Altogether there exist 13 possible effective sources of initiation of explosive atmosphere. One of the basic steps in the process of risk analysis is their identification, assessment and potential elimination.
| Ignition source | Examples of causes |
|---|---|
| Hot surfaces | radiators, dryers, heating spirals, friction joints, mechanical brakes friction of rotating parts, malfunctions of devices operating in high temperatures, failures of thermal insulation, machining of materials, malfunctions of joints, brakes, bearings, blowing of mechanisms |
| Flames, hot gases (including hot particles) | sparks emerging during welding and cutting, devices for combustion, work with flame |
| Sparks from mechanical ignition | friction, impacts, abrasive processes (grinding, polishing), foreign objects in devices, cutting, malfunction of brakes, bearings and rotating mechanisms |
| Electric devices | connecting and disconnecting of electric circuits, loosening of connections, stray currents, electric arcs |
| Stray electric currents | reversing currents in devices for energy generation, short circuit, ground fault, magnetic induction, failures of insulations of high voltage wires and devices, lightning strike |
| Static electricity | cluster discharges, discharge from charged isolated conductive parts, crawling discharges, conic discharges, discharges from cloud, friction advancement |
| Lightning strike | lightning, heating up of lightning rod |
| High-frequency electromagnetic waves | malfunctions of radio and other transmitters, malfunctions of measuring and medical apparatuses, high-frequency generators |
| Electromagnetic waves | focused radiation through objects (lenses, reflectors), intensive light sources (constant or flashing), lasers (including measuring devices), sources of strong radiation |
| Ionizing rays | X-rays, radioactivity, subsequent chemical reactions (splitting exothermic reactions) |
| Ultrasound waves | absorption of ultrasound waves from electro acoustic transformer |
| Adiabatic compressions and impact waves | heat at significant, rapid adiabatic compressions, impact wave arising by sudden release of high-pressure gases into piping, warming during passing of the impact wave through the piping |
| Exothermic reactions including self-ignition of dusts | exothermic chemical reaction, reaction of pyrophoric substances with air, reaction of alkali metals with water, self-ignition of flammable dusts, self-warming of feeding mixtures caused by biological decomposition, decomposition of organic peroxides, polymerizing reactions |