volatile hydrocarbons located in the container space 4 is covered by a floating cover 5 the floating cover 5 is supported by a ring pontoon 6 above the liquid which is arranged around the peripheral area of the floating cover 5 the annular space 8 remaining between the outer wall 7 of the floating cover 5 and the inner side of the container wall 3 is closed by flexible sealing elements 9 such that on the one hand no precipitation water can penetrate into the space below the floating cover 5 and on the other hand no vapors from the space below the floating cover 5 can escape wherein such vapors also accumulate in the annular space 8 above the liquid surface 10 as indicated in the figure a plurality of supports 11 with which the floating cover 5 rests on the container base 2 when the storage liquid is emptied from the container 1 to a residual volume is located on the underside of the floating cover 5 distributed over its surface after the still remaining liquid is completely emptied out of the container 1 and the space 4 between the container bottom 2 and the floating cover 5 is degassed the floating cover can also be inspected and maintained at the underside located in the floating cover 5 is on the one hand a fitting in the form of an overpressure valve 12 for the autonomous checking of an overpressure in the container space 4 and on the other hand a fitting in the form of a vacuum safety valve 13 for the autonomous checking of a vacuum in the container space 4 both fittings 12 13 are connected via.