The explosive limits (also called limits of flammability or limits of inflammability) determine whether a gas or vapor mixture with air/oxygen will combust.

For a gas mixture, two explosive limits should be given:

Any gas mixture with a concentration between the LEL and UEL can cause an explosion!

Also keep in mind:

  • LEL and UEL are dependent on temperature and pressure. Generally, higher pressure and temperature will expand the explosive regime (more danger).
  • LEL and UEL are usually specified for mixtures in air, but will be different for mixtures in oxygen.
  • Free flowing, explosive gas mixtures with concentrations above the UEL can easily mix with surrounding air, and consequently cause an explosion.
  • The presence of other explosive gases in a mixture will also affect the LEL and UEL
If you ever need this data, verify it in reputable sources, such as the CRC Handbook of Chemistry and Physics.

Log in or register to write something here or to contact authors.