State of the Arc (Mapping)

NFPA 921 Guide for Fire and Explosion Investigations considers the technique arc mapping to be one of the methodologies used in isolating a fire’s origin and spread. Provided the technique is used properly and understanding its limitations, it is a tool for investigators. Synthesized here is the latest peer-reviewed research and discussions on the implications of increased use of ground- and arc-fault circuit interrupters on arc mapping analysis. Incorporated are case studies and evaluations of recent legal decisions. The goal is to arm investigators with what’s needed to maximize the arc mapping’s efficacy and best present its use and results.

Aplicação do método científico (NFPA 921-2017) em perícias de incêndio - o caso da fábrica de tintas

O presente trabalho consiste em um relato de experiência a respeito da utilização do método científico, derivado da norma internacional NFPA 921, quando da realização de perícia de local de incêndio em uma fábrica de tintas. Para tanto, aplicaram-se ao exame pericial as etapas pertinentes ao referido padrão metodológico, o que permitiu a perícia inferir sobre causas do sinistro. No presente relato são discutidos os aspectos práticos observados quando da aplicação do método, ratificando sua importância como um padrão de atuação na realização de exames periciais em locais de incêndio.Palavras-Chave: Incêndio. Tolueno. Engenharia legal. Perícia Criminal. NFPA.

Forensic Engineering Analysis of an Explosion Allegedly Caused by an Overfilled Propane Cylinder

Analyzing the origin and cause of fires or explosions for the purposes of legal proceedings requires the smooth integration of a reliable fire investigative methodology with sound engineering principles and practices. The origin of a building fire was first determined based on the methodology of NFPA 921 Guide for Fire and Explosion Investigations. Engineering analysis was applied to witness observations, arc mapping, fire dynamics, and the evaluation of fire patterns. The fire cause was then evaluated considering NFPA 921 and integrated applied engineering analysis and calculations. The allegations of an overfilled propane cylinder as the cause of the fire were considered. Spoliation issues, poor investigation methodology, and the lack of sound engineering principles (resulting in unreliable opinions) are also contrasted and discussed.

Forensic Engineering Critique Of The Methodology Eliminating Fire Cause Possibilities

In A Case Involving A Residential Fire With Fatalities, Plaintiff Experts Alleged That The Fire Originated In A Bedroom As A Result Of An Electrical Failure In An Oscillating Pedestal Fan. At The Time Of The Fire, The Fan Was Plugged Into A Six Foot Extension Cord That Was Lying On The Floor Under The Bed And Plugged Into A Standard 115 Volt Duplex Receptacle. The Plaintiffs, Specific In Their Allegations, Opined That The Failure Occurred In The Rotary Switch That Controlled The Speed Of The Fan Even Though No Physical Evidence Of A Failure Of That Nature Was Identified Or Collected During The Analyses Of The Fire Scene. Since No Physical Evidence Of A Failure Was Identified, Nfpa 921, Guide For Fire & Explosion Investigations, Requires That All Other Potential Ignition Sources In The Area Of Origin Be Eliminated As A Possible Cause. Plaintiffs Eliminated The Power Cord For The Fan, The Extension Cord And The Cord Plug And Cord Receptacle Connection Under The Theory That The Material Was Pvc With A Vw-1 Fire Rating. Plaintiffs Testified That The Self Extinguishing Characteristics Of Vw-1 Material Were Such That, Even With An Electrical Failure In One Of Those Components That Resulted In The Ignition Of The Material, There Would Be Insufficient Heat Released To Ignite The Box Spring For The Bed. Plaintiffs Also Eliminated Improperly Discarded Smoking Material As A Potential Cause.Efendants Were In Sharp Disagreement With Plaintiff Case In Chief Regarding The Elimination Of The Vw-1 Materials As A Potential Fire Cause, Since The Material Will Combust In Situations With A Sustained Electrical Fault. Defendants Conducted Tests Which Not Only Demonstrated An Electrical Failure With Ignition At The Extension Cord Plug Receptacle Interface, But Also That The Burning Vw-1 Pvc Released Sufficient Heat Energy To Ignite A Box Spring Similar To The Box Spring Involved In The Fire. The Results Of Those Tests Assisted In The Resolution Of The Case Prior To Trial.

An Engineering Review Of Nfpa Standard 921

National Fire Protection Association (Nfpa) Guide 921 Was Published In 1992. Nfpa 921 Is Entitled; Guide For Fire And Explosion Investigations. This Paper Will Review Nfpa 921 And Analyze Its Significant Impact On The Field Of Forensic Engineering. Future Revisions And Planned Additions To The Document Which Affect Forensic Engineering Will Also Be Discussed.