טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAltus Keren
SubjectImplementation of AFMEA (Advanced Failure Mode and Effect
Analysis) for Process Analysis
DepartmentDepartment of Quality Assurance and Reliability
Supervisor Dr. Pavel Grabov


Abstract

Failure Mode and Effect Analysis (FMEA) is one of the well-known risk assessment methodologies. FMEA represents a ‘step by step’ procedure implying, at its first steps, a tabulation of system functions or system equipment items and the possible failure modes. After the failure effects have been identified, the consequences associated with each effect should be evaluated. Obtained ranks of severity (S), occurrence (O) and detectability (D) are used for risk assessment via an index called RPN (Risk Priority Number) calculated by multiplying the severity, occurrence and detectability ranking factors for every cause:

RPN = S * O * D

Once all items have been analyzed and assigned a RPN value, it is common to plan corrective actions from the highest RPN  value down.

There are, usually, several possible competitive corrective actions that, theoretically, are capable of reducing the RPN for any given failure mode. Since conventional

FMEA does not provide any guidelines for the optimal choice between competitive corrective actions, the FMEA team faces a difficult task. Priority of the alternatives under comparison is usually established subjectively, based on intuition, experience and/or feelings of FMEA team members.

The AMFEA procedure provides the basis for the optimal corrective action choice. This procedure implies evaluation of both the feasibility of the corrective action implementation and the expected RPN value after implementing this action.

AFMEA takes into consideration both the chance of success (i.e. the RPN reduction) and the probability of an undesirable impact (on people, system, product, process or environment) as a result of a corrective action implementation.

This work describes an implementation of AFMEA on a chemical process. The production process was illustrated using a flow chart, and analyzed by a team according to the AFMEA method.