There is a propane storage tank in a backyard of a house, as shown in the Figure 3. A fire accident may occur due to release of propane. As a safety measure, a fire alarm coupled with flammable gas detector is installed. On actuation of alarm appropriate safety measures are planned. It is important to note that alarm and gas detector is ineffective for catastrophic failure of storage vessel.
a) Calculate the probability of a fire accident using fault tree.
b) Discuss the safety measures which can apply to reduce the failure probability of initiating events and hence the top event probability?
Rate of occurrence (/month)
Leak from pipeline 1
Leak from valve 1
Leak from tank
Overfilling causing catastrophic failure of the tank
Leak from pipeline 2
Leak from valve 2
Leak during downloading of propane from tanker
Gas detector and alarm failed
Presence of ignition source
Figure 3. The Schematic diagram related to propane storage tank