One way to decide is to follow the manufacturers' rules.
Federal standards do not apply to recreational diesel fuel fills nor to exhaust hose but ABYC standards are written for both. ABYC adopts SAE standards that apply to fill hose and adopts a separate SAE standard for exhaust hose. Certain ABYC approved fuel fill hose also meets the separate exhaust hose standards. For example, fill hose designated A1 can typically be used for both fill and exhaust.
The obvious point is that the hose manufacturer labels the hose and will tell you in their catalog whether their fuel fill hose can also be used for exhaust hose.
Charles