Dual Line : Two lines of hose, in some cases delivering separate extinguishing agents for combined effect, but more commonly used to provide the desired capacity to a pumper or nozzle
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}