Põlevuspiiri

Põlevuspiiri, a term originating from Estonian, translates to "flammable limit" or "explosive limit" in English. It refers to the range of concentrations of a flammable substance in air or another oxidant within which an explosion or fire can occur. Below the lower flammable limit, the concentration of the fuel is too low to ignite. Above the upper flammable limit, there is too little oxygen available to support combustion.

There are two primary flammable limits: the lower flammable limit (LFL) and the upper flammable limit (UFL). The LFL is the minimum concentration of a combustible gas or vapor in air that will burn or explode when an ignition source is present. The UFL is the maximum concentration of a combustible gas or vapor in air that will burn or explode. The range between the LFL and UFL is known as the flammable range or explosive range.

Understanding põlevuspiiri is crucial for safety in industries where flammable materials are handled, such as chemical processing, petroleum refining, and mining. It informs the design of ventilation systems, the selection of explosion-proof equipment, and the implementation of safety procedures to prevent fires and explosions. For example, maintaining concentrations below the LFL or above the UFL through ventilation can render an atmosphere non-flammable. The specific values for LFL and UFL vary depending on the substance, temperature, pressure, and the presence of other gases.