Non-transferability of fracture data from specimen level to component level is a serious limitation of conventional fracture mechanics, as fracture resistance data obtained is largely geometry dependant. The difficulty is largely overcome by GTN model which models the drop in load carrying capacity of a material with the increase in plastic strain, considering nucleation, growth and coalescence of micro-voids in the material. However, determination of the modelparameters with experiments is extremely difficult and doubtful. Hence, a parameter-study has been done to find out the effects of different parameters on material behaviour to asses the parameter for best practical result with least metallographic study. The parameters were finally verified by predicting ductile fracture in a real life piping component.