I am writing a spec for a new steam turbine lube oil vapour mist fan. The oil could be entrained with Hydrogen from the generator cooling system. Does anyone have any experience and therefore advice to offer with respect to whether the fan needs to be explosion proof (ATEX certified)?
Historically it seems this was not thought necessary, but on what basis?

would not worry about hydrogen since oil mist is very flamable I would use a sealed unit or one for an exsplosive atmosphere.
bruce