Failure Mode and Effect Analysis - FMEA Audits

FMEA (Failure Mode and Effect Analysis) in this context is in essence a risk analysis of the criticality of a given asset.

FMEA is a tool which is used to guide people's time and effort when carrying out maintenance, be it planned or unplanned maintenance. Giving each asset a rating which defines how critical it is to the operation of the business yields the following benefits:

• Ensures the most important machinery is properly maintained
• Maximises time and resource against the most critical assets in the case of planned maintenance and breakdown maintenance
• Provides guidance on which assets should have the most spares purchased i.e. critical spares
• In cases where resource and budgets are scarce it can be used to "weed out" unnecessary maintenance requirements
• Can be used to formulate a spares policy holding procedure i.e. keeping maximum stock for critical assets, basic stock for semi-critical assets, and no stock for non-critical assets

What is Criticality?

Operational businesses usually have machinery assets which have been procured or are being used in order to meet certain objectives of that business. Each individual asset that is in use is making a contribution to business aims and goals. However, some assets are more important than others in that the contribution to meeting customer needs they make is immediate and direct. It is these assets that are 'critical' to a business and it is with Failure Mode and Effect Analysis that we can define the 'level' of that criticality.

The Case for Understanding Criticality

In most businesses that have large numbers of assets there is little or no understanding of the criticality of those assets to the achievement of business goals and targets. A critical asset is usually defined as one that is causing many problems in customer complaints or breakdowns for example. In this way the process is a reactive one which means that planning the best use of time, effort and money is difficult or impossible.

An operational unit is built up of large numbers of interconnecting systems, each of which is made up of many individual assets. The design and functionality of these systems and assets depends on their age and for which purpose they were installed. In most cases individual systems and their relationships with other systems have been built up 'organically' (i.e. over time and in response to a particular 'burning issues of the day'). This means that defining which assets are important to a business is a difficult task.

It is important to be able to objectively determine asset criticality for several reasons.

Engineering Resource

Within an operations function there are usually many assets most of which require some level of attention in order to ensure that they reliably meet the requirements for which they were designed. This attention is given in the form of maintenance and is usually provided utilising the services of a dedicated engineering resource.

Traditionally the maintenance provided on an asset has been designed to ensure that it is kept in as close to 'as new' condition as possible. This usually means that maintenance periods and schedules have been designed using manufacturers' recommendations and apply to an asset in isolation. The resulting maintenance schedule for a particular asset is usually very comprehensive and takes a considerable amount of skilled engineering time to complete.

In a situation where there are few assets or where there is sufficient engineering resource this approach causes no undue problem. However in most organisations an engineering function is viewed as an on-cost and therefore budgets, personnel numbers and spending is kept to a minimum. This means that there is no way an engineering function can realistically carry out all of the required maintenance on all of the operational assets. In these cases any form of planned maintenance system breaks down and the engineering function quickly becomes a reactive force responding to whoever 'shouts loudest' for attention to assets.

It is therefore very important that asset criticality is determined in order that limited engineering time, effort and resource can be directed to the assets that have the biggest impact on the organisation's ability to meet customer needs.

Spare parts Inventory Holdings

The criticality of an asset to a business will also have a large impact on the spares inventory holdings for an organisation. In simple terms the more critical an asset the more comprehensive its spares holding. As with budgets for personnel, the amount of monies available for spares holdings is limited and minimised.

It is important that the available money is spent on parts that will have the greatest positive impact on the ability of the company to meet customer needs. This means that parts are held primarily for critical assets.

Quality Systems

Many quality systems have direct reference to 'Critical Assets' and the need to maintain all assets that 'have a direct impact on the quality of a company's products'. The use of FMEA can objectively determine criticality and this can be incorporated into a businesses quality system.

Breakdown Priority

Traditionally engineers engaged in some form of maintenance activity wish to complete the current task before moving onto another, or they have their own idea as to which particular task is more important than another. This approach can often lead to conflict with an operations function whose priorities may be different. In a business that has defined and agreed across all functions the criticality of its assets, this type of conflict can never arise because there can be no argument as to which particular task an engineer should be doing. In this situation an engineer will always give priority to work on a more critical asset.

FMEA and Strategic Maintenance Planning Ltd

Strategic Maintenance Planning recognises the importance of criticality definition and has developed a structured, comprehensive, yet simple methodology to determine that criticality. Essentially FMEA is a risk assessment of the potential impact that failure of an asset will cause to a business' ability to meet customer needs.

A simple overview of the methodology is as follows:

The determination of 'Detection', 'Probability' and 'Effect' can each be a relatively subjective rating. However, Strategic Maintenance Planning with its wide range of industrial experience and large library of information on a multitude of assets can ensure that ratings are as objective as possible.

The determination of overall rating is achieved through a simple mathematical formula and as such ensures a good level of objectivity no matter how relatively subjective each individual rating.

This process ensures that:

• The definition of Criticality is achieved in a structured and objective manner
• The criticality of assets is determined such that time, effort, resources and spending can be directed to the right places
• Criticality ratings can be agreed between all involved functional disciplines
• Criticality can easily be periodically reviewed to ensure that ratings have not been affected by the changing business environment
• Criticality of Assets are identified for quality system purposes
• Everybody knows where their priorities should lie

Overall the process employed by Strategic Maintenance Planning can help YOUR company to improve the effectiveness of its Maintenance.

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