Ladder 4 : A piece of equipment used for climbing that consists of two side rails joined at regular intervals by cross pieces, called rungs. See also: Aerial Ladder, Attic ladder, bangor ladder
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}