Verified calculation capability

Valve flow coefficient Calculation Capability

Incompressible liquid valve Q_m³/h=Kv √(Δp_bar/SG). Kv=0.865 Cv (IEC 60534-1). SI Q in m³/s, Δp in Pa. Not a venturi wrap, not orifice, not Q=Av, not Darcy. · Physics · Fluid

Capability ID physics.fluid.valve_cv · version 1.0.0

Open calculator REST API MCP Evidence Evidence JSON Review policy

Model

Kv: Q_m³/h = Kv √(Δp_bar / SG)
Conversion: Kv = 0.865 Cv
SI: Q = (Kv/3600) √((Δp/10⁵) / SG)

Solve modes: flow · pressure · Kv · Cv

Inputs / Outputs

Canonical symbols for this capability. Agent schemas remain the contract.

Symbol	Quantity	Unit	Role
`Kv`	IEC Kv in m³/h at 1 bar. Alternative: Cv. Do not send both.	—	input / output
`Cv`	US Cv. Alternative: Kv. Kv=0.865 Cv. Do not send both.	—	input / output
`dP`	Differential pressure in Pa. Required except pressure invert.	—	input / output
`Q`	Volumetric flow in m³/s. Required for pressure, Kv, and Cv invert. Do not send with flow.	—	input / output
`SG`	Specific gravity relative to water. Default 1. Alternative: rho. Do not send both.	—	input / output
`rho`	Density in kg/m³. Sets SG=ρ/1000. Alternative: SG. Do not send both.	—	input / output
`Q_m3_h`	—	—	output
`k`	—	—	output
`model`	—	—	output

Assumptions / Validity

Declared scope for this capability. Do not use it outside this domain.

Assumptions

Incompressible liquid; Q_m³/h = Kv √(Δp_bar/SG); default SG=1
Kv = 0.865 Cv (IEC 60534-1); frozen, not a US-gpm engine
Not gas, not choked, not IEC 60534-2-1 xT/Y
Not a venturi, not an orifice, not Q=Av, not Darcy, not minor-loss K

Not supported

venturi D1/D2
orifice C_d
Q=Av
Darcy
minor-loss K
gas/choked IEC 60534-2-1

Example

One numerical check. The calculator page holds worked steps and FAQ.

Kv=10 dP=1e5 → Q=10/3600

Open this example in the calculator

Trust

Review-policy: engine tested — automated tests, sources, version lock, and evidence published. Supplemental to CVP; not Domain Expert Review. See CVP and Review policy.

Tier: Engine tested — catalog token engine_tested
Calculation version: 1.0.0
Evidence tests: 17/17 calculation tests · golden 2/2 · boundary 10/10 · property 5/5
Engine tested: Yes
Source checked: Yes
Supplemental domain review: Not performed
Named expert review: Not performed
Version lock: Supported (409 VERSION_MISMATCH)
Artifact consistency: Build verified · 1.0.0 (workspace artifacts agree)

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

Call this capability

Human page, REST, and MCP share the same engine and calculation_version. Build verified hashes workspace artifacts only. After deploy, attest:production GETs canonical URLs twice — the public/cached view an Agent actually hits, and origin — including every /capabilities/{id} HTML page. Public Capability HTML version must match catalog before production attestation passes. Live Trust rows above fetch /.well-known/calculatorx-production-attestation.json and the output schema const. Build hashes: release integrity. That proves currently published page / engine / schema / evidence / MCP agree — not that a historical version is independently immutable. Reference Calculation Standard — Production surface contract 3/3.

Tool id: valve-flow-coefficient
Engine: valve-flow-coefficient
REST: POST /api/v1/calc/valve-flow-coefficient
MCP: execute_calculation with capability_id: "physics.fluid.valve_cv"
Agent input schema: Canonical (MCP / Agent)
Output schema: JSON Schema (latest)
Versioned input schema: Immutable pin (1.0.0)
Versioned output schema: Immutable pin (1.0.0)

References

Human-readable sources plus CVP reference evidence classes.

Sources

IEC 60534-1 — Industrial-process control valves — Flow capacity — Kv and the Kv–Cv relation
ISA-75.01.01 — Flow Equations for Sizing Control Valves — Liquid sizing with Cv

Try with an agent

Inspect this capability via same-origin MCP, then call execute_calculation.

curl -sS -X POST 'https://www.calculatorx.com/mcp' \
  -H 'Content-Type: application/json' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/call' \
  -H 'Mcp-Name: inspect_capability' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"inspect_capability","arguments":{"capability_id":"physics.fluid.valve_cv"}}}'

Inspect the trust tier and required assurance level before execution. Pin calculation_version (1.0.0) when reproducibility matters. Full protocol notes: MCP docs.