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
Details, formula, and sources
With the net drawdown time and steady-state sustainable flow when a continuous resupply rate is entered.
t = V / GPM; with continuous resupply R: if R >= GPM the supply is effectively sustained (report sustainable flow = R); else t = V / (GPM - R).
Volume/flow continuity (first principles); required-duration context per NFPA 1142 (rural/suburban water supply), by name.
NFPA 1142 free read-only at nfpa.org/freeaccess.
Estimate. AHJ and licensed fire protection engineer govern.
Field names used by the API: volume_gal, flow_gpm, duration_min, net_drain_gpm
- Constant flow the demand flow is held constant; resupply is continuouscontinuity