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Developing and delivering a maintenance plan: the basics Malcolm Hide, Senior Consultant, Strategic Maintenance Ltd.

Introduction
So how do you go about setting up all of the maintenance requirements for several thousand discretely maintainable assets? This was the challenge facing us when we needed to set up the maintenance requirements package for a baggage handling system in a new airport terminal in a major international airport.

From previous experience, and the Airport requirements, we had a good idea of what needed to be done.  The challenge was about the sheer size of the system - with a total asset base of over 28,000 discretely maintainable assets, we needed to find a more efficient way of doing things.  As a result of this we developed a three-step process that delivers a robust maintenance plan, based on a clearly defined strategy, which is easy to review and enables the implementation of changes when necessary. We have found that the principles hold well irrespective of the size of the system.

Methodology
Phase 1 – Identify all Assets
Assets are assets, what can be difficult about identifying them?  Well that depends entirely on how far you might want to go down the asset tree.  Take a conveyor for example, do we take the asset structure down to component level, such as the drive motor, or do we leave the asset at conveyor level and take a motor as a component?  We defined a maintainable asset as an item we could isolate individually, and as a result we opted for the latter.  This did, in some instances, create some exceptions; for example a vertical sorter unit (see Image 2) was taken as a single asset, even though it clearly contains three individual conveyors.  In another instance a pneumatic conveyor extender at fire breaks was taken as a discrete sub-asset of a conveyor, to simplify the development of the maintenance strategies.
Ultimately, asset identification becomes a fine balance between the identification of local classes (similar equipment) and discrete equipment.  This may sound simple, but there is an art to doing it in a way that helps to simplify the development of your overall maintenance strategy.  We will try to clarify what local classes mean in Phase 2.

Once you have identified all of the discrete assets in your system, you will need to define how critical they are to the performance of your business.  To do this you might want to take a process layout of your system, and mark off large areas such as “Check-In Island A” or “Picking Floor C”, which has a measurable impact on your business.  Now define a series of business-related questions with five possible realistic answers for your business, such as:
1.    What would happen to our business if the identified section was out of operation for 24 hours?
a.    Production loss of over €1 million
b.    Production loss of over €500k
c.    Production loss of over €100k
d.    Significant production loss which could be supplemented by another site
e.    Minor production losses which could be supplemented by another area on our site
2.    How would our customers react to the identified section being out of operation for 24 hours?
a.    Losses in sales in excess of €1 million
b.    Losses in sales in excess of €500k
c.    Losses in sales in excess of €100k
d.    Significant losses in sales which could be supplemented by another site.
e.    Minor losses in sales which could be supplemented by another area on our site.
You need to make sure that the several aspects of your business, such as environmental impact, media coverage, customer perception, reputation and any other issues that have a direct impact on your business and its ability to function and operate in future are addressed.  You need to be aware that both the questions and their relevance might change over time, as the business and its environment changes.
Once the business criticality for an area has been determined, you will need to consider the failures that could take place on the equipment in that area, and the frequency at which these failures might occur.  These should not be operational issues such as bag jams, but rather equipment failure issues that would require component replacement or adjustment, such as motor failure or belt adjustment.  At this stage you should ignore the length of time it takes to repair the failure - we are more concerned at this stage with the frequency of maintenance-related disturbances.
The two values, Business Risk and Frequency are mapped onto the grid (see Image 3) to define the resulting criticality for the area.  This process needs to be repeated for all of the areas you have defined on your process layout.  Two items you will need to be aware of when performing this activity:
•    If the business risk incorporates a question related to health and safety in relation to people performing maintenance on the equipment, these risks need to be carefully considered.  While the resulting injury could be extremely serious, this risk of injury needs to be mitigated in the risk assessments and resulting method statements or redesign, not in increasing the business risk.  The reason for this is if the business risk is too high, then you might consider doubling up on the equipment to reduce the risk, but this adds to an injury risk when maintaining the equipment
•    All of the equipment and process routes in an area do not necessarily fall into the same criticality as the main routes for the area.  You will need to identify the main process routes, secondary and tertiary process routes through the area and assign lower priorities based on their potential impact on the area.

This process needs to be kept as simple and flexible as possible, and ensure all decisions are well documented to eliminate the possibility of misinterpretation or to support any decisions made, should that become necessary.  Remember that the business need and market forces will change over time and this criticality review will need to be re-evaluated fairly frequently (usually annually or in major shifts of the economy) to ensure you are still applying the correct strategies.  Changes to your environment could quite possibly change the maintenance plan you have adopted for the equipment on site over time.

Phase 2 – Identifying Local Classes and Strategies
When looking through all of the equipment on your site, you will notice that there are several pieces of equipment that are very similar.  The probability is high that the maintenance strategy applied to them can be the same, while making allowances for various criticality levels.  We identify these equipment groups by giving them a Local Class designation, and develop the maintenance strategies for each of these local classes, defining different frequencies (and strategies if necessary) for all five criticality levels at the same time.  This process allowed us to reduce the baggage system from 28,000 items to 122 local classes that we needed to define maintenance strategies for.
Based on your list of local classes, you will need to:

a)    Draw up a list of every activity that you will possibly perform on this equipment/local class, including:
i)    Component Replacements, where you need to consider the level at which you want to carry out your maintenance.  For example, in Western Europe, if a bearing on a motor reducer unit failed, and a replacement unit cost less than €150, then due to the time and effort required to manage the repair, you might opt to replace and not carry out a repair.  Converse to this in Central Africa, component availability and/or lower labour rates might mean a repair is the most cost-effective solution based on the resources at your disposal.
ii)    Component Adjustments, covering activities such as belt tensioning, oil replacement and defragmenting hard drives.
iii)    Cleaning Activities, covering the equipment and the immediate surroundings should this be in a restricted-entry area.  In many instances cleaning could fall to a lower skill level; however it should not be ignored from the maintenance plan as it forms part of a holistic approach to maintenance. At a food processing plant, we reduced downtime by 20% by reducing dirt in the system and from staff noticing future problems while cleaning – problems which could then be averted.  

iv)    Inspections, covering visual inspections, stoppage inspections and statutory inspections.
v)    All condition-based inspections such as Vibration, Thermography and Ultrasound.  If there is no in-house expertise to perform these activities, you could contract them out to specialist companies to perform the work. In our experience contracting out can be set up and managed well, or poorly, so consider the options carefully. A well-managed process of ‘contracting-to-inhousing’ can be most beneficial.
b)    Estimate the following:
i)    How long each of the identified tasks will take to complete (Mean Time to Repair [MTTR]), and how many people will be needed to complete the work.

ii)    Predict the Mean Time between Failures (MTBF) for replacements and adjustments. To define the MTBF, you might want to look at the design or predicted life of a component that you intend to replace or adjust.
iii)    Decide if the work will require the equipment to be isolated in order to complete the work.
c)    Define one of the following strategies for each of the criticalities you are using (see Image 4 – Strategy Sheet):
i)    Time Based, where you define a set frequency to perform the maintenance activity.  Some of the tasks are in themselves a strategy, such as a thermal inspection (Thermography) or vibration inspection (Vibration Monitoring), in which case you need to define a frequency based on an anticipated PF failure curve
ii)    Operational Based, which sets out the flow or operations required between maintenance activities
iii)    Condition Based, using an inspection or other strategy which will identify the onset of failure and allow for reaction time to address the failure
iv)    Run to Fail, which allows the component to fail before replacements or adjustments are made.
As part of the creation of the maintenance strategies you can also develop safe working practice method statements and generic risk assessments for all of the maintenance tasks that you have identified.  These method statements and risk assessments are an ideal way of helping to develop a training plan for new employees.
By developing these individual strategies, we found it relatively easy to adopt a cohesive maintenance strategy across the entire baggage system.  
Do also remember that all of the condition-based inspections, such as Vibration, Thermography and Ultrasound, are supportive of a sound maintenance strategy, and should not be performed in isolation.

Phase 3 – Extract the Maintenance Plan
Phases 1 and 2 can be progressed in tandem, however they need to be complete before continuing with Phase 3 of the work.  At this point we know all of the equipment we aim to maintain, how critical it is to your business, what strategies we will be using and what maintenance we will be performing.  We now need to extract this as a maintenance plan for each piece of equipment and insert it into our Computerised Maintenance Management System (CMMS).
This is where things started getting a little tricky!  While for many situations this is a manageable task, in the baggage system discussed above, we had around four time-based activities per piece of equipment, therefore amounting to 112,000 planned maintenance activities to enter onto the CMMS.  These tasks ranged from weekly visual inspections through to oil replacements every three years on the motor reducers.  Downloading this many planned maintenance tasks is clearly a significant task, not to mention the work involved in planning and managing a weekly paper trail of around 31,000 work orders.  Clearly we needed a way of grouping these activities into more manageable groups, while still keeping the maintenance information at equipment level.  To achieve this we created a software program to reduce the work involved.  This then fed the CMMS system we were using which managed this level of complexity in the form of maintenance routes.

In order to develop a manageable maintenance plan, you will need to identify and group these PM tasks together, based on frequency, strategy, skill and on a physical line of equipment to restrict the impact on the system during a stop inspection (an inspection requiring the equipment to be turned off).  Our experience has also shown us that these maintenance routes need to be limited to one person for a maximum of 4 hours per route, otherwise the impact on the system will be too great and the likelihood of completion during a shift will be low.  In the baggage system, this resulted in around 1200 planned maintenance routes, which was far easier to manage than individual job cards on every piece of equipment, and could be managed by one planner.
At this point there are a few key items to consider:

•    The maintenance plan needs to be flexible:
o    It should allow you to review and enhance the strategy, adding/modifying/deleting tasks or check list items.
o    It should allow you to review criticality (impacting on the frequency and strategy applied)
•    Every time these change, the maintenance routes and any checklists need to be updated to reflect this change in strategy.
Once all of the maintenance routes are entered into the CMMS, you will need to ensure that the risks associated with performing the maintenance are correctly addressed.  The generic risk assessments developed during Phase 1 of this process need to be refined given the actual environment in which individual pieces of equipment are installed. This ensures that all risks are identified and people are trained accordingly.

Conclusion
The development of this process allowed us to produce a cohesive maintenance strategy and a comprehensive maintenance plan for a very large system, but the process also holds well for smaller systems.  More than enabling the creation of the strategy and plan, it also helped to:
•    determine the manpower needed to support and maintain the system
•    anticipate the spares consumption for the site for the first 10 years of operation
•    create the training material used to train the engineers on the maintenance of the equipment.
Overall the process helped to minimise the operating cost of the maintenance operation from the outset, where we found the maintenance personnel level required was 15% lower compared to similar asset numbers elsewhere in the airport.  In addition, since everything was well documented, we were able to perform a review of the applied strategies and the maintenance routes, and refine them as a result of the lessons learned over the first 18 months of operation.  We believe that without this process and the tools we developed to support the overall delivery of the maintenance plan, the initial maintenance plans would still be in development, rather than having gone through the first major review and refinement.


Malcolm Hide, Senior Consultant, Strategic Maintenance Ltd
www.strategicmaintenance.co.uk


Malcolm is happy to respond to requests.  He can be contacted at:
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Tel: +44 (0) 1753 271924
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