Fire · Topic 3 · Ch. 4
Firematics: how fire and smoke behave
What your coach says about this topic
Coach FLSDAI
Why it matters
It is the shortest chapter of the Fire part (5 pages), and in our bank its questions come as scenarios: they describe what happens in a room and you name it (backdraft, flashover, radiation). Little study, sure points.
This topic is worth about 3 of the 120 questions of the Fire exam (estimated from the booklet's pages).
Texts prepared by AI from the official FDNY booklet. Not a person and not the FDNY.
≈ 3 of 120 questions
Estimated from the FDNY booklet; the FDNY does not publish the exact distribution.
How it's estimated
This topic takes up 5 of the 206 pages of chapters 1-12 of the booklet (2.4%). 2.4% of the 120 questions of the Fire exam = 2.9 ≈ 3.
Official data (FDNY Notice of Exam F-89/T-89, p. 3): the General Topics and Fire course (Component 1: Part I, chapters 1-8, and Part II, chapters 9-12) lasts at least 20 hours; the Non-Fire course (Component 2: Part III, chapters 13-17; Part IV, chapters 18-19; Part V, chapters 20-22) at least 11 hours. Those are class hours, not exam questions, so they are not part of the estimate.
What to memorize
- Fire tetrahedron: fuel, an oxidizing agent (oxygen), heat and an uninhibited chemical chain reaction; remove one and the fire goes out (§4.1, p. 95).
- How each method works: covering the flame removes oxygen; removing what burns removes fuel; water removes heat; extinguishing chemicals break the chain reaction (§4.1, pp. 95-96).
- Incipient stage: the only one in which a portable fire extinguisher can control the fire (§4.2.1, p. 96).
- Radiation: heat travels as waves in all directions and can pass through a window to ignite objects inside (§4.2.2, pp. 96-97).
- Flashover: everything in the room ignites at once, up to about 1,000 °F in seconds; warning signs are dense black smoke in tight curls or smoke banked down to doorknob height (§4.2.4, p. 98).
- Backdraft: an explosion when oxygen enters a closed space full of hot, oxygen-starved gases, for example when a door is opened (§4.2.4, pp. 98-99).
Memory trick
Backdraft = "back door": it happens when someone OPENS the door and air rushes in. Flashover = "flash over everything": the whole room lights up at once, with no door opened.
Ch. 4, §4.2.4, pp. 98-99
Practice this topic
Loading...
Next: topic 4, Building construction and primary fire protection systems
Sources
- FDNY, Fire and Life Safety Director Curriculum, Version .02 (2022)
- FDNY, Notice of Exam F-89/T-89 (2022)
Questions and texts are our own, written from the official FDNY material, with help from AI. If anything differs, the FDNY material prevails.