Study of the explosible properties of textile dusts

In the past, the risk of dust explosions in the textile industry was considered very limited or even negligible. This was probably a consequence of the limited number of accidents that affected this industry, according to the available statistics (Abbasi and Abbasi, 2007; U.S. Chemical Safety Board, 2006; Yuan et al., 2015). However, despite these data, the textile industry has in fact suffered from some very severe dust explosions over the years, with fatalities, monetary losses and serious damage (Bowen, 1988; Eckhoff, 2003; Marmo, 2010; Piccinini, 2008; Salatino et al., 2012). The textile industry deals with "non-traditional dusts", which mainly originate from fibrous materials as a result of fragmentation and abrasion. There is still very little knowledge about the explosion properties of textile fibers, as fibers have only recently been explicitly included in the list of materials considered dangerous through technical standards that regulate the protection from explosions of industrial processes. This lack of knowledge is demonstrated, from a practical point of view, by the scarce amount of data on textile fibers available in such databases as the well-known one (GESTIS-DUST-EX) by the Institut fuer Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung (IFA). The main aim of this work was to enlarge the knowledge on hazards related to textile-derived dusts. To this aim, an extensive survey has been carried out, in cooperation with a local federation of textile employers in a northern Italian district, on the characteristics of the dusts that are present as by-products. More than one hundred dust samples were collected from several industrial sites and from different processes. Some of these industries were part of the wool manufacturing chain, while others operated in the field of natural or synthetic fibers. The samples were analyzed to determine the particle size distribution. Wet-sieving and/or laser diffraction methods were used, depending on the nature of the sample. Twenty-two samples were submitted to the speditive explosibility test (SET), which was developed at the Politecnico di Torino (Danzi et al., 2016), and of these samples, 21 were found to be explosible. The samples, including those which were negative to SET, were submitted to a traditional test in a 20 l sphere to measure the maximum pressure (Pmax) and the deflagration index (KST). The minimum ignition energy (MIE) was measured with a Mike 3 device. Chemical and morphological characterizations of these samples were also performed. A discussion on the explosion risk in textile processes can be made on the basis of the obtained results. Details of the experimental program and all the obtained results are described in the paper