Research — Illustrative (draft, unvalidated)
Pipe velocity regimes — auto
Flow is held at 300 L/min while the pipe diameter grows from 15 mm to 200 mm. Narrow pipe is far over the small-pipe limit. Through the 2 to 3 inch range no limit is cited, so the page shows neutral 'not applicable', never green, even though the velocity is falling. Past 3 inches the large-pipe limit takes over and the pipe finally passes.
Pipe diameter at 300 L/min
15 mmticks: 2 in and 3 in (the gap between them)200 mm
Reading —
Pipe section, diameter regimes and velocity gauge (schematic; gap sizes are hatched, not green)
Pipe velocity
Velocity
Cited limit
Margin to limit
How the check read it
Client-side port:the logic and table in this page are a TypeScript port of the harness function, checked against values exported from the Python tests. Not a live API call. Domain maturity, quoted from the research page: “Draft; no mechanical or thermal engineer has reviewed it yet. An audit of the input data caught real discrepancies, and the functions use whatever value a caller passes without correcting it. Pipe-velocity limits are cited to ASHRAE through secondary sources only.” The small-pipe limit (4 fps, 1.2192 m/s, up to 2 in) and the absolute ceiling (15 fps, 4.572 m/s) come from the ASHRAE Handbook through secondary sources; the large-pipe limit (2.1 m/s, above 3 in) is attributed to ASHRAE TC 9.9's Liquid Cooling Guidelines (2014) through a secondary trade-press source, with the primary text not accessed. The 300 L/min flow is a generic example number chosen for this sweep; the sequence is staged.Real function this maps to:
evaluate_pipe_velocity_for_flow_rate.Not modeled: pressure drop (no Darcy-Weisbach), inside diameter or schedule wall thickness (nominal diameter is used, so real velocity is somewhat higher), fluid properties, any rule for the 2 to 3 inch range, and automatic size selection. The harness never picks a pipe size; a gap-size result is not a pass.See also:Pipe velocity, interactive