NAFI CFEI Study Guide Exam 2025

Evidence - demonstrative - -tangible items; see, touch, smell, hear. Evidence - documentary - -written form; business records, banking, calendars, phone records, fire reports, etc... Evidence - testimonial - -competent live witness speaking under oath; two types; fact and expert Evidence - illustrative - -photos, sketches, maps, diagrams. Modes are frequently used at trial. Evidence - illustrative - -photos and videos; what, why, how, when Evidence collection - -document in place, document the collection, use proper container, (flag, bag, & tag) Evidence - collection - -fuel gas powered tools outside the perimeter. Find out where tools were refuels. Heat transfer - -conduction, convection, radiation Interviews - -purpose of the interview; prepare for the interview, document the interview Vehicle fires - -sparks from an aluminum wheel are not a competent ignition source. Vehicle fires - -the most common source of an open flame in a vehicle is an exhaust system backfire out of a carburetor. Vehicle fires - -carburetor backfire leaves a distinct pattern on the hood. Vehicle fires - -two basic fuel systems: vacuum/low pressure carbureted system, and high-pressure, fuel injected system. Vehicle fires - -loose battery connections; not over-current protected; loose connections can result in intermittent arcing. Vehicle fires - -power steering fluid: flashpoint 347-356*f, autoignition 680-720*f. Vehicle fires - -automatic transmission fluid: flashpoint 302-536*f, autoignition 626 716*f. Vehicle fires - -overcharging a battery does not cause it to explode. NAFI NAFI Explosions - -low order damage: characterized by walls bulge out or laid down, virtually intact, next to the structure. Roofs slightly left. Explosions - -high order damage: shattering of the structure, producing small debris pieces. Explosions - -post blast effects: burned debris away-fire preceded, unburned the debris away-no fire. Explosions - -dust explosions: most often occur in confined areas of relatively wide dispersal. Explosions - -search 1.5 times further than the farthest piece of debris. Fire effects/ fire patterns - -char shrinks as it forms. More reliable for evaluating fire spread, deduce the direction based on depth, large shiny blisters (alligatoring) is not evidence of the use of an accelerant. Fire effects/fire patterns - -spalling: loss of surface material due to cracking, breaking, chipping, breakdown in surface tensile strength, moisture present in the concrete, may appear lighter in color. Fire effects/fire patterns - -crazed glass: caused by rapid cooling. Fire effects/fire patterns - -light bulbs 25w or more "pull" (gases expand and bubble out); 25w or less contain a vacuum and can pull in. Fire effects/fire patterns - -annealing (softening) of springs may provide clues concerning direction, duration, and intensity. Fire effects/fire patterns - -saddle burns - a u-shaped burn pattern found on the top of floor joists, caused by fire burning down through the floor. Often, a saddle burn is caused by a burning liquid on the floor or radiant heat from a material close to the floor. Saddle burns display deep charring. Fire effects/fire patterns - -inverted cone burns are indicative of the vertical flame plume not reaching the ceiling, short-lived fires with a low hrr Fire effects/fire patterns - -melting temperatures: copper 1981*f; aluminum 1220*f; steel 2760*f Heat sources - -mechanical: converted to heat when two materials rub against each other and create friction. Chemical: chemical reaction; exothermic and endothermic. NAFI NAFI Electrical: converted to heat energy; flowing through a conductor. Nuclear: splitting the nucleus of an atom into two smaller nuclei (nuclear fission) Electrical - -resistance heating: properly installed, produces low resistance. Loose connections: high resistance with increased heating at the contact. Electrical - -ground fault: the purpose if grounding an electrical system is to make sure that any housings or exposed metal in the system or connected to it cannot become electrically charged. Electrical - -sleeving: the softening and sagging of thermoplastic conductor insulation due to the heating of the conductor. Electrical - -lightning: a form of static electricity, a polarized electrostatic charge in the clouds. Electrical - -9.2.2.2.2: the unit of measurement of potential difference or voltage is usually volts. Electrical - -9.2.2.3: the rate of charge flow is called electrical current, and current is measured in amperes. Electrical - -9.2.6.1: power - the rate at which energy is used. Electrical - -9.3.3: the cables of a service drop go into a weather-head, which is designed to keep water from entering the system, and then down a service raceway to a meter base. Electrical - -9.6.2.1: fuses are basically non-mechanical devices with a fusible element in a small enclosure. Electrical - -9.6.3.1: a circuit breaker is a switch that opens either automatically with over-current or manually by pushing a handle. Electrical - -9.7: branch circuits: the individual circuits that feed lighting, receptacles, and various appliances are the branch circuits. Electrical - -9.9.4.1: arc: is a high temperature luminous