Investigations into protection from explosion when using cooling lubricants in machine tools

Project No. BG10 #029


completed 09/1997


Accidents caused by detonation of cooling lubricant fumes/vapours. Goal: determining the flammability and explosive pressure of atomised straight cooling lubricants under practical working conditions


Determining explosion parameters in test vessels, ignition of free cooling lubricant vapour jets through mechanical sparking, electrical heating elements, hot surfaces; ignition of vapour sprays during grinding and drilling work at a lathe


The maximum explosion pressure in closed vessels amounted to 3.5 to 4.5 bar; all cooling lubricants with a flashpoint over 200 °C can be ignited by electrical sparks under 10 J and by hot surfaces (over 800 °C, during drilling and grinding); mechanical sparks (steel) do not cause the vapour to ignite.


Hirsch, W.; Hempel, D.; Förster, H.: Untersuchungen zum Explosionsschutz beim Einsatz von Kühlschmierstoffen in Werkzeugmaschinen. PTB-Bericht ThEx-2. Physikalisch-Technische Bundesanstalt, Braunschweig 1997

Last Update:

22 Aug 2000


Financed by:
  • Berufsgenossenschaft der Feinmechanik und Elektrotechnik und Industrie (Kühlschmierstoff-Hersteller und -Anwender)
Research institution(s):
  • Physikalisch-Technische Bundesanstalt
  • Braunschweig

electrical engineering

Type of hazard:

dangerous substances


Brand- und Explosionsschutz, chemische Arbeitsstoffe, Gefährdungsbeurteilung

Description, key words:

Danger of explosions through cooling lubricant aerosols