Ladder 2 : A device consisting of two beams (side rails) joined at regular intervals by cross pieces called rungs on which a person is supported during climbs for ascending or descending. See also: Pompier Ladder
NFPA 1931 Standard for Manufacturer's Design of Fire Department Ground Ladders, 2004 ed. https://www.nfpa.org/assets/files/AboutTheCodes/19 32/1932-A2004-ROP.pdf, (Std: Mfg Design of Fr Dept Gr Ladr - Amer) {419 NFC}