Читать книгу Maintenance and Reliability Best Practices - Ramesh Gulati - Страница 14
ОглавлениеWork Management: Planning andScheduling
A goal without a plan is just a wish.
—ANTOINE DE SAINT-EXUPÉRY
After reading the chapter, you will be able to understand:
• The basic workflow process
• The role of planners, schedulers, and others in managing work
• Work classification and prioritization
• The importance of backlog management
• Why planning is necessary
• The planning process
• Why scheduling is necessary
• The scheduling process
• Turnaround management
Maintenance tasks should be performed efficiently to ensure that factory/plant capacity is sustained cost-effectively. In the previous chapters,we discussed developing the proper maintenance tasks to keep our assets working. In order to reduce overall operations and maintenance costs,these tasks must be executed efficiently and effectively. Basically, this is achieved by eliminating or minimizing avoidable delays and wait time.
Imagine yourself repairing a leaky faucet or dishwasher at home. Your spouse has asked you repeatedly to fix it. Finally, you find the time to take on this assignment. Can you recall the number of times you went back and forth to the garage, to the toolbox, or to the hardware store to acquire the correct-sized tool, washer, or seal? It probably took about 4 or more hours to finish this task.
Imagine again, a couple of months later, a similar type of problem occurred. This time you are not available, and your spouse calls a plumber. The plumber comes in and assesses the problem, goes back to the truck, gets the right tools and parts, corrects the problem, and leaves in 40–45 minutes. Does this sound familiar? Maybe if you had the right tools and right parts and better instructions, your task would have taken less than 2 hours instead of 4 hours or more? The point here is that proper work planning with the right tools, parts, and instructions can save time and avoid wasteful activities.
Figure 4.1 shows a job without planning (sometimes called “on-the-run” planning) and one with proper planning.
FIGURE 4.1 Impact of Good Planning
Figure 4.1a shows a disorganized work activity with frequent work interruptions and restarts, evidence of inadequate planning. The frequent work interruptions encountered could be due to a lack of availability of the right parts or tools or to improper work instructions. A well-planned job with up-front planning and no interruptions is shown in Figure 4.1b. Planned and scheduled jobs take substantially less time than unplanned jobs.
For many years, industry experts have pointed to the low productivity levels in the maintenance departments of many companies around the world. Several studies and survey results reported at major maintenance and reliability conferences such as IMC (International Maintenance Conference) and SMRP have indicated that maintenance craft productivity varies anywhere from 30 to 60%, or 3 to 5 hours of average productive time for an 8-hour shift. Some call this productive time wrench time, during which maintenance craft personnel actually spend their efforts repairing the assets, as opposed to walking to the store to get the right tools, receiving unclear instructions, waiting for other craftworkers to arrive or for release of the asset from operations,and other wasteful activities.
In general, every hour invested in work planning saves 1–3 hours in work execution. Abraham Lincoln once said, “If I had eight hours to cut a tree, I’d spend six hours in sharpening the axe.” What he meant was that he would take more time to prepare and plan for the task; then,less time would be needed to complete the actual task safely.
There are, of course, some managers who say they would be thrilled to hear that their maintenance craftworkers are sitting idle most of the time waiting for breakdowns to happen. The “Maytag repairman” image of a maintenance department should not be compared with a fire department, where fewer fires to battle are better. A maintenance department can be far more productive in so many ways, becoming proactive instead of responding to emergencies like fire departments do. Maintenance departments should perform preventive and condition-based maintenance tasks, participate in process improvement projects, and work on capital improvement initiatives. Maintenance workers can upgrade their skills, train others, and educate operators to run the assets properly to minimize errors. In essence, good planning and scheduling will avoid delays and minimize wait time, other wasteful activities, and nonproductive work.
Planning and scheduling (P&S) is a disciplined approach both for utilizing maintenance resources effectively and for executing maintenance tasks such as PM/CBM or corrective maintenance tasks efficiently. This is accomplished through:
• Defining and clarifying the right work
• Prioritizing work
• Developing the work sequence and steps to complete the task
• Identifying necessary tools, materials, and skill sets
• Assuring on-schedule availability of materials and assets
• Scheduling the work to be done with agreement from production on the scheduled time
• Ensuring details of completed work are documented in CMMS
A work plan is the key deliverable of the planning process. This product is where the largest gains in productivity can be made. In some organizations, a single person provides both planning and scheduling functions. In larger organizations, these functions are often split, allowing additional resources for each role.
To move from reactive to proactive maintenance, at least 80% of the work should be planned on a weekly basis. Compliance with this work schedule should be at least 90%.
In this chapter, we will discuss the “what and how” of planning and scheduling maintenance tasks so that they can be executed effectively as well as some associated topics (workflow and roles, work categorization and priority, turnarounds, etc.).
Asset Criticality (AC)
Asset criticality is a ranking of factory/plant assets according to potential operational impact. Criticality supports prioritization of assets that are important to monitor and should be maintained at an agreed-upon level of maintenance based on the consequences of failure.
Bill of Material (BOM)
A list of materials needed to complete a particular assembly or fabrication job. The BOM can also be a list of items necessary to support the operations and maintenance of an asset or component.
Computerized Maintenance Management System/ Enterprise Asset Management (CMMS/EAM)
A software system that keeps records and tracks all maintenances activities, including maintenance work orders, PM schedules, PM masters, material parts, work plans, and asset history. Usually, it is integrated with support systems such as inventory control, purchasing, accounting, manufacturing, and controls maintenance and warehouse activities. Newer integrated systems are known as EAMs.
Coordinators
Individuals who oversee the execution of all work within a facility, including maintenance. They are accountable to the asset or process owner for ensuring that the asset or process is available to perform its function in a safe and efficient manner and to help prioritize the work according to the operational needs.
Planned Work
Work that has gone through a formal planning process to identify labor, materials, tools, work sequence, safety requirements, etc., to perform that work effectively. This information is assembled into a job plan or work package and is communicated to craftworkers prior to the start of the work.
Planner
A dedicated role with the single function of planning work tasks and activities.
Planning
The process of determining the resources and methods needed, including safety precautions, tools, skills, and time necessary to perform maintenance work efficiently and effectively. Planning is different from scheduling. In short, planning defines what and how, whereas scheduling defines who and when.
Preventive Maintenance (PM) Schedule Compliance
The number of PM work orders (or labor hours) completed, including PdM/CBM, divided by the total number of PM work orders (or labor hours) scheduled during a specific time period.
Schedule Compliance
A measure of adherence to the schedule. It is calculated by the number of scheduled jobs (or scheduled labor hours) actually accomplished during the period covered by an approved daily/ weekly schedule, expressed as a percentage.
Scheduled Work
The work that has been identified in advance and is logged in a schedule so that it may be accomplished in a timely manner based upon its criticality.
Schedulers
Individuals who establish daily, weekly, monthly, and/or rolling yearly maintenance work schedules of executable work in their facility. The schedule includes who will perform and when the work will be performed. The schedule is developed in concert with the maintenance craft supervisor and operations.
Scheduling
The process of determining which jobs get worked on, when, and by whom based on the priority, the resources, and asset availability. The scheduling process should take place before the job is executed. In short, scheduling defines when and who executes the work tasks.
Turnaround
The planned shutdown of equipment, production line, or process unit to clean, change catalyst, and make repairs, etc., after a normal run. Duration is usually in days or weeks; it is the elapsed time between shutting down the unit and putting the unit onstream/online again
Work Order (WO)
Paper or electronic document specifying the work needed on an asset. A work order is a unique control document that comprehensively describes the job to be done, including a formal requisition for maintenance, authorization, and charge codes.
Work Order Parts Kitting
The collection and staging of parts required for each individual work order. This step is usually accomplished in a plant’s storeroom within the maintenance shop. Each kit is identified by a number or label so that it can be staged or delivered to the right maintenance crew.
Work Plan
An information packet, sometimes called a job or work package, provided to the worker; it contains job-specific requirements such as task descriptions sequenced in steps; job-specific instructions; and safety permits/procedures, drawings, materials, and tools required to perform the job effectively.
Figure 4.2 illustrates a simple maintenance workflow process. There are three types of work:
• PM—work that includes CBM/PdM
• CM—new work resulting from PM/CBM activities
• CM—breakdown/emergency work (reactive work; usually no planning is done)
Preventive maintenance (PM) work should have already been planned, therefore going directly to scheduling. Corrective maintenance (CM)—breakdown/emergency work—can be executed while bypassing the planning process, and sometimes even the scheduling process based on its urgency, depending on whether there is enough time to plan this type of work. The new CM work identified from PM tasks, including CBM activities, should be planned and scheduled before it is executed.
FIGURE 4.2 Simple Workflow Process
Figure 4.3 illustrates the workflow and key players in the maintenance workflow process. The following are the key players in this process:
• Coordinator—asset/resource
• Planner
• Scheduler
• Configuration specialist/systems engineer
• Craft supervisor
• Work performer
FIGURE 4.3 Workflow with Role Process
In addition, other players,such as maintenance/systems engineers and MRO/material personnel, play supportive roles in the workflow process.
Initially, the required or requested work task gets routed to an asset/resource coordinator. This person represents the asset owner and may work for maintenance or operations. The coordinator helps to prioritize the work, ensuring required resources are in the budget, and to schedule asset outages if necessary. The coordinator forwards the work task to a planner/scheduler or directly to the craft supervisor or maintenance crew, depending on the task’s priority and planning needs. For example, PM-type work, which should already be planned, could go directly to the maintenance scheduler. The coordinator may also work with the maintenance engineer or configuration management personnel for any technical help or if a configuration change request is needed.
As the work order gets routed from one stage to another, a WO status is assigned based on what’s being done to that WO. Figure 4.4 is a suggested list of work order status codes. In addition, work type,as suggested in Figure 4.5, is also assigned by the coordinator or the planner/scheduler. It is a good practice to code the work orders to help analyze the data for improvements. More will be said about work order classification in the next section.
Maintenance planners plan the job and create a work plan or job package that consists of what work needs to be done; how it will be done; what materials, tools, or special equipment is needed; estimated time; and skills required. The planners need to identify long delivery items and work with stores and purchasing personnel to ensure timely delivery. Planners may need to work with maintenance/systems engineers and craft supervisors for technical support to ensure that the work plan is feasible with sufficient technical details.
Maintenance schedulers—in working with the craft supervisor,coordinator, and other support staff—develop weekly, monthly, and rolling annual long-range plans to execute maintenance work. They are more concerned with when the job should be executed in order to optimize the available resources with the work at hand.
FIGURE 4.4 Work Order Status Codes
FIGURE 4.5 Work-Type Category Codes
Craft supervisors take the weekly schedule and assign who will do the job on a daily basis. In addition, they review work plans from an execution point of view and recommend necessary changes in work plans to the planner and the scheduler. It is also their responsibility to ensure that the high work quality is maintained and details of work completed are documented properly in the system.
Figure 4.6 illustrates a workflow process with its key elements;it includes an example of a productivity report based on delay hours reported and a work-estimating subprocess within the planning process utilizing the maintenance standards database.
Work Classification and Prioritization
Maintenance Work Task Classifications
Maintenance work tasks can be classified into the following categories as discussed in Chapter 3:
Preventive Maintenance (PM)
• Time (calendar)-based maintenance (TBM), age related
• Run-based maintenance (RBM), usage related
• Condition-based maintenance (CBM, aka predictive), health related
• Operator-based maintenance (OBM, aka autonomous maintenance, a pillar of TPM), operations related
Corrective Maintenance (CM)
• CM—routine work resulting from PMs, planned and scheduled
• CM—major repairs/projects, planned and scheduled
• CM—reactive, unplanned/unscheduled (aka breakdown/ emergency)
In this chapter, we explore each of these further.
FIGURE 4.6 Workflow Process
Preventive Maintenance
Preventive maintenance refers to a series of actions that are performed on an asset on schedule. That schedule may be either calendar time–based or machine operations–dependent (i.e., runtime or the number of machine cycles). These actions are designed to detect, preclude, or mitigate the degradation of a system and its components. PM includes cleaning, adjusting, and lubricating, as well as minor component replacement, to extend the life of assets and facilities. The goal of a preventive maintenance approach is to minimize system and component degradation and thus sustain or extend the useful life of the asset. Assets within your facilities should not be allowed to run to the breaking point unless a run-to-failure strategy has been selected for that specific asset. The PM work can be further classified into these categories:
PM: Time (Calendar)-Based
Time (calendar)-based maintenance is typically performed on selected calendar time. Maintenance personnel schedules periodic visits to an asset based on fixed time intervals, for example, every 3 or 6 months. Although better than no PM at all, calendar-based PMs are not the optimal way to run PM programs. They may result in too much time being spent on an asset. Numerous visits to assets with “no data—no abnormalities found” can be regarded as wasted maintenance dollars. If this happens, the PM time frame should be reevaluated and adjusted. Nevertheless, time-based PMs are a good approach for assets having a fixed operating schedule such as a 24/7 or 80 hours/week operation.
PM: Run-Based
Run-based maintenance is typically the next step up from calendar-based maintenance. It involves performing PMs based on asset cycles or runtime. Intuitively, this approach makes sense. An asset does not have to have PM if it has not been used. Generally speaking, for some failure modes, it is the actual operation of the asset that wears it down, so it makes sense to check the asset after it has been working for a specified amount of time to cause some wear. It may be necessary to either adjust or replace the component.
Condition-Based Maintenance
Condition-based maintenance, also known as predictive maintenance (PdM), attempts to evaluate the condition of an asset by performing periodic or continuous asset monitoring. This approach is the next level up from runtime-based maintenance. The ultimate goal of CBM is to perform maintenance at a scheduled time when the maintenance activity is most cost-effective, yet before the asset fails in service. The “predictive”component stems from the goal of predicting the future trend of the asset’s condition. This approach uses principles of statistical process control and trend analysis to determine when—at what point in the future—maintenance activities will be appropriate and cost-effective.
Operator-Based Maintenance
Operator-based maintenance uses the fact that operators are often the first line of defense against unplanned asset downtime. OBM assumes that the operators who are in daily contact with the assets can use their knowledge and skills to predict and prevent breakdowns and other losses. OBM is synonymous with autonomous maintenance, one of the basic pillars of total productive maintenance. TPM is a Japanese maintenance philosophy that involves operators performing some basic maintenance activities. The operators learn the maintenance skills they need through a training program and use those skills on a daily basis during operations.
Corrective Maintenance
CM, sometimes called repair, is performed to correct the deficiencies found during PM and CBM assessment; it restores the asset to good working condition after it has failed or stopped working. CM is also an action initiated as a result of an asset’s observed or measured condition before or after the functional failure. The CM work can be further classified into three categories.
CM—Scheduled
Scheduled CM is a repair activity performed to mitigate potential asset failure or correct deficiencies found during PM and CBM tasks. It brings an asset to its designed capacity or to an acceptable level in a planned way. This work should be planned and scheduled.
CM—Major Repairs/Projects (Planned and Scheduled)
In many organizations, all major repairs or improvement work valued over a certain threshold—e.g., overhauls and turnaround projects—are treated as capital projects for tax purposes. If these projects are to bring the asset back to the designed capacity, not to add additional capabilities, they should be treated as corrective maintenance. In that case, these projects should always be planned and scheduled.
CM—Reactive (Unscheduled), Aka Breakdowns/Emergency
Reactive (unscheduled) corrective maintenance basically repairs assets after they fail. This work is also known as breakdown or failure repair work. Most of the time, completing this work interferes with the regular weekly schedule. Unscheduled work costs much more than planned and scheduled work.
Some maintenance professionals classify maintenance in the following categories: PM, CBM/PdM, proactive work resulting from PM and CBM/PdM, and reactive CM (breakdowns/emergency). As we discussed in the previous chapter, it really does not matter how we classify them as long as maintenance management systems can provide us data in the desired format to help us to make the right decisions. Our objective is to reduce reactive breakdowns and then adjust or increase PM and CBM work accordingly.
Sometimes we try to mix maintenance work types with how we respond to get the work done. For example, is emergency work really unplanned/unscheduled CM, or is it reactive work that needs to be done now? In some organizations, the breakdown work is called urgent maintenance but could be done within 48 hours. Some regular work, also sometimes called routine work, may need to be completed in 5 or 7 days. These examples are not the work type, but just how we respond to get it done.
Sometimes a decision is made to take no actions or make no efforts to maintain the asset as the original equipment manufacturer (OEM)originally intended. Therefore, no PM program is established for that particular asset. This maintenance strategy, called run-to-failure (RTF),should be applied only after a risk to the business has been analyzed and its cost-effectiveness determined. In reality, this work should not be considered a failure or reactive work because we made the decision in advance not to perform any PM or CBM based on economic justification.
All maintenance work needs to be documented and classified in a CMMS/EAM system. Then, to optimize resources, all jobs should be prioritized per the organization’s priority system for execution. Every organization should, if it doesn’t have one, establish a jobs/work order priority system. Asset criticality is one of the factors in calculating job priority. Asset criticality is a ranking of factory/plant assets according to potential operational impact. Criticality supports prioritization of assets, which are important to monitor and should be maintained at a determined level of maintenance. Criticality helps to optimize resource utilization.
Asset Criticality Analysis
Asset criticality analysis (ACA) is performed to evaluate how an asset failure can impact organizational performance. ACA provides the basis for determining the level of rigor for each asset with respect to the maintenance strategy development processes.
ACA is based on a risk analysis including established criteria such as safety, environmental, and quality risks; operational impact (supply chain, demand, profitability, etc.); maintenance and reliability impact (consequence and severity of failure); single point of failure; asset replacement cost; and spares lead time. The purpose is to help us perform the appropriate level of maintenance to minimize risk and to optimize resource utilization, performance, and reliability.
The asset criticality number (ACN) is calculated by the following equation:
ACN = consequence of failure ×
(sum of severity of failure factors)
The asset’s criticality can be established, ranked, and named based on failure impact and its consequences, as shown below for each asset in the plant:
• Catastrophic or very high (VH), 4 out of 4, 8–9 out of 9
• Severe, high (H), 3 out of 4, 6–7 out of 9
• Moderate, medium (M), 2 out of 4, 3–5 out of 9
• Minor, low (L), 1 out of 4, 1–2 out of 9
This is just one example of establishing and ranking asset criticality. Some professionals rank just in 3 (A, B, C) or 1–9 or as shown above. Establishing criticality in a smaller group of 3 or 4 is a little easier,but higher grouping in 5, 9, or other amounts enhances the granularity. Grouping in 3, 4, or 5 is very common.
Figure 4.7 provides an example of establishing a criticality number or ranking based on established criteria. In this example, five criteria elements on the left are evaluated and assessed based on the consequences of failure on the right. The criteria elements could each have the same weighting factor or different ones. An aggregate of all factors divided by the number of factors produces the asset’s criticality number.
Suppose all five factors have the same weighting and the assessment criteria indicate the following:
| 1. Safety | Severe | 3 |
| 2. Environment | Minor | 1 |
| 3. Production/operation | Moderate | 2 |
| 4. Maintenance | Severe | 3 |
| 4. Other considerations | Minor | 1 |
| Total = 10 | ||
| Criticality = 10/5 = 2 (moderate) |
Therefore, in this example, the asset has a criticality of 2, or moderate.
Generally, the criticality ranking number is stored in a separate field against each asset in a CMMS/EAM system.
FIGURE 4.7 Asset Criticality and Consequences
Some benefits of having an asset criticality rating are:
• It supports the overall priority structure and importance of performing maintenance tasks.
• It determines the type of risk mitigation strategy to be applied to the assets.
• It determines and ensures that the optimum level of spare parts is stocked for highly critical assets.
• It provides input into the capital program so that highly critical assets are given a higher priority for upgrade or replacement.
• It guides reliability/maintenance engineers and professionals so that they focus their reliability improvement efforts on the most “critical” assets.
A mitigation strategy should be established for various types of criticality to ensure the appropriate level and quality of maintenance performed on assets. Figure 4.8 shows an example of a mitigation strategy for a different level of criticality.
FIGURE 4.8 Example of Asset Criticality and Mitigation Plan
There is definitely nothing more wasteful than spending lots of time assessing the criticality of every asset in the organization, loading this information into the CMMS/EAM system, and then doing nothing with it.
Job Priority
Priority codes allow ranking of work orders to get work accomplished in order of importance. Too many organizations neglect the benefits of a clearly defined prioritization system. The organizational discipline that comes through communication, education, and management support is key to the correct usage of priority codes.
Many organizations have more than one prioritization system;however,most of them have been found to be ineffective. The drawbacks of not clearly defining the priorities include:
• Wasted maintenance labor hours on tasks of low relative importance
• Critical tasks being lost in the maintenance backlog
• Dissatisfied operations customers
• Lack of faith in the effectiveness of the maintenance delivery functions
A disciplined method of prioritization will eliminate tasks being done on a whim and instead allow work to proceed according to its true impact on the overall operations of the plant. It will also allow the maintenance delivery function to be executed in a far more effective manner.
Priority System Guidelines
The system needs to cater to the following requirements equally and provide a universal method of coding all works orders:
• Plant-wide asset priorities, allowing for better plant-wide utilization of resources
• Operations requirements
• Improvement projects
Accurate prioritization covers two distinct decision-making processes. These are:
• Asset criticality
• Impact of task or work to be done on the overall operations
The original priority of the work orders needs to be set by the originator of the work order and should be validated by the coordinator. The work originator is the most qualified to make an initial assessment of asset criticality and impact of the work. Lists of major assets and their criticality will help in decision making for final priority ranking.
All the plant assets should be assessed to establish a criticality number by a team of plant professionals who are familiar with the assets and the impact of their failure. Most of the CMMS/EAM systems have a field for entering each asset’s criticality number. Lower criticality items or areas will then be easier to recognize. The following criteria can be used to assign asset criticality and work impact (if not corrected), which can then be used to make an objective assessment of overall job priority:
Asset Criticality
| Criticality # | Description |
| 5 | Critical safety-related items and protective devices |
| 4 | Critical to continued production of primary product |
| 3 | Ancillary (support) system to main production process |
| 2 | Standby unit in a critical system |
| 1 | Other ancillary assets |
Work Impact, if Not Corrected
| Work Impact # | Description |
| 5 | Poses an immediate threat to safety of people and/or plant |
| 4 | Limits operations’ ability to meet its primary goals |
| 3 | Creates hazardous situations for people or machinery, although not an immediate threat |
| 2 | Will affect operations after some time, not immediately |
| 1 | Improves the efficiency of the operation process |
Work Priority = Asset Criticality × Work Impact
WO #1: Asset criticality of 5 and work impact of 4 gives an overall job priority of 20.
WO #2: Asset criticality of 4 and work impact of 4 gives an overall job priority of 16.
In this case, WO #1 will have a higher priority than WO #2. The combination of the criticality and the impact of the work can be cross-referenced to give relative weight to each task when compared with all other work.
Backlog Management
The combination of work classification and job priority allows an organization to make sense out of its maintenance backlog. A maintenance backlog is very simply the essential maintenance task to repair or prevent equipment failures that have not been completed yet. By classifying these maintenance tasks into different categories and then prioritizing within those categories, maintenance backlogs can be developed from an overall organizational perspective or within smaller organizational groups or categories (e.g., PM, CM).
Why manage your backlog at all? Why not just work whatever maintenance tasks come due? The more toward proactive maintenance that an organization moves, the more likely it is, at least in the beginning, that the organization will identify more maintenance tasks than can possibly be addressed within that immediate time period (typically that week). Therefore, to keep from addressing the low-priority tasks or the categories of work that will not have the largest impact on the overall reliability of the organization, a backlog management system must be developed. Then the most effective approach to the backlog management system requires appropriate work classification and priority.
A backlog of 4–6 weeks is an industry benchmark. For example,say a maintenance department/section has on average 10 technicians. Then we get
Average labor hours available/week =
10 × 40 = 400 labor hours
Therefore, this department should have a backlog of between
400 × 4 = 1,600 labor hours
and
400 × 6 = 2,400 labor hours
On average, the backlog should be about 2,000 labor hours.
The right amount of backlog ensures that all the employees have the right work to do with appropriate planning (planned work) and that they are not hunting for work or sitting idle.
Poor planning leads to poor performance.
—AUTHOR UNKNOWN, BUT A WISE PERSON
Basics of Planning
Planning defines what work will be accomplished and how. Scheduling identifies when the work will be completed and who will do it. Planning and scheduling are dependent on one another to be effective. However,planning is the first step. The ultimate goal of the planning process is to identify and prepare a maintenance craftworker or technician with the tools and resources to accomplish this work in a timely and efficient manner. In other words, planning provides maintenance craftworkers with everything they need to complete the task efficiently.
Many maintenance engineers and managers consider planning to be nothing more than job estimating and work scheduling. This is not true. Planning is the key enabler in reducing waste and nonproductive time, thereby improving the productivity of the maintenance workforce. Many organizations have started considering planning to be an important function.
However, they realize that proper planning is not an easy task. It takes time to do it right. The time needed to plan a job properly can be considerable, but it has a high rate of return. It has been documented by many studies—including one by Doc Palmer, noted author of Maintenance Planning and Scheduling Handbook—and the author’s own experience that proper planning can save one to three times the resources in job execution. If a maintenance job is repeatable, as most are, then it is essential to plan the work properly because it will have a much higher rate of return.
Consider a maintenance shop AB where most of the work is performed on a reactive basis. The shop has no planner or scheduler on the staff. It has:
• 20 maintenance craft personnel
• 0 planner/scheduler
• 1 supervisor
• Estimated wrench time = 40%
The wrench time, also called tool touch time, varies between 25% and 65% for all industries. In North America, wrench time is, on average, around 40%.
The estimated productive work available (or performed) for AB shop per week, assuming 40% wrench time, is:
20 people × 40 hours/week × 0.40
320 labor hours/week
Now, consider another maintenance shop XY that has a reliability culture and has demonstrated a wrench time of 60%. This shop has the following staff:
• 18 maintenance craft personnel
• 2 planners/schedulers
• 1 supervisor
• Estimated wrench time 5 60%
The estimated productive work available (or performed) for XY per week is:
18 people × 40 hours/week × 0.60
432 labor hours/week
The XY shop has performed 112 hours (432 – 320) of additional work with the same number of personnel as the AB shop. This equates to a 32% increase in resources, or 5.7 more people on the staff. The increase in productivity is the result of planning and scheduling of work tasks by two people who were reassigned to handle the planning and scheduling.
But as mentioned earlier, planning requires more than just changing personnel from a craft function to a planner/scheduler function. The person must have the skills and experience to understand the different types of work and the various details that will need to be organized and assembled for that specific task (skills and resources, steps and procedures, parts, and tools).
Understanding Work
The work to be performed needs to be clearly understood. If the scope of the work has not been defined clearly, the maintenance planner must talk to the requester, visit the jobsite, and identify what steps, procedures, specifications, and tools are required to perform the job correctly. If the job is too large or complicated, it may have to be broken down into smaller subtasks for ease of estimating and planning.
Resources Required and Skill Levels
The skill level of the person required to perform the work must be identified along with the estimated hours. The job may include one highly skilled craftsperson and one or more low-to-mid-level skilled maintenance technicians. Many times, maintenance professionals believe that it is difficult to estimate the time required to perform a specific job, especially if the skills of the maintenance staff range from very low to very high with everyone theoretically at the same pay grade and position.
Therefore, planners must have a good knowledge of workforce capabilities and the environment. The skill of the maintenance workers and basic understanding and knowledge of their trade and plant assets will determine the level of detailed steps and work instructions required in the planning process. Highly skilled workforces may not need detailed instructions. Job estimating can become easier and potentially more accurate when the jobs are broken down into smaller elements. Long and complex jobs can be difficult to estimate as a whole.
A job standard database such as RSMeans standards other standard benchmarks can be used to estimate jobs. It is a good practice to build a labor standards library for specific jobs, e.g., removing/installing motors, 5–50 HP, 100–500 HP; replacing brake shoes on an overhead crane or forklift; or aligning a pump-motor unit. Predetermined motion times, time studies, and slotting techniques can be used to develop good estimates if tasks are repetitive in nature. An estimate should include work content, travel time, and personal and fatigue allowances.
The following are essential to good estimating practices:
• Be familiar with jobs and plant assets.
• Compare jobs against benchmarks.
• Be cautious when using historical data as it may have built-in delays.
• Don’t try to be 100% accurate.
It is a good practice for the planner to be a former senior craftsperson or a craft supervisor who has been given training in job estimating.
Steps and Procedures
Steps and procedures must be developed with specifications identified to ensure high work quality. The work instructions to disassemble or assemble a complex component should be clear, with sketches and drawings as needed. They should include steps at which data such as bearing clearances or temperature readings should be recorded. Human error causes more failures of assets than any other type of error in an organization.
Parts and Tools
Materials, including parts and kit lists, must be identified in order to have the parts available on-site before the job is scheduled. Special tools need to be identified in order to ensure the work is completed without delays. For example, does the maintenance person need a torque wrench to tighten a bolt instead of a box end wrench? Furthermore, the torque wrench is of no value if the torque value is not known. Inadequate information may lead to a number of self-induced failures. The objective is to reduce the likelihood that an error could occur by using the wrong part or the potential for a maintenance person to stop work to locate the right tools required for the job. A planned job template is shown in Figure 4.9.
It is a good practice to have a planning checklist to ensure that all the steps and documentation have been prepared or arranged. Figure 4.10 shows an example of a planner’s checklist.
Symptoms of Ineffective Planning
The following are some symptoms of ineffective planning:
• Maintenance people standing around waiting for parts
• High rework
• Poor work performance
• High stockout in the storeroom
• Planners being used to expedite parts
• Maintenance personnel arriving at the jobsite and waiting for the asset/system to be shut down (wait is over 15 minutes)
• Frequent trips to storeroom by maintenance personnel
• Production downtime always more than estimated
Enhancing Planning Capabilities
Planning capabilities can be enhanced by ensuring the following:
• Employees are involved and understand their roles. Educate all maintenance stakeholders, from plant managers to the maintenance technician in the P&S process, to ensure all players understand their roles.
• Planners may require additional assistance in developing effective work plans. It is recommended that a senior maintenance technician be assigned to the maintenance planners for a few hours each day. This will help in developing better work plans. Rotating other personnel such as craft supervisors and senior craft personnel in planning support jobs is a good practice. It helps them to understand why planning is important and how it functions.
FIGURE 4.9 A Planned Job Template
FIGURE 4.10 A Planner’s Checklist
• Maintenance planners must have a library of information,including equipment manuals, drawings, specifications, and specific equipment manufacturer manuals and other documentation.
• Planners shouldn’t perform additional work such as filling in for a temporary or relief supervisor or safety or environmental representative. The planner is not a secretary or clerk.
Additionally, planners shouldn’t expedite parts for breakdowns or problems. Their responsibility is to ensure that future work is planned properly so it can be executed effectively. This also ensures that they do not get wrapped up in the day-to-day operations and maintenance issues. Two points to keep in mind:
• Planners should have technical and hands-on experience as a maintenance technician or craftsperson.
• The planned work package should be reviewed by a craft supervisor to validate that the work package is doable as planned before scheduling.
Understanding Scheduling Basics
Scheduling ensures that resources—personnel, material, and the asset on which the job is to be performed—will be available for maintenance at a specified time and place. Scheduling is a joint maintenance and operations activity in which maintenance agrees to make resources available at a specific time when the asset can also be made available by the operations. Jobs should be scheduled to have the least impact on normal operations.
Once a job has been planned, its status is moved to “Ready to Schedule.” Now the job will go to the scheduler, who works with operations and maintenance supervision to develop a schedule that optimizes operations needs with the availability and capacity of the maintenance resources. Organizations use different strategies for scheduling plans. For example, some use monthly, weekly, and daily schedules, whereas others use only weekly schedules. Many organizations also maintain a rolling quarterly and yearly schedule. A yearly schedule usually consists of high-level schedules providing visibility of major outage and turnaround plans.
Scheduling of equipment—the assets for maintenance—is not an easy task. Many times production/operations are busy meeting customers’ needs or have an excuse not to release equipment for maintenance activities for various reasons. Generally, there are four key stakeholders (group/departments) that need assets to produce or perform some maintenance work or improvement/capital project work. Those stakeholders are the operations/production department, plant maintenance,capital projects group, and utility group including controls/SCADA people. Organizations should establish a process where the needs of all stakeholders are collected and conflicts resolved in a timely manner so that all stakeholders get the asset on an agreeable schedule. Figure 4.11 illustrates an example of the organization’s integrated scheduling process. It helps to resolve conflicts and keeps all players engaged and able to get their work accomplished.
Schedules are built by assigning dates as requested by the requester. Some jobs need to be reprioritized to attend to the most pressing problems first. Thereafter, the large majority of the available time remaining in the schedule is filled with jobs that are selected in accordance with management’s priority or other important criteria. Preventive maintenance jobs should be given high priority; they need to be scheduled to meet their due dates.
Once a job is on the schedule, the materials list should go to the MRO store for parts kitting and material staging before the specified schedule date. In many organizations, the CMMS/EAM system does this work automatically. In addition, the job work package will be delivered or made available to the individuals who will execute the job.
When the scheduled time for the job arrives, the maintenance personnel will have everything they need for the job:
FIGURE 4.11 Integrated Scheduling Plan
1. A work permit to execute the job
2. The asset ready to be released by operations personnel:
a. Ready for lockout/tagout measures
b. The system already flushed or cleaned if necessary
3. The material/parts on hand including specified tools and material-handling equipment (or at the site)
4. The right maintenance personnel with proper safety measures—appropriate personal protection equipment (PPE)
5. The job or work package that has all the details and work instructions explaining how work will be executed
There should be no delays when the maintenance personnel arrive at the jobsite. They should only have to complete the permits and set their own locks of the asset before starting the job. Ideally, the job should progress without any hitch; however, there will be some issues. The planner/scheduler should be available to answer any job-related questions, and the craft supervisor needs to ensure the quality of work.
Doc Palmer, mentioned earlier in the chapter, is a noted authority in the area of maintenance planning and scheduling. He cites six basic scheduling principles:
1. Job plans providing the number of persons required, lowest required craft skill level, craftwork hours per skill, and job duration information are necessary for effective scheduling.
2. Weekly and daily schedules must be adhered to as closely as possible. Proper priorities must be placed on new work orders to prevent undue interruption of these schedules.
3. A scheduler develops a 1-week schedule for each crew based on craft hours available, forecast that shows the highest skill available, job priorities, and information from the job plans. Consideration is also made of multiple jobs on the same equipment or system and proactive and reactive work available.
4. The 1-week schedule assigns work for every available work hour. The schedule allows for emergencies and high-priority,reactive jobs by scheduling a significant amount of work on easily interrupted tasks. Preference is given to completing higher-priority work by underutilizing available skill levels for completing lower-priority work.
5. The crew supervisor develops a daily schedule 1 day in advance using current job progress, the 1-week schedule, and new high-priority, reactive jobs as a guide. The crew supervisor matches personnel skills and tasks. The crew supervisor handles the current day’s work and problems even to rescheduling the entire crew for emergencies.
6. Wrench time is the primary measure of workforce efficiency and planning and scheduling effectiveness. Work that is planned before assignment reduces unnecessary delays during jobs, and work that is scheduled reduces delays between jobs. Schedule compliance is the measure of adherence to the 1-week schedule and its effectiveness.
A major downtime that “just happens” can be disastrous for a plant. A planned shutdown can provide maintenance organizations an opportunity to identify and address major potential problems or failures in a timely manner to improve plant safety and efficiency. Usually, a system or a process is shut down until the requested and specified work is completed and then restarted, thus “turning around” the process/plant. Examples of this type of work can be relining a large furnace, overhauling and upgrading an assembly system, replacing turbine or compressor blades, cleaning and upgrading a chemical reactor, or replacing process tanks. In a production facility, a turnaround usually consists of combinations of investment projects, maintenance projects or overhauls, and typical maintenance activities such as PMs or corrective maintenance activities that require the plant to be removed from service.
All the major heavy metal and process industries—steel mills,refining, petrochemicals, power generation, pulp and paper, etc.—have their own nomenclature for their maintenance projects. These are called turnarounds, maintenance shutdowns, planned outages, or just maintenance repair projects.
Shutdowns for scheduled major maintenance work and large capital investments are the most expensive and time-consuming maintenance projects because of the loss of production and the expense of the turnaround itself. They can be complex, especially in terms of shared resources; as the complexity increases, they become more costly and difficult to manage. Scheduled shutdowns usually are of short duration and high intensity. They can consume an equivalent cost of a yearly maintenance budget in just a few weeks. They also require the greatest percentage of the yearly process outage days. Controlling turnaround costs and duration represents a challenge.
A shutdown always has a negative financial impact. This negative impact is due to both losses of production revenue and a major cash outlay for the shutdown expenses. The positive side is not as obvious; therefore, it is often overlooked. The positive impacts are an increase in asset reliability, continued production integrity, investment in infrastructure,and a reduction in the risk of unscheduled outages or catastrophic failure.
Scope management is one of the major challenges in a turnaround. The scope will change, sometimes dramatically, and it will impact the schedule. Typically, the scope is developed based on information gathered from operating parameters, capital investments, preventive maintenance actions, and predictive tools. Sometimes, we don’t have a good understanding of the scope until an asset or system is opened for inspection. As an asset is opened, cleaned, and inspected, the extent of required repairs can be determined and planned.
There are distinct differences between turnaround maintenance work and capital projects. Work scope is well defined in capital projects;however, in turnarounds, the scope is dynamic and fluctuates a lot. Figure 4.12 lists the major differences between capital projects and turnarounds.
Identifying and appointing a turnaround planner well in advance,maybe 6–8 months, is a good practice. This planner helps to develop the scope, integrate the full scope of work including resources, and assure readiness for the execution of the turnaround. Similarly, identifying and appointing a turnaround manager well in advance, maybe 3–4 months,is also a good practice. The turnaround manager should have the delegated authority to lead the turnaround effort to a successful conclusion. In some organizations, new turnaround managers and planners get appointed just after completion of the last turnaround, as an ongoing process to begin planning for the next turnaround. Lessons learned from the previous turnaround are then transferred to the planning and execution of the next turnaround.
FIGURE 4.12 Capital Projects versus Turnaround Maintenance
The following is a suggested checklist for a turnaround manager:
• Identify the rough scope of the work and resources required,specifically who will be planning, scheduling, and supervising the work.
• For scope finalization, work with key players to identify the scope as soon as possible. As a minimum, freeze the scope 4 weeks before the start of a turnaround, depending on the size and complexity of the turnaround. There will be changes. Accommodate them as they arise within the contingency allowances of the turnaround. Significant additions that exceed contingency plans require revisiting the total scope of the work and authorization of changes by the stakeholders.
• In planning work, plan the work and prepare job packages with the help of planners and craftworkers who are familiar with the work/area.
• Ensure the work plans have been reviewed by the assigned craft supervisors from an execution point of view.
• Ensure that all drawings, repair instructions, and required material have been identified and updated and that their availability has been validated. Check that arrangements have been made to stage the material at the proper location.
• Check that special tools and lifting devices (e.g., forklifts, a mobile crane of correct capacity) have been arranged and will be available at the site on the scheduled day. Make sure that lift plans, equipment capacity, and condition for service have been validated prior to scheduled lifts.
• In scheduling work, break large work into smaller work tasks and then schedule them based on resource availability and duration of the shutdown. Schedule all work to be completed in 90% of the approved duration. Leave 10% time as a contingency.
• Identify “critical path” tasks that can impact the overall schedule and focus your attention on them.
• Make sure all material, tools, cranes, etc., have been arranged to be delivered at least 1 day before the start of the shutdown.
• Ensure that all the necessary permits have been procured and that the lockout and tagout plans have been arranged to provide for safe, efficient access to the scheduled work.
• Establish a communication system. How is work accomplished? Once problems have been encountered or uncovered and corrective action is taken, how will this information be communicated, and how will feedback be provided in a timely manner? For large and critical tasks, communication may be necessary on every shift. Arrange to meet face-to-face with task leaders, planners, and schedulers on a daily basis for schedule execution and on a weekly basis to review progress and change in direction, if needed. The schedule is intended to accomplish the overall goals while maintaining enough flexibility to accomplish minor changes.
• Arrange a face-to-face meeting with all your key players,including operations personnel, to discuss the goal and schedule of the shutdown. Make sure they understand the cost of this undertaking and the impact of delays. Emphasize safety and quality of work. This meeting should be held a few days before the start of the shutdown. At a minimum, the operations personnel should be included in the weekly progress reviews.
• On the first day of the shutdown, make sure that all safety measures are taken in shutting down the system and that appropriate personal protection equipment is used. All lockout/tagout measures should be completed properly.
Attention to the following items may be required and appropriate corrective action planned:
• Barricades. These should be considered to restrict the movement into or the presence of people in restricted areas where overhead lifting, high voltage, radiography, and hazardous materials may be present. Ensure that proper safety signs are displayed in appropriate areas.
• Dust control management. A large shutdown can also be the source of excessive dust, depending upon the area and work to be accomplished. Make necessary arrangements to control the dust.
• Emergency showers and eye baths. Make certain that emergency showers and eye baths are available at the right locations.
• Liquid and solid waste handling. Certain cleaning operations may create liquid and solid waste that can be handled within the in-plant industrial sewer system. Other wastes—including asbestos, spent chemicals, and sandblast media—may create materials that require special handling, disposal, and access limitations. Unanticipated disturbance or creations of hazardous materials are showstoppers often overlooked during the planning process. Develop and review policies for spill control and for containment and disposal of hazardous material including potential handling problems
• Noise control. Some repair steps may generate excessive levels of noise. These operations need to be identified and corrective action taken that may require the use of earplugs and posting of “high-noise” area.
• Scaffolding control. During a shutdown, scaffolding is often moved from one location to another. Ensure all scaffolding from different sources is properly marked and color coded if necessary. Portable, motorized lift devices add significant flexibility to any scaffold plan for large turnaround.
• “Return to service.” Ensure that return to service is well planned. What are the critical items that need to be insured before the system can be released for a start-up? Involve operations personnel in developing and executing the return-toservice plan, integrating their standard operating procedures with special concerns involving new or modified equipment. Make sure those critical items are OK. The right sequence of operating and energizing electrical devices safely is very important.
Holding a post-turnaround meeting is one of the important tasks for the turnaround manager. The area of turnaround planning that is most often underestimated is the area of lessons learned. Assuming the manager and planners keep good meeting notes or logs during the planning and execution phases, these notes provide an excellent source of lessons learned and process improvements for future turnarounds.
The time to collect this information is throughout the entire duration of planning and executing the turnaround. The lessons learned are compiled and reviewed with the turnaround team and stakeholders in a post-turnaround session. The purpose of the meeting is to discuss what worked and what did not work in the turnaround process,while the memories of the turnaround are still fresh in everyone’s mind. Recommendations from the team are then woven into the process for future reference and implementation.
The planning and scheduling processes, like other processes, need to be measured and evaluated to make improvements. A few examples of performance measures and benchmark data include:
1. Percentage of planned work. This measure is the percentage of all jobs that have been planned. It assumes that all parts,procedures, specifications, tools, drawings, etc., have been identified before the job is scheduled. The benchmark is 85% or better.
2. Percentage of schedule compliance. This measure is the percentage of work accomplished that is agreed upon or on the weekly schedule. The benchmark is 90% or better.
3. Percentage of time that kits (materials and parts) are delivered on time. This measure is calculated as the number of times the kits (material and parts) were delivered on time,divided by the total number of kits delivered. This measure affects the planner’s ability to plan jobs properly. Expediting parts adds unnecessary and wasteful cost to the P&S process.
4. Percentage of time the right parts are delivered. As part of the planning process, planners and schedulers should have the confidence that a specific vendor will deliver the right part when required. Otherwise, this problem could create a delay in performing the work. The benchmark is 99% or higher.
5. Percentage of work generated from a formal work PM/CBM. Most work should come from identifying the degradation of a component or asset far enough in advance of any PM/CBM tasks that the job can be planned and scheduled properly, thus minimizing unexpected delays and production loss.
6. Percentage of rework. This measure is the percentage of work orders requiring rework. Each organization needs to define what rework means to it. The definition may differ from one organization to another. Examples of rework include revisiting an asset to fix something within 7, 15, or 30 days of a PM or major repair work performed. The benchmark number is less than 2%.
7. Backlog. This measure shows how much work is ready to be performed. This measure is important to keep maintenance effectively utilized. A 4–6 week’s backlog of work is a good benchmark.
Planning and scheduling have the highest potential impact on the timely and effective accomplishment of maintenance work. The planning and scheduling functions are where all maintenance activities are coordinated. Although planning and scheduling are closely related, they are two distinct functions:
• Planning. The what and how—what and how work will be performed
• Scheduling. The when and who—when the work will be done and who will do the work
Planning encompasses what the job is and how to do the job. It’s an advanced preparation of a work task so that it can be executed in an efficient and effective manner sometime in the future. It involves detailed analysis to determine and describe the work to be performed,task sequence, and identification of required resources—including skills,crew size, labor hours, spare parts and other service materials, special tools, and any lifting device or equipment needed. It also includes identification of special lockout/tagout measures and any special permit required before the start of the task.
Planners are oftentimes very talented and great at multitasking,but many times they get pulled into duties that take them away from their primary function. Planners should always think of tomorrow—future work. They shouldn’t be tasked to:
• Be a supervisor
• Be a quality inspector
• Be a material expeditor
• Perform administrative/clerical activities
• React to emergencies
• Be the “help desk”
Scheduling encompasses when the job is going to be done and who is going to do it. It’s a process by which resources are allocated to a specific job based on operational requirements and resource availability.
Planning and scheduling eliminate or minimize the waiting time and delays. When maintenance personnel have to return to the storeroom numerous times to locate the required parts or to locate a specific tool, it delays the work execution and adds additional cost to the job. Poor planning and scheduling lead to poor utilization of maintenance resources.
Asset criticality analysis and work-job prioritization are two elements that can help in planning and resource optimization. The purpose of asset criticality is to facilitate asset decision making by identifying the assets that present the highest levels of risks to the organization and prioritizing their treatment. Work-job prioritization helps us to schedule asset maintenance and repairs based on asset criticality and the consequence of work impact.
Q4.1 Draw a workflow chart to show work from a request to completion.
Q4.2 Explain each role as shown in the workflow chart from Q4.1.
Q4.3 Who is the work coordinator? Explain that person’s role and responsibilities.
Q4.4 What is the purpose of a job priority system?
Q4.5 Why do we need to manage maintenance backlog? What is a good benchmark?
Q4.6 What are the symptoms of ineffective planning?
Q4.7 Should planners help schedulers or craft supervisors during an emergency? If yes, explain.
Q4.8 What are the job requirements for a planner?
Q4.9 Who are key players in the scheduling process? Explain their roles.
Q4.10 What are the key differences between planning and scheduling processes?
Q4.11 Discuss work types and the benefits of work classifications.
Q4.12 What are the key differences between capital projects and turnarounds?
Q4.13 What are activities the planner shouldn’t be doing?
Q4.14 What key elements should be part of criticality criteria?
Q4.15 Give an example of maintenance rework and how it will be calculated.
References and Suggested Reading
Kister, Timothy, and Bruce Hawkins. Maintenance Planning and Scheduling Handbook. Elsevier Science & Technology, 2006.
Levitt, Joel. Handbook of Maintenance Management. Industrial Press, 1997.
Nyman, Don. Maintenance Management training notes. Seminars,1994–1996.
Nyman, Don, and Joel Levitt. Maintenance Planning, Scheduling, and Coordination. Industrial Press, 2001.
Palmer, Doc. Maintenance Planning and Scheduling Handbook, 4th ed. McGraw-Hill, 2019.
