physics.fluid.hazen_williams

Three distinct suites: educational examples on the calculator page, this legacy regression count (17/17 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.0.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-25.o2-o3. Calculation version 1.0.0. CVP 1.0.0-proposed. 4/4 golden · 8/8 CVP boundary · 9/9 invalid · 1/1 property · 1/1 metamorphic · 8/8 O3 · 2/2 cross-interface · 6/6 CVP contract. digest f294c00f3e84. O2: SI Hazen–Williams vs a separate-module identity (≤2 ULP). Not Darcy, not Colebrook, not Manning, and not Q=Av. ≤2 ULP vs O3 applies only to the published tabulated Hazen–Williams vectors. Not Darcy, not Colebrook, not Manning, and not Q=Av.

• Golden (oracle-backed) 4 / 4
• CVP boundary 8 / 8
• Invalid input 9 / 9
• Property 1 / 1
• Metamorphic 1 / 1
• O3 high-precision 8 / 8
• Cross-interface 2 / 2
• CVP contract 6 / 6
• Interfaces PASS · UI (SSR) / REST / MCP
• Interface claim ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
• Verified scope SI hf = 10.67 L Q^1.852 / (C^1.852 D^4.87), plus flow, diameter, and C solves, + O3 mpmath tabulated head loss.
• Assurance Engineering
• Deferred Not Darcy, not Colebrook, not Manning, and not US customary gpm/in.

• release artifacts aligned PASS
• schema output required declared PASS
• schema valid input executes PASS
• engine success output validates schema PASS
• schema rejects incomplete input PASS
• rest success payload validates schema PASS

Fingerprint sha256:d408aa5ed3f1e0fa778bb51ce68fefeb2a63dd1d69468db502bd68867c116c51

Input schema sha256:1ba406f7d6fa954f4e1167326caf3a5e5413a77d4616742d63a9e3e51cf6cb25 · Output schema sha256:63a1653c24addc4ac4815a5458b81ac356d07614b73de617595f162be7a86808 · 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.

Tool

hazen-williams

Engine

hazen-williams

Engine build

2026-09-17

Evidence core

2026-09-17T04:33:23.369Z

Rendered

2026-11-10T05:18:41.929Z

Last reviewed

—

Assumptions

• SI Hazen–Williams k=10.67
• Circular full-flow water pipe
• Empirical C; not Darcy f, not Colebrook, not Manning n
• Not Q=Av identities
• Not US customary gpm/in

Limitations

• SI Hazen–Williams: hf = 10.67 L Q^{1.852} / (C^{1.852} D^{4.87})
• Circular full-flow water pipe; empirical C; k=10.67; not US gpm/in
• Not Darcy–Weisbach, not Colebrook, not Manning, not Q=Av