Fuel Tank Stored in Bus Garage - Classification

[elecshop]

I have an open bay bus garage - roofed ceiling / sloped structure, and toward the end of the bay there is a fuel tank and oil tank. No walls are in the bays, only roofed and attached to an adjacent office building. The building does contain parts storage rooms, but is not a repair garage.
Looking at NEC 511.3, I could not find information that helps identify the Class and Division of the space. I know that the tanks are Class I Division 2, but how far does this zone extend? Looking at table 511.3(C): if the area is ventilated it would be unclassified.
Can someone help in clarifying my confusion?

Thanks!

 

[petersonra]

The oil tank may well not require classification at all.

The fuel tank, depends on the fuel.

 

[elecshop]

Fuel is diesel. Also this building is classified as S1 type occupancy - minor repair garage, with no fuel dispensing. But these two tanks are being relocated from a different place to this new building.
The fuel tank is underneath a structure, at finished floor level (not underground) but there are no walls enclosing the space where it is located - it is an open bay. Would this classify it as Class I Div 2?

 

[tom baker]

Diesel is not a classified fuel

 

[JoeStillman]

Depending on the amount of diesel, you may require four-hour fire rating for the room. I've seen it done with concrete vault-tanks too. But Tom is right, it's not a Class I space.