From my very limited dealing in this field I'm not sure there is a class for things like Cranes.
We made trolleys & storage racks/pallets etc for stores at a previous employer. At one point we were looking into making some of them blast resistant to help meet IM requirements. I don't remember the racks or trolleys having to meet some recognized standard by themselves.
There were I think maybe grades of how insensitive a munition is, which could include packaging effects, but that's not directly applicable to you.
There are standards for bomb shelters etc but I don't know that they would pertain to cranes.
Either way, based on your second post it seems that your products weren't intentionally designed to be explosion proof.
KENAT, probably the least qualified checker you'll ever meet...