Enclosure 17 : wall An interior wall enclosing a stairwell, elevator shaft, duct space, or any other vertical opening through a floor; it may be either bearing or nonbearing
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}