BETA · Process Calculations is under development and not independently verified. Check every result independently before any engineering use. See the disclaimer on the calculator page.
← CalculatorInitial formula review November 11, 2026; model milestones updated November 12, 2026. Basis: U.S. edition, copyright 2010, reprinted October 2010, plus the publisher’s U.S. errata dated November 14, 2013.
Current gas-method review: Crane / Fanno audit, comparisons and open validation items. The historical milestones below retain their original scope and test counts.
| Component | Result |
|---|---|
| Pipe friction | Darcy–Weisbach retained. Laminar treatment ends at Re 2000; transitional results are flagged. Serghides is an implementation approximation checked against independently iterated Colebrook, not a claim that Crane prints the same algorithm. |
| Fitting reference | Updated the reference friction table to 2010 A-27. Operating pipe roughness is separate from fitting reference friction. The app converts reference-bore K to the actual pipe velocity basis using the fourth power of the diameter ratio (equation 2-9). |
| Reference bore | Default is Schedule 40 carbon steel, corresponding to class 300 and lower. Higher classes or different fitting bores require an explicit confirmed reference bore. Unavailable reference dimensions require input; catalog entries needing review remain flagged. |
| Butterfly valves | Standard, double-offset and triple-offset presets now select coefficients by reference size. Existing saved fixed-coefficient modes remain intact and receive a size-dependence warning. |
| Reducers and expansions | Retained the checked sudden and conical correlations and explicit small-/large-bore velocity bases. The implementation agrees with the published equation 2-16 correction: the sudden-contraction expression is not squared as a whole. Geometry loss and static-pressure recovery are separate. |
| Tees and valves | Simple tee factors remain identified as legacy estimates; they do not implement the 2010 flow-ratio junction method. Diaphragm geometry needs confirmation, and the through-pattern workbook value remains unverified. Check-valve full lift and plug-valve flow path are flagged. |
| Legacy gas (initial review) | Retained mean-density, constant-temperature and constant-Z approximation. An independent test checks the simplified horizontal isothermal pressure relation. This is not the complete equation 1-27. A total-path pressure-drop limit prevents bypassing the model boundary by adding segments. |
| Standard volume | SCFM keeps the workbook’s 68°F, 14.7 psia reference; Crane uses 60°F. This intentional difference is stated in the app. Use mass flow for unambiguous comparisons. |
The pipeline contraction correction was checked directly. Parallel resistance, junction tables, control-valve reducers and metering corrections concern methods not implemented here. The app’s generic pipeline reducer must not be substituted for the control-valve installation-factor method.
22 automated tests passed, including independent Poiseuille and hydrostatic benchmarks, Colebrook comparison, unit equivalence, fitting velocity-basis invariance, reducer hand calculations, size-dependent butterfly cases, invalid inputs, and the gas path guard. JavaScript syntax checks passed. A fresh browser interaction check was unavailable in this session.
Legacy gas results stop above outlet Mach 0.30 or 20% segment/total-path loss of inlet absolute pressure. These are application guardrails, not Crane acceptance limits or an accuracy guarantee. Distributed compressible acceleration is omitted. Liquid vapor pressure is not supplied, so the app does not establish absence of cavitation. Flow changes require separately justified junction losses; the app does not solve splits or loops.
Previously saved projects preserve their legacy fitting modes. To apply the new basis, select “Crane table × fT” for an appropriate fixed-multiplier fitting or “Crane butterfly (auto)” for butterfly valves, and check the reference bore. Use a confirmed direct K for vendor-specific components and junctions. The audit updates the web app; it does not represent a rewritten hydraulic Excel workbook.
Added operating-Cv loss, ideal pressure reduction, terminal flow-control capacity checking, terminal backpressure duty checking and user-supplied regulator curves. Valve equations follow the Emerson Control Valve Handbook chapter 5 and are an addition to this Crane review. Gas requires manufacturer xT/xTP and remains subject to the app’s existing pipe-model limits. Optional liquid recovery/vapor-pressure screening blocks choked or flashing continuation. Recovery factors must match the installation and operating opening; viscosity corrections and automatic valve-assembly reducer factors are not implemented.
The expanded suite passes 40 tests, including 18 valve tests: independent liquid benchmarks, effective-Cv setpoint calculations, capacity failure, gas inversion, published gas example operands, downstream propagation and curve boundaries. The rounded operands in the published gas example evaluate to Cv 171.872; this is checked as arithmetic rather than copying the text’s rounded final Cv. Backpressure is a duty check, not a source-pressure solver. See Calculation basis in the app for operation and scope.
Added nominal OD/wall tubing geometry for 304L and 316L using the user-supplied Eagle chart. Two printed ID arithmetic discrepancies are recorded and corrected by geometry. Charlotte DC-PR comparisons cover 43 of the 80 existing PVC/CPVC entries; average OD/minimum-wall references are shown separately, and existing hydraulic IDs are retained for supplier review. The current catalog update passes 50 tests and browser checks for tubing selection and the comparison table. Product grade availability and pressure ratings remain supplier-specific.
The selectable connected isothermal model now includes distributed pipe acceleration, common path mass flow, operating friction and limited-range equivalent-K fittings at segment outlets. It supports a uniform horizontal bore. Valves/regulators, fixed equipment loss, elevation and area-change integration remain pending; adiabatic/Fanno is core-only. Existing projects without an explicit model retain the legacy engine and its guards. The extended suite passes 78 tests, including independently integrated full-path examples, segmentation consistency and pressure-component balance. Browser checks cover model switching, inherited flow, the 29.1% pressure-drop example and persisted selection.
Cv devices now use local pipe-outlet pressure and density in the connected isothermal path. Valve choking is independent of pipe limits and regulation status. Pressure regulators report required/available Cv and actual fully-open outlet pressure when a setpoint is missed. A single flow controller may prescribe path flow. Fixed-Cv choked duty needs an explicit local outlet boundary; backpressure remains a terminal duty check. Device outlets are held at the specified operating temperature; real-gas throttling and connection kinetic-temperature corrections are omitted. Unknown system flow from pressure boundaries remains pending. Manufacturer factors must match the evaluated opening. The suite now passes 102 tests; browser checks confirm choked regulation, full-open missed setpoints, downstream continuation and persistence.
The connected isothermal model now also solves common mass flow from inlet and final system outlet pressures for pipes, limited-range generic fittings, fixed Cv and at most one pressure-reducing regulator. Target-controlled and full-open capacity-limited states are distinguished, including choked valves. A reverse pressure calculation is checked by the forward path and final-pressure residual; conflicting and nonunique states are withheld. A low final pressure beyond the supported pipe branch does not receive a fabricated downstream expansion solution. Other regulator modes, multiple pressure regulators, elevation, transitions and adiabatic path integration remain pending in boundary mode. All 129 tests and JavaScript syntax checks pass. Browser checks cover both regulator states, inherited flow, mode switching, invalid boundaries, saved inputs, JSON and CSV exports. The pipe catalog is unchanged.
The supplied North American Q2 2026 catalog checks all 254 original HDPE entries: 236 printed average IDs match, two 65-inch values change by 0.001 in, five 1600 mm / 63-inch designations are restored, and eleven entries remain excluded. Added 140 DIPS combinations as a separate family. Existing HDPE keys retain IPS/metric geometry; DIPS does not inherit an automatic steel-fitting reference. Catalog average ID uses minimum wall plus 6%, with actual bore variation; full ASTM tolerance-table compliance and service suitability are not certified. FM Class 200/250, FM Class 335 (requested as 355) and dual containment are deferred; ordinary ASTM DR9/DR11 remain. The suite passes 139 tests.
The supplied ASME B36.10-2026 / B36.19-2026 and C151-23 snippets check 274 original steel and unlined ductile records. Three carbon IDs are corrected and six unsupported schedule labels require Custom bore. Thirty-four stainless entries are restored from explicit S-schedule tables. Fifty-five existing ductile bores match; the 64-inch Class 300 OD anomaly retains its prior bore under Review. Added the 3-inch pressure-class row and 110 special thickness classes, with joint-specific availability and a separate flag for the 16-inch mechanical-joint class-label anomaly. Lining remains project-specific. The suite passes 149 tests and syntax checks; no new browser check is claimed after a URL-policy block.
Connected gas paths now support sudden/conical pipeline reducers and expanders in prescribed-flow and supported pressure-boundary modes. Shared Crane K uses smaller-bore velocity; an explicit local isothermal mechanical-energy adaptation calculates separate irreversible loss and signed static-pressure recovery. Both endpoint Mach numbers are limited to 0.30 and absolute static-pressure change to 10% of local inlet pressure. These are application restrictions, not physical transition-choking predictions. A manufacturer-owned outlet transition is counted within the preceding Cv assembly only when explicitly selected; its independent loss/acceleration is omitted and the downstream pipe bore is used for the valve outlet state. Manufacturer factors are not derived. Detected nonmonotone/recovery-driven boundary cases are withheld; the sampled screening does not prove global uniqueness. The suite passes 168 tests, including 19 new transition cases, with syntax checks. Pipe data is unchanged. No new browser interaction check is claimed after the earlier URL-policy block.
Connected isothermal paths now integrate elevation along constant-slope pipes using local gas density and the full steady momentum balance. Actual centerline length must be at least absolute elevation change. Friction, elevation and acceleration pressure components remain separate; the design allowance excludes elevation and acceleration. The zero-flow limit is the exponential barometric law. Both calculation modes include hydrostatic head, including downhill final pressures above source or local regulator outlet. Detected nonmonotone or unsupported recovery-driven boundary branches remain withheld; the numerical screening does not prove global uniqueness. Horizontal calculations retain their existing core, and valve choking/regulator capacity equations are unchanged. The suite passes 192 tests, including 24 new elevation cases with independent pressure integration and hydrostatic checks. The pipe catalog is unchanged. Browser interaction verification remains unavailable after the earlier URL-policy block.
A separate selectable Fanno path now propagates static pressure and temperature through horizontal, constant-bore ideal-gas straight pipes, with constant gamma/viscosity and no heat transfer. Prescribed flow and pressure-boundary flow solving are available. Active fittings, elevation, reducers, equipment and Cv devices require adiabatic component models and are rejected in this initial scope. The interface and CSV expose static/stagnation temperature, stagnation pressure, entropy generation and mass/energy residuals. Pipe M = 1 remains separate from a valve choking criterion. Very-low-Mach core bracketing and exact zero-length propagation are corrected and regression tested. All 220 tests pass, including independent momentum/energy/friction integration and a published analytical benchmark. The pipe catalog is unchanged. No new browser interaction check is claimed after the earlier URL-policy block.
The current suite passes 228 tests, including eight new audit checks. Each thermal model is checked against its own equations. Crane Example 7-22 rounded arithmetic is reproduced, but the literal pipe-static Fanno comparison remains an open equivalent-system question because source energy and exit-loss conventions differ. No production Y-chart solver, coefficients or pipe-data changes are included. Read inputs, results, sources and limits.