Ignition Source

Ignition Source and Mitigation

  1. Flames 
  2. Direct fired space and process heating. This risk is mitigated by using isolation material. 
  3. Use of cigarettes/matches etc. This risk is mitigated by risk assessment and ATEX directive.  
  4. Cutting and welding flames. This risk is mitigated by risk assessment and ATEX directive. 
  5. Hot surfaces. This risk is mitigated by using isolation material.
  6. Heated process vessels such as dryers and furnaces. This risk is mitigated by using isolation material. 
  7. Hot process vessels. This risk is mitigated by using isolation material. 
  8. Space heating equipment. This risk is mitigated by using ATEX certified equipment. 
  9. Electrical equipment and lights. This risk is mitigated by using ATEX certified equipment. 
  10. Sparks from electrical equipment. This risk is mitigated by using ATEX certified equipment. 
  11. Stray currents from electrical equipment. This risk is mitigated by earthing system and lightning protection system. 
  12. Electrostatic discharge sparks. This risk is mitigated by earthing system. 
  13. Lightning strikes. This risk is mitigated by lightning protection system. 
  14. Vehicles, unless specially designed or modified are likely to contain a range of potential ignition sources. This risk is mitigated by risk assessment and ATEX directive. 
  15. Mechanical machinery. 
  16. Spontaneous heating. 
  17. Friction heating or sparks.  
  18. Impact sparks.
  19. Electromagnetic radiation of different wavelengths 

Minimum Ignition Energy

In order to ignite a gas or vapour, a spark needs a certain amount of energy. The minimum ignition energy is the spark energy in Joules, it is required to ignite the gases. Another parameter is the Minimum Ignition Current (MIC). The Minimum Ignition Current is mostly used as a ratio relative to that of methane.

Liquids :

  1. Benzene : Approx 200 µJ
  2. Hexane : Approx 240 µJ
  3. Acetone : Approx 1.15 mJ

Gases :

  1. Hydrogen : Approx 20 µJ
  2. Ethylene : Approx 95 µJ
  3. Propane : Approx 260 µJ
  4. Methane : Approx 280 µJ

Flash Point :

Flash points are normally related to liquids, but some materials can emit solid vapor. The flash point of a flammable material is the minimum temperature at which the material emits vapor in an amount capable of forming a flammable vapor / air mixture. Combustible gas or vapor ignites instantly upon application of an effective ignition source.

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