ARC MAPPING: AN EFFECTIVE TOOL TO DETERMINE FIRE AREA OF ORIGIN IN FIRE INVESTIGATION

Abstract

The fire accidents often happen in the residential and commercial structures. The investigation of fire in the accident site is a complex process and there is a difficulty in identifying the cause of fire. The commonly encountered problem in fire investigation is the false statements of witness information, hidden evidences and insufficient data provided by the occupier of the premises. The investigation of fire accident done by the corresponding authority should follow a procedural method. The effective investigation results in accurate determination of cause of fire and other factors that led to the spread of fire. There are several investigation tools and techniques used for fire investigation such as Fire Pattern analysis, Heat and Flame Vector analysis, Depth of Char and Calcination Survey, Arc Mapping and Fire Dynamics. This paper discusses about the tool arc mapping which is used to identify the fire area of origin where fire involves electrical systems and this paper focuses on the possibility of arcs in the circuits which is energized and drawing power, energized and not drawing power and un-energized circuits. How the identification of arcs in the electrical line diagram of accident sites helps to determine the fire area of origin is also discussed. The differentiation between melting of wire and arcing between wires is illustrated as per NFPA 921. The possibility of number of arcs in the three phase system is more than single phase system. The different types of arc formations in the three phase electrical supply system are explained in this paper.