Barrier 11 : Any obstruction to the spreadof a fire, especially fire walls, smoke partitions, automatic fire doors, and areas or strips without any flammable fuel
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}