Public evidence

physics.fluid.npsh

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

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Verification

14/14 calculation tests · Production surface contract 4/4

Golden tests 2 / 2
Boundary tests 7 / 7
Property tests 5 / 5
Production surface contract 4 / 4
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 163 CURRENT) @ 2026-09-17T06:27:56.932Z
Semantic contract PASS
Evidence attested at 2026-09-17T06:27:56.176Z
Last production check 2026-09-17T06:27:56.176Z
Public / cache PASS
Origin PASS
Supplemental domain review Not performed
Named expert review Not performed

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS

Fingerprint sha256:d5b3082a766fb3f71a877c6f768057b8b8d12c7a39d98164672515b31dadfe70

Input schema sha256:4d99adcedf50829825531778ad1444c70c70aea4e5079b77a91f01e7814a4e34 · Output schema sha256:38d11ab23ad0d1d705d2d3d584e0fa3b4a702f6486b4eaa3ae638c46b13a9a24 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool: npsh
Engine: npsh
Engine build: 2026-09-17
Evidence core: 2026-09-17T03:58:19.307Z
Rendered: 2026-09-17T06:35:12.144Z
Last reviewed: —

Assumptions

NPSHa = (p_s − p_v)/(ρ g) + v_s²/(2g) + z_s; pressures absolute; SI
Open tank: p_s=p_atm (default 101325 Pa), z_s=z−hf, v_s=0; hf is an input
Not pump power, not orifice, not weir, not Q=Av, not Darcy, not a catalog NPSHr curve, not steam p_v(T)

Limitations

NPSHa = (p_s − p_v)/(ρ g) + v_s²/(2g) + z_s; pressures absolute; SI
Open tank: p_s=p_atm (default 101325 Pa), z_s=z−hf, v_s=0; hf is an input
Not pump power, not orifice, not weir, not Q=Av, not Darcy, not a catalog NPSHr curve, not steam p_v(T)

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

ISO 9906 — Rotodynamic pumps — Hydraulic performance acceptance tests — NPSH available at the pump datum
Supports: NPSHa from absolute suction pressure, vapor pressure, and velocity head
ANSI/HI 1.3 — Rotodynamic Pumps for Design and Application — NPSH available and required
Supports: NPSHa from suction-tank static head minus suction-line losses; NPSHr from the manufacturer

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`golden-npsh-tank`	golden	pass	Expected NPSHa=11.59376290578332 · kind=open_tank · mode=available · model=npsh · Actual mode=available · kind=open_tank · NPSHa=11.59376290578332 · p_atm=101325 · p_v=2339 · z=2 · hf=0.5 · rho=1000
`golden-npsh-flange`	golden	pass	Expected NPSHa=9.142877537181402 · kind=flange · model=npsh · Actual mode=available · kind=flange · NPSHa=9.142877537181402 · p_s=90000 · p_v=2339 · v_s=2 · z_s=0 · rho=1000
`boundary-npsh-margin`	boundary	pass	Expected NPSHa=11.59376290578332 · NPSHr=4 · margin=7.59376290578332 · cavitation=false · model=npsh · Actual mode=margin · kind=open_tank · NPSHa=11.59376290578332 · p_atm=101325 · p_v=2339 · z=2 · hf=0.5 · rho=1000
`boundary-npsh-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-npsh-hf`	boundary	pass	Expected VALUE_OUT_OF_RANGE · Actual VALUE_OUT_OF_RANGE
`boundary-npsh-mixed`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`boundary-npsh-pump-q`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`boundary-npsh-cd`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`boundary-npsh-pump-mode`	boundary	pass	Expected INVALID_MODE · Actual INVALID_MODE
`property-npsh-tank`	property	pass	(p_atm−p_v)/ρg+z−hf
`property-npsh-flange`	property	pass	(p_s−p_v)/ρg+v²/2g
`property-npsh-z`	property	pass	z increases NPSHa
`property-npsh-pv`	property	pass	p_v decreases NPSHa
`property-npsh-margin`	property	pass	margin=NPSHa−NPSHr