Pump and piping calculation software: LOGOS compared with PIPE-FLO, AFT Fathom and EPANET

Short answer

The right pump and piping software depends on the size of the problem, not on which tool is “better”.

• Whole plant piping network, many pumps interacting, operating scenarios: use a dedicated hydraulic simulator such as PIPE-FLO (Engineered Software Inc.) or Fathom (Datacor, formerly AFT Fathom).
• Municipal water distribution network, extended-period simulation, water quality: use EPANET (U.S. EPA), which is public domain and free to copy and distribute.
• Pressure surge simulation with the method of characteristics (MOC): use a transient simulator such as Impulse (Datacor, formerly AFT Impulse).
• Sizing one industrial pumping system, control valve, orifice plate, relief valve or water hammer check, with the method and standard named and a Word (.docx) calculation report: LOGOS does that in the browser, with the calculation running on the server.

Comparison table

Cells marked “Consult the vendor” are items we could not confirm on the vendor’s public pages at the time of writing, so we do not state them.

When to choose PIPE-FLO

PIPE-FLO fits when the deliverable is a model of an existing or new piping system that the plant will keep using. According to its developer and trade coverage, PIPE-FLO takes design and operational data, including equipment performance, and simulates the system by calculating the flows and pressures throughout it, with wizards that step the designer through pump and valve sizing and selection. That model-of-the-plant approach is what you want for troubleshooting an operating system or evaluating “what if” scenarios across many interconnected lines.

When to choose AFT Fathom (Fathom by Datacor)

Fathom fits when you need steady-state pressure drop and flow distribution across a complex network of liquid or low-velocity gas piping. The vendor page lists centrifugal and positive displacement pumps with variable speed control, impeller trimming and NPSH evaluation, heat transfer, a Goal Seek module that finds inputs for target outputs and simulates control functions, and the Chempak database of almost 700 liquids and 600 gases. For waterhammer, Datacor sells Impulse, which predicts surge pressures, flows and forces with an MOC-based transient solver including cavitation, column separation, pump trips and surge protection devices. If your project requires a full transient study, Impulse (or an equivalent MOC tool) is the correct choice, not a closed-form estimate.

When to choose EPANET

EPANET fits water distribution networks: pipes, junctions, pumps, valves, storage tanks and reservoirs, with the flow in each pipe, the pressure at each node and the water level in each tank over an extended period, plus water-quality modeling. It is public domain software from the U.S. EPA, developed further as an open-source project on GitHub, and it runs on Windows. For a utility network, a campus water system or any analysis that needs water age or chlorine decay, EPANET is the natural tool, and LOGOS does not replace it.

When LOGOS is the right fit

LOGOS fits the day-to-day sizing work of an industrial project: one pumping system at a time, sized with named methods and documented for review.

• Pumping systems: system curve with Darcy-Weisbach, h_f = f·(L/D)·(v²/2g), friction factor by Colebrook-White / Swamee-Jain, plus minor losses h_m = K·v²/2g; operating point against a pump curve fitted from catalog points; NPSH available. Variants for pumps in series, in parallel, with recirculation, with a control valve or an orifice plate in the line, gravity flow, and multi-branch networks.
• Valves and meters: control valves for liquids and steam per IEC 60534 (Cv = Q·√(SG/ΔP) for liquids, with the FL choked-flow limit), orifice plates per ISO 5167, relief valves for liquids and safety valves for steam per API 520 Part 1 and API 526.
• Water hammer: Joukowsky surge ΔP = rho·a·ΔV for fast closure and Michaud for gradual closure, to size the minimum closure time or flag the need for protection.
• Report: a Word (.docx) calculation report generated on the server by recomputing the result from the inputs.

The design calculations run in versioned server-side functions and require an account. The quick hydraulic calculations — velocity and diameter, pressure, flow, power, affinity laws, tank fill/drain time, Cv↔Kv, Joukowsky — run in the browser on the same TypeScript module and are open on the public page, free and without sign-up.

What LOGOS does not do

LOGOS is not a general hydraulic network simulator. Specifically, LOGOS does not:

• simulate looped networks of arbitrary topology (it solves defined topologies, including one closed unification loop);
• run extended-period simulation or water-quality modeling;
• run a method-of-characteristics transient simulation with column separation and surge devices;
• model compressible gas flow networks.

For those cases, use EPANET, PIPE-FLO, Fathom or Impulse. A LOGOS result also does not replace the professional responsibility of the engineer who signs the design.

Using them together

The tools are complementary. A practical workflow is: size the pump, control valve, orifice plate and relief valve in LOGOS during the conceptual and basic design, with a .docx report for the design review; then build the full plant or network model in PIPE-FLO, Fathom or EPANET when the layout is frozen, and run Impulse or an equivalent tool if a transient study is required. Comparing both results at the same operating point is a cheap independent check.

Trademark note

PIPE-FLO, AFT Fathom, Fathom, Impulse, Datacor and EPANET are trademarks or names of their respective owners. Information about third-party products comes from their public pages as of October 2026 and may change; check the vendor for current details.