BOOK 83, Fire Investigation Flashcards
The primary responsibility to determine the cause of all fires, including all criminal and non criminal fires is?
The bureau of fire suppression and rescue (ESB)
The responsibility for determining the most probable cause of a fire rest with?
The IC
The follow up investigation responsibility of fires where the total loss is less that $25000 lies with?
ESB
In this phase of a fire, air from surrounding atmosphere is drawn into the fire/ oxygen content is usually reduced to 16-18%. Flashover frequently occurs is this phase.
Free burning
The chemical decomposition of matter through the action of heat describes?
Pyrolysis
The lowest temp. Of a liquid in an open container at which vapors evolve fast enough to support continuous combustion describes?
Fire point
Liquids having a flash point below 100F best describes?
Flammable liquid
The transfer of heat from one new object to another through direct physical contact describes?
Conduction
Carbon monoxide is one of the most common gases found in structural fires and is highly flammable. The explosive limit of carbon monoxide is?
12.5-74%
Most fires can be divided into ? Separate phases.
3
The responsibility for the investigation of fires is?
Shared between the ESB and the bureau of fire prevention
The transfer of heat is unusually the key element in ignition of most fires. Heat is transferred in ? Ways.
4
Flashover may cause an area to appear to have been exposed to flammable accelerants. Carful examination should indicate all of the following?
Burning over top surfaces of materials
Lack of accelerant residue
Lack of normal fire spread from point of origin
As it relates to structural loads and loading, the weight of the building and any equip. Permanently attached or built in to a structure defines?
Dead loads
Attic areas unprotected concealed space cannot exceed ? Square feet without fire walls.
3000
The stage of the fire when all combustibles in an area have become heated to their ignition temp, then ignited simultaneously, describes?
Flashover
The form of heat transfer most responsible for fire spread in structural fires is?
Convection
The purpose of fire cause investigations is to establish?
How the fire started
The motive for starting it
The ignition temp of ordinary combustibles is between?
300-1000 degrees
The minimum temp. A which a liquid gives off vapors in sufficient concentrations to form an ignitable mixture with are near the structure of the liquid defines?
Flashpoint
As a substance burns, it mixes with oxygen and produces heat best describes?
Oxidation
The maximum vapor to air concentration above which propagation of flame will not occur best describes?
Upper flammable limit
The authority granted the fire dept. to investigate fires occurring in the city of LA is found under?
The city charter
Flashover is the stage of the fire when al combustibles In an area have become heated to their ignition temperature, then ignite simultaneously. Flashover occurs when heat produced but the fire collects at ceiling level, and is returned to lower areas by?
Thermal radiation feedback
Accurate cause and origin determination requires the fire scene investigator to develop a well organized and coordinated procedure. The examination of the interior of the structure should be?
Wording from the least to the most damaged fire areas
Which of the following factors do influence burn patterns?
Fuel load
Venting FF activities
Weather
The normal growth of a fire is usually ?
Outward and upward
Fire has four parts which are necessary for self sustaining, open flaming combustion. I the flame, many chemical reactions occur which produce additional het. When certain extinguishing agents are introduces, it breaks up this chemical reaction and extinguishes the fire without affecting the heat, fuel or oxygen sides of the fire trainable. These extinguishing agents are?
Dry chemical
Halon
The foundation from which any fire cause investigation should be developed is?
Basic understanding of the behavior of fire
In order to determine whether a flashover occurred, your examination should indicate?
Lack of normal fire spread from the point of origin
The fundamental facts or elements necessary to prove the commission of a crime describes?
Corpus Delecti
Free burning may cease in the fire area as the area fills with dense smoke. Oxygen may drop below 15 % and the temp. Reach 1000 degrees. Throughout the area. This is known as ?
Smoldering phase
Type ? Construction is known as ordinary construction and is described as, construction in which exterior bearing walls or bearing partitions of exterior walls are of combustible materials and have a minimum hourly fire resistive rating. Word allowed for interior use.
TYPE III
Which of the following be considered a sign of slow smoldering fire?
Uniform overhead damage
A wide angle V pattern
Large cracks and heavy smoke damage on glass
When subjected to ? Degrees, light bulbs may swell toward the point of heat.
900
Cigarettes may not ignite dry vegetation unless the real active humidity is under?
22 percent
Two pressure waves result from an explosion. The negative wave has about ? Percent of the power developed by the positive wave.
60
A backdraft is the rapid combustion of flammable gases that have been heated above their ignition point. The is condition develops due to insufficient oxygen. It usually occurs during the ? Phase of a fire as oxygen is introduced Tina the confined space .
Smoldering
Determining the sauce and origin of a fire starts prior to arrival at the fire. One of your considerations should be the color of the fire and smoke. Little or no smoke is an indicator of?
Complete combustion
Burn patterns are the burned areas as opposed to unturned areas and their relationship to each other. This will be indicated by angle, or where the burn is as opposed to where It is not. Which two method of transferring heat play a major role in producing burn patterns?
Convection and radiation
In most cases, ghost marks are caused by the application of a flammable liquid to a surface covered with asphalt tile. Ghost marks have a ? Dis colored mark where the tile edge was located.
Dark
The normal growth of a fire is usually upward and outward and a usual indicator that will point towards the origin of the fire is?
V patterns
An exit hermitic reaction produces ?
Heat
A fire where circumstances and logic indicate an incendiary fire, and an accident cause cannot be eliminated best defines?
Suspicious
The are of origin can best be determined by having knowledges and experience to recognize burn patterns or incident indicators. There are definite relationships between the ? An the fire cause.
Point of origin
Narrow V patterns with sharp line of demarcation may indicated?
Flaming, rapid combustion
A fire indicator that is usually found near the point of origin and may be a good indicator to help locate the point of origin?
Deep char
The explosive breaking off of pieces of concrete during exposure to fire describes ?
Spalling
V patterns may sissy I identifying the point of origin of a fire and are usually found on walls. To sits in locating V patterns, the investigators first observations should attempt to locate?
Ceiling damage
The fire scene investigator should work ? In relationship to the fires travel or spread.
Backwards
Relative depth of char usually indicates?
Length of time exposed to fire
The closer to the point of origin, the ? The smoke line.
Lower
The minimum temp to which a fuel in air must be heated in order to initiate or cause self sustained combustion independent of the heat source is known as?
Ignition temperature
