Network — District Flush/Recharge Time
District Flush/Recharge Time for ventilation network design and surveying.
Air age is the district's metabolic rate: after any ventilation change, gas readings need ~three time-constants before they mean anything. Crews that re-enter on the nominal V/Q figure are breathing the OLD atmosphere with a fresh label; the 3τ output is the patient version of the same number.
Formula
Note: Mine ventilation is statutory and life-safety territory: airflow quantities, gas limits and re-entry times must be set by the registered ventilation engineer/manager under your jurisdiction's mining regulations — this calculator is a planning and training aid.
District Flush/Recharge Time for ventilation network design and surveying. A free mine ventilation & air quality tool — no sign-up, no upload, instant results in your browser.
About Network — District Flush/Recharge Time
Network — District Flush/Recharge Time computes the governing relationship τ = V/Q · 95% replacement ≈ 3τ (mixing) live as you type. Air age is the district's metabolic rate: after any ventilation change, gas readings need ~three time-constants before they mean anything. Crews that re-enter on the nominal V/Q figure are breathing the OLD atmosphere with a fresh label; the 3τ output is the patient version of the same number. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Network — District Flush/Recharge Time
- 1Enter your values — District air volume, District airflow (sensible defaults are pre-filled).
- 2Read the live results: Nominal air age, 95% flush time.
- 3Check the "with your numbers" line to see τ = V/Q · 95% replacement ≈ 3τ (mixing) substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Network — District Flush/Recharge Time?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula τ = V/Q · 95% replacement ≈ 3τ (mixing) with authoritative sources cited on the page (McPherson, M.J., Subsurface Ventilation and Environmental Engineering; Hartman et al., Mine Ventilation and Air Conditioning, 3rd ed.)
- ✓Air age is the district's metabolic rate: after any ventilation change, gas readings need ~three time-constants before they mean anything.
- ✓Niche-specific defaults give a meaningful worked answer the moment the page loads
Frequently asked questions
What formula does the network — district flush/recharge time use?+
It evaluates τ = V/Q · 95% replacement ≈ 3τ (mixing), exactly as published. Sources: McPherson, M.J., Subsurface Ventilation and Environmental Engineering; Hartman et al., Mine Ventilation and Air Conditioning, 3rd ed.. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
Air age is the district's metabolic rate: after any ventilation change, gas readings need ~three time-constants before they mean anything. Mine ventilation is statutory and life-safety territory: airflow quantities, gas limits and re-entry times must be set by the registered ventilation engineer/manager under your jurisdiction's mining regulations — this calculator is a planning and training aid.
When is this calculator the right tool for the job?+
District Flush/Recharge Time for ventilation network design and surveying. A free mine ventilation & air quality tool. Crews that re-enter on the nominal V/Q figure are breathing the OLD atmosphere with a fresh label; the 3τ output is the patient version of the same number. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Do I need to install anything or create an account?+
No. The tool is pure client-side JavaScript: open the page and it works, offline once loaded, with no account, no quota and no data leaving your device.
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