Flaming Combustion Residence Time

Infer steady-front flaming residence from measured zone depth and normal front speed and compare observed duration; not ignition delay or a universal fuel burn time.

Description

A steady flaming front occupies a zone whose depth divided by normal spread speed gives residence time.

A steady flaming front occupies a zone whose depth divided by normal spread speed gives residence time. Comparing a measured duration retains disagreement with that geometry.^[1]

Infer steady-front flaming residence from measured zone depth and normal front speed and compare observed duration; not ignition delay or a universal fuel burn time.

When to use Flaming Combustion Residence Time

Use this tool to infer steady-front flaming residence from measured zone depth and normal front speed and compare observed duration; not ignition delay or a universal fuel burn time.

Gather the tree inventory, plot measurements or model parameters. Check diameter, area, time and moisture conventions; keep paired observations aligned.

How to use Flaming Combustion Residence Time and understand its results

Gather the tree inventory, plot measurements or model parameters. Check diameter, area, time and moisture conventions; keep paired observations aligned.
Enter flamingZoneDepthM, normalFrontSpreadMPerSecond, observedFlamingDurationSeconds using the field table and calculation rules, then run the tool.
Read zoneTransitResidenceSeconds, observedMinusModelResidenceSeconds. 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
flamingZoneDepthM	Flaming zone depth m	number	Required
normalFrontSpreadMPerSecond	Normal front spread m per second	number	Required
observedFlamingDurationSeconds	Observed flaming duration seconds	number	Required

Use positive normal spread m/s, nonnegative zone depth meters and observed duration seconds. Return modeled residence and signed observed-minus-modeled duration.

zone-transit seconds=flaming-zone depth/normal front speed

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

Output field	Meaning	Value type
zoneTransitResidenceSeconds	Zone transit residence seconds	number
observedMinusModelResidenceSeconds	Observed minus model residence seconds	number

json

{
  "input": {
    "flamingZoneDepthM": 2,
    "normalFrontSpreadMPerSecond": 0.5,
    "observedFlamingDurationSeconds": 3
  },
  "output": {
    "zoneTransitResidenceSeconds": 4,
    "observedMinusModelResidenceSeconds": -1
  }
}

Limitations and assumptions

Ignition delay and universal fuel burn time are not inferred. A steady-front approximation is assumed.

Numeric inputs and returned numeric values must be finite; an unrepresentable returned value produces an error. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Byram Fireline Intensity kW/m: Compute Byram heat-yield×consumed-fuel×front-spread fireline intensity using supplied dry fuel consumption, not full fuel load or a fire-danger/response recommendation. For a complementary task, use Flame Length From Fireline Intensity: Apply supplied unit-specific fireline-intensity/flame-length calibration inside its domain; no universal coefficient or tactics/safe-distance determination.

References

Flaming Combustion Residence Time — tool.io

Similar or alternative tools

Byram Fireline Intensity kW/m
Compute Byram heat-yield×consumed-fuel×front-spread fireline intensity using supplied dry fuel consumption, not full fuel load or a fire-danger/response recommendation.
Flame Length From Fireline Intensity
Apply supplied unit-specific fireline-intensity/flame-length calibration inside its domain; no universal coefficient or tactics/safe-distance determination.