Sprinkler Zone Flow for a Target Precip Rate
The inverse of the sprinkler-precip-rate tile: the total zone flow a target precipitation rate needs over a covered area, gpm = PR x zone area / 96.3 -- how a designer picks nozzles to sum to the right flow. A 1.5 in/hr rate over 1,200 ft^2 needs about 18.7 gpm of heads. Answers 'how much flow for this rate' instead of the rate from a set flow. Keep sprays and rotors on separate valves; the supply and valve must pass the flow. A design estimate, not a system audit.
Formula and source
required_gpm = target_precip_in_hr x zone_ft2 / 96.3, the inverse of precip_in_hr = 96.3 x zone_gpm / zone_ft2 (the 96.3 constant = 231 in^3/gal / 144 in^2/ft^2 x 60 min/hr spreads 1 gpm over 1 ft^2).
First-principles precipitation-rate relation with the Irrigation Association design references and the Rain Bird / Hunter design manuals (by name), solved for the flow; no edition cycle.
Audience
This tile is built for trades and the adjacent professions in the Agriculture and Forestry group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.