Last edited 29 May 2019

Main author

ConSIG CWG Institute / association Website

Failure modes and effect analysis (FMEA)

Contents

[edit] What is FMEA and when is it used?

FMEA is a step by step approach for collecting knowledge about possible points of failure in a design, manufacturing or construction process, product or service:

  • When a process, product or service is being designed or redesigned
  • When an existing process, product or service is being applied in a new way
  • Before developing control plans for a new or modified process
  • When improvement goals are planned for an existing process, product or service
  • When analysing failures of an existing process, product or service
  • Periodically throughout the life of the process, product or service.

[American Society for Quality (ASQ) 2017]

[edit] History of FMEA

FMEA was first used by the US navy in 1949 to understand and control the risks in their procedures, including operation of weapon systems. It was also used in the 1960’s for the Apollo missions and then from the 1970’s by the automotive industry.

[edit] Use of FMEA in the project Lifecycle

It can be used by project teams to assess and control how a process or item can fail for example:

[edit] Benefits

[edit] Steps to undertake the FMEA

[edit] Setup

Preparation for Workshop

Assembling the Team

Creating FMEA Template

  • Link to template
  • Adjusts to suit

[edit] Consider potential failures (for each critical item / process list the potential points of failure)

Observation: Potential failure mode(s)
Concrete not curing

Failure Mode

  • How can the item or process fail?
  • E.g. fatigue, cracking, deformation….
Potential effect(s) of failure
Crack
Settlement

Effect of failure

Potential cause(s) of failure
Incorrect Mix
Weather

Cause of failure

  • What has caused the failure to occur
  • Important to understand the ‘root’ cause.
Current process controls
No control
Cube tests

Current controls

  • Controls & tests that are already in place which may highlight failures that occur

[edit] Assessment of failure

Occurrence (OCC)

  • How frequent will the failure happen
  • Probability of occurrence
  • Higher number more likely to occur

Severity (SEV)

  • Worst case scenario of impact if the failure occurred
  • Higher number worse impact

Detection (DET)

  • Likelihood of the failure being detected with current controls
  • Higher number less likely to detect

Risk Priority Number (RPN)

  • RPN = OCC x SEV x DET
  • Special attention should be given to high severity

[edit] Actions to be taken

Corrective Actions

  • Actions to reduce the RPN
  • RPN should ideally be less than 25

Revised Assessment

  • Completed actions should reduce occurrence, severity or improve detectability
  • RPN updated accordingly

Post FMEA

  • Regular review important to check assessment still valid and to pick up any changes that occur.

[edit] Related Tools

  • DFMEA – procedure used in engineering to explore the possibility of a design failing in a real world situation.
  • PFMEA – procedure which focuses on the failures of a process
  • FMECA – extension to FMEA which introduces an additional metric called criticality.

This article was originally written by Alan Grogan on behalf of the CQI Construction Special Interest Group, reviewed by members of the Competency Working Group and approved for publication by the Steering Committee on 1 May 2019.

--ConSIG CWG 20:27, 26 May 2019 (BST)

[edit] Related articles on Designing Buildings Wiki