There may be different sources of energy that produce heat necessary to cause a fire. They are between them:
Chemical heat energy as a result of a chemical reaction. Heat can be generated by combustion, heat of decomposition, spontaneous heating and heat by dissolution.
Heat energy of electrical origin, caused by resistance, dielectric heating, induction heating, heating caused by leakage currents, heat due to electric arc or heat due to static electricity.
Heat energy of mechanical origin caused by friction. Sparks may arise, heat due to friction and compression.
The ignition sources necessary for a fire to occur are:
- Thermal focuses. Action to smoke or use ignition tools (lighters and matches), heat generating facilities, furnaces, boilers, etc.), solar rays, welding or oxyfuel, vehicles and motor machines.
- Electric lights. Sparks, short circuits, overloads, static charges and atmospheric electrical discharges.
- Mechanical lights. Sparks of tools, mechanical friction and shoe-floor sparks.
- Chemical focuses. Exothermic reactions, reactive substances and antioxidants.