SU 8393 is a layer of opus signinum which served as the bottom of a basin occupying the northern half of Room I-22. It appears to have been the (at least) second signinum bottom of the basin, as it covers an additional signinum surface (SU 8395). This basin is clearly associated with the basin in room I-20, which sits directly beneath the hole in wall SU 8340; any liquid would have drained through this hole (probably through a spoliated pipe of some sort) and into the basin in I-20. The height of these features in Room I-22, as well as the fact that the neighboring basin in I-20 appears to be cut into earlier floors, suggests that these features are associated with the latest phase of the building, and seem to represent a new industrial or productive function. Indeed, taken as a whole, these features appear quite similar to the pressing facilities located in NE area I (excavated in 2016 and 2017; SUs 8028, 8029, 8047), which were also interpreted as a later phase re-organization and shift in function.