Characteristics of the fire scene
There are several sources of information that should be taken into account in this regard (NFPA 921, 2004):
First, one should analyze the patterns of the fire scene i.e. the physical ‘signs’ left by the flame;
Second, the evidence by the witnesses or the ones who informed about fire shall be considered. They can explain the conditions of the fire e.g. time, whether, people around etc.
Third, the fire physics, as well as the chemistry of its initiation and growth are the obligatory elements of the investigation in order to establish the possible sources of the fire;
Finally, the geographical location of the fire scene, as well as the existence of electricity sources are crucial for the fire investigation.
The difference between deflagration and detonation, definition of taggant.
The main difference between deflagration and detonation is that the latter does not prescribe the involvement of oxygen. The process of detonation involves the reaction between molecules which are chemically unstable, while deflagration does not have such characteristics (DeHaan).
The violent disruption associated with explosion produces large amounts of different gases (carbon dioxide, nitrogen) and water.
Taggants are special ‘markers’ which are colored used in order to trace the origin of the explosives. They are used to prevent the spread of the explosives all over the world and to prevent the threats to world’s peace and security. The more taggants are utilized, the less is the number of the potential explosions (Fialka, 1996).
The procedures are the following:
Color spot tests used to identify the precise chemical of the substance;
Thin-layer chromatography for separation of the mixtures that are not violent by their nature;
Infrared spectroscopy used for determining of contention of a particular substance;
Gas chromatography-mass spectrometry need for the purpose of establishing the contention of gases in the air and in relation to the mass.
References
(2004). Guide for fire and explosions investigations. NFPA. 921-134
DeHaan, J.D. Deflagrations vs. Detonations. California Institute of Criminalistics. Web. 05 June 2015
Fialka, J.J. (1996). Tracing Explosives. The Wall Street Journal. Web. 05 June 2015
