Iowa Rate-of-Flow (Volume Method)
The Royer-Nelson volume-method fire flow, beside the area-based NFA formula.
Example
You enter
- Compartment length (ft) 20
- Compartment width (ft) 30
- Compartment height / ceiling (ft) 10
You get
- Compartment volume 6000 ft^3
- Water to control (total) 30 gal
- Rate of flow (30-second knockdown) 60 gpm
Details, formula, and sources
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.
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.
The Iowa rate-of-flow formula is public fire-service / fire-behavior training material; incident command governs the actual attack.
Estimate. AHJ and licensed professional govern.
Field names used by the API: length_ft, width_ft, height_ft, volume_ft3, total_gal, rate_gpm
- Steam basis one gallon of water controls about 200 ft^3 of compartment (steam heat absorption, with margin)Royer-Nelson / Iowa State
- 30-second burst the rate is the control water applied in a 30-second knockdown, so gpm = volume / 100; not a sustained flowRoyer-Nelson / Iowa State