OSAC Lexicon

The process of recreating the physical scene during fire scene analysis investigation or through the removal of debris and the placement of contents or structural elements in their pre-fire positions.

The body of knowledge concerning the study of fire and related subjects (such as combustion, flame, products of combustion, heat release, heat transfer, fire and explosion chemistry, fire and explosion dynamics, thermodynamics, kinetics, fluid mechanics, fire safety) and their interaction with people, structures, and the environment.

The body of knowledge concerning the study of fire and related subjects (such as combustion, flame, products of combustion, heat release, heat transfer, fire and explosion chemistry, fire and explosion dynamics, thermodynamics, kinetics, fluid mechanics, fire safety) and their interaction with people, structures, and the environment.

The movement of fire from one place to another.

see «suppression»

A symbol used to describe the necessary requirements for fire to occur: fuel, heat, oxidizer, and an uninhibited chemical chain reaction.

A symbol used to describe the necessary requirements for fire to occur in which the three sides represent fuel, oxidizer, and a source of ignition. The connection of the sides to form a triangle symbolizes the chain of reaction.

A discipline of forensic science charged with conducting comparison examinations of tools and toolmarks and reporting the conclusion. When the tool is a firearm, the discipline also seeks to answer relevant questions about the firearms or ammunition components involved in an incident.

A person who has completed training in the discipline of firearm and toolmark examination and who is currently authorized to perform work in this discipline.

A person seeking employment as a firearm and toolmark examiner trainee.

A person who is entering or undergoing, but has not yet completed, training in the discipline of firearm and toolmark examination.

The first fuel ignited is that which first sustains combustion beyond the ignition source.

The first impression made with the stamp after inking.

Any individual responding to a crime scene, including but not limited to: law enforcement, investigative, medical, fire/paramedic, and laboratory personnel

The portion of an oral dose metabolized in the intestine, gut wall, or liver before reaching the systemic circulation.

A process or reagent that helps secure the blood to the substrate or secures the substrate itself (e.g.,snow, sand, etc.) so that it is not destroyed or degraded during chemical enhancement.

A schedule of reinforcement in which rewards for a correct response occur after a fixed period of time.

A schedule of reinforcement in which the subject is rewarded after a set number of unrewarded correct responses.

Clear plastic sheet with a pressure sensitive adhesive layer.

A body or stream of gaseous material involved in the combustion process and emitting radiant energy at specific wavelength bands determined by the combustion chemistry of the fuel. In most cases, some portion of the emitted radiant energy is visible to the human eye.

A hot, usually luminous zone of gas that is undergoing combustion.

The flaming leading edge of a propagating combustion reaction zone.

The condition where unburned fuel (pyrolysate) from the originating fire has accumulated in the upper layer to a sufficient concentration (i.e., at or above the lower flammable limit) that it ignites and burns. This can occur without ignition of, or prior to the ignition of, other fuels separate from the origin.

Capable of burning with a flame.

The upper or lower concentration limit at a specified temperature and pressure of a flammable gas or a vapor of an ignitible liquid and air, expressed as a percentage of fuel by volume that can be ignited.

A liquid that has a closed-cup flash point that is below 37.8C (100F) and a maximum vapor pressure of 2068 mm Hg (40 psia) at 37.8C (100F). (See also 3.3.34, Combustible Liquid.)

The range of concentrations between the lower and upper flammable limits.

A fire that spreads by means of a flame front rapidly through a diffuse fuel, such as dust, gas, or the vapors of an ignitible liquid, without the production of damaging pressure.

The lowest temperature of a liquid, as determined by specific laboratory tests, at which the liquid gives off vapors at a sufficient rate to support a momentary flame across its surface.

A transition phase in the development of a compartment fire in which surfaces exposed to thermal radiation reach ignition temperature more or less simultaneously and, given sufficient availability of oxygen, fire spreads rapidly throughout the space, resulting in full room involvement or total involvement of the compartment or enclosed space.

The text of the stamp die is not raised but flat on the die plate. Micropores remain open to allow ink to exit from the stamp onto the substrate producing the stamp image. Light burst and thermal printing are two technologies used to produce flat die stamps.

A fingerprint image resulting from the touching of a single finger to a livescan platen orpaper fingerprint card without any rolling motion. Also known as a single-finger plainimpression.

A process by which radiant flux of certain wavelengths is absorbed and reradiated nonthermally at other, usually longer, wavelengths.

Surface topography measurement method whereby the sharpness of the surface image (or anotherproperty of the reflected light at optimum focus) in an optical microscope is used to determine thesurface height at each position along the surface.