References & further reading
- Crane Co., Flow of Fluids Through Valves, Fittings, and Pipe (TP-410) — industry K-factor practice.
- Idelchik, Handbook of Hydraulic Resistance — background on local losses.
Model assumptions
- Tabulated L/D and K correlations are representative of clean commercial fittings; field roughness and aging can increase losses.
- Reduced-bore valves and non-standard geometries should use manufacturer data when available.
- Velocity basis is the pipe ID you supply; sudden expansion/contraction modules follow simplified correlations.
Shareable URL
When the toolbar exposes “Copy shareable link”, inputs can be encoded in the URL so colleagues can reopen the same case. All computations run locally in your browser; this tool may not expose share links yet.
Frequently asked questions
- Can I sum K from multiple rows?
- Yes; the grid totals ΣK for use in major/minor loss combinations elsewhere.
- What is the difference between K and valve flow coefficient Cv/Kv?
- K is a dimensionless local resistance coefficient (ΔP = K·ρv²/2) referenced to the velocity head at your pipe inner diameter. Cv/Kv are valve flow coefficients (volumetric flow versus sqrt(ΔP), with units). They are convertible but defined differently — use Cv/Kv for valve sizing (see the valve-kv tool) and K for summing system losses.
- How does the L/D equivalent-length method differ from a direct K value?
- The equivalent-length method converts a fitting into an equivalent straight-pipe length added to the pipe friction; the K-value method lists the local loss separately as K·ρv²/2. This tool derives K from Crane TP-410 L/D ratios scaled by the flow regime — the two agree in fully turbulent flow and differ slightly in the transition region.
Extended copy on this page (headings, references, assumptions, FAQs) may be drafted or localized with AI assistance; engineering judgment and governing codes still apply. Numerical models run locally in your browser as implemented. For contract-critical work, cite primary standards and qualified review.