An additive manufacturing apparatus builds a part by selectively consolidating flowable material in a layer-by-layer building process. The apparatus has an inert gas vessel having a build chamber a layering device for depositing layers of material in the build chamber; a scanner for delivering an energy beam to selected areas of each layer to consolidate flowable material of the layer, a gas flow circuit for generating an inert gas flow through the build chamber and a cooling device arranged to cool an internal surface of the gas flow circuit to generate cooled inert gas. The gas flow circuit is arranged such that the cooled inert gas can be delivered into the build chamber.