ANALYSIS OF SUSCEPTIBILITY TO IGNITION OF SELECTED INDUSTRY DUST FROM A HEATED SURFACE – COMPARATIVE VALUE OF MINIMAL IGNITION TEMPERATURES OF A DUST LAYER AND CLOUDS

摘要

In the article was described combustible properties of dust. Those properties decide about fire andrnexplosion hazard for dust in layer and in cloud according to PN-EN 50281-2-1:2007. There were determinedrnprotection against fire and explosion requirements of buildings structural elements and appliances used in spacernwhere dust accumulates. The article also consists safety requirements of using appliances in explosion hazardrnareas according to PN-EN 50281-1-2:2002 and PN-EN 60079-10-2:2009. The paper presents an analysis of thernminimum ignition temperature of dust layer (MITL) and the minimum ignition temperatures of dust cloudsrn(MTCD). Tests have been performed for selected dusts: dried carrot, corn starch, sunflower hulls, hop, lemonrnbalm, nettle, senna fruit, valerian, buckwheat, burley, semolina, cornflakes, oatmeal and rice flakes, furniturerndust without admixture and with the admixture of 30% sunflower seed coats, hay and mineral wool. Tests havernbeen performed in accordance with EN 50281-2-1. Method A consists in determining the minimum temperaturernat which ignition occurs of dust and/or its decomposition on a hot plate at a constant temperature. The study isrnused to identify the threats from industrial equipment and construction, which while working have hot surfaces,rnon which can create a layer of combustible dust. Method B is used for determining the minimum ignitionrntemperature of a dust cloud or other particulate solids. Method B is complementary to the method A. It is usedrnin relation to industrial equipment, inside which dust may exist in the form of short-term cloud. In the articlernare presented results of values of maximum acceptable surface temperature (MAST) of machines operating inrnthe presence of dust cloud and chosen dust layer with thickness of 5 and 12,5mm.