Explosion is a rapid chemical reaction between flammable substances and oxygen, followed by the release of energy (in the form of heat and light).

Only by simultaneously issuing the following three factors in advance will an explosion occur:

1. Flammable materials (appropriate amount);

2. Combustion agent (usually oxygen present in the atmosphere);

3. Ignition source.

If one of these three factors is missing, the explosion will not occur.

Some characteristics of flammable materials should be considered to understand how potential explosive atmospheres are formed.

The ignition temperature (flash point TFL) of a flammable liquid is the lowest temperature at which the liquid releases vapor. At this temperature, the concentration of the liquid causes it to form a flammable mixture with the air near the liquid surface (at atmospheric pressure). If the flash point is much higher than the maximum achievable temperature, an explosive environment will not be generated. However, it must be considered that the flash point of mixtures of more substances may be lower than the values of individual components. Flash point and boiling point are used together to classify liquids into three categories: highly flammable, highly flammable, and combustible.

In order to create a potentially explosive environment, flammable substances must be at a given concentration. If the concentration is too high or too low, an explosion may not occur.

The lower explosive limit (L.E.L.) and upper explosive limit (U.E.L.) specify the concentration range within which a given substance can explode when dissolved in air. In fact, the mixture can only be ignited when the concentration of substances in the air is between L.E.L. and U.E.L.

The ignition temperature is the lowest temperature at which a mixture of air/gas or air/steam spontaneously ignites under normal atmospheric conditions.

The last aspect involves ignition sources. Potential explosive environments require ignition sources to explode, and the most common ones are the following:

-Hot surface

-Flames and Heat

-Sparks generated by machinery

-Electrical equipment

-Static electricity

-Electromagnetic waves (high frequency)

-Optical radiation

-Ionizing radiation

-Ultrasonic waves

-Adiabatic compression and shock waves.

Please download the materials for details!