A question concerning peoples experience about the relevant vessel nozzle loads limits under blast+operation conditions.
In a current job, client is unable to specify nozzle load limits for the blast case. However, nozzle limits are specified without reference to type of loads.
The blast load criteria is that the item must not fail but permanent deflections are allowable. We have been given no indication on whether the standard stress limits (m+b 1.5f, m+b+g 2.25f - item is to PD 5500, though query applies also to ASME) must be applied for blast condition and our client, not main contractor, says its up to us.
In performing the piping stress analysis, one could ignore the blast case and use specified nozzle loads limits for operating and operating+wind load cases only.
Including the blast loads in the same excercise would mean additional restraints/supports around the numerous vessels.
However, a factor could be applied to the specified loads when checking piping loads under blast+operation load case.
Can not locate information on such approach, or any extended stress limits for blast load when applied to local stresses. I am hoping that your combined experience may shed some light on a possible 'standard practice'
A similar question has been raised by my colleague under the pressure vessel category.
Thanks
Isseck
In a current job, client is unable to specify nozzle load limits for the blast case. However, nozzle limits are specified without reference to type of loads.
The blast load criteria is that the item must not fail but permanent deflections are allowable. We have been given no indication on whether the standard stress limits (m+b 1.5f, m+b+g 2.25f - item is to PD 5500, though query applies also to ASME) must be applied for blast condition and our client, not main contractor, says its up to us.
In performing the piping stress analysis, one could ignore the blast case and use specified nozzle loads limits for operating and operating+wind load cases only.
Including the blast loads in the same excercise would mean additional restraints/supports around the numerous vessels.
However, a factor could be applied to the specified loads when checking piping loads under blast+operation load case.
Can not locate information on such approach, or any extended stress limits for blast load when applied to local stresses. I am hoping that your combined experience may shed some light on a possible 'standard practice'
A similar question has been raised by my colleague under the pressure vessel category.
Thanks
Isseck
