Assessing the current condition of the material of engineering structures is an important task faced by engineers involved in strength analysis. It is a complex assignment due to the complex nature of the effects of various factors on the material of the structure. In the case of district heating pipelines, these can be thermal interactions, conditions of long-term mechanical loading and the operating environment leading to the development of corrosion and hydrogen damage [1,2]. An important aspect is that the presence of defects is not assumed at the development and implementation stage of a structure. Howev-er, for operational reasons, the formation and development of cracks in the structure under consideration cannot be ruled out, which can have a determining effect on its ability to carry loads [3]. In such cases, the implementation of fracture mechanics procedures is an essential part of the strength assessment, in order to avoid dangerous consequences as a result of failure [4]. The development of computer tech-niques makes it possible to carry out strength analysis of structures on the basis of the results of numeri-cal simulations using FEM. It is then possible to determine the characteristic quantities of mechanical fields (stresses, strains, stress triaxiality factor) before the crack front, and on their basis to formulate conclusions about the condition of the material and the strength of the structure [5,6]. This paper pre-sents the assumptions of the proposed procedure for assessing the strength of steel for energy pipelines, with emphasis on the implementation in the procedure of simulations using FEM.