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Marine investigation · Last updated November 2026

Certified Marine Fire Investigator (CMFI): free practice test

IAMI's advanced certification for investigators of vessel, marina and boatyard fires. Candidates must have held the IAMI CMI for at least a year, be active fire investigators with at least 10 marine fire investigations in the last 6 years, hold a recognized fire investigator certification (for example IAAI-CFI or NAFI CFEI) and earn 250 eligibility points. The study guide is built on NFPA 921, NFPA 1033, ABYC standards and the CFR.

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About the IAMI CMFI exam

IAMI's advanced certification for investigators of vessel, marina and boatyard fires. Candidates must have held the IAMI CMI for at least a year, be active fire investigators with at least 10 marine fire investigations in the last 6 years, hold a recognized fire investigator certification (for example IAAI-CFI or NAFI CFEI) and earn 250 eligibility points. The study guide is built on NFPA 921, NFPA 1033, ABYC standards and the CFR.

What's on the exam

IAMI CMFI
Fire Science and Fire Dynamics
7 key facts
NFPA 921 Methodology, Origin and Cause
7 key facts
Vessel Construction, Materials and Fire Behavior
7 key facts
Marine Fuel, Electrical and Ignition Sources
7 key facts
Fire Protection Systems, Marinas and Boatyards
7 key facts
Scene Examination, Documentation, Evidence and Safety
7 key facts
Insurance, Legal Considerations and Testimony
7 key facts

Each branch is a topic in the official outline. Members see every key fact on the full mind map. Read the free study guide →

How to pass the IAMI CMFI exam

  • IAMI does not publish topic weights. Its required core fire classes are vessel fire origin and cause, documentation, fire scene examination, and insurance and legal considerations, so give those the most time.
  • Expect NFPA 921 methodology to run through everything: the scientific method, hypothesis testing, cause classification and why negative corpus is rejected.
  • Marine questions turn on systems the land-based fire certifications skip: gasoline vapor in bilges, wet exhaust cooling, shore power inlets, ignition protection and fixed engine-room extinguishing systems.
  • Approved applications are valid for one year and the exam is given at IAMI seminars, so plan your sitting around the next Annual Training Seminar and confirm with IAMI HQ.

Save your results and get your Readiness Score

Create a free account after the test: your score by topic, a mistakes bank, the complete study notes for the first topic, flashcards and the ABYC Numbers & Formulas Sheet.

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What's in the premium IAMI CMFI prep

Premium IAMI CMFI prep is studied one topic at a time. Each step starts with that topic's key notes and flashcard deck, then its own question sets of 25, so you master one topic before you move to the next. When every topic is strong, the 6 full mock exams show you're ready.

3,000practice questions, every answer explained
6full-length mock exams, 150 questions each, timed
800flashcards with spaced repetition, sorted by topic
60comprehensive key notes across 7 topics

Your step-by-step study path

  1. 1
    Fire Science and Fire Dynamics9 key notes, 115 flashcards, then 450 practice questions in 18 sets of 25
    Notes free with an account
  2. 2
    NFPA 921 Methodology, Origin and Cause9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  3. 3
    Vessel Construction, Materials and Fire Behavior9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  4. 4
    Marine Fuel, Electrical and Ignition Sources9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  5. 5
    Fire Protection Systems, Marinas and Boatyards8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  6. 6
    Scene Examination, Documentation, Evidence and Safety8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  7. 7
    Insurance, Legal Considerations and Testimony8 key notes, 110 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  8. Final step: 6 full mock exams150 questions each, timed like test day. Pass them, then book your exam.
    Premium
Free with an account

Read the complete IAMI CMFI study notes for “Fire Science and Fire Dynamics”

Our first full set of comprehensive notes, about 15 minutes of reading: Combustion basics · Flammable limits and vapor density · Heat transfer · Compartment fire development, a worked exam example, the traps examiners use and a one-minute recap. Create a free account to read it and see how premium notes work before you decide.

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Study tools included

3,000 practice questions

3,000 exam-style questions per exam, organized topic by topic in sets of 25. Every answer explained, with the rule it comes from.

6 full mock exams

6 full-length timed mock exams per exam, with real question counts and time limits, so test day feels like practice day.

Exam Readiness Score

One 0 to 100 number that tells you when you're ready to book. Reach 80 and you're covered by our Pass Guarantee.

800 flashcards + spaced repetition

800 flashcards per exam, in a deck for each topic, that come back right before you'd forget them. Five minutes a day keeps every number fresh.

60 comprehensive key notes

60 key notes per exam, split across its topics and each explained in full: the concepts, worked exam examples, the traps examiners use and a quick recap. Your first set is free with an account.

Mind maps

See the whole exam on one screen: every topic and the facts under it.

Sample questions with answers

These are the questions in the free test above, with answers. Try the test first. You'll learn more by getting some wrong.

1. A vapor detector reads a gasoline vapor concentration of about 0.8% by volume in an engine compartment. If a spark occurs there, what is expected?
Answer: No ignition: the mixture is below the lower limit. Gasoline's flammable range is roughly 1.4% to 7.6% by volume in air. At 0.8% the mixture is too lean to propagate flame, although it can quickly enter the range if vapor keeps accumulating, which is why the blower is run before starting. A mixture above about 7.6% is too rich.
2. A boat's enclosed salon shows heavy burning throughout, with low burns under furniture and floor-level damage across the whole space. What does NFPA 921 warn about interpreting this?
Answer: Post-flashover burning can create them anywhere. Once a compartment goes to flashover and full-room involvement, radiant heat and ventilation can produce low burns, floor damage and holes far from the origin. NFPA 921 cautions against reading these as multiple origins or as proof of an ignitable liquid without laboratory confirmation and the other data.
3. An investigator rules out every accidental source they can think of in a burned cuddy cabin, finds no ignition source and no ignitable liquid, and calls the fire incendiary. How does NFPA 921 treat this?
Answer: As negative corpus, which NFPA 921 rejects. Concluding a cause without evidence supporting it, simply because other causes were eliminated, is negative corpus; NFPA 921 says it is improper. A hypothesis about a specific ignition source must be supported by facts. Without that, the proper classification is undetermined.
4. An investigator has developed the hypothesis that a battery charger mounted under the berth started the fire. What is the next step in the NFPA 921 scientific method?
Answer: Test the hypothesis deductively against all the collected data. In NFPA 921 the investigator analyzes the data (inductive reasoning), develops a hypothesis, and then tests it by deductive reasoning: does it fit the arc mapping, burn patterns, timeline and witness accounts, and can alternatives be excluded? Only a hypothesis that survives testing is selected as final.
5. The origin is fixed at the stern, but both the shore power inlet and a nearby battery charger remain viable ignition sources that the evidence cannot separate. How should the cause be classified?
Answer: Undetermined. NFPA 921 classifies cause as accidental, natural, incendiary or undetermined. When more than one hypothesis cannot be eliminated, or the evidence doesn't reach a probable level of certainty, the cause is undetermined; the investigator can still report the origin and the competing hypotheses. Picking one without proof overstates the evidence.
6. After a fire on a boat with an aluminum hardtop, the top has melted and collapsed. What does the melting alone tell the investigator?
Answer: Temperatures above about 1,100 °F, common in ordinary fires. Aluminum alloys melt at roughly 1,100 to 1,220 °F (about 600 to 660 °C), well below flame and post-flashover temperatures in ordinary fires fed by resin, foam and furnishings. Melted aluminum shows exposure to that temperature, not accelerant use, duration or the origin.
7. A fiberglass sport boat burned to the waterline at its slip. What does the extent of damage, by itself, indicate about the cause?
Answer: Nothing: resin hulls are a large fuel load. The polyester or vinylester resin in FRP laminate is a fuel, so an unattended boat fire often consumes the hull to the waterline whatever the cause. Extent of damage reflects fuel load, ventilation and suppression time, not cause; the origin must be found from patterns and evidence that survive.
8. A fire starts in the engine compartment at cruising speed. The fiberglass wet-exhaust muffler and hose are charred inside and out, and the raw-water pump impeller is missing most of its vanes. What is the most likely mechanism?
Answer: Loss of cooling water to the wet exhaust. Wet exhaust systems rely on raw cooling water injected into the exhaust; if the impeller fails, exhaust gas runs hot enough to char and ignite rubber hose and fiberglass mufflers. The failed impeller and the char pattern inside the exhaust run support this. Shore power is disconnected under way.
9. In a gasoline-powered boat's engine compartment the investigator finds a replacement alternator taken from a car. Why is this significant?
Answer: It is likely not ignition protected for vapor spaces. Electrical components in gasoline engine and fuel tank spaces must be ignition protected (33 CFR 183.410, tested to SAE J1171 or UL 1500) so internal sparks can't ignite surrounding vapor. Automotive alternators generally are not. Finding one supports an ignition source hypothesis that must still be tested against the data.
10. Fire damage is heaviest at a boat's shore power inlet. The inlet's contacts are pitted and heavily discoloured, and the cord plug body is melted around one blade. What mechanism best fits?
Answer: Resistive heating at a loose or corroded connection. Corrosion or a loose fit at the plug and inlet raises contact resistance, so normal load current produces localized heating (I squared R) that can char and ignite the plastic without tripping any breaker. Discoloured, pitted contacts and melting focused on one blade are typical. ABYC E-11 covers shore power inlet and cord requirements.
11. A fixed clean-agent system discharged into an engine room, but the fire reignited. The engines and engine-room blowers were still running at discharge. Why does this matter?
Answer: Running machinery pulls the agent out. Fixed systems depend on holding a design concentration in the compartment for long enough to stop reignition. Running engines and blowers pull air through and exhaust the agent, so ABYC A-4 calls for engines, generators and blowers to be shut down when the system discharges. Check whether the shutdown worked and how long the compartment stayed closed.
12. A burned cruiser has sunk at its slip, and the insurer wants it raised and hauled tomorrow. What is the investigator's priority before salvage begins?
Answer: Notify interested parties and document the raising and recovery. Raising and hauling can move, destroy or wash away evidence, so NFPA 921 spoliation guidance calls for notifying interested parties (owner, insurers, manufacturers, marina) so they can attend, and for documenting the salvage process. Removing components or washing debris before others can examine them risks spoliation.
13. Before entering the closed cabin of a fire-damaged boat the morning after, what should the investigator do first?
Answer: Test the air, isolate power and check stability. Closed spaces after a fire can hold carbon monoxide, hydrogen cyanide and low oxygen; batteries and shore power may still be live; and a damaged hull can list or take on water. Monitor the atmosphere, isolate power and check stability before entry. Starting machinery or moving batteries alters the scene and can cause ignition.
14. The owner's expert discards the burned battery charger before the insurer's expert can examine it. What consequence may a court impose?
Answer: Spoliation sanctions such as an adverse inference. Destroying relevant evidence that another party had a right to examine is spoliation. Depending on the jurisdiction and fault, courts can instruct the jury to infer the evidence was unfavourable, exclude related testimony or dismiss claims. Photographs rarely substitute for an object that needed physical examination.
15. In a subrogation suit against a charger manufacturer, opposing counsel challenges the fire investigator's opinion under Daubert. Which foundation best supports admission?
Answer: A documented NFPA 921 method with tested hypotheses. Under Federal Rule of Evidence 702 and Daubert, the court looks at whether the opinion rests on reliable methodology reliably applied to the facts. Courts widely treat NFPA 921 as the recognized methodology, so documented data collection and hypothesis testing is the strongest foundation. Experience matters but cannot replace method.

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IAMI CMFI exam FAQ

How many questions are on the IAMI CMFI exam?

No more than 150 true/false and multiple-choice questions, with a time limit of no longer than 3 hours. Format: closed book, proctored paper exam, graded by the cmi committee within 30 days. the real exam mixes true/false and multiple-choice items; practice here uses 4-option single-best-answer questions. the cmfi does not certify you as a fire investigator: you must already hold a recognized fire investigator certification.

What is the passing score for IAMI CMFI?

80%; results are reported only as pass or fail, and individual scores are not released.

How much does the IAMI CMFI exam cost?

US$95 application fee plus US$350 examination fee (non-refundable, payable in US funds). A retest fee is waived for one year or until the next Annual Training Seminar. Recertification every 5 years: US$95. IAMI membership dues are separate. ABYC charges members less than nonmembers, so confirm current fees with ABYC before you book.

Which languages is the IAMI CMFI exam offered in?

English (no other languages are published by IAMI).

Where do I take the IAMI CMFI exam?

Proctored at IAMI Annual Training Seminars and other locations set by the IAMI Board; photo ID required.

Is this IAMI CMFI practice test free?

Yes. The 15-question practice test on this page is free, with an explanation for every answer and no signup. A free account also unlocks the complete study notes for the first topic. The full IAMI CMFI prep is Premium at $147 a month for this exam.

What's in the premium IAMI CMFI prep?

3,000 practice questions organized topic by topic (Fire Science and Fire Dynamics: 450; NFPA 921 Methodology, Origin and Cause: 425; Vessel Construction, Materials and Fire Behavior: 425; Marine Fuel, Electrical and Ignition Sources: 425; Fire Protection Systems, Marinas and Boatyards: 425; Scene Examination, Documentation, Evidence and Safety: 425; Insurance, Legal Considerations and Testimony: 425), 6 full-length timed mock exams of 150 questions, 800 flashcards and 60 comprehensive key notes split across all 7 topics, plus a mistakes bank and the Readiness Score.

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Exam details are summarized from the official candidate information available in November 2026. ABYC changes formats and fees, so confirm with International Association of Marine Investigators (IAMI), CMI Committee (CMFI program) before you book. ABYCExamPrep is not affiliated with the American Boat & Yacht Council.

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