Cause Failure Analysis

Common cause failure analysis (CCFA) or common cause analysis is used primarily to evaluate multiple failures that may be caused by a single event or causal factor common to or shared by multiple components. It is especially important in evaluating the true reliability pr uced by redundant systems or components. 

Common causes of failure can be a common or shared environment or location, common (same) manufacturer, common maintenance or operations personnel and/or procedures, common power and/or fuel supply or circuits, common control signals or circuits, common design specifications, and a common service life. 

If redundant elements are relied upon to provide the required level of safety and reliability in critical systems, these elements must not be subject to failure caused by a common single event or common causal factors. 

During the late 1980s two air tragedies resulted from very similar common cause failures. In both cases (a Japan Air Lines Boeing 747 and a United Airlines DC-10), hydraulic control was lost when the redundant hydraulic systems (seven in the 747 and three in the DC-10) were disabled by loss of hydraulic fluid when the hydraulic lines in the rudder of the aircraft were severed. Only one hydraulic system in either aircraft would have been sufficient to maintain control of the aircraft. The only location on either aircraft where all the hydraulic lines were in close proximity was in the rudder. Even though the trigger event was different for each aircraft (aft pressure bulkhead failure and sudden depressurization in the 747 and an engine explosion in the DC-10), both aircraft crashed due to common cause failure of redundant hydraulic control systems. 

A general approach to common cause failure analysis is to identify critical systems or components and then use energy trace and barrier analysis (ETBA) to evaluate vulnerability to common environmental hazards, unwanted energy flows, and barrier failures (see Chapter 13). 

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Waller, R. A., A Brief Survey and Comparison of Common Cause Failure Analysis, June 1985... 

The bulk of the information in the report is included in a 317-page appendix that contains systems descriptions, station blackout fault trees, diesel generator historical data, and diesel generator common cause failure analysis results for 18 different nuclear power plants. Tables and graphs are well organized and present data correlated to each plant studied. The study also contains conclusions and recommendations for improving reliability. 

Rasmuson, D.M., Mosleh, A., June 20, 2007. A Brief History of Common-Cause Failure Analysis, Presentation at the IAEA Technical Meeting on CCF in Digital Instrumentation and Control Systems for Nuclear Power Plants , Bethesda, Maryland, USA. 

Improved Root Cause Failure Analysis (RCFA)... 

Root cause failure analysis (RCFA) is conducted by different teams and departments to identify the main causes of a failure. Different tools are in use by the industry to conduct these analyses. A robust RCFA system provides critical information to the operators and advice on the sequence of corrective actions. The industry has gained several benefits including the integration of several information sources resulting in more automated and proactive conditions with possible diagnosis and advice (Weidl 2004). The purpose of such analyses could be to resolve problems related... 

Mobley, R. K. 1999. Root cause failure analysis. Plant engineering maintenance series. USA Newnes Publishers. 

Siu, N. and A. Mosleh (1989). Treating data uncertainties in common-cause failure analysis. Nu-clear Technology 84, 265-281. 

Bowers (at Life Cycle Engineering, cbowerse LCE.com) mentions the following risk assessment tools that can be employed to help preserve asset resources Simplified Failure Mode Effects Analysis, Root Cause Failure Analysis, and Reliability-Centered Maintenance. Should safety and health professionals step forward to train maintenance managers in risk assessment concepts ... 

Common Cause Failure Analysis A system safety analytical technique (also known as common cause analysis) used primarily in the evaluation of multiple failures that have the occurrence of a single event as a common causal factor. 

The API000 common-cause failure analysis follows a three-step process ... 

Where relevant, it may be necessary to carry out fauit tree anaiysis, equipment performance analysis, or common cause failure analysis... 

Special attention should be given to the valve actuator when conducting a root cause failure analysis. Many of the problems associated with both process and fluid-power control valves are really actuator problems. 

As in any proactive maintenance organiTation you must perform Root Cause Failure Analysis in order to eliminate liiture component failures. Most maintenance problems or failures will repeat themselves without someone identilying what caused the failure and proactively eliminating it. A preferred method is to inspect and analyze all component failures. Identify the following ... 

An acknowledgment is also made to JBF Associates, Inc. (J. S. Arendt, D. F. Montague, H. M. Paula, L. E. Palko) for their preparation of the subsection on common cause failure analysis (Section 3.3.1) and inclusion of additional material in the section on fault tree analysis (Section 3.2.1), and the Meridian Corporation (C. O. Schultz and W. S. Perry) for the preparation of the section on toxic gas effects (Section 2.3.1). 

Procedures for conducting common cause failure analysis 1992 in probabilistic safety assessment... 

Song, H. 2007. The Studies of methodology and applications for common cause failure analysis of probabilistic safety assessment for third Qinshan nuclear power plant. Shanghai Jiao-tong University. 

Parry, G. (1991) Common cause failure analysis A critique and some suggestions. Reliability Engineering and System Safety 34 309-320. 

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