The invention relates to a seal system (100, 200, 300) for an installation (400) for producing a three-dimensional workpiece by means of an additive layer manufacturing method, the seal system (100, 200, 300) comprising: a first seal (102), which is configured to seal an intermediate space (116) at a first periphery (108) between a process chamber inner wall (110) and a powder-material-supporting plate assembly (112) in a process chamber (410) of the installation (400); and a second seal (104), which is configured to seal the intermediate space (116) at a second periphery (114) between the process chamber inner wall (110) and the powder-material-supporting plate assembly (112) in the process chamber (410) of the installation (400), the first seal (102) being spaced apart from the second seal (104) such that, when the intermediate space (116) is sealed between the process chamber inner wall (110) and the plate assembly (112) by means of the first seal (102) and the second seal (104), a channel (106) is formed between the first seal (102) and the second seal (104) at an edge of the seal system (110).