Pump Total Dynamic Head Calculator

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Required pumped flow. 151.4 L/min ≈ 40 GPM, a common sewage-ejector design point.
gpm
Actual inside diameter of the discharge pipe. 52.5 mm ≈ 2 in Sch-40 — the usual sewage-ejector minimum for 2 in solids.
in
Straight discharge run PLUS the equivalent length of every elbow, check valve and gate valve (from a fitting-equivalent chart). 30.48 m ≈ 100 ft.
ft
Vertical height from the pump-off liquid level in the basin to the highest point of the discharge before it turns down. 3.658 m ≈ 12 ft.
ft
Head equivalent of any pressure the pump discharges into (a pressurized force main); 0 for an open or gravity connection. 1 psi ≈ 0.70 m (2.31 ft).
ft
Roughness coefficient: ~150 new plastic, ~140 new copper/cement-lined, ~120 typical design value, ~100 older/scaled. Lower = rougher = more friction.

Results

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Total dynamic head(TDH)
15.97ft
Pass

Static + friction + pressure — read the pump curve at this head for flow-at-head.

Also computed

Discharge velocity(v)Pass3.824ft/s

3.82 ft/s — above the 2 ft/s scour floor; solids stay suspended.

Must clear the 2 ft/s (0.61 m/s) scour floor so solids stay suspended.

Friction head(H_f)3.97ft

Hazen-Williams loss over the equivalent length.

Method notes 4 notes
  • TDH = static lift + Hazen-Williams friction head + discharge pressure head. Velocity head is small here and folded into the friction allowance, not added separately — the standard plumbing-engineer simplification.
  • Equivalent length must include the fitting allowances (elbows, check valve, gate valve) from a fitting-equivalent chart — they often add more head than the straight run on a short lift.
  • Read the manufacturer pump curve at this TDH to get the flow the pump actually delivers; that flow-at-head is the input the sump-pump-capacity screen needs (never the zero-head rating).
  • Pumped sewage/sump discharge must hold ≥ 2 ft/s (0.61 m/s) so solids stay suspended (the scouring velocity); the adopted plumbing code and the pump maker govern the final selection.

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