A single-use biopharmaceutical device for producing, storing, transporting biopharmaceutical product, comprising at least one multilayer segment of biopharmaceutical tube, having a peripheral side wall limiting a longitudinal empty space and including a contact layer and a functional layer with the outer face of the contact layer and the inner face of the functional layer being secured together, at least one biopharmaceutical bag, and, optionally, at least one biopharmaceutical connector, each being single use, and having a contact layer made of a material chosen to be suitable for being in contact with the biopharmaceutical product without resulting in degradation of the contact layer and of the biopharmaceutical product and for being weldable to itself, welded together in communicating, continuous, rigid and leaktight manner, having a certain amount of flexibility and made of plastic, characterized in that: - the contact layer of the biopharmaceutical tube is made of a material chosen to be suitable for being in contact with the biopharmaceutical product without degradation of the contact layer and of the biopharmaceutical product and of being weldable on itself, other than PVC and chosen from the family comprising polyethylene and in particular linear low-density polyethylene (LLDPE), polyethylene vinyl acetate, polypropylene, ethylene-tetrafluoroethylene (ETFE) polyvinylidene fluoride (PVDF), the inner face of which limits the longitudinal empty space and is suitable for being in contact with the biopharmaceutical product, i.e. is suitable essentially for performing the containing and physical separation function of the at least one biopharmaceutical tube and forming the inner face thereof, - the functional layer of the biopharmaceutical tube comprises at least one functional elementary layer made of a material chosen for its function of flexibility, robustness, handling, opacity or, conversely, transparence, barrier to gases, non-degradable intrinsically or in association with a protective layer, other than PVC and chosen from the family comprising polyethylene and in particular linear low-density polyethylene (LLDPE), polyethylene terephthalate, a polyamide, polyethylene vinyl acetate, ethylene vinyl alcohol (EVOH), styrene ethylene butadiene styrene (SEBS), polyethylene terephthalate glycol (PETG...), polyvinylidene fluoride (PVDF), i.e. suitable for performing the functions making it possible to satisfy the other physical, chemical, biological and operational properties adapted to the relevant purpose and application of the single-use biopharmaceutical device, - the contact layer of the bag, of another segment of tube and/or of a connector, is made of a material chosen to be identical or analogous to the material of the contact layer of the at least one biopharmaceutical tube, - the contact layer of the biopharmaceutical tube is welded to the contact layer of the bag, of another tube segment and/or of a connector, with substantial physical continuity between the respective contact layers (12, 16). - the contact layer of the biopharmaceutical tube is made of a material chosen to be suitable for being in contact with the biopharmaceutical product without degradation of the contact layer and of the biopharmaceutical product and of being weldable on itself, other than PVC and chosen from the family comprising polyethylene and in particular linear low-density polyethylene (LLDPE), polyethylene vinyl acetate, polypropylene, ethylene-tetrafluoroethylene (ETFE) polyvinylidene fluoride (PVDF), the inner face of which limits the longitudinal empty space and is suitable for being in contact with the biopharmaceutical product, i.e. is suitable essentially for performing the containing and physical separation function of the at least one biopharmaceutical tube and forming the inner face thereof, - the functional layer of the biopharmaceutical tube comprises at least one functional elementary layer made of a material chosen for its function of flexibility, robustness, handling, opacity or, conversely, transparence, barrier to gases, non-degradable intrinsically or in association with a protective layer, other than PVC and chosen from the family comprising polyethylene and in particular linear low-density polyethylene (LLDPE), polyethylene terephthalate, a polyamide, polyethylene vinyl acetate, ethylene vinyl alcohol (EVOH), styrene ethylene butadiene styrene (SEBS), polyethylene terephthalate glycol (PETG...), polyvinylidene fluoride (PVDF), i.e. suitable for performing the functions making it possible to satisfy the other physical, chemical, biological and operational properties adapted to the relevant purpose and application of the single-use biopharmaceutical device, - the contact layer of the bag, of another segment of tube and/or of a connector, is made of a material chosen to be identical or analogous to the material of the contact layer of the at least one biopharmaceutical tube, - the contact layer of the biopharmaceutical tube is welded to the contact layer of the bag, of another tube segment and/or of a connector, with substantial physical continuity between the respective contact layers (12, 16).