iipe script

8/2/2019 IIPE Script

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Defining Recession

A recession is a contraction phase of the business cycle where significant declinein economic activity lasts more than a few months, which is normally visible inreal GDP, real income, employment, industrial production, and wholesale-retail

sales.

Global Prospective

The current economic recession has hardly spared any country on earth. Richcountries like USA, UK, Germany, Australia, Japan, Canada- almost all the richcountries have got badly hurt from the recession. So, there is no reason to besurprised to know that Indian economy is also getting hurt from the globaleconomic recession.

Impact of Recession on Indian Economy

The following graph shows the changing trend over the Years in all the majorsectors which contributes the overall development of the Indian Economy

Low or No Appraisals Salary Cuts Layoffs


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Less Hiring's Minimal projects in hand Declining share in global market No Plans for Greenfield projects No diversification or expansion

Present Scenario

As per a survey of 480 Indian companies over December 2008 andJanuary 2009 conducted by hr consultancy firm Hewitt - despite theeconomic slowdown, a majority of Indian companies are still hiringemployees. Here are some interesting revelations of this survey

Average salary hike in India in 2009 will be 8.2% (the highest in the Asiapacific region however first time in six years that India is likely to seesingle-digit salary increases)

Projected salary hike is lower than the increase of 13.3% seen in 2008

The hike higher than china (8%) USA (3.2%) and Japan (2.3%) Sectors expected to see the highest raises are FMCG, durables andtelecom.

Healthcare is sector that is doing well globally and in India. In 2008,hospitals had awarded the lowest salary increases but have been placedamong the top five sectors for 2009.

Nowadays, plant maintenance has gained significant recognition as a veryimportant process, which can be transformed to a potential profit generator forthe corporation. The development of a suitable maintenance concept enables thedecision of specific maintenance strategies based on the existing situational

factors that affect the organisation. A clear maintenance concept permits thedesign of the maintenance system that will be responsible for efficient andeffective plant maintenance.

The definition of maintenance often states maintenance as an activity carried outfor any equipment to ensure its reliability to perform its functions. Maintenance tomost people is any activity carried out on an asset in order to ensure that theasset continues to perform its intended functions, or to repair any equipment thathas failed, or to keep the equipment running, or to restore to its favourableoperating condition. Over the years, many new strategies have beenimplemented as maintenance strategies which are intended to overcome theproblems which are related to equipment breakdown. Some of the commonmaintenance strategies are predictive, preventive and proactive.

Proper maintenance of plant equipment can significantly reduce the overalloperating cost, while boosting the productivity of the plant. Although manymanagement personnel often view plant maintenance as an expense, a more


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positive approach in looking at it is to view maintenance works as a profit center.The key to this approach lies in a new perspective of proactive maintenanceapproach.

There are a number of important reasons for having an

efficient, well

organized, cost

effective and innovativemaintenance team including: Ensure high plant availability Ensure equipment reliability Deliver effective maintenance Ensure value for money Provide best maintenance practices Guarantee statutory compliance

Effective maintenance requires an understanding of current maintenancepractices and capability, clear ideas about areas requiring development and a

realistic plan for putting this in place.

There are many other challenges facing Plant staff at this time around the issueof reliability and maintenance, including:

Plant Maintenance Optimization Optimizing ConditionBased Maintenance Cost Constraints of a Budget Environment improvement Energy management Shutdowns & Turnarounds

1.Overview of the elements of Reliability

At its very heart, plant reliability is a quest for profitability. Reliable plants aresafer. And improved safety translates into higher profitability by reducing theneed for potentially high risk maintenance activities, the likelihood of safetyrelated failures and injuries, and the production of offspecification products.o Cost pressures and reliabilityo A look at Reliability based strategieso Benchmarks and best practiceso Key reliability work processes that will transformyour planto Operations and Maintenance Partnership

2. A comprehensive look at various reliability/maintenance practicesReliability affects the bottom line. There are both basic and advancedtechnologies out there that can shape your maintenance program.


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o Preventative Maintenance / Essential careo Predictive Maintenance (Condition Monitoring Techniques)o Proactive Maintenanceo Operator Driven Reliability

3. PMO Plant Maintenance Optimization Maintenance Analysis of theFuture

Regardless of how a maintenance has been developed, there is a constant needto review and update the program based on failure history, changing operatingcircumstances and the advent of new predictive maintenance technologies. Thegeneric process used to perform such analysis is known as PM Optimization(PMO). PMO as a technique has been refined to reflect the RCM decision logicsince the formulation of RCM in 1978o Cost pressures and reliabilityo A look at Reliability based strategies

o Differences between PMO and RCM: when toapply RCM

4. how to set up an effective Preventative/ Predictive Maintenance Program(condition monitoring program)

A predictive maintenance approach strives to detect the onset of equipmentdegradation and to address the problems as they are identified. This allowscasual stressors to be eliminated or controlled, prior to any significantdeterioration in the physical state of the component or equipment. This leads toboth current and future functional capabilities.o Reliability Basics

o Failure Developingo How to accurately predict equipment breakdowno Equipment life cycle and how to deal with assetdeteriorationo Selecting the most effective Methodo Documentations strategies and pointers onsoftware (CMMS)

5.Root Cause Problem Elimination An effective root cause analysis process can improve production reliabilitysignificantly. But, few organizations have a functioning root cause analysisprocess in place. This session will discuss common problems and solutionsin order to improve root cause problem eliminationo An overviewo Creative and critical thinkingo Root cause stepso Implementing root cause problem elimination inyour planto Case Study


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6.Implementing Best Practices in Maintenance Execution, Planning &SchedulingGiven the huge impact maintenance management can have on productionoutput, as well as the increasing tendency for maintenance departments to be

asked to do more with less it is essential that Maintenance Managers strivetoward the implementation of best practices in maintenance planning& executiono World Class Maintenance Planningo Prioritization and backlog managemento Scheduling and Coordination of worko Operations role in Maintenance planning andschedulingo Maintenance of assemblies: Integrating plant,store , workshop and supplierso Shutdown Management

7.Management aspects if implanting improved reliabilityFocusing on management aspects and taking measures to analyze current planswill allow for significant continued improvement of reliability strategies.o Implementation Ideaso Vision, Mission, Goalo Assessing current state vs best practiceo Implementation planso Launching improvemento Cultures and peopleo Trainingo Measuring success

What is maintenance

Most engineering, maintenance and operating decisions involve some aspect ofcost/risk trade-off. Such decisions range from evaluating a proposed designchange, determining the optimal maintenance or inspection interval, when toreplace an ageing asset, or which and how many spares to hold. The decisionsinvolve deliberate expenditure in order to achieve some hoped-for reliability,performance or other benefit. We may know the costs involved, but it is oftendifficult to quantify the potential impact of reduced risks, improved efficiency orsafety, or longer equipment life. Not only are the benefits difficult to quantify, butthe objectives often conflict with each other (we could clean the heat exchangermore often to achieve better performance, but the cleaning may damage thetubes and shorten their life). Finding the optimal strategy is difficult, therefore, butthe wrong maintenance interval will result in excessive costs, risks or losses.The European collaboration project MACRO, has developed a structured set of


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procedures to make sure that the right questions are asked, and sophisticatedwhat if? analysis tools to calculate the optimum combinations of equipmentreliability, performance, lifespan and cost. Specifically designed to be used wherehard data is poor, and engineering judgement or range-estimates provide themain raw material, these Cost/Risk Optimisation techniques are the

acknowledged best practice when justifying design, maintenance, conditionmonitoring, replacement or spares decisions. The following mini-guide outlinesthe underlying concepts of the approach, with illustrations of their application to avariety of decisions.

2 What is Optimisation?The first concept that needs clarifying is the meaning of optimum. The word isoften used very loosely in phrases such as the optimum maintenance strategyor the optimum performance. In areas where there are conflicting interests,such as pressures to reduce costs at the same time as the desire to increasereliability/performance/safety, an optimum represents some sort of compromise.

It is clearly impossible to achieve the component ideals - zero costs at the sametime as total (100%) reliability/safety etc. Reliability costs money, or, to put it theother way around, to spend less money we must choose what not to do orachieve. The resulting and inevitable trade-off can be drawn graphically (seefigure 1), but we must be careful with the labelling.

Cost/Risk Optimisation 2 Copyright The Woodhouse Partnership Ltd 1999

2.1.1 Optimum is defined as minimal Total Business ImpactMany such diagrams show the bottom of the Total Impact curve neatly alignedabove the cross-over point of the conflicting components, giving rise to confusionas to where and what is the true optimum. The Total Impact is the sum of thecosts and risks etc. When this sum is at a minimum, we have defined theoptimum combination of the components: the best value mixture of costsincurred, residual risks, performance losses etc. Crossover points do not signifythe optimum; they merely show where the components are equal (i.e. the risks or


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losses have the same value as the amounts being spent to control them). Theconcepts of balancing costs and risk or finding a breakeven point aredangerous, therefore, because they imply this equivalence point as a target,rather than focus on the best value-for-money combination.

3 Why this is difficult to findIf we knew exactly what the risks were, and what they are worth, we couldcalculate the optimum amount of risk to take, and costs to incur. Similarly, wecould make better (more optimal) decisions if we knew the value of improvedperformance, longer life, greater safety or quality. But the risks are difficult toquantify and many of the factors are intangible; i.e. it is extremely difficult toplace an economic value on them. The first barrier, therefore, to cost/riskoptimisation is the

_lack of relevant hard data.This is not the only constraint. Whether or not there is suitable information, the

complexity of the interactions is also a barrier. Reliability is a complex subject:the effects of one failure mode upon the probabilities of suffering other forms offailure involve nasty mathematics. These relationships have been known for along time (over 20 years) but, especially in the absence of useful data, they havebeen limited in usefulness to academic or special case studies. So, whatever thestate of information, the additional problem is

_how we would use the data if it were available.

3.1.1 What data? versus How would we use it?

These problems appear to be linked (if we do not have suitable data, how can weimprove the usage mechanisms?) but have, in fact, quite separate effects. Thetraditional reaction to poor data and subjective decision-making is to a) startcollecting more/better data and b) hope that it will somehow tell us what to do .This approach does not work. Without knowing how we would use it, how do weknow what data is worth collecting in the first place? Even if we were luckyenough to guess correctly on the data that is needed, how (and when) would we


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know that we had collected enough? What is enough, and is itphysically/economically possible to collect it?Without a clear idea of how it will be used, and the sensitivity to data inaccuracy,it is impossible to say what data is needed, and to what precision. The firstchallenge is therefore the understanding of what information is required for

specific decisions, and how it should be used. This issue can be addressed bydesigning and using templates and checklists; to make sure that the rightquestions are asked in the first place.Even if hard data is not available, there is a considerable volume of knowledge inthe operators, maintainers and engineers. This can be obtained in the form ofrange estimates or worst case and best case extremes of opinion. With arange of possible interpretation, we can see if the decision is affected whetherwe need to dig deeper, and at what cost. This is achievable if we have the meansrapidly to calculate the Total Impact for different assumptions. We must adopt aWhat if? approach to the problem: try the optimistic extreme and the pessimistic

does the data uncertainty have a significant effect?

The calculations require specialist software tools the maths are too hard formental arithmetic or even spreadsheets. Given their availability, however, evenrough or range estimates can be explored for their effect. Sensitivity testingreveals which pieces of information are important, and which have little or noeffect upon the relevant decision. Even with rough guesses, we can find theenvelope in which the optimum strategy must lie. In a surprising proportion ofcases, this reveals that the decision is robust over the full range of datainterpretation (i.e. the range estimates are enough to arrive at a firm andprovable conclusion).

3.1.2 Using range estimates to locate optimum strategy

3.2 Example: pump overhaulsIf the performance of a pump deteriorates as its impeller becomes fouled, andthe reduced capacity is having an effect upon production or process efficiency,then there must be an optimum time to clean the impeller. To determine the bestmaintenance strategy, we need to know how the performance falls with time or


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use, the economic effect of the losses (perhaps the pump has to operate forlonger to deliver the required volumes, or maybe the drive motor draws moreelectricity to compensate). We also need the cost of cleaning (including anyoperational downtime to do it). Some of this information may be known if there issome operational experience, but otherwise it must be range-estimated and

explored for sensitivity:3.2.1 Data estimates:_ By 6 months of operation, pump performance is 5-10% down, and this islikely to accelerate if left further.

_ 10% lost performance is worth 10-30/day in extra energy/productionimpact or extended operating costs.

_ The costs of cleaning or overhaul are 6-800 in labour and materials, and 2-3 hours downtime to swap over to an alternative pump.

3.2.2 Calculating the impactThe first step involves fitting a performance curve to the examples given:

Then, a series of calculations can show the Total Impact of performance losses,

cleaning costs and equipment downtime for various maintenance intervals:

3.2.3 Sensitivity testingThe worst case and best case interpretations combine the extremes of all therange-estimates. They show that the cleaning interval must be between 11 and16 months. No interpretation of the problem could justify more, or less, frequentcleaning:


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DEVELOPING A MAINTENANCE STRATEGYPresented byPeter StockNew Dimension Solutions, Inc.

1 INTRODUCTIONThe world of physical asset management has changed dramatically over the lasttwenty to thirty years. These changes have come in light of businesses becomingmore and more dependant on machines, leading to an explosive growth in thenumbers of machines that need to be maintained throughout the world. Thedesigns of the physical assets have also changed from robust over-designedmachines that required minimal maintenance in 1940s to more complex andhighly automated, mechanized processes of today. Along with this growth ourexpectations as users and owners of these machines have also changed.Previously our focus was primarily on minimizing downtime and reducingmaintenance costs, whereas today not only do we focus just higher availability

but we also focus on higher reliability, as well as better product quality. Ourattention has also been focused on those failures that have serious safety andenvironmental consequences. No longer is it acceptable to allow equipment tofail where it is not going to conform to societys safety and environmentalexpectations, otherwise we will get shutdown. Finally, as our dependence onphysical assets grows so does the cost of owning and operating them continue toescalate.


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This is going to have an impact on our return on investment if it not managedproperly, hence we need to ensure that the machines operate efficiently and aremaintained cost effectively throughout their technological useful lives.

Another area of change is challenging our fundamental belief about therelationship between operating age and failure. In the past we were led to believe

that most failures were age related and as a result developed maintenancepolicies accordingly. This was generally true for those failures where theequipment came into direct contact with the product, i.e. a pump impeller.However, through new research, it is apparent that there is less and lessconnection between the operating age of most physical assets and how likelythey are to fail. We need to point out though that the equipment itself hasbecome more complex and has led to substantial changes in the failure behavior.Consequently, there is not just one pattern of failure but six and these need to berecognized when selecting suitable failure management policies.Finally, another area where there has been rapid growth is in new maintenancetechniques and concepts.

Looking at condition monitoring on its own there are between 300 and 400techniques of which about a third can be applied effectively to modern dayphysical assets. Engineers are also are a lot more focused about reliability andmaintainability when it comes to designing equipment. Another trend withorganizations today is the shift towards teamwork and more involvement of thework force in decision making.In light of the above, the challenge facing organizations today is to find out whichof these techniques will be worthwhile and cost effective.

2 DEVELOPING A MAINTENANCE STRATEGYGiven all the day-to-day pressures facing maintenance managers, the first

question is where does one start? The answer lies with the fact that everyphysical asset is put into service because someone wants its to do something. Inother words, it is expected to fulfil a specific function or functions. Thereforemaintenance is all about preserving the functions of physical assets to ensurethey continue to do what their users want them to do. It is only when thesefunctions have been defined that it becomes clear exactly what maintenance istrying to achieve and precisely what is meant by failed. This makes it possibleto move on the next step, which is to identify the reasonably likely causes andeffects of each failed state. Once failure causes (or failure modes) and effectshave been identified, we are then in a position to assess how much each failurematters. This in turn enables us to determine which of the full array of failuremanagement options should be used to manage each failure mode.

At this point, we have decided what must be done to preserve the functions ofour assets. This process is often called work identification.When the tasks that need to be done the maintenance requirements of eachasset have been clearly identified, the next step is to decide sensibly whatresources are needed to do each task by asking the following questions: Who is to do each task: skilled maintainer? The operator? A contractor? Thetraining department


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(if training is required)? Engineers (if the asset must be redesigned)? What spares and tools are needed to do each task, including tools such ascondition monitoring equipment.It is only when the resource requirements are clearly understood that we candecide exactly what systems are needed to manage the resources in such a way

that the task gets done, and hence that the functions of the assets are preserved.This process can be likened to building a house. The foundations are themaintenance requirements of each asset, the walls are the resources required tofulfil the maintenance requirements (people/skills and spares/materials/tools) andthe roof represents the systems needed to manage the resources (CMMS).To summarize, a maintenance strategy is developed and executed in threestages: To formulate a maintenance strategy for each asset (work identification) Acquire the resources needed to execute the strategy effectively (people,spares, tools) Execute the strategy (acquire, deploy and operate the systems needed to

manage the resourcesefficiently).

In other words build your foundations first, then your walls, then your roof.In the absence of any comparable asset management strategy formulationprocesses, the only really effective way to do all this at once for modern, complexindustrial processes is to arrange for groups of appropriately trained operators,maintainers, supervisors and specialists who live with the asset on a day-todaybasis to apply Reliability-Centered Maintenance under the guidance of a suitablyqualified facilitator.

3 RELIABILITY-CENTERED MAINTENANCEReliability-centered Maintenance is defined as a process used to determine whatmust be done to ensure that any physical asset continues to do whatever itsusers want it to do in its present operating context. The RCM process entailsasking seven questions about the asset or system under review, as follows: What are the functions and associated performance standards of the asset in itspresent operating context? In what ways does it fail to fulfill its functions? What causes each functional failure? What happens when each failure occurs? In what way does each failure matter? What can be done to predict or prevent each failure? What should be done if a suitable proactive task cannot be found?

3.1 Functions and Performance StandardsPart two of this paper mentioned that it is only when the functions of an assethave been defined that it becomes clear exactly what maintenance is trying toachieve, and also precisely what is meant by failed.


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For this reason the first step in the RCM process is to define the functions ofeach asset in its operating context, together with the associated desiredstandards of performance. The users of the assets are usually in the bestposition to know exactly what contribution each asset makes to the physical andfinancial wellbeing of the organization as a whole, so it is essential that they are

involved in the RCM process from the outset.

3.2 Functional Failures

The objectives of maintenance are defined by the functions and associatedperformance expectations of the asset. But how does maintenance achievethese objectives? The only occurrence that is likely to stop any asset performingto a standard required by its users is somekind of failure. However, before we can apply a suitable blend of failuremanagement tools, we need to identify what failures can occur. The RCMprocess does this at two levels:

By identifying what circumstances amount to a failed state Then by asking what events can cause the asset to get into a failed state.In the world of RCM, failed states are known as functional failures because theyoccur when an asset is unable to fulfill a function to a standard of performancewhich is acceptable to the user. In addition to the total inability to function, thisdefinition encompasses partial failures, where the asset still functions but at anunacceptable level of performance (including situations where the asset cannotsustain acceptable levels of quality or accuracy).

3.3 Failure Modes

Once each functional failure has been identified, the next step is to try to identifyall the events, which are reasonably likely to cause each failed state. Theseevents are known as failure modes. Reasonably likely failure modes includethose that have occurred on the same or similar equipment operating in the samecontext, failures, which are currently being prevented by existing maintenanceregimes, and failures that have not happened yet but that are considered to bereal possibilities in the context in question. Most traditional lists of failure modesincorporate failures by deterioration or normal wear and tear.

However, the list should include failures caused by human errors (by operators ormaintainers) and design flaws so that all reasonably likely causes of equipmentfailure can be identified and dealt with appropriately. It is also important toidentify the cause of each failure in enough detail to make it possible to identify asuitable failure management policy.

3.4 Failure EffectsThe fourth step in the RCM process entails listing failure effects, which describewhat physically happens when each failure mode occurs. These descriptions


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should include all the information needed to support the evaluation of theconsequences of failure, such as: What evidence (if any) that the failure has occurred? In what ways (if any) it poses a threat to safety or the environment? In what ways (if any) it affects production or operations?

What physical damage (if any) is caused by the failure? What must be done to repair the failure?

3.5 Failure ConsequencesA detailed analysis of an average industrial undertaking is likely to yield betweenthree and ten thousand possible failure modes. As mentioned in the introductionof this paper, each of these failures affects the organization in some way, but ineach case, the consequences are different. The RCM process classifies theseconsequences into four groups, as follows: Hidden failure consequences: Hidden failures have no direct impact, but theyexpose the organization to multiple failures with serious, often catastrophic,

consequences. Safety and environmental consequences:A failure has safety consequencesif it could hurt or kill someone. It has environmental consequences if it could leadto a breach of any corporate, regional, national or international environmentalstandard. Operational consequences: A failure has operational consequences if itaffects production (output, product quality, customer service or operating costs inaddition to direct cost of repair) Non-operational consequences: Evident failures that fall into this categoryaffect neither safety or production, so they involve only the direct cost of repair.The RCM process uses these categories as the basis of a strategic framework

for maintenance decisionmaking.By forcing a structured review of the consequences of each failure mode in termsof these categories, it focuses attention on the maintenance activities which havethe most effect on the performance of the organization, and diverts energy awayfrom those that have little or no effect (or which may even be activelycounterproductive). It also encourages users to think more broadly aboutdifferent ways of managing failure, rather than to concentrate only on failureprevention.

3.6 Failure Management Policy SelectionFailure management policies are divided into two categories: Proactive tasks: these tasks undertaken before a failure occurs, in order toprevent the item from getting into a failed state. As discussed below, RCM furthersubdivides these tasks into scheduled restoration, scheduled discard and on-condition maintenance Default actions: these deal with the failed state, and are chosen when it is notpossible to identify an effective proactive task. Default actions include failure-finding, redesign and run-to-failure. Scheduled restoration and scheduled discardtasks


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Scheduled restoration entails remanufacturing a component or overhauling anassembly at or before a specified age limit, regardless of its condition at the time.Similarly, scheduled discard entails discarding an item at or before a specified lifelimit, regardless of its condition at the time. Collectively, these two types of tasksare now generally known as preventive maintenance.

On-condition tasksOn-condition techniques rely on the fact that most failures give some warning ofthe fact that they are about to occur. These warnings are known as potentialfailures, and are defined as identifiable physical conditions, which indicate that afunctional failure is about to occur or is in the process of occurring.On-condition tasks are used to detect potential failures so that action can betaken to reduce or eliminate the consequences that could occur if they were todegenerate into functional failures. This category of tasks includes all forms of

predictive maintenance, condition-based maintenance and condition monitoring.Failure-finding

Failure-finding entails checking hidden functions to find out if they have failed(asopposed to the on condition tasks described above, which entail checking ifsomething is failing).

RedesignRedesign entails making any one-time change to the built-in capability of asystem. This includes changes to hardware, one-time changes to proceduresand if necessary, training.

No scheduled maintenanceThis default entails making no effort to anticipate or prevent failure modes to

which it is applied, and so those failures are simply allowed to occur and thenrepaired. This default is also called run-to-failure.

3.7 The RCM Task Selection ProcessThe RCM process applies a highly structured consequence evaluation and policyselection algorithm to each failure mode. It incorporates precise and easilyunderstood criteria for deciding which (if any) of the proactive tasks is technicallyfeasible in any context, and if so for deciding how often and by whom the tasksshould be done. It also incorporates criteria for deciding whether any task isworth doing, a decision, which is governed by how well, the candidate task dealswith the consequences of the failure. Finally, if a proactive task cannot be foundthat is both technically feasible and worth doing, the algorithm leads users to themost suitable default action for dealing with the failure.This approach means that proactive tasks are only specified for failures thatreally need them, which in turn leads to substantial reductions in routineworkloads. In fact, if RCM is correctly applied to existing maintenance programs,it reduces the amount of routine work (in other words, tasks to be undertaken oncyclic basis) issued in each period, usually by 40% to 70%. On the other hand, ifRCM is used to develop a new maintenance program, the resulting scheduled


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workload is much lower than if the program is developed by traditional methods.Less routine work also means that the remaining tasks are more likely to be doneproperly. This together with the elimination of counterproductive tasks leads tomore effective maintenance.

CASE STUDY 1A brewery neglected to perform routine maintenance on its compressed air system for years. As aresult, two of its centrifugal compressors, whose impellers had been rubbing against theirshrouds, were unable to deliver the volume of air they were rated for and one of those units hadburned up several motors during its lifetime. In addition, plant personnel did not inspect thesystems condensate traps regularly. These traps were of a type that clogged easily, whichprevented the removal of moisture and affected product quality. Also, the condensate drains wereset to operate under the highest humidity conditions, so they would actuate frequently, whichincreased the systems air demand. As a result, energy use was excessively high, equipmentrepair and replacement costs were incurred unnecessarily, and product quality suffered. All of thiscould have been avoided through regular maintenance.Like all electro-mechanical equipment, industrial compressed air systems require periodic

maintenance to operate at peak efficiency and minimize unscheduled downtime. Inadequatemaintenance can increase energy consumption via lower compression efficiency, air leakage, orpressure variability. It also can lead to high operating temperatures, poor moisture control,excessive contamination, and unsafe working environments. Most issues are minor and can becorrected with simple adjustments, cleaning, part replacement, or elimination of adverseconditions. Compressed air system maintenance is similar to that performed on cars; filters andfluids are replaced, cooling water is inspected, belts are adjusted, and leaks are identified andrepaired.A good example of excess costs from inadequate maintenance can be seen with pipeline filterelements. Dirty filters increase pressure drop, which decreases the efficiency of a compressor. Forexample, a compressed air system that is served by a 100-horsepower (hp) compressor operatingcontinuously at a cost of $0.08/kilowatt-hour (kWh) has annual energy costs of $63,232. With adirty coalescing filter (not changed at regular intervals), the pressure drop across the filter couldincrease to as much as 6 pounds per square inch (psi), vs. 2 psi when clean, resulting in a need forincreased system pressure. The pressure drop of 4 psi above the normal drop of 2 psi accounts for2% of the systems annual compressed air energy costs, or $1,265 per year. A pressuredifferential gauge is recommended to monitor the condition of compressor inlet filters. A rule ofthumb is that a pressure drop of 2 psi will reduce the capacity by 1%.

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