Test silo for dust explosions Álvaro Ramírez-Gómez 1 *, Alberto Tascón 2 , Pedro José Aguado 2 , Francisco Ayuga 1 1 BIPREE Research Group, Universidad Politécnica de Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain 2 INRUMA Research Group. Dpto. Agricultura y Alimentación. Universidad de La Rioja, Avda. de la Paz, 93. 26006 Logroño. Spain. 3 INRUMA Research Group. Dpto. Ingeniería y Ciencias Agrarias. ESTI Agraria. Universidad de León. Avda. de Portugal 41. 24071 León. Spain. *Corresponding author. E-mail: alvaro.ramirez@upm.es Abstrat It is common to find storage installations in the agri-food industries. The processes of filling and discharge carried out in these installations usually lead to dust clouds, and therefore potential explosive atmospheres. It is known that prevention and protection are the main measures to be followed in these situations. Nowadays, there are many technical and economical difficulties that avoid to achieve a viable protection in the agricultural silos. Some studies have shown differences between standards in this regard, this is the case of the European code (EN 14491, 2006) and the North American code (NFPA 68, 2007). This implies that research is needed in this direction. Further knowledge about the explosion process and venting is needed in order to arrive to optimal designs. Experimental work is essential, because of that three research groups, two from the Universidad Politécnica de Madrid and one from the Universidad de León, have joined efforts to develop an installation that will allow the study of the explosion phenomenon and will allow to optimize the design of protection devices. Key words: Silo, dust, explosion, design, venting. 1. Introduction When the organic material is finely divided and on the air forming a cloud of dust, a potential explosive atmosphere can be formed if the dust concentration is enough (Eckhoff, 2003). Operations as transport, load and discharge may generate dust clouds able to produce explosions in agricultural industries involving loss of goods and materials. When a dust cloud is ignited in a confined environment exothermic reactions are produced, being developed a rapid increase of pressure until values of 7-10 bar (700-1000 kPa). The EU legislation establishes the conditions that must fulfil the equipment to be mounted in potential explosive atmospheres and the working conditions in two directives (ATEX 94/9/CE, 1994 and ATEX 1999/92/CE, 1999). These Directives receives the colloquial acronym ATEX (ATmosphère EXplosible). The basic system of protection against explosions in silos are venting devices, which allow to release pressure generated when a dust cloud ignite in a controlled manner by means of its rupture. During the 80s and 90s several researchers have contributed to the knowledge of the dust explosions in silos by means of the development of explosion tests. Remarkable tests are those developed by Eckhoff in a silo of 500 m3 (Eckhoff, 1984); and in one of 236 m3 (Eckhoff, 1988); results by Bartknecht in 20 m3 (1985); the test of Siwek in 10, 25 and 250 m3 (Siwek, 1989); the tests of Tamanini in 63,7 m3 (Tamanini, 1996); Deng in 95 m3 (Deng, 1993); Hattwig and Hesel in silos of square section of 45 and 85 m3 (Hattwig, 1993); and those developed by Eibl, Nars, Leuckel and Hochst in 50 m3 (Höchst, 1998).