Posted by: Ramin
WRC 386 checking for Manways - 05/11/12 09:37 AM
Hi everyone,
I have read a lot of stuffs about WRC386 checking of manways on this forum, I have a couple of questions regarding what is the right approach to check manway nozzles:
To my best knowledge, most manways fail WRC107 provided thrust pressure is activated in checking. This means that WRC107 is so conservative at least for manways. In most stress reports that I came acroos with no one checked manways against WRC107 with thrust pressure!
On the otherhand, thrust pressure is an existing axial load, that I believe needs to be checked and this leads to checking it against WRC386 that I recently discovered! I'm not familiar with this bulletin a lot, but I seem to have difficulty checking the manways in the vessel I am modeling now.
My vessel spec is:
D=OD=36-in and d=Manway OD=24-in
There is a parameter in WRC 386 i.e. D/d that needs to be less than 0.5 for stress parameters to be within suggested range, which in my case is NOT (D/d=0.67) and I get this warning in Caesar that the checking may NOT be accurate!
Does any one come across this issue? How are manways checked in general and how one makes sure if they are properly designed in case of large D/d as in my case? I'd rather avoid checking it by FEA due to time shortage.
Thanks,
Ramin
I have read a lot of stuffs about WRC386 checking of manways on this forum, I have a couple of questions regarding what is the right approach to check manway nozzles:
To my best knowledge, most manways fail WRC107 provided thrust pressure is activated in checking. This means that WRC107 is so conservative at least for manways. In most stress reports that I came acroos with no one checked manways against WRC107 with thrust pressure!
On the otherhand, thrust pressure is an existing axial load, that I believe needs to be checked and this leads to checking it against WRC386 that I recently discovered! I'm not familiar with this bulletin a lot, but I seem to have difficulty checking the manways in the vessel I am modeling now.
My vessel spec is:
D=OD=36-in and d=Manway OD=24-in
There is a parameter in WRC 386 i.e. D/d that needs to be less than 0.5 for stress parameters to be within suggested range, which in my case is NOT (D/d=0.67) and I get this warning in Caesar that the checking may NOT be accurate!
Does any one come across this issue? How are manways checked in general and how one makes sure if they are properly designed in case of large D/d as in my case? I'd rather avoid checking it by FEA due to time shortage.
Thanks,
Ramin