Lecture 9 - Explosions 9 Flashcards
what do most explosive accidents result from
the improper storage and transportation of explosive material
are we tor dry substances more sensitive to shock
dry
if primary explosives are contained in a small space what happens
they detonate rather than deflagrate
what is ANFO made of that makes it hard to determine the oxygen balance
fuel oil = a mixture of hydrocarbons
so when calculating the oxygen balance we do an idealised version
what is the observed colour of the smoke plume of ANFO when exposed to large amounts of oxygen and what does this tell us
red - caused by the NO2 gas
indicated the detonation of ANFO is more complicated that the normal
how can we approximate and observe the magnitude of an explosion e.g ‘the equivalent tons of TNT’
using the blast wave - now this can generally be documented by social media or audio and visual data of the surrounding areas
look at the timings on these compared to the location of the detonation
light travels quicker than sound so when the light is seen time can be set to 0.00 seconds
What is a fuel-air explosion
an explosion that uses O2 in the air as its oxidiser (the oxidiser isn’t contained within the fuel itself) e.g petrol
K-W rules do not apply to these as they are combustions not detonations
where are fuel air explosions used in the military
as large thermobaric weapons
the fuel is normally ethylene oxide or propylene oxide
with fuel air explosions why does the detonation location not need to be as accurate
as the shock wave generated propagates as it reacts with oxygen causing damage
what is the general equation of a combustion
fuel + oxygen -> CO2 and H2O
what were the 3 lessons learned from the Buncefield Explosion
(oil tank overflowed and caused big explosion)
secondary containment systems of fuels may be needed
better detection systems and alarms needed of flammable gases
investigators need to consider possible ignition sources further from the containment of an explosive
why does petrol as a fuel have the potential to be very damaging
it is very volatile so vapour spread much further and quicker than liquids
what are the important control measured needed for storage and transportation of flammable and energetic materials (5)
separate flammable, primary, secondary and tertiary explosives
avoid exposure to environment that can cause chemical modifications making explosives more sensitive/reactive
dryness of mixtures can alter sensitivity
use high quality containment and detection systems of flammables
assess all possible ignition sources surround the explosives
