Title
Assessment of the impact of spruce wood particle size and water content on the ignition temperature of dust clouds
Authors
JOZEF MARTINKA PETER RANTUCH and KAROL BALOG

Received January 11, 2014
Published Volume 49 Issue 5-6 May-June
Keywords dust cloud, dust fire, explosion, fire risk assessment, ignition temperature, Norway spruce wood, wood dust

Abstract
This paper aims to assess the impact of water content and particle size of Norway spruce (Picea abies (L.) Karst.) wood dust on the ignition temperature of dust clouds. Dust samples were divided into four size fractions: less than 71 µm, from 71 to 150 µm, from 150 to 200 µm, and from 200 to 250 µm. Three different water contents, i.e. 0, 4 and 8 wt%, were analysed for each fraction. Ignition temperatures were determined for three different sample weights: 0.1, 0.2 and 0.5 g and for three different values of air pressure: 20, 30 and 50 kPa according to EN 50281-2-1:1998. The results showed that minimum ignition temperature (400 °C) was measured for a sample of 0.5 g weight and air pressure of 30 and 50 kPa. The determined ignition temperatures under the examined conditions were evaluated using one-way analysis of variance followed by Duncan’s multiple range test. The results of the analyses indicate that water content in the examined interval does not have a significant impact on ignition temperature. On the other hand, ignition temperature increases almost linearly with the increasing particle size.