Water-Supply Duration
Sustainable duration of an available water volume at a selected flow.
Example
You enter
- Available water volume (gal) 3000
- Required / selected flow (GPM) 250
You get
- Duration (min) 12
- Net drain (GPM) 250
Checked against published worked examples from: Volume/flow continuity + NFPA 1142 context.
Details, formula, and sources
ScopeWith the net drawdown time and steady-state sustainable flow when a continuous resupply rate is entered.
Formula or tablet = V / GPM; with continuous resupply R: if R >= GPM the supply is effectively sustained (report sustainable flow = R); else t = V / (GPM - R).
Source and editionVolume/flow continuity (first principles); required-duration context per NFPA 1142 (rural/suburban water supply), by name.
Free accessNFPA 1142 free read-only at nfpa.org/freeaccess.
What governsEstimate. AHJ and licensed fire protection engineer govern.
API field namesvolume_gal, flow_gpm, duration_min, net_drain_gpm
- Constant flow the demand flow is held constant; resupply is continuouscontinuity