Editing Fault tree analysis (section)

{{short description|Failure analysis system used in safety engineering and reliability engineering}}[[Image:Fault tree.svg|thumb|A fault tree diagram]]

'''Fault tree analysis''' ('''FTA''') is a type of [[failure analysis]] in which an undesired state of a system is examined. This analysis method is mainly used in [[safety engineering]] and [[reliability engineering]] to understand how systems can fail, to identify the best ways to reduce risk and to determine (or get a feeling for) event rates of a safety accident or a particular system level (functional) failure. FTA is used in the [[aerospace]],<ref name="NASA SE Toolbox">{{cite book|last1=Goldberg|first1=B. E.|last2=Everhart|first2=K.|last3=Stevens|first3=R.|last4=Babbitt|first4=N.|last5=Clemens|first5=P.|last6=Stout|first6=L.|title=System engineering toolbox for design-oriented engineers|date=1994|location=Marshall Space Flight Center|pages=3–35 to 3–48|chapter-url=https://ntrs.nasa.gov/search.jsp?R=19950012517|language=en|chapter=3}}</ref> [[nuclear power]], [[Process manufacturing|chemical and process]],<ref>{{cite book
| last                  = Center for Chemical Process Safety
| title                 = Guidelines for Hazard Evaluation Procedures
| url                   = http://www.aiche.org/ccps/publications/books/guidelines-hazard-evaluation-procedures-3rd-edition
| edition               = 3rd
|date=April 2008
| publisher             = Wiley
| isbn                  = 978-0-471-97815-2
}}</ref><ref>{{cite book
| last                  = Center for Chemical Process Safety
| title                 = Guidelines for Chemical Process Quantitative Risk Analysis
| url                   = http://www.aiche.org/ccps/publications/books/guidelines-chemical-process-quantitative-risk-analysis-2nd-edition
| edition               = 2nd
|date=October 1999
| publisher             = American Institute of Chemical Engineers
| isbn                  = 978-0-8169-0720-5
}}</ref><ref>{{cite book
| last                  = U.S. Department of Labor Occupational Safety and Health Administration
| title                 = Process Safety Management Guidelines for Compliance
| url                   = https://www.osha.gov/Publications/osha3133.pdf
| year                  = 1994
| id                    = OSHA 3133
| publisher             = U.S. Government Printing Office}}</ref> [[Pharmaceutical drug|pharmaceutical]],<ref>ICH Harmonised Tripartite Guidelines. Quality Guidelines (January 2006). [http://www.ich.org/fileadmin/Public_Web_Site/ICH_Products/Guidelines/Quality/Q9/Step4/Q9_Guideline.pdf ''Q9 Quality Risk Management''].
</ref> [[petrochemical]] and other high-hazard industries; but is also used in fields as diverse as risk factor identification relating to [[social services|social service]] system failure.<ref>{{Cite journal
  | last = Lacey
  | first = Peter
  | title = An Application of Fault Tree Analysis to the Identification and Management of Risks in Government Funded Human Service Delivery
  | journal = Proceedings of the 2nd International Conference on Public Policy and Social Sciences
  | year = 2011
  | ssrn = 2171117
  }}</ref> FTA is also used in software engineering for debugging purposes and is closely related to cause-elimination technique used to detect bugs.

In aerospace, the more general term "system failure condition" is used for the "undesired state" / top event of the fault tree. These conditions are classified by the severity of their effects. The most severe conditions require the most extensive fault tree analysis. These system failure conditions and their classification are often previously determined in the functional [[hazard analysis]].