A controlled-atmosphere clean room comprising: a plurality of partitioning walls defining a inner controlled-atmosphere environment separated from an external non controlled atmosphere environment, at least one filtration device configured to supply filtered air for defining said controlled-atmosphere environment, at least one septum arranged at one of said partitioning walls, the septum comprising: • at least one main body configured to define at least part of the partitioning wall, said main body comprising a plurality of through openings identical to each other in shape and size; • a plurality of intermediate bodies, each of them stably engaging the through openings, each intermediate body comprising a first and second main surfaces (4a, 4b) respectively arranged towards the controlled-atmosphere environment and towards the external environment, characterised in that the intermediate bodies comprise: ∘ at least one plurality of connecting elements engaged with the through openings, each connecting element having at least one through hole and an inner attachment device at the through hole, said inner attachment device being suitable for being connected to operative devices or machines housed inside the clean room, and ∘ at least one plurality of closing elements, each of them is hermetically engaged with the through openings. a plurality of partitioning walls defining a inner controlled-atmosphere environment separated from an external non controlled atmosphere environment, at least one filtration device configured to supply filtered air for defining said controlled-atmosphere environment, at least one septum arranged at one of said partitioning walls, the septum comprising: • at least one main body configured to define at least part of the partitioning wall, said main body comprising a plurality of through openings identical to each other in shape and size; • a plurality of intermediate bodies, each of them stably engaging the through openings, each intermediate body comprising a first and second main surfaces (4a, 4b) respectively arranged towards the controlled-atmosphere environment and towards the external environment, characterised in that the intermediate bodies comprise: ∘ at least one plurality of connecting elements engaged with the through openings, each connecting element having at least one through hole and an inner attachment device at the through hole, said inner attachment device being suitable for being connected to operative devices or machines housed inside the clean room, and ∘ at least one plurality of closing elements, each of them is hermetically engaged with the through openings. • at least one main body configured to define at least part of the partitioning wall, said main body comprising a plurality of through openings identical to each other in shape and size; • a plurality of intermediate bodies, each of them stably engaging the through openings, each intermediate body comprising a first and second main surfaces (4a, 4b) respectively arranged towards the controlled-atmosphere environment and towards the external environment, characterised in that the intermediate bodies comprise: ∘ at least one plurality of connecting elements engaged with the through openings, each connecting element having at least one through hole and an inner attachment device at the through hole, said inner attachment device being suitable for being connected to operative devices or machines housed inside the clean room, and ∘ at least one plurality of closing elements, each of them is hermetically engaged with the through openings. ∘ at least one plurality of connecting elements engaged with the through openings, each connecting element having at least one through hole and an inner attachment device at the through hole, said inner attachment device being suitable for being connected to operative devices or machines housed inside the clean room, and ∘ at least one plurality of closing elements, each of them is hermetically engaged with the through openings.