Hazard vs. Flash Points
The flash point of a chemical is the lowest temperature where it will evaporate enough fluid to form a combustible concentration of gas. The flash point is an indication of how easy a chemical may burn.
Materials with higher flash points are less flammable or hazardous than chemicals with lower flash points.
| Hazard | Flash Point |
|---|---|
| Very Low Hazard | > 200oF (93oC) |
| Moderate Low Hazard | 150oF to 200oF (66oC to 93oC) |
| High to Moderate Hazard | 100oF to 150oF (38oC to 66oC) |
| Extreme to High Hazard | 0oF to 100oF (-18oC to 38oC) |
| Extreme Hazard | < 0oF (-18oC) |
An open flame is not always necessary to ignite a gas. A hot surface - like a heating element or warm machine - will do for chemicals with more than high hazard.
See Autoignition temperature and flash point of different hydrocarbons and Flash Point - Fuels for measured values of flash point.
The Flash Point is not the same as the Auto-Ignition Temperature. The Auto-Ignition Temperature is the minimum temperature required to ignite a gas or vapor in air without a spark or flame present.
Related Topics
• Material Properties
Material properties of gases, fluids and solids - densities, specific heats, viscosities and more.
• Risk, Reliability and Safety
Risk, reliability and safety in process control systems.
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