From the standard:
“Low-Pressure Coupled and Uncoupled Synthetic Rubber Tube and Cover (SAE 30R6), (SAE 30R7), (SAE 30R8) Hose which may be supplied either coupled or uncoupled for use with gasoline, diesel fuel, lubrication oil, or the vapor present in either the fuel system or in the crankcase of internal combustion engines in mobile, stationary, and marine applications. Exposure of these hoses to gasoline or diesel fuel which contain high levels, greater than 5% by volume, of oxygenates, i.e., ethanol, methanol, or MTBE (methyl tertiary butyl ether), may result in significantly higher permeation rates than those listed for 30R6, 7, or 8. This hose is for maximum working pressures of 0.34 MPa (50 psi) up to and including 9.53 mm (3/8 in) ID and 0.24 MPa (35 psi) for over 9.53 mm (3/8 in). For 30R6 hose in excess of 25.40 mm (1 in), the working pressure is 0.11 MPa (16 psi). The hose may be furnished in long lengths, specific cut lengths, or as a part preformed to a specific configuration. This hose is suitable for use in temperatures up to 100 °C (212 °F) for 30R6, 125 °C (257 °F) for 30R7, 150 °C (302 °F) intermittently and 135 °C (275 °F) continuously for 30R8.”
So, the standard for 30R6, 30R7 and 30R8 hose says that the permeation rate may be significantly higher with ethanol extended gasoline in excess of 5%.
As to Starlite FBU0600:
All information states it can be used as a fuel line.
But there is no notation of it being rated submersible.
-6 AN. Fuel, lube, and coolant compatible. Nylon sheath. Will only work with full flow reusable hose ends or Starlite crimp style fittings.[/i]
This ( above in RED )would tend to lead you to believe it is designed for external tank usage only.