RISK MANAGEMENT TOOLS - Risk Management Applications in Pharmaceutical and Biopharmaceutical Manufacturing - page 33

Mixing motor for batch process overheats

Motor
failure

Temperature >
than allowed
maximum temp.

Excessive current
to motor

Current >
max.
current

Heat

Excessive current
in circuit

Fuse fails to open

High
current

Fuse failure

Basic wiring
failure

Basic power
supply failure

Wiring short Power surge

To explain the relationship of the
event
The output event occurs if any of the
input events occur

Fault event

OR gate

The output event occurs if all of the
input events occur

AND gate

The lowest level event for which
probability of occurrence or reliability
information is avaliable

Basic event

Figure 2.7 Example of an FTA.