flanges on hydro generator: stardards

[uhpo]

Hi
I try to search some standards that show how a frange must be done on a hydro generator, (forged shaft).... and also some information about tolerances on holes and bolts that join the two shafts (generator and turbine) this is cause i find on one water turbine a problem, maybe related to offsets of the shafts... so i wonder how is the standards about it