System for buffer storage and sequencing of loads, configured to receive non-sequenced loads coming from at least one external unit, via at least one outward entry conveyor (CAE, CAE'), and to supply sequenced loads to at least one preparation station (PP, PP'), via at least one outward exit conveyor (CAS, CAS'), said system being characterised in that it comprises: - a buffer storage unit (US) comprising N entry levels (VE 1 to VE N ) disposed vertically, each of the N entry levels comprising a conveyor of the "first in first out" type in a first direction and having a single entry and a single exit, with N≥2; - an alternative entry elevator (EAE) and an alternative exit elevator (EAS), of the discontinuous type, positioned respectively facing the single entries and facing the single exits of the N entry levels, the alternative exit elevator (EAS) being configured to take the loads only on the single exits of the conveyors of the "first in first out" type of the N entry levels; and - a control unit (UP) configured to organise, subject to a constraint to deliver, on said at least one outward exit conveyor, at least one sequence comprising loads in a required order: first movements of loads from said at least one outward entry conveyor to the alternative entry elevator, second movements of loads from the alternative entry elevator to the single entries of the N entry levels of the buffer storage unit, third movements of loads from the single exits of the N entry levels of the buffer storage unit to the alternative exit elevator, and fourth movements of loads from the alternative exit elevator to said at least one outward exit conveyor, and in that the buffer storage unit comprises at least one recirculation level (VR) disposed vertically with the N entry levels (VE 1 to VE N ) and comprising a conveyor of the "first in first out" type in a second direction opposite to the first direction and having a single entry and a single exit, and in that the control unit is configured to organise, subject to said constraint: fifth movements of loads from the alternative exit elevator to the single entry of said at least one recirculation level, and sixth movements of loads from the single exit of said at least one recirculation level to the alternative entry elevator. - a buffer storage unit (US) comprising N entry levels (VE 1 to VE N ) disposed vertically, each of the N entry levels comprising a conveyor of the "first in first out" type in a first direction and having a single entry and a single exit, with N≥2; - an alternative entry elevator (EAE) and an alternative exit elevator (EAS), of the discontinuous type, positioned respectively facing the single entries and facing the single exits of the N entry levels, the alternative exit elevator (EAS) being configured to take the loads only on the single exits of the conveyors of the "first in first out" type of the N entry levels; and - a control unit (UP) configured to organise, subject to a constraint to deliver, on said at least one outward exit conveyor, at least one sequence comprising loads in a required order: first movements of loads from said at least one outward entry conveyor to the alternative entry elevator, second movements of loads from the alternative entry elevator to the single entries of the N entry levels of the buffer storage unit, third movements of loads from the single exits of the N entry levels of the buffer storage unit to the alternative exit elevator, and fourth movements of loads from the alternative exit elevator to said at least one outward exit conveyor, <EOS>