General information on explosivity.

Preconditions for a gas- or vapor explosion.

  • Fuel
  • Oxygen (from the air or elsewhere)
  • Ignition source.

The danger of an explosion may be present for only a short while.

Preconditions for a dust explosion.

  • Fuel
  • Oxygen (from the air or elsewhere)
  • Ignition source.
  • Turbulence (swirling up dust).

The danger of an explosion may exist as long as the dust remains.

Other influencing parameters:

  • Appropriate mixing ratio (explosion limits)
  • PSD = Particle Size Distribution (for dust)
    The finer the worst. Criterium isoften 63µm.
  • Temperature (self ignition, flame point)
  • Pressure (widening explosion limits)
  • Humidity (influence on explosion limits)
    For gasses and vapors, explosion limits approach one and another at an increasing humity. For dust the explosion limits become higher at an increasing humity.

Explosion properties.

Following properties determine the properties of an explosion or the explosivity of a substance. These aspects are checked in an explosivity investigation.

  • Explosion limits / concentrations / influence of flegmatisation.
  • Ignitability (MIE, MOT)
    For as well dust clouds as deposited dust layers.
  • Oxygen limit concentration (LOC)
  • Maximum explosion pressure(Pmax)
  • Maximum pressure rise speed (Kst and cubic law)
  • Combustional behavior (BZ)

Safety at explosion danger.

  • Preventive measures.
    Explosion safe execution of equipment.
    Work safely in Ex-zones.
    Respect operational hygiene.
  • Protection from ignitition danger.
    Operate outside of explosion limit range explosiegrenzen.
    Prevent effective ignition sources.
    Operate under the  LOC.
  • Ensure limiting measures.
    Prevention of explosion expansion.
    Constructive measures like:
    → Explosion resistant constructions
    → Explosion pressure relief
    → Explosion surpression

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