During pipeline operations, several types of failures can occur, which can compromise their integrity. These failures generate financial costs for transport companies and can also cause damage to the population and property around them. This project studies the consequences of failure in pipelines carrying natural gas. A radiation heat flow model resulting from fire jets was improved and models were developed for calculating the volume leaked along the pipeline for containment failure sizes classified in percentages: pinhole (5 percent), hole (25 percent) and rupture (100 percent). These percentages represent the ratio between the diameter of the orifice generated by the failure and the internal diameter of the studied pipeline. A fatality probability function linked to thermal radiation exposure was added to the heat flux model developed. This probability function provides a measurement of the harmful degree by a given dose of thermal radiation. The risks arising from each type of failure portrayed were, then, analyzed. The models developed to assess the risks related to the different types of defects caused to the gas pipelines can help to improve mitigating actions in response.