Ignition sources for hazardous areas

What can cause an explosion in an hazardous area?

As we have learned, explosives hazardous areas occur where flammable liquids, vapors, gases or combustible dusts are likely to occur in quantities sufficient to cause a fire or explosion. These atmospheres are created where gas, vapors, dusts and liquids are in contact with oxygen. Limiting oxygen or gas is difficult, and you therefore need to look at the third component which can cause an explosion, namely the ignition source. The ignition source is sometimes also referred to as the threshold temperature or ignition temperature. 


What is an ignition source?


  • Flames
  • Direct fired space and process heating
  • Use of cigarettes/matches etc
  • Cutting and welding flames
  • Hot surfaces
  • Heated process vessels such as dryers and furnaces
  • Hot process vessels
  • Space heating equipment
  • Mechanical machinery
  • Electrical equipment and lights
  • Spontaneous heating
  • Friction heating or sparks
  • Impact sparks
  • Sparks from electrical equipment
  • Stray currents from electrical equipment
  • Electrostatic discharge sparks
  • Lightning strikes
  • Electromagnetic radiation of different wavelengths
  • Concentrated light (Optical radiation, OP IS)
  • Batteries short circuiting


Sources: HSE Government UK, BARTEC TECHNOR and IECEx websites.