How to Become a Certified Fire Investigator

To become a certified fire investigator, you build up documented experience and training, apply to a certifying body, and pass its exam. In the US you can do that through the International Association of Arson Investigators, which awards the IAAI-CFI, or the National Association of Fire Investigators (NAFI), which awards the Certified Fire and Explosion Investigator (CFEI). Each starts with an application review, followed by a closed-book, two-hour exam of up to 100 questions, and each has to be renewed every five years (IAAI manual; NAFI CFEI guidelines).

The biggest difference is what it takes to apply. IAAI-CFI requires five years as a fire investigator, 400 hours of training, signed field evaluations and sworn testimony. CFEI scores your background on a credit scale and requires 150 credits.

Where NFPA 921 and NFPA 1033 fit

Both credentials are built on two NFPA documents:

• NFPA 1033, Standard for Professional Qualifications for Fire Investigator, sets out the job performance requirements (JPRs) a fire investigator has to meet. The current edition is 2027. NFPA issued it on April 16, 2026, and it took effect May 6, 2026 (NFPA 1033).
• NFPA 921, Guide for Fire and Explosion Investigations, sets out the scientific method for working out a fire’s origin and cause. The current edition is 2024 (NFPA 921).

The IAAI-CFI exam can cover any of the JPRs in NFPA 1033 and draws on NFPA 921 and other references (IAAI manual). NAFI’s application packet says CFEI questions are based on the current NFPA 1033 and taken from the current NFPA 921 (NAFI CFEI guidelines). NAFI’s website names NFPA 921 as the main reference for its exam (NAFI CFEI). IAAI’s recommended reading list names the 2024 edition of NFPA 921 (IAAI manual, Appendix A). Neither organization’s published materials say which edition of NFPA 1033 its current exam follows, so ask before you buy study materials.

IAAI-CFI requirements

IAAI’s CFI page and its Certifications Manual (effective May 2025, updated August 2026) list what you need to apply (IAAI-CFI; IAAI manual):

• At least five years working as a fire investigator under the NFPA 1033 job performance requirements, documented with letters from employers or others who can confirm it.
• 400 hours of training. That total includes the 40-hour IAAI Fundamentals of Fire Investigation course or an approved substitute, 28 hours of required CFITrainer.net modules, and 332 hours of courses that meet the NFPA 1033 JPRs. Up to 33 of those hours can be untested or not directly about fire investigation.
• JPR check sheets signed by an IAAI-approved evaluator who has watched you work fire scenes, required since May 1, 2025. Finding an evaluator is up to you, and the sheets can be filled in over weeks, months or years.
• Two instances of sworn testimony on the origin and cause of a fire or explosion, in a setting where you were subject to cross-examination, such as a deposition or trial. IAAI’s Expert Witness Courtroom Testimony course is an accepted alternative.
• A high school diploma or equivalent.

IAAI’s manual says reviews are finished within 30 days unless more information is needed. Once approved, you have one year to complete the exam (same manual).

The IAAI-CFI exam has no more than 100 true/false and multiple-choice questions. It’s closed book, you get two hours, and you need 70% to pass. IAAI never discloses your percentage score, only whether you passed (IAAI manual).

You recertify every five years with 100 hours of tested training (up to 10% can be untested), three years of NFPA 1033 job experience during the cycle and at least 10 CFITrainer.net courses. Lectures you give can make up to half of your training hours. You don’t retake the exam if you apply on time. IAAI accepts renewals up to six months before expiration and allows a 90-day grace period afterward (same manual).

NAFI CFEI requirements

NAFI’s guidelines and application packet set these minimums (NAFI CFEI guidelines):

• NAFI membership in good standing, kept current after certification.
• Age 18 or older, with a high school diploma, GED or equivalent.
• Active involvement in investigating fire and explosion incidents, or in the litigation that follows them, with responsibility for that work in your job.
• At least 150 credits on the application, including minimums in four sections: employment experience (15), formal education (10), seminar and in-service training (10), and fire investigation experience.

The fire investigation experience section gives 1 credit per fire or explosion investigated in which you played a significant role. The minimum depends on your education and fire service background: 30 credits if you have no formal education to list, dropping to 15 with, for example, a fire-related bachelor’s degree or more than 10 years in the fire service. For employment, a full-time fire investigator earns 10 credits a year. Firefighters, police officers, evidence technicians and military personnel in fire-related work earn 6 a year, and the employment section tops out at 50 credits.

NAFI wants original paper applications by mail or express delivery, not email or fax. The application fee is $135, and review can take up to four weeks.

The CFEI exam has 100 multiple-choice and true/false questions drawn at random from NAFI’s pool. It’s closed book, you get two hours, and you need 75% to pass. Results are recorded only as pass or fail. Results arrive by email. NAFI’s website says within four weeks, and its application packet says within six.

You recertify every five years from your original certification date by earning at least 40 credits during the cycle. NAFI training programs count 2 credits per hour, other fire and explosion investigation training counts 1 credit per hour, and teaching counts 2 credits per hour. There’s no recertification fee. NAFI recommends at least 8 credits of continuing education a year but doesn’t require it (NAFI recertification guidelines, effective August 1, 2024).

Side by side

	IAAI-CFI	NAFI CFEI
Membership	Not required (members pay less)	Required
Experience	5 years as a fire investigator	Credit-based; at least 15 to 30 investigations, depending on background
Training	400 hours, including set courses	At least 10 credits of seminars and in-service training
Field evaluation	Signed JPR check sheets	Not part of the listed requirements
Testimony	2 sworn instances, or an approved course	Earns credits (up to 25), not required
Exam	Up to 100 questions, 2 hours, 70% to pass	100 questions, 2 hours, 75% to pass
Renewal	Every 5 years: 100 training hours and 3 years’ experience	Every 5 years: 40 credits
Application fee	$250 members, $570 non-members	$135, plus NAFI membership
Renewal fee	$200 members, $520 non-members	None

Sources: IAAI-CFI page, IAAI manual, Appendix B, NAFI CFEI guidelines, NAFI recertification guidelines.

Choosing between them

Which one fits depends on your situation:

• Ask investigators you work with which credential employers and attorneys in your area expect.
• IAAI-CFI is accredited by the National Board of Fire Service Professional Qualifications (Pro Board) and the Forensic Specialties Accreditation Board (IAAI-CFI).
• Look at what you can document now. CFEI credits a mix of education, training, fire-related employment and case count. IAAI-CFI requires five years of investigator work plus field evaluations and testimony, so it suits investigators who already have years of casework behind them.
• Count membership dues along with application and renewal fees when you compare costs.

Building toward certification

• Get into a role where investigation is part of the job. NAFI’s application gives credit for full- and part-time fire investigators, supervisors of investigators (including attorneys and adjusters), fire protection engineers, manufacturers and designers, and firefighters, police officers, evidence technicians and military personnel in fire-related roles (NAFI CFEI guidelines). If you’re still at the hiring stage in law enforcement, see what a police entrance exam tests.
• Keep records from your first case: certificates that show hours, transcripts, and a list of every deposition or trial with the case name, location and date. Both programs turn down claims you can’t document.
• Take a fundamentals course early. IAAI’s 40-hour Fundamentals of Fire Investigation course, or an approved equivalent, is required for IAAI-CFI and is also part of the IAAI-FIT requirements.
• Study the source documents. IAAI’s recommended references include NFPA 921 (2024 edition), Fire Investigator: Principles and Practice to NFPA 921 and 1033 (6th edition), Kirk’s Fire Investigation (7th edition) and Forensic Fire Scene Reconstruction (3rd edition) (IAAI manual, Appendix A).