Every foot of head, accounted for.
Pipe losses, grade-line profiles, and pump-system analysis.
Project notes & report information
Pipe friction
Add segments along one hydraulic path. Enter actual inside diameters.
Minor losses
Select a valve or fitting, then add it to the worksheet. Choose Branch for fittings in one pump leg and Header for fittings after the flows combine. Branch quantities are per leg. Pump analysis uses Q/N for branches and total Q for headers; system mode inherits flow and diameter from the selected segment. K remains editable.
Choose an item, then use + Add fitting above.
K-value basis
Gate, globe, angle, swing check, elbow, entrance, exit, and return-bend presets follow EPA EPANET Table 3.3. Butterfly, smooth bend, tee, wye, and contraction values retain your original worksheet. Tilting-disc check K = 2 follows your attached sheet. All K values are editable.
Items marked provisional use preliminary assumed K values, not manufacturer ratings. Valve starting values assume fully open service. Replace them with data for the actual size, port geometry, opening, and operating flow. Control-valve K = 10 and custom K = 1 are editable placeholders; expansion/reducer K = 0.3 is a placeholder requiring geometry-specific confirmation. A blank K is not zero. PRV and control-valve entries represent a specified loss only; they do not simulate pressure regulation. Use a separate row when flow, diameter, K, or HGL location differs.
EPA coefficient reference ↗| Description | Pipe segment / role | Calculated flow gpm | ID in | K | Qty | hₘ ft |
|---|
Hydraulic grade line
Enter the alignment EG at 100-foot stations and at every high point. Calculate the required HGL at a selected system flow, without a pump curve. All elevations use one datum.
Manual boundary and segment defaults
Pipe HGL is z + p/γ before the first pump. A reservoir boundary has zero approach velocity. Pump head is added at each segment’s start; assigned minor losses occur at its end. Split a pipe to locate a fitting or high point more precisely.
Segment endpoint defaults & manual pump heads
Segment elevations & pump head
| Segment | Start station | End station | End centerline ft | End ground surface ft | Pump head ft · at start |
|---|
Assign minor losses to segments
Each fitting is counted once, using its own flow and diameter from Section 02. New fittings default to the last segment.
Alignment pressure checks
Segment results
| Segment | Start HGL ft · before pump | End HGL ft | End EGL ft | End pressure head ft | End pressure psi | Friction ft | Minor ft |
|---|
HGL = EGL − V²/(2g); pressure head = HGL − pipe-centerline elevation. EGL advances by pump head minus friction and minor losses. Changes in velocity head are included at diameter or flow changes (energy coefficient α = 1).
Static lift in the TDH summary is a design input, not an additional HGL loss. In manual mode, pump heads entered here are independent of that summary. In duty-point mode, the selected system scenario supplies flows, losses, and pump head; manual head inputs are ignored. Ground surface is a reference profile. Station pipe elevations control the pressure check; blank pipe elevations use EG minus the entered depth to centerline. Elevations are interpolated between stations. Add actual high points between 100-foot stations. Negative gauge pressure is flagged; full-pipe steady flow is assumed. This profile follows one identical pump branch and the common header; it does not solve an arbitrary network, air pockets, or transients.
Reference: USBR energy balance and grade lines ↗System curves & optional pump selection
System head versus flow uses the same pipe, fitting, and boundary inputs as the HGL. Add a pump curve when ready to check operating points.
Pipe-condition scenarios
Darcy scenarios follow each pipe’s material or custom absolute roughness from Section 01: new = 0.75 × normal, moderate = normal, conservative = 1.25 × normal. Mixed-material runs use each pipe’s own baseline. These are roughness sensitivities, not direct percentage changes in friction factor or headloss. Hazen–Williams C values remain separate inputs.
Branch / header assignments
Reuse the lengths, diameters, and K values above. Each branch represents one identical pump leg, evaluated at Q/N; each common header item uses total Q. Leave all items as header for a single hydraulic input set. Quantity on a branch is per pump leg.
Base pump curve & VFD sweep
Paste two columns from the manufacturer’s curve: flow (gpm), head (ft). System curves work without pump data.
No manufacturer pump curve entered.
Optional comparison of three inside diameters at each VFD curve point.
Solid system curves: Pump Off / maximum static. Dashed: Pump On / minimum static. Dotted: VFD pump curves. Filled circles mark duty points for the chosen scenario and water level. Each callout shows speed, total flow, and TDH. Select a legend item to hide or show a curve.
Operating points · displayed pump count and method
Intersections use straight-line interpolation between pump points and the continuous system-loss equation, bounded by entered pump data and maximum sweep flow. Identical pumps share flow equally. No extrapolation.
| Scenario | Level | Hz | Total Q gpm | Q / pump gpm | Head ft | Flow target | Status |
|---|
System-curve table · displayed pump count and method
VFD velocity sweep · displayed pump count
Velocities use combined flow through each comparison diameter. Curve points are not operating points. “Meets threshold” is only a velocity comparison.
Methods & VBA differences
System head = discharge HGL − wet-well level + branch loss at Q/N + header loss at Q + endpoint velocity head (pressurized-pipe boundary only). A reservoir boundary assumes negligible terminal velocity; include an applicable exit loss in the fitting list. The zero-flow row is always included. All existing fitting K values are reused without replacement; add reducers as K fittings with the applicable reference diameter.
This section reproduces the VBA Darcy method: g = 32.174 ft/s², ν entered directly, f = 64/Re below Re 2,000 and Swamee–Jain above it. Re 2,000–4,000 is uncertain. Sections 01–03 retain Colebrook–White and temperature-based viscosity, so small differences are expected.
Hazen–Williams is corrected to hƒ = 4.727 L (Q/448.831)1.852 / [C1.852(D/12)4.871] for Q in gpm, D in inches, and L/head in feet. The VBA’s 10.67 coefficient is for SI inputs and is not used with gpm/inches.
Affinity scaling: Q = Qbase × (Hz/BaseHz) × N; H = Hbase × (Hz/BaseHz)². Speed is assumed proportional to frequency, with unchanged impeller and identical pumps at the same speed. These estimates do not check NPSH, efficiency, power, motor cooling, or manufacturer operating limits. Endpoint velocity-head requirements must be included consistently in the loss model; avoid double-counting exit and velocity head.
Ground elevations, the HGL profile’s added pump heads, and the Section 01 TDH static-lift input do not set these system curves. Use the water-level inputs in this section.
EPA headloss equations ↗ · Pump affinity laws ↗Calculation method & assumptions ＋
hƒ = f · (L / D) · V² / (2g) hₘ = Σ(K · n · V² / 2g)
A = πD²/4 · V = Q/A · Re = VD/ν · TDH = static lift + Σhƒ + Σhₘ.
Darcy friction factor: 64/Re below Re = 2,000; iterative Colebrook–White at Re ≥ 4,000. Between these limits, a linear blend is used and flagged as uncertain. At zero flow, friction and minor losses are zero.
Water viscosity is interpolated from a temperature table (32–200 °F); 70 °F uses ν = 0.00001052 ft²/s from the supplied worksheet. Gravity = 32.2 ft/s². Pressure equivalent assumes water specific weight = 62.4 lb/ft³ (psi = ft × 62.4/144).
Material roughness presets supply the normal baseline for the scenario comparison, in feet. Actual roughness and fitting coefficients depend on condition and geometry; confirm design values. Fitting defaults combine the original worksheet, EPA presets, and explicitly provisional starting assumptions; they are not universal coefficients. A K = 1 velocity-head row should be included only where applicable to the chosen energy-equation endpoints.
Losses are summed along a single path; this is not a branched-network solver. Differing segment flows must reflect known withdrawals or additions. Static lift is discharge elevation minus suction elevation; add any required endpoint pressure-head difference to this input. These worksheet totals do not solve an operating point; use Section 04 for pump and system-curve intersections.
Reference: EPA hydraulic modeling / Darcy–Weisbach ↗Calculation verification & design limits
Built-in numerical checks run against fixed reference cases. They verify these cases only; they do not certify a project design.
Steady-state, full-pipe analysis with identical parallel pumps and one modeled hydraulic path. Review high points, valve data, and actual pipe IDs. The pressure screen is not a pump NPSH calculation or transient/surge analysis. A qualified reviewer should verify project inputs, duty range, manufacturer limits, and required design criteria.