In recent decades, many accidents involving pressure vessels and piping components (PVP) have occurred in North-America. Several studies have been conducted to understand their causes and find suitable solutions to reduce their frequency. Most of the researches have focused on the technical causes of these accidents and the subsequent implementation of safety management strategies. These researches highlight that the main technical causes are leak and rupture. From this standpoint, it is important to deepen the study of these causes to better understand the risk of accident in PVP applications. In Alberta alone, the Alberta Energy Regulator (AER) showed that more than 15 root causes initiated leak and rupture failures in PVP since 1990. This paper presents an analysis of the frequency of accidents, their severity, their causes and the risk associated in the Alberta petrochemical industry from 2008 to 2017. This study proposes an exponential decay function to estimate the frequency of accidents involving PVP and identifies the most important causes based on a severity analysis. The results based on the frequency model show that there is a good agreement between the predicted and observed accidents frequency from 2008 to 2017. The severity analysis results shows that the main factors contributing to accidents are corrosion, construction deficiency, and overpressure. Finally, the proposed model of frequency and severity of observed and predicted PVP failures, is a useful tool for risk assessment and prevention program implementation.