I have been researching details on diesel storage for a back-up generator. The generator will be outside but in an small enclosure. The diesel fuel tank is a sub base tank so the engine will be mounted on top of the tank. I want to better understand the reasons behind not having to classify the diesel fuel. The unit will sit outside on a concrete pad. It isn't usual for the summer ambient temps to reach 115 degrees which could be as high as 125 degrees on the concrete. Depending on the type of diesel fuel, I feel it could reach its flash point or be very close. The forums that I've been reading have people stating that since diesel fuel is only a combustible liquid then classification isn't needed which I don't necessarily agree with or find their understand their justification. I think the installation that I describe above would warrant some considerations of CIDII. What are everyone thoughts/comments?