Fire Investigator (1st Edition)
Complete List of Terms

Ampacity
The amount of electrical current (amperage) that a conductor can safely carry on a continuous basis.

Ampere
Basic unit of electrical current that may be abbreviated either by A or I.

Arc
A luminous discharge of electricity across a gap. Arcs produce very high temperature.

Area of Origin
The room or area where the fire began.

Artifacts
The remains of materials involved in the fire that are in some way related to ignition, development, or spread of the fire or explosion.

Beam
Structural member subjected to loads perpendicular to its length.

Bolted Fault
A condition occurring when two conductors in a circuit come into firm, direct contact with each other. Also called a "dead short."

Branch Circuit
The wiring between the point of application (outlets) and the final overcurrent device protecting the circuit.

Circuit Breaker
An on/off switch designed to allow a circuit to be opened or closed manually, and to open automatically when a predetermined overcurrent occurs.

Commodity Flowcharting
Portrays the movement of a tangible item, such as money or stolen property, through a system.

Compression
Force that tends to push the mass of a material together.

Conduction
The point-to-point transmission of heat energy.

Contamination
Condition of impurity resulting from mixture or contact with foreign substance. (Blacks Law Dictionary, Sixth Edition).

Convection
The transfer of heat energy by the movement of heated liquids or gases.

Crazing
Formation of patterns of short cracks throughout the pane. It is thought to be the result of heating of one side of a pane while the other side remains cool.

Current
The rate of electrical flowing a conductor. Measured in amperes.

Dead Load
Load on a structure due to its own weight and other fixed weights.

Depth of Field
The range that is in focus in front of and behind the subject of the photograph.

Due Process
The requirement that certain procedures that conform with recognized standards of fairness must be followed before a person's life, liberty, or property can be taken away.

Event Flowcharting
Chronologically displays the movements of events or occurrences either over time or through a system.

Evidence
Information the investigator collects and analyzes.

Exclusionary Evidence
Collected to show that a particular device or scenario can be ruled out with relation to the ignition or fire spread scenario.

Fire Cause
The sequence of events that allows the source of ignition and the fuel to come together.

Fire Patterns
Visible or measurable physical effects that remain after a fire.

Focal Length
The focal length of a lens is the distance behind the lens where light from an object is sharply focused when the lens is set to infinity.

Footing
The part of the building that rests on the bearing soil and is wider than the foundation wall. Also the base for a column.

Fuse
A single-acting protective device designed to open a circuit on a predetermined overcurrent.

Girder
Large, horizontal structural member used to support the ends of joists and beams.

Grounded Conductor
That conductor in a branch circuit which carries the return current but which is not energized. Often called the common or neutral conductor. The covering will be white or natural gray in color. It will be connected to the service neutral.

Ground Fault
A current that flows to ground outside of the normal current path, such as through a ground conductor, metal pipes, or a person.

Ground-Fault Circuit Interrupter (GFCI)
A device designed to protect people from electrical shock by opening (de-energizing) a circuit when a current to ground exceeds a predetermined value but that is still at less than life-threatening levels.

Grounding Conductor
That conductor in a branch circuit that connects exposed metal parts of appliances to the ground system of the service to minimize the chance of electric shock. This conductor carries no current unless a fault has occurred. The conductor will be bare or have a green or green with yellow-stripe covering.

Heat
Energy transferred between two bodies of differing temperature, such as the sun and the earth.

Heat of Ignition
The heat energy that brings about ignition. Heat energy comes from various forms and usually from a specific object or source. Therefore, the heat of ignition is divided into two parts: (a) equipment involved in ignition and (b) form of heat of ignition.

Incendiary
A fire deliberately set under circumstances in which the responsible party knows it should not be ignited.

Inference Development
The development of a meaningful hypothesis, conclusion, prediction, or estimate based on the data available and the knowledge, experience, and expertise of the investigation.

Interrogation
A formal line of questioning of an individual who is suspected of committing a crime or who may be reluctant to provide answers to the investigator's questions.

Interrupt Rating
The highest current at rated voltage that a device is intended to interrupt under standard test conditions.

Interview
The questioning of an individual for the purpose of obtaining information related to the investigation.

Joist
Framing member that directly supports the floor.

Kinetic Energy
The energy possessed by a moving object.

Layering
The deposition of fire debris in identifiable layers that is above or below a floor assembly, ceiling materials, or roof assembly.

Light
Visible radiation produced at the atomic level, such as a flame produced during the combustion reaction.

Link Analysis
Method of computing, organizing, and utilizing data relating to an investigation. It allows the analysis and presentation of complex data in a clear and concise manner.

Live Load
Furniture, people, or other movable loads not included as a permanent part of the structure.

Load
The sum of the wattages of the various devices being served by a circuit.

Material First Ignited
The fuel that is first set on fire by the heat of ignition. To be meaningful, both a type of material and a form of material should be identified.

Matter
Anything that occupies space and has mass.

Ohm
The basic unit of electrical resistance symbolized either by W or R. One ohm is the resistance between two points in a conductor when one volt produces one ampere of current.

Ohm's Law
The mathematical relationship between a circuit's voltage (V), current (1), and resistance (R): V = 1R.

Overcurrent
Any current that is in excess of the rated current of equipment or the ampacity of a conductor and maybe caused by an overload, short circuit, or ground fault.

Overload
Operation of equipment or a conductor in excess of its rated ampacity. If continued for a sufficient length of time, overheating to the point of damage may occur.

Panel Board
Single or multiple panels that contain conductive bus bars and automatic overcurrent protection devices such as circuit breakers or fuses. These panels may also contain manually operated switches.

Parapet
Low wall at the edge of a roof.

Partition
Interior wall that separates a space into rooms.

Point of Origin
The exact physical location where the heat source and fuel come in contact with each other and a fire begins.

Potential Energy
Energy possessed by an object that can be released in the future.

Power
Amount of energy delivered over a given period of time.

Radiation
The transmission of energy as an electromagnetic wave (such as light waves, radio waves, or X rays) without an intervening medium.

Resistance
The opposition to the flow of an electric current in a conductor or component. Measured in ohms (W).

Shear Stress
Stress resulting when two forces act on a body in opposite directions in parallel adjacent planes.

Sheathing
Covering applied to the framing of a building to which siding is applied.

Short Circuit
An abnormal path of current in a circuit that normally leads to an overcurrent condition.

Slab
(1) Heavy steel plate used under a steel column. (2) The reinforced concrete floor itself.

Spalling
Expansion of moisture within concrete due to exposure to the heat of a fire. The expansion causes sections of the concrete surface to violently disintegrate.

Spoliation
The intentional destruction of evidence, and when it is established, fact finder may draw inference that evidence destroyed was unfavorable to party responsible for spoliation. (Blacks Law Dictionary, Sixth Edition)

Tensile
Force of pulling apart or stretching.

Trailer
Often used in intentionally set fires to connect remote fuel packages (combustible materials, pools of ignitable liquid, etc.) with each other.

Trip Curve
The relationship between current and time that determines when circuit protective devices operate. (This data is provided by the manufacturer.)

Ungrounded Conductor
That conductor in a branch circuit which is energized and supplies current to load devices. The covering will be some color other than white, gray, or green. Often called the hot conductor.

V Pattern
One of the patterns often found during an interior examination. A cone-shaped plume of hot gas that forms above the flames.

Volt
The basic unit of electrical voltage and may be abbreviated either V or E. It is the difference in potential (electromotive force) needed to create a current of one ampere through the resistance of one ohm.

Voltage
The electrical force that causes a charge (electrons) to move through a conductor. Sometimes called the electromotive force (EMF). Measured in volts (V)

Watt (W)
The basic unit of power. In simple electrical systems, power is equal to voltage times current. One watt is equal to a current of one ampere under the potential of one volt.