2012 Spring Meeting & 8th Global Congress on Process Safety

(104b) Detonation of A Gaseous CHARGE In A Confined and SEMI-Confined Workshop

Author

Sochet, I. - Presenter, Institut PRISME, Ecole Nationale Supérieure d'ingénieurs de Bourges


Detonation of a gaseous charge in a confined and semi-confined workshop.

Sauvan
P.E., Sochet I.1, Trélat S.2, Boulanger R.3,
Nozeres F.3, Minard J.P.4, Le Naour B.4, Munoz
D.5, Julien B.5

1 Ecole Nationale Supérieure d'Ingénieurs de Bourges ?
Laboratoire PRISME ? UPRES EA 4229 ? 88 boulevard Lahitolle, 18020 Bourges
Cedex ? France

2 Institut de Radioprotection et de Sûreté
Nucléaire ? DSU/SERIC/BEXI ? 31 avenue de la Division Leclerc, 92260
Fontenay-aux-Roses? France 3 Nexter Munitions - 7 Route de Guerry, 18023 Bourges
Cedex 4 MBDA - Rond point Marcel Hanriot, Route d'Issoudun, 18020 Bourges
cedex. 5 Direction Générale de l'Armement,
Techniques Terrestres - Rocade Est, Echangeur de Guerry - 18000 Bourges.

Corresponding author: isabelle.sochet@ensi-bourges.fr

  Abstract

            The detonation of a charge
within a pyrotechnic workshop represents a significant hazard to the structure
and its employees. The assessment of pressure and impulses produced by shock waves
is studied in this paper to investigate how blast propagates through a
pyrotechnic workshop and how the propagation is affected by different
parameters.

Small scale
experiments are conducted with a Plexiglas model of a pyrotechnic workshop and
the explosive charge is represented by a homogeneous hemispherical gaseous
charge (stoichiometric propane-oxygen mixture). Three positions of the charge
are considered: in the centre of the workshop, on the axis and in a corner
located at the opposite side of the chimney. Pressure gauges are distributed on
the floor and at the centre of each wall. Three main configurations are
studied: without a roof, with a roof and without a chimney, with a roof and
with a chimney. Pressure-time histories are compared with each other so as to
determine the influence of the roof and the chimney on overpressure and impulse
levels. Each configuration is tested with and without an obstacle (this
obstacle standing for a machine tool) in order to assess its influence on shock
waves propagation. The present study highlights that the detonation of an
explosive charge in a confined or semi-confined workshop generates Mach stems
along walls. This phenomenon significantly increases overpressures and impulses
in the vicinity of walls and injuries induced by such a Mach stem are more
serious than those caused by the incident shock wave.