Determination of safety characteristics of combustible substances

04.11.2015
  • Dusts
  • Liquids and their vapours
  • Gases
  • Mists / Aerosols of combustible liquids and hybrid mixtures

The safety characteristics of combustible substances have been determined in the laboratories of the IBExU Institut für Sicherheitstechnik GmbH since 1990. They form the basis of explosion protection and have applications in the primary, secondary and constructive explosion protection.

In primary explosion protection which is the avoidance of potentially explosive atmospheres the Flash Point, the explosion points and the Limiting Oxygen Concentration, for example, play a fundamental role. To avoid effective ignition sources (secondary explosion protection) safety characteristics such as the Ignition Temperature and the Maximum Experimental Safe Gap are consulted. The deciding factor for structural explosion protection is, among other things, the maximum explosion pressure.

In the IBExU Institut für Sicherheitstechnik GmbH laboratories there exists the potential for determining the above in addition to a multiplicity of other safety characteristics of combustible dusts, gases, liquids and their vapours as well as mists / aerosols of combustible liquids and hybrid mixtures. The determination takes place as a rule in accordance with the specified formalities.

Liquids

  • Flash Point
    EN ISO 1516 | EN ISO 1523 | EN ISO 2719 | EN ISO 13736
  • Lower explosion point
    EN 15794
  • Upper explosion point
    EN 15794

Gases, liquids and their vapours

  • Lower Explosion Limit (LEL)
    EN 1839
  • Upper Explosion Limit (UEL)
    EN 1839
  • Limiting Oxygen Concentration (LOC)
    EN 14756
  • Ignition Temperature
    EN 14522
  • Maximum Experimental Safe Gap (MESG)
    EN 60079-20-1
  • Maximum explosion pressure (pmax)
    EN 15967
  • Maximum rate of pressure rise ((dp/dt)max / KG-value)
    EN 15967
  • Specific electrical conductivity
    EN 60247 | EN 60079-32-2

Mists / Aerosols of combustible liquids and hybrid mixtures

  • Explosibility (“yes” / “no”)
  • Lower Explosion Limit (LEL)
  • Maximum explosion pressure (pmax)
  • Maximum rate of pressure rise ((dp/dt)max)

Dust layers

  • Minimum Ignition Temperature (MIT) of a dust layer
    EN 50281-2-1
  • Auto Ignition Temperature (AIT)
    EN 15188
  • Burning behaviour / Class
  • Testing in terms of class 4.1, 4.2 and 4.3 / Rating in hazard categories
  • CLP regulation
  • Oxidizing properties
  • Electrostatic charge
  • Specific electrical resistivity
    EN 61241-2-2 | EN 60079-32-2
  • Deflagration capability
  • Impact sensitivity
  • Friction sensitivity
  • Exothermic decomposition

Dispersed dusts

  • Lower Explosion Limit (LEL)
    EN 14034-3
  • Limiting Oxygen Concentration (LOC)
    EN 14034-4
  • Minimum Ignition Temperature (MIT) of a dust cloud
    EN 50281-2-1
  • Minimum Ignition Energy (MIE)
    EN 13821
  • Maximum explosion pressure (pmax)
    EN 14034-1
  • Maximum rate of pressure rise ((dp/dt)max / KSt-value / Dust explosion class)
    EN 14034-2

The safety characteristics of dusts are heavily dependent on the grain size distribution, the content of volatile matter in addition to the water and ash content of the respective dust sample.

Moreover, the factors influencing the safety characteristics are the temperature, the pressure, the respective inert gas, the ignition sources and their arrangement within the ignition vessel as well as their geometry and material.