I realize this thread is a few years old.

1) Can anyone point to which section of BS 7159 indicates that only OPE case needs to be checked? I remember seeing it but haven't been able to locate it since and didn't tab it.

2) Should the Sustained & Expansion cases be checked using those stress types (SUS/EXP) as well? Or should the load cases be built the same (W+P1 & Expansion=Operating-Sustained) and only the OPE case types be used for all cases?

3) Can someone please confirm that analysis including Wind loads does NOT result in an increase in the allowable stress? I assume I could confirm this myself if I received the answer to item 1 above.

Thank you for the help as always.
Dmitriy