A Model for Quantifying Risk for Arc-Flash Hazards


The purpose of this article is to present a simplified method for evaluating and quantifying risk factors associated with arc-flash electrical hazards. Once these risk factors are determined, a consistent risk assessment can be performed in accordance with NFPA 70E, Annex F, Hazard Risk Evaluation Procedure. This article will introduce the use of failure rates and failure multipliers in determining failure probabilities associated with equipment condition and a facility’s preventive maintenance program. Second, it will introduce the concept of applying probability multipliers associated with work tasks to be performed and a facility’s workplace culture as implemented through their safety program. We will then combine this information mathematically in an attempt to effectively model risk assessments using arc- flash analysis data, failure probabilities, and probability multipliers.