note this is the exact same formula as criteria 3) shown above.
Am i therefore correct in making the following statements:
If you have a cone roof tank where the roof plates are supported by an internal structure or columns you only have to carry out uplift criteria calculation 3) and criterias 1) & 2) do not apply.
If you have any other type of roof such as Floating roof, Dome roof or a self supporting Cone roof you must carry out and satisfy uplift criteria calculations 1) 2) and 3).
Thanks
Looking at API 650 12th Edition............The uplift criteria for unanchored tanks has yet again been changed.
Clause 5.11.2.1 states that Unanchored tanks need to satisfy criteria:
1) 0.6Mw + Mpi < Mdl/1.5 + Mdlr
2) Mw + Fp(Mpi) < (Mdl + Mf )/2 + Mdlr
3) Mws + Fp(Mpi) < Mdl/1.5 + Mdlr
Clause 5.11.2.2 then follows on to say that unanchored tanks with supported cone roofs (i.e. where the roof plates are resting on and supported by an internal roof structure ) shall satisfy the following criteria:
Mws + Fp(Mpi) < Mdl/1.5 + Mdlr...note this is the exact same formula as criteria 3) shown above.
Am i therefore correct in making the following statements:
If you have a cone roof tank where the roof plates are supported by an internal structure or columns you only have to carry out uplift criteria calculation 3) and criterias 1) & 2) do not apply.
If you have any other type of roof such as Floating roof, Dome roof or a self supporting Cone roof you must carry out and satisfy uplift criteria calculations 1) 2) and 3).
Thanks