Working Length : The length of a non-self-supporting portable ladder measured along the beams from the base support point of the ladder to the point of bearing at the top. NFPA 1932, 2004 ed
National Fire Protection Association, Illustrated Dictionary of Fire Service Terms, Jones & Bartlett Publishers, MA. USA 2006. https://books.google.com.kw/books?id=W0WIRa3Gl4QC& printsec=frontcover&source=gbs_ge_summary_r&cad=0# v=onepage&q&f=false, (Fr Srvc - Amer) {141}
NFPA 1932 Standard on Use, Maintenance, and Service Testing of In-Service Fire Department Ground Ladders, 2004 ed. http://www.nfpa.org/assets/files/AboutTheCodes/193 1/1931-A2004-ROP.pdf, (Std: Use, Maint and Srvc Tst of In-Srvc Fr Dept Gr Ladr - Amer) {420 NFC}