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TheBlueprintof Water

True Pipe Flow Calculator

Every device in the line, solved at the flow it actually sees. The free page asks you to look the losses up; this one identifies each device from what you can see and iterates it automatically.

Blueprint Pro · saves as a System
Pro · Spec 2B
per-device iterated

This calculator estimates deliverable flow. Measuring beats estimating. If the line exists, open the valve that normally draws on it and clock the meter. Use this tool for design cases, lines you cannot flow on demand, or to sanity-check what you measured.

Estimated deliverable flow · every device iterated at the flow it sees

≈ 43 to 45 gpm (ceiling)

Static-reading mode, a ceiling. The supply will sag under flow. Range spans nominal C to C × 0.85.

pipe friction 15.2 psibackflow, reduced pressure 1½″ 8.8 psicontrol valve 1″ · cv 12 14.0 psisoftener 24″ 28.5 psielevation 3.5 psidestination pressure 5.0 psi

Of 75.0 psi available at 45 gpm, 75.0 psi is spent getting water to the destination.

No devices · bare pipe≈ 100 gpm
One pipe size larger≈ 50 gpm
Low estimate · C × 0.85≈ 43 gpm
The pressure budget, by name · at 45 gpm
Itempsi% of budget

This is the 200-vs-100 lesson with names on it. The miss is never the math, it is the inventory.

This flow exceeds the softener’s design service rate: 45 gpm through a vessel rated 31.4 gpm. Expect elevated ΔP and hardness leakage late in the run. Size the softener →

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Sites, systems, and saved comparisons arrive with accounts. The result stays on screen either way.

Next stationsThe free page, Pipe Flow Rate →Size the softener this line feeds →

Sources & assumptions: Hazen-Williams with Sch40 IDs (ASME B36.10). C-factors per standard references, range = nominal to C × 0.85. Backflow curves typical of RP/DC assemblies (Watts, Febco, Zurn Wilkins; verify one curve per type and cite). Valve Cv typical of manufacturer catalogs (Fisher/Emerson, Cla-Val, ASCO; actual ±40% by trim, enter the submittal Cv when you have it). Strainer and meter per typical clean-strainer and AWWA C700/C701 allowances (a dirty strainer loses 3 to 5 times this, one more reason to measure). Softener ΔP = rated × (Q/Qᵣ)¹·⁸. The calculator estimates; the field measures.