Ignition sources and their causes
| Ignition source | Cause (example) |
| Hot surfaces | Heating devices, mechanical processes due to friction and chipping, heat losses (friction coupling and braking) |
| Electric arcs | Mechanically generated sparks (e.g., due to friction, impact or machining processes), electrical sparks, electrical switch arcs |
| Flames and hot gases | Flames or their hot reaction products such as hot gases and glowing material particles can ignite an explosive atmosphere. |
| Sparks generated mechanically | Friction, impact or machining processes such as grinding, tools such as wrenches, pliers or tools such as a ladder; work on rusty components with aluminum tools (thermite reaction) |
| Electrical systems | Opening and closing of electrical circuits, equalizing currents, electromagnetic fields, conductive dust Note: Protective low voltage is not a measure to protect against explosion, since ignition is also possible with less than 50 V! |
| Cathode corrosion protection | Reverse current to the current source, induction, short or ground faults |
| Static electricity | Static electric discharge |
| Lightening strike | - |
| Electromagnetic fields | Frequency ranges from 9 x 103 to 3 x 1011 Hz. These include high-frequency equipment such as radio equipment or high-frequency generators. |
| Electromagnetic radiation | Frequency ranges from 3 x 1011 to 3 x 1015 Hz and wavelengths of 1000 to 0.1 μm. This includes optical radiation such as sunlight, lasers, lightning strikes, electric arcs. |
| Ionizing radiation | Ignition due to energy absorption, with causes such as short-wave UV rays, X-rays or radioactive materials |
| Ultrasound | Ignition due to energy absorption, with causes such as short-wave UV rays, X-rays or radioactive materials. |
| Adiabatic compression and streaming gases | Due to the high temperatures that occur due to shock waves and in instances of adiabatic compression, an atmosphere subject to explosion can ignite. |
| Chemical reaction | Due to chemical reactions that cause heat development (exothermic reactions), materials heat up and can cause an explosion. |
