What Is the Le Chatelier Lower Explosive Limit (LEL) Mixture Calculator?
The Lower Explosive Limit (LEL) is the minimum volumetric concentration of a combustible gas in air that will propagate a flame when ignited.
How Does the Le Chatelier Lower Explosive Limit (LEL) Mixture Calculator Work?
Sums the ratios of volume fraction to individual LEL.
Divides 100 by the sum of ratios.
Le Chatelier Lower Explosive Limit (LEL) Mixture Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
LEL_mix = 100 / [ ∑ (y_i / LEL_i) ]
Le Chatelier harmonic flammability mixing rule based on thermal ignition energy additivity.
How to Use the Le Chatelier Lower Explosive Limit (LEL) Mixture Calculator
- Enter volumetric percentage of each gas in the fuel mixture.
- Input published LEL percentage in air for each constituent.
Step-by-Step Example Calculation
50/50 Methane-Propane Fuel Gas Blend
Input Values:
volume1:50
lel1:5
volume2:50
lel2:2.1
Worked Steps: Equal mixture of methane and propane yielding ~2.96% composite LEL in air.
Understanding Your Result
Outputs composite LEL in volume percent in air.
Industrial safety standards (OSHA/NFPA) mandate alarms at 10% to 25% of composite LEL.
Factors That Affect the Result
- Mixture temperature and pressure (elevated temperatures lower the LEL).
When Should You Use This Calculator?
- Industrial hygiene gas monitoring, chemical process safety, and hazardous area classification.
Assumptions & Limitations
- Valid for simple hydrocarbon and permanent flammable gas mixtures.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard NFPA 69 / OSHA process safety rule.