Double Lay : A hose-laying operation at fires in which more than one line of hose is laid by a unit, either from divided hose body or in each direction between the fire and the water supply
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}