Plumbing Valve Cavitation Index Calculator

Audit actual upstream-referenced (P1−Pv)/(P1−P2) valve index with explicit absolute pressures, signed reversed drops retained; alternative sigma conventions distinct, not cavitation safety classification.

Description

A valve cavitation index compares inlet pressure above vapor pressure with the valve pressure drop.

A valve cavitation index compares inlet pressure above vapor pressure with the valve pressure drop. Pressure order controls the sign.^[1]

The returned values include Caller upstream referenced cavitation indices. The How section below explains the calculation, input rules and interpretation.

When to use Plumbing Valve Cavitation Index Calculator

Use Plumbing Valve Cavitation Index Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. No cavitation onset threshold or safe valve operating envelope is inferred.

Prepare measured flows, pressures, temperatures or inventories with consistent units. For catalog tools, use independently verified capacities at the stated operating conditions and supply the explicit design demand.

How to use Plumbing Valve Cavitation Index Calculator and understand its results

Prepare measured flows, pressures, temperatures or inventories with consistent units. For catalog tools, use independently verified capacities at the stated operating conditions and supply the explicit design demand.
Enter observedValveUpstreamAbsoluteKpa, observedValveDownstreamAbsoluteKpa, callerMatchedFluidVaporAbsoluteKpa using the field table and calculation rules, then run the tool.
Read callerUpstreamReferencedCavitationIndices. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
observedValveUpstreamAbsoluteKpa	Observed valve upstream absolute kpa	list of number	Required
observedValveDownstreamAbsoluteKpa	Observed valve downstream absolute kpa	list of number	Required
callerMatchedFluidVaporAbsoluteKpa	Caller matched fluid vapor absolute kpa	list of number	Required

Enter aligned nonempty positive inlet and outlet absolute pressures and nonnegative vapor pressures. Reject zero pressure drop; negative drops and negative indexes remain signed. Return each index.

index=(inletAbsolute−vaporAbsolute)/(inletAbsolute−outletAbsolute)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
callerUpstreamReferencedCavitationIndices	Caller upstream referenced cavitation indices	list of number

json

{
  "input": {
    "observedValveUpstreamAbsoluteKpa": [
      200,
      150
    ],
    "observedValveDownstreamAbsoluteKpa": [
      100,
      160
    ],
    "callerMatchedFluidVaporAbsoluteKpa": [
      10,
      10
    ]
  },
  "output": {
    "callerUpstreamReferencedCavitationIndices": [
      1.9,
      -14
    ]
  }
}

Limitations and assumptions

No cavitation onset threshold or safe valve operating envelope is inferred.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Plumbing Valve Choked Flow Check Calculator: Liquid choked-flow screening compares observed valve pressure drop with a pressure-recovery threshold. Absolute pressure is required for the vapor-pressure term. For a complementary task, use Plumbing Control Valve Authority Calculator: Valve authority compares a valve’s pressure drop with its total circuit drop at the same design flow. It is dimensionless.

References

Plumbing Valve Cavitation Index Calculator — tool.io

Similar or alternative tools

Plumbing Valve Choked Flow Check Calculator
Liquid choked-flow screening compares observed valve pressure drop with a pressure-recovery threshold. Absolute pressure is required for the vapor-pressure term.
Plumbing Control Valve Authority Calculator
Valve authority compares a valve’s pressure drop with its total circuit drop at the same design flow. It is dimensionless.