This article briefly discuss about the use of Fault-Tree Analysis (FTA) for the investigation of "top" fault (abnormal condition) or failure event in pharmaceutical industry.


We know that a system is a collection of components in a defined architecture with the sole purpose of accomplishing that system’s function and the functional failure probability of that function is determined by the integrity of the constituent components as well as the logic of the systems’ architecture. 


The more complex the system, the more there is a need for an in-depth analysis technique to identify all possible combinations of failure that could result in loss of the system’s integrity. The Fault Tree Analysis (FTA) is such a technique. 


  • A fault tree shows graphically, by means of a specified notation, the logical relationship between a particular system failure and all its contributing causes.

  • FTA is used to show how an undesirable top-level failure (or event) may occur via the combination(s) of individual contributing failures, events and/or errors.


In the process of safety assessment, FTA has the following functions:

1. analyze failure reasons of the top events combined with the system architecture;

2. quantify the probabilities of the top events;

3. allocate the safety requirements of the top events to the lower level events;

4. assess the effects of the development errors through the combination of qualitative and quantitative methods;

5. assess the effects of single and combined failures;

6. assess the effects of the exposure time of the hidden failures on the system safety;

7. assess the source of common cause failures;

8. assess the nature of fail-safe design (fault tolerance and error tolerance);

9. assess the effects of design change on safety;


FTA can serve as an effective measure to investigate failure reasons after a major failure or accident occurs; it can be used as a guidance for fault diagnosis and to improve usage scenarios and maintenance plans; it can also be used to spot reliability and safety weaknesses and take measures to improve them.


An FTA can be conducted for both positive and negative events.


Below some applications of FTA:

  •  Fault Tree Analysis in Design
  • Standards for Risk Assessment and Safety Instrumented Systems
  • Safety Analysis Methods for Train Control Systems
  • Maximizing Machinery Uptime
  • Preliminary System Safety Assessment
  • Risk assessment management for a new product
  • Maximizing Machinery Uptime