The Pennsylvanian design was succeeded by the auburn model, which was a slight modification on the Pennsylvaniamodel. This model had two back-to-back rows with multi-tired cells arranged in a linear plan Carlson and Garrett (2007). The cell measured 3.5 by 7 by 7 feet. This style dominated the USprison housing in the 19th and the early 20th century. The number of cells ranged from six to several dozens in one row, with each block being joined at the center to give access to both blocks.
Initially the buildings had little amenities in them; they used natural lighting and windows for ventilation. As time went on electrical, plumbing and ventilation systems were added, with a few feet added to the back-to-back rows to accommodate this facility US Bureau of Prisons (1949). The cells in this system were organized in the middle with their fronts facing the building’s exterior walls. This is unlike thePennsylvaniamodel; in the auburn model the cells do not face each other. In large institutions, they use cross over corridors at mid point of the blocks. At these cross over corridors, were located the group showers.