Q1: What is the calculated probability of a fire in a year, with the probability and frequency data as given in Fig. 1? (Examine the logic tree). In this plant welding happens on average 4 times per year for 3 hours each time. Also, electric motors drive in the plant on average twice per day for 25 minutes each time. fuel leaking drain valve joint open P=0.015 P=0.030 oxygen ruptured pipe P=0.001 ignition welding happening Figure 1 electric motor Q2: What is the value of Bow-tie diagram that makes it often required by the regulators?