Deluge valve

NFPA 15 / NFPA 13 / NFPA 20 / ISO 13702 (fire protection) / company legend practice (NFPA 15)

Drawn as

A valve drawn filled (normally closed) on the firewater supply with a trip actuator on top (often a solenoid "S" box or hydraulic latch), and "DV" or the deluge zone written beside it. Open (dry) pipework leads to the nozzles downstream.

Meaning

Deluge valve: opens on confirmed fire (or manually) to flood a zone through open nozzles. Becomes deluge-valve-skid (valve set with isolations, trim and test line).

Variants

Alarm check valves for wet sprinkler systems look similar and are marked "ACV"
The skid usually shows LO isolation valves either side