When analyzing flammability, which limits are most commonly referenced?

The most commonly referenced limits when analyzing flammability are the Lower Flammable Limit (LFL) and Upper Flammable Limit (UFL). These two parameters define the concentration range of flammable vapors in the air that can support combustion.

The Lower Flammable Limit represents the minimum concentration of vapor in the air below which the mixture will not ignite. On the other hand, the Upper Flammable Limit signifies the maximum concentration of vapor in the air beyond which the mixture becomes too rich to ignite. Together, these limits establish a crucial safety guideline for ensuring that environments are maintained outside these limits to prevent fires and explosions.

In contrast, while the flash point and fire point are important measures for determining the ignition risk of a substance, they do not provide information about the concentration of vapor in the air needed for combustion. Autoignition temperature and combustion temperature are relevant to the ignition of materials but again do not address the concentration ranges in which flammability is a concern. Lastly, evaporation rate and vapor pressure are important physical properties that influence how easily a substance may vaporize, but they do not define the flammability limits directly. Understanding the LFL and UFL is key for safety and risk assessment in environments where flammable substances are present.