(a) What is meant by "Root Cause Analysis"? marks)(b) One graphical method of Root Cause Analysis is Fault Tree Analysis. Detail the stepsneeded to undertake a Fault Tree Analysis.(7 marks)

(7 marks)(c) Figure 2 depicts a system for the treatment of a chemical plant effluent and its release to a watercourse. Effluent material from the plant should normally be treated in treatment tanks 1 and 2 (each tank removes different toxic chemicals) and then safely released, via outlet 1, to the watercourse. However, both treatments can fail, under circumstances shown in Table 1.In an emergency, if the system becomes over-pressurised, an emergency pressure safety valve (PSV) will activate to prevent a dangerous explosion. In this emergency scenario waste released should be collected in an overflow tank. However, on days where factory output is 20% higher than average, the overflow tank level can be exceeded, and toxic material will flow through outlet 2 into the watercourse. Table 1 shows the frequency and duration of the unwanted events. (i) Sketch a fault tree showing the scenarios that could lead to toxic material being released into the watercourse. You may assume that the high-output and the dangerous over-pressure condition are independent events. (9 marks)(ii) Calculate the frequency, per year, of toxic material being released from Outlet 1? (iii) Calculate the frequency, per year, of toxic material being released into the water course from either Outlet 1 or Outlet 2?(5 marks)