Textbook Notes (368,439)
Canada (161,878)
FSC239Y5 (39)
Cahn (12)

FSC239 Ch 25

3 Pages
Unlock Document

Forensic Science

FSC239 January 6 th Ch. 25 – pgs 507 to 524 Basic Fire and Explosion Investigation - the basic method is the systematic approach that address the following criteria o 1. recognition of the need: determine how the fire or explosion occurred o 2. definition of the problem: how can the problem be solved o 3. collection of the data: facts about the fire incident are now collected o 4. analysis of the data: all the collected and observed data is analyzed Fire - fire: the rapid oxidation process with the evolution of heat and light - 4 components necessary for fire: fuel, heat, oxygen, and uninhibited chemical chain reactions - fuel: any substance that will burn or support combustion o 3 basic states: solid, liquid, gaseous vapour  can only be volitalized and consumed in the vapour form - if oxygen in the environment is limited, it results in the production of CO o carbon monoxide asphyxiation is the primary cause of death in fires - flashpoint: the temperature at which a liquid gives off sufficient vapours to form an ignitable mixture at its surface - fire point: the temperature at which a liquid produces vapours that will sustain combustion – generally several degrees higher than the flashpoint - heat: the component necessary to increase the temperature of the fuel in the presence of oxygen and cause ignition o energy possessed by a material or substance due to molecular activity - 5 basic methods of heat production o 1. chemical: production of rapid oxidation o 2. mechanical: production of friction o 3. electrical: product of arcing, shorting, or other electrical malfunction o 4. compressed gas: molecular activity is increased – heat is generated o 5. nuclear: product or splitting of atomic particles - 3 forms of heat transfer o 1. conduction: transfer of heat through direct contact o 2. convection: transfer of heat by a circulation medium – air/water o 3. radiation: - chemical chain reaction require 2 things: o 1. oxidation reaction produces sufficient heat to maintain continued oxidation o 2. the fuel mass must be broken down into similar compounds and liberate from the mass itself - fire follows a path of least resistance - during fire’s progression, it normally transcends 4 phases o 1. incipient: may last a fraction of a second to several hours or days depending on the fuel or ignition source o 2. emergent smouldering: products of combustion become increasingly pronounced o 3. fire burning: rate and intensity of open fire increases – intensity doubles with each 18 F/10 C o 4. oxygen regulated smouldering: when the oxygen in the air is
More Less

Related notes for FSC239Y5

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.