Fan Engineering — Operating Point (Quadratic Estimate)
Operating Point (Quadratic Estimate) for mine and tunnel fan systems.
The mine gets the airflow where the fan curve crosses the system curve — never the catalog's headline number. This quadratic stand-in for the real curve teaches the core dynamic: tighten the circuit (raise R) and the point slides up-left, less air at more pressure, edging toward the stall region real curves hide up there.
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.
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.
Operating Point (Quadratic Estimate) for mine and tunnel fan systems. A free mine ventilation & air quality tool — no sign-up, no upload, instant results in your browser.
About Fan Engineering — Operating Point (Quadratic Estimate)
Fan Engineering — Operating Point (Quadratic Estimate) computes the governing relationship fan: p = p_max(1 − Q²/Q_max²) meets system: p = R·Q² live as you type. The mine gets the airflow where the fan curve crosses the system curve — never the catalog's headline number. This quadratic stand-in for the real curve teaches the core dynamic: tighten the circuit (raise R) and the point slides up-left, less air at more pressure, edging toward the stall region real curves hide up there. 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 Fan Engineering — Operating Point (Quadratic Estimate)
- 1Enter your values — Fan shutoff pressure, Free-delivery quantity, Circuit resistance R (sensible defaults are pre-filled).
- 2Read the live results: Operating quantity, Operating pressure.
- 3Check the "with your numbers" line to see fan: p = p_max(1 − Q²/Q_max²) meets system: p = R·Q² substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Fan Engineering — Operating Point (Quadratic Estimate)?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula fan: p = p_max(1 − Q²/Q_max²) meets system: p = R·Q² 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.)
- ✓The mine gets the airflow where the fan curve crosses the system curve — never the catalog's headline number.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the fan engineering — operating point (quadratic estimate) use?+
It evaluates fan: p = p_max(1 − Q²/Q_max²) meets system: p = R·Q², 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?+
The mine gets the airflow where the fan curve crosses the system curve — never the catalog's headline number. 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?+
Operating Point (Quadratic Estimate) for mine and tunnel fan systems. A free mine ventilation & air quality tool. This quadratic stand-in for the real curve teaches the core dynamic: tighten the circuit (raise R) and the point slides up-left, less air at more pressure, edging toward the stall region real curves hide up there. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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