Chapter 19 Cause Determination

Question 1

The process of identifying the first fuel ignited, the ignition source, the oxidizing agent, and the circumstances that resulted in the fire.

Answer 1

Fire cause determination.

Question 2

Fire cause determination generally follows

Answer 2

origin determination.

Question 3

The determination of the cause of a fire requires

Answer 3

the identification of those factors that were necessary for the fire to have occurred.

Question 4

The factors that were necessary for the fire to have occurred include

Answer 4

the first fuel ignited

the circumstances, such as failures or human actions, that allowed the factors to come together and start the fire.

Question 5

The function of the investigator is to

Answer 5

identify those factors that contribute to the fire.

Question 6

The first fuel ignited is that

Answer 6

which first sustains combustion beyond the ignition source.

Question 7

The ignition source will be where?

Answer 7

at or near the point of origin at the time of ignition, although in some circumstances, such as the ignitioin of flammable vapors, the two may not appear to coincide.

Question 8

Generally, the oxidant is

Answer 8

the oxygen in the earth’s atmosphere.

Question 9

Fire results from the combination of

Answer 9

Fuel

an oxidant

and an ignition source.

Question 10

The overall methodology for determining the cause of the fire is the

Answer 10

scientific method

Question 11

The scientific method includes

Answer 11

Recognize the need

defining the problem to be solved

collecting data

analyzing the data

developing a hypothesis

testing the hypothesis

Select Final hypothesis

Question 12

How many steps are in the scientific method as per NFPA 921?

Answer 12

7

Question 13

Data should be collected to identify

Answer 13

all potential fuels, ignition sources, and oxidants withing the are or areas of origin.

Question 14

Identifying the initial fuel is necessary for evaluating the

Answer 14

compentency of potential ignition sources.

Question 15

The investigator should identify easily ignited items that, once ignited,

Answer 15

could provide the heat source to damage or involve harder to ignite items.

Question 16

Information should be sought from persons having knowledge (such as occupants) about recent activities in the area of origin and

Answer 16

what fuel items should or should not have been present.

Question 17

The investigator should develop data that can be used to

Answer 17

analyze the events that brought the fuel and ignition source together.

(ignition sequence)

Question 18

The fuel must be capable of being ignited by the hypothesized ignition source. The ignition temerpature of the fuel

Answer 18

should be understood.

Question 19

Ignitioin Source Analysis

Answer 19

the investigator should evaluate all potential ignition sources in the are of origin to determine if they are competent.

Question 20

A competent ignition source will

Answer 20

have sufficient energy and be capable of transferring that energy to the fuel long enough to raise the fuel to its ignition temperature.

Question 21

There are times when there is no physical evidence of the ignition source found at the origin, but where an ignition sequence can logically be inferred using other data. This inference may be arrived at

Answer 21

through the testing of alternate hypotheses involving potential ignition sequences, provided that the conclusion regarding the remaining ignition sequence is consistent with all known facts.

Question 22

Testing of the hypothesis is done by

Answer 22

the principle of deductive reasoning, in which the investigator compares the hypothesis to all known facts as well as the body of knowledge.

Question 23

Hypotheses Testing Questions

Answer 23

1. Is the hypothesized ignition source a compentent ignition source for the first fuel ignited?
2. Is the required time for ignition consistent with the time line associated with the cause hypothesis and facts of the incident?

What were the circumstances that brought the ignition source in contact with the first fuel ignited

4. What, if any, were the failure modes required for ignition to occur?

Question 24

The ______ is an intergral part of the scientific method.

Answer 24

Process of elimination.

Question 25

It is improper to opine a specific fire cause, ignition source, fuel or cause classication that

Answer 25

has no evidence to support it even though all other such hypothesized elements were eliminated.

Question 26

The cause of a fire is defined as

Answer 26

“the circumstances, conditions, or agencies that bring together a fuel, ignition source, and oxidizer resulting in a fire or a combustion explosion.

Question 27

The identification of an ignition source and a first fuel is not sufficient to determine?

Answer 27

A cause.

you must consider the relationship between the competency of the ignition source and the first fuel ignited.

Question 28

If the level of certainty of the opinion is only “possible” or “suspected,” the

Answer 28

fire cause is unresolved and should be classified as “undetermined.”