NFPA 921, "Guide for Fire and Explosion Investigations", is a Natiional Fire Code published by the National Fire Protection Association (NFPA). Its purpose is "to establish guidelines and recommendations for the safe and systematic investigation or analysis of fire and explosion incidents" (section 1.2). Familiarity with NFPA 921 is strongly recommended by NAFI and the International Association of Arson Investigators (IAAI). NFPA 921 forms a large basis of the information which a professional fire investigator must know to pass the various Fire Investgator Certification (NAFI and IAAI) examinations.