Abstract Topic of this work is the integrity assessment of the pipeline section from hydropower plant Pirot. Crack-like defect size, maximum depth, is determined based on non-destructive evaluation - the largest crack depth is taken as the initial value for load carrying capacity estimation. Also, the crack dimensions (both length and depth) are varied. Limit pressure values are determined from 3D and 2D models of pipes with axial cracks on external surface. The influence of tensile loading on the load carrying capacity of the pipes with circumferential cracks is also examined. Integrity of pipes with both types of defects (axial and circumferential) is assessed through application of FAD diagrams.