This test is designed as qualitative pre-test of the explosion behavior of a dust/air mixture.

The product, which is milled down to a particle size of max 63 µm (main part), is whirled up in a vertical pyrex glass tube by an air blow. A test is considered to be positive if the indication instrument shows a deflection of the hinged cover (indication "1" or "2"), or if a dust fire occurs (even if the hinged cover is not moved, indication "0"). The test has to be carried out at different dust concentrations.

Only dust explosions leading to an indication "1" in the Modified Hartmann-Apparatus are true St 1 dusts. These data are therefore suited as a base for designing explosion protection measures.

Otherwise, for the indication "0" and "2", additional tests in the 20L-Apparatus are necessary.

Swiss Institute for the Promotion of Safety and Security

Adrien Bisel, Phone +41 (0)61 696 55 99, Fax +41 (0)61 696 70 72

Petra Meier, Phone +41 (0)61 696 57 24, Fax +41 (0)61 696 70 72