Post Indicator Valve 5 : (PIV) A valve used in sprinkler systems and other water distribution systems that indicates open and shut positions, and is usually located on the exterior of the protected building
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}