The risk level of the HDD project is a key parameter when assessing the project feasibility and making the project pricing. It is also a starting point for introducing the risk management strategy which aims to reduce the number of installation failures and their negative consequences. The objective of this work was to develop a new mathematical model for the qualitative and quantitative risk assessment of HDD projects of various sizes (MINI, MIDI and MAXI), which allows to consider the installation specificity (the optional possibility of applying various tools and machines). The risk assessment was carried out applying the Fuzzy Fault Tree Analysis. The unwanted events were divided into 4 classes: problems with the ground, machines, environment and management. Applying the fuzzy set theory in the proposed model made it possible to decrease the uncertainty, the lack of precision and the difficulties with gaining the crisp values of the basic events probability, which occur in the conventional Fault Tree Analysis. The practical application of the proposed model for the MINI, MIDI and MAXI HDD projects was shown on four examples.
