A speditive explosibility test for dusts

Combustible dusts explosion risk depends on a huge number of dust characteristics which allows the analyst to assess its behavior at different conditions. To characterize dust behavior a huge number of parameters can be measured according to several technical standards. In general, each standard describes how to measure a single parameter, which characterize a specific dust behavior. Nowadays there’s no standard conceived to simply determine if the dust can cause an explosion. As available standard tests are often costly in terms of time and money for both laboratory analysts and customers, moreover the latter are sometimes in the condition to submit to expensive tests dust samples that could not explode. The aim of this paper is to describe a simplified and straightforward test that can assess whether a dust is explosible or not. The test is called Speditive Esplosibility Test (SET). It is composed of 4 different tests, each of them representing a different ignition mechanism derived from standards procedures. These are: -High voltage continuous arc ignition and glowing wire ignition in Hartman 1.2l tube (based on UNI EN 13821:2004); -Dust cloud ignition in G-G furnace and dust layer ignition on hot plate (based on UNI EN 50281:1999). In this context the 4 experimental procedures were slightly modified respect to standards procedures: the test conditions have to be “as worst as possible” in terms of energy transferred to the sample. This approach assure that also dusts that have relative weak tendency to ignite is considered and classified. The test classifies dusts in 3 categories: explosible at ambient temperature (in case of ignition in Hartmann tube tests), explosible at high temperature (in case of ignition in GG or hot plate tests), not explosible (in case of no ignition). Fundamentally, the test procedure is configured as a statistical investigation in which a defined number of tests is made. Screening test has been performed for several types of dusts and results compared with kst tests in 20l Siwek Sphere for some of the samples. Results sees to confirm the hypothesis of the Screening Test and its reliability to assess explosibility of combustible dusts.