How K values relate to ΔP in your system
Local losses are expressed as K×ρv²/2. This calculator helps assemble K from catalogs and custom entries; pair it with the line pressure-drop tool for full station 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.
- Multiphase, choked compressible flow, and two-phase choking are not modeled.
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.
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.
- Are these K values legally binding?
- They are engineering estimates; critical designs need validated vendor data.
- Does the page call a remote solver?
- No. Calculations are local.
Extended copy on this page (headings, assumptions, references, 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.