(d) Discuss the meaning and need for "multilayer protection" with reference to the "Swiss Cheese" model. [3 marks] (e) Give an account (with brief explanations) of explosion safety measures that can be deployed in a process enclosure to protect from an internal explosion, illustrating the multilayer protection principle. [3 marks] (f) A heptane storage tank 30m in diameter, 10m tall is on fire at the top. The heptane density is 675kg/m3. The estimated maximum burning rate of the liquid is 0.1kg/(m2s) (i) Using a point source model, estimate the heat flux received by a similar neighbouring tank 30m away (tank wall to tank wall) and comment on the severity of this heat flux. (ii) If left unattended how long would it take for the fire to consume all the fuel? [8 marks]