Water Spray / Deluge (NFPA 15/16)

Rates a fixed water-spray (deluge) system where every open nozzle discharges simultaneously — no most-remote-area search — checking delivered density over the protected surface (vessel/transformer/structural), plus an NFPA 16 foam-water solution split and proportioner sizing.

Delivered demand is the direct sum N·K√P over all open nozzles (no branch back-calc needed, since all nozzles flow at once); density is checked over the protected surface area (cylindrical shell, flat/hemispherical tank ends, or transformer box top+sides). For foam-water, the solution flow is split into water + concentrate by the proportioning percentage and the proportioner pressure drop is evaluated from a fixed value or a K-curve.