Iowa Rate-of-Flow (Volume Method)
The Royer-Nelson volume-method fire flow, beside the area-based NFA formula: volume = L x W x H, total water = volume / 200 (one gallon controls ~200 ft^3), rate = volume / 100 (that water in the 30-second knockdown burst). A 20 x 30 x 10 ft room is 6,000 ft^3 -> 30 gal, 60 gpm - a fraction of the NFA's 200 gpm for the same footprint, because Iowa is a brief interior knockdown burst and the NFA is sustained. A fire-behavior teaching and size-up aid, not a water-supply design.
Formula and source
volume_ft3 = length_ft x width_ft x height_ft; total_gal = volume_ft3 / 200; rate_gpm = volume_ft3 / 100.
Iowa rate-of-flow formula (Royer-Nelson / Iowa State fire behavior), by name.
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