Stair Pressurization 2 : A system by which the air pressure in a stairway can be increased to prevent smoke, heat, and other products of combustion on a fire floor from entering it
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}