CO2 Exposure Time-Weighted Limit Checker

Actual complete cave CO2observed interval weighted mean, versus independently applicable same-durationTWA. No unknown interval zero fill, short-term/ceiling substitution or safe-entry approval.

Description

A carbon-dioxide TWA weights measured concentration by observed interval duration.

A carbon-dioxide TWA weights measured concentration by observed interval duration.^[1]

The resulting sampled-window mean depends on complete independently established coverage of the relevant interval.

When to use CO2 Exposure Time-Weighted Limit Checker

Use this tool to obtain observedCompleteIntervalTwaPpm, signedCallerTwaMarginPpm from the supplied records using the stated calculation. Establish the survey or observation scope, reference frame, units and independently applicable calibration or qualified plan.

How to use CO2 Exposure Time-Weighted Limit Checker and understand its results

Establish the survey or observation scope, reference frame, units and independently applicable calibration or qualified plan.
Enter actualCo2IntervalPpm, actualIntervalHours, callerApplicableTwaLimitPpm, using the field meanings and rules below, then run the tool.
Read result.observedCompleteIntervalTwaPpm, result.signedCallerTwaMarginPpm. Use the units and sign conventions below, and review any unknown records separately.
Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.

Input field	Meaning	Value type	Requirement
actualCo2IntervalPpm	Actual co2 interval ppm	list of number	Required
actualIntervalHours	Actual interval hours	list of number	Required
callerApplicableTwaLimitPpm	Caller applicable twa limit ppm	number	Required

Supply nonempty aligned nonnegative carbon-dioxide ppm values and positive interval hours, plus a positive independently applicable TWA limit in ppm. Calculate the hour-weighted mean over only the supplied intervals and return limit-minus-mean. Coverage, disjointness and the applicable averaging window are external; no fixed shift hours are inserted.

observedTwaPpm=Σ(ppm_i×hours_i)/Σhours_i; signedMarginPpm=limitPpm−observedTwaPpm

Use the matching field units and the exact boundary, ordering and reference rules above.

Output field	Meaning	Value type
result	Qualified observed calculation or explicit reference	object
result.observedCompleteIntervalTwaPpm	Hour-weighted mean over the supplied observed intervals, whose coverage is externally established.	number
result.signedCallerTwaMarginPpm	Caller-applicable TWA limit minus the observed interval-weighted mean.	number

json

{
  "input": {
    "actualCo2IntervalPpm": [
      100,
      200
    ],
    "actualIntervalHours": [
      1,
      3
    ],
    "callerApplicableTwaLimitPpm": 150
  },
  "output": {
    "result": {
      "observedCompleteIntervalTwaPpm": 175,
      "signedCallerTwaMarginPpm": -25
    }
  }
}

Limitations and assumptions

The actual observation coverage, calibration and qualified plan determine applicability. A numerical result does not establish survey accuracy, route suitability, atmosphere conditions or equipment adequacy beyond the declared comparison.

Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite. Lists and matrices must be dense, without missing cells. Numeric lists allow at most 10000 entries, subject to the narrower lengths and code rules above. Extremely large composite outputs are rejected.

Alternative or Complementary methods

For a related step, use Oxygen Depletion Percent Calculator: An oxygen comparison subtracts a calibrated measured percentage from a declared reference percentage. For a complementary comparison, use CO2 Air Concentration Safety Threshold Checker: Carbon-dioxide concentration needs calibrated contemporaneous measurement and applicable assessment context.

References

CO2 Exposure Time-Weighted Limit Checker — tool.io

Similar or alternative tools

Oxygen Depletion Percent Calculator
An oxygen comparison subtracts a calibrated measured percentage from a declared reference percentage.
CO2 Air Concentration Safety Threshold Checker
Carbon-dioxide concentration needs calibrated contemporaneous measurement and applicable assessment context.