NFPA 921 Chapter 18 Flashcards

Questions and Answers

What is the area of origin?

A structure

Part of a structure

General geographic location within the fire scene

All of the above (correct)

What is the exact location within the area of origin where a heat source and fuel interact?

Point of origin

What factors are considered in the determination of the origin of the fire?

Witness information, fire patterns, arc mapping, fire dynamics

What involves recognizing and defining the problem, collecting and analyzing data, and testing hypotheses?

Scientific method Signup and view all the answers

The hypothesis is considered ____________ until testing may be discarded, revised, or expanded.

working hypothesis Signup and view all the answers

What requires an understanding of the associated fire events and the growth of fire?

Origin hypothesis Signup and view all the answers

What type of analysis determines if physical damage is consistent with the area of origin hypothesis?

Fire spread Signup and view all the answers

Scenarios should be analyzed using the principles of _____________.

Fire dynamics Signup and view all the answers

What should an investigator do when a plausible hypothesis fails to consider some evidence?

Reconcile the two Signup and view all the answers

What follows a routine sequence during an investigation?

Origin determination Signup and view all the answers

What is an important factor in determining the sequence of pattern production?

Ventilation Signup and view all the answers

Data collection for origin determination occurs during which phases?

Initial scene assessment, excavation, reconstruction, witness collection Signup and view all the answers

What is the purpose of the initial assessment in a fire investigation?

To determine the complexity and extent of the investigation Signup and view all the answers

The point at which the investigator may begin the initial scene assessment is after what?

Safety issues Signup and view all the answers

What will follow a routine sequence during the investigation?

Order of the examination Signup and view all the answers

During an examination, investigators can canvas the neighborhood for what?

Witnesses Signup and view all the answers

What should be noted about the construction method and occupancy classification?

Degree of destruction Signup and view all the answers

What should be determined at the conclusion of the preliminary scene assessment?

Safety of the fire scene, staffing and equipment requirements Signup and view all the answers

What allows observers to see patterns on exposed surfaces and locate evidence?

Excavation and reconstruction Signup and view all the answers

What careful analysis may help to reduce the task of debris removal?

Debris removal Signup and view all the answers

What should discuss ___________ to prevent discarding evidence prematurely?

The purpose Signup and view all the answers

What should cease whenever a person enters an area of hazard?

Operation of heavy equipment Signup and view all the answers

If contamination is a concern, what should be collected for comparison purposes?

Samples of the equipment fluids Signup and view all the answers

By positioning equipment outside the building, how will the heavy equipment be?

Less destructive Signup and view all the answers

What should be used to minimize damage when lifting potential pieces of evidence?

Rigging Signup and view all the answers

Consider _____________ as an alternative to demolition when appropriate.

Shoring Signup and view all the answers

Removal of debris off site can limit further investigation but is sometimes necessary and requires what?

Documentation Signup and view all the answers

When using equipment to systematically progress into a building, the equipment is only located in positions that have already?

Been examined Signup and view all the answers

In the hope that subsequent information will pinpoint the location, document the contents in all?

Probable positions Signup and view all the answers

It is important to identify the potential first fuel ignited and also identify what?

Subsequent fuels Signup and view all the answers

The location, size, and condition of all openings should be recorded along with what?

Structures or obstructions affecting the flow of fire gases Signup and view all the answers

What may be indicated by smoke movement or fire damage sustained by structures?

Wind direction Signup and view all the answers

Documentation of the means to distribute electricity should begin with?

Incoming electrical service Signup and view all the answers

The tracing of circuits is to identify what?

Switches, receptacles, and fixtures Signup and view all the answers

Use caution when interpreting damage to electrical wiring as it may be difficult to distinguish what?

Cause from effect Signup and view all the answers

The examination of the fuel gas system should include testing for leaks and determining what?

Supply pressure Signup and view all the answers

Security cameras can be very useful for providing what?

Hard times Signup and view all the answers

Analysis of data is based on what aspects?

Knowledge, training, experience, and expertise Signup and view all the answers

What represents the total history of the fire?

Damage and burn patterns Signup and view all the answers

Ventilation influences the production of what?

Fire patterns Signup and view all the answers

Fire patterns are generated by which two mechanisms?

Spread of fire or intensity of burning Signup and view all the answers

Patterns that arise are invariably better indicators of what?

The area of origin Signup and view all the answers

Patterns that cannot be accounted for in terms of ventilation require what?

Careful examination Signup and view all the answers

The method of noting the interpretations of the direction of heat or flame spread uses what?

Arrows Signup and view all the answers

Each vector should be identified as to what it represents?

The respective fire pattern Signup and view all the answers

The location on the diagram allows details of fire patterns including height above floor, pattern geometry, and what?

Nature of the surface upon which the pattern appears Signup and view all the answers

Complementary vectors can be considered together to show what?

Actual heat and flame spread directions Signup and view all the answers

What is the ultimate purpose of vector analysis?

To discuss and graphically document the investigator's interpretation of fire patterns Signup and view all the answers

What is defined as any fuel package that creates an identifiable pattern?

Heat source Signup and view all the answers

What may help the investigator to locate areas of greater or lesser heat damage?

A depth chart or depth of calcination survey Signup and view all the answers

Lines can be drawn connecting points of equal char or calcination depth which may reveal what?

Identifiable patterns Signup and view all the answers

Analysis of depth of char is more reliable for evaluating what?

Fire spread Signup and view all the answers

The relative depth of char is key to appropriate use of charing, particularly regarding what factors?

Exposure, ventilation, or fuel placement Signup and view all the answers

Char depth measurements should be made at the _____________ of char blisters rather than in or near crevices.

Center Signup and view all the answers

What adds to the overall depth measurement of char?

Missing depth of wood Signup and view all the answers

When they are the initial fuel sources for fires, fugitive fuel gases produce what?

Relatively even depth of char Signup and view all the answers

Progressive changes in depth of char are used to trace what?

Fire spread Signup and view all the answers

The technique for measuring and analyzing depth chart of calcination should be performed using?

A probe survey Signup and view all the answers

The spatial relationship of the arc sites can be identified as what?

A pattern Signup and view all the answers

The identification of arc sites in the area of fire origin may help to identify what?

Potential ignition sources Signup and view all the answers

Investigators should consider that conductors are only available for what?

Arcing in certain areas Signup and view all the answers

When setting boundaries of each zone, what should be considered?

Conductors routed through other zones Signup and view all the answers

Handling conductors may result in what?

Fractures Signup and view all the answers

If a conductor is arc severed, it can be concluded that parting events downstream happened when?

Before the severance Signup and view all the answers

What can cause back feeding?

Pre-fire wiring errors, uninterruptible power supply systems, generators Signup and view all the answers

Fire damage to copper conductors can mimic what kind of damage?

Arc damage Signup and view all the answers

Analysis of sequential events gathers much of the data from whom?

Witnesses Signup and view all the answers

One tool an investigator may consider for fire pattern history is to divide each compartment into what?

Volumes Signup and view all the answers

What allows the investigator to organize and plan the remainder of the origin investigation?

Initial hypothesis Signup and view all the answers

Once a hypothesis is developed, test it using what?

Deductive reasoning Signup and view all the answers

If the hypothesis is true, then the fire scene should exhibit what?

Certain characteristics Signup and view all the answers

Every potential ignition source should be considered unless there is reliable evidence to narrow the origin to what?

A particular portion of the room Signup and view all the answers

The hypothetical origin should account for physical damage to the structure and the exposure of whom?

Occupants Signup and view all the answers

Fire dynamic analytical tools can be used to estimate what?

Time dependent events in fire conditions Signup and view all the answers

Although the area of origin is commonly described, it should be articulated in terms of what?

Three dimensional space including boundaries Signup and view all the answers

Study Notes

Fire Investigation Concepts

Area of Origin: General geographic location within the fire scene believed to be the location of a fire or explosion.
Point of Origin: Specific location within the area of origin where a heat source and fuel interact to initiate a fire or explosion.

Determination Process

Origin determination relies on witness statements, fire patterns, arc mapping, and fire dynamics.
Scientific Method: Involves defining problems, collecting and analyzing data, developing and testing hypotheses.
A working hypothesis is subject to modification as new data becomes available during the investigation.

Testing and Analysis

Origin Hypothesis: Testing requires understanding fire events, growth, and spread within the structure.
Fire spread analysis verifies if damage and data align with the area of origin hypothesis.

Examination Protocol

Initial Assessment: Identifies investigation complexity, equipment needs, staffing, and areas for further analysis.
Safety concerns must be resolved before beginning scene assessments.
Order of Examination: Follows a routine sequence, with concurrent activities during investigation.

Evidence and Reconstruction

Excavation and Reconstruction: Techniques are used to observe fire patterns and locate evidence for accurate analysis.
Debris Removal: May limit further investigation; documentation is crucial when off-site removal is necessary.

Equipment and Caution

Use heavy equipment cautiously; operations should stop when individuals enter hazardous areas.
Collect samples from powered equipment to prevent contamination during investigations.

Fire Dynamics and Evidence Collection

Document details such as the construction method and degree of destruction within structures.
Identify potential first fuels ignited, and recognize subsequent fuels involved to estimate fire behavior.

Fire Patterns and Vector Analysis

Fire patterns indicate growth movement and air flow; certain patterns indicate the area of origin.
Use arrows for directionality and vector analysis to document heat and flame spread interpretations.

Char Depth Measurement

Char depth measurements guide reliable evaluations of fire spread; the center of char blisters is the primary measurement point.
Depth of calcination indicates severity and helps locate areas of greatest damage due to exposure or fuel placement.

Investigative History and Human Factors

Witness accounts are essential for gathering data on sequential fire events.
All potential ignition sources should be considered without preconceptions until evidence narrows the origin.

Analytical Tools

Fire dynamics analytical tools estimate the timing and conditions of fire events.
Understand the importance of three-dimensional space when describing the area of origin in investigations.

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Description

Test your knowledge on fire origin determination with these flashcards based on NFPA 921 Chapter 18. This quiz covers essential concepts such as area of origin and point of origin, crucial for understanding fire investigation. Perfect for students and professionals in fire science.