Double Hydrant 2 : A hydrant barrel that has two outlets; usually they are 2 1/2 inches but occasionally the hydrant may have one or two "steamer" outlets in-stead
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}