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Maintenance Performance: Precision in Maintenance Planning, Scheduling and Work Control

In a previous article about maintenance performance, we stated that the cornerstones of maintenance development are maintenance analysis and a maintenance management plan that is designed to provide p…

In a previous article about maintenance performance, we stated that the cornerstones of maintenance development are maintenance analysis and a maintenance management plan that is designed to provide preventive, predictable, proactive and optimized maintenance [1]. Maintenance Planning, Scheduling and Work Control are essential tools that call for the highest level of precision to successfully establish these cornerstones.

Why plan, schedule and control maintenance work?

A plant has to be productive in order to maximize its return on investment in both the short and long terms. It is essential for the plant to maximize output and minimize inputs while respecting the safety, environmental, quality and other plant standards. This involves seeking a balance between the customers and the business criteria.

Furthermore, a reliable plant meets its productivity objectives. A reliable plant is also synonymous with a reliable production chain as depicted in Figure 1 which shows that maintenance contributes to the operational reliability of the assets.

During the lifetime of an asset, whether the asset is an entire plant or a particular piece of equipment, the Operation and Maintenance costs can range from 30 to 50% of the total lifecycle cost, and sometimes even more:

Direct maintenance costs primarily include labour, materials, contracting, administration and depreciation and correspond with the maintenance budget. These costs only represent the tip of the iceberg

Indirect costs can result from equipment unavailability or low performance. They include safety, environmental, energy and production losses and can be linked to the motivation of personnel

Indirect costs can be several times higher than direct costs. Therefore, the potential risk of encountering indirect maintenance costs must absolutely be minimized.

Both types of costs can be addressed by targeting the maintenance Global Labour Productivity (GLP) that measures the time a skilled maintenance worker spends on the actual execution of a job, i.e. the “wrench time”, by taking into account the utilization, methods and performance aspects.

GLP measurement results obtained to date show a majority of maintenance organizations with a productivity ranging from 20-40% while the World Class Maintenance (WCM) benchmark is currently at 75%. Therefore, by improving GLP from 20-30% in a maintenance organization that has, for example 30 workers, is the equivalent of adding 15 new employees working at the initial productivity rate.

Focusing on planning, scheduling and work control has a positive impact on the GLP due to the attention given to the who, what, when, where, why, and how of the jobs needed to meet the requester’s expectations in the most effective and efficient manner. The equivalent extra workforce generated results in enhanced operational reliability, meaning improved reliability of the production equipment and the reliability of the industrial production chain, and therefore positive plant bottom-line results.

Developing a solid foundation

Planning, scheduling and work control are inter-related maintenance management processes. They are also connected with many other aspects of maintenance and cannot really function alone. The basic elements that support planning, scheduling and work control include:

maintenance personnel

the work order system

equipment data, specifications and history

Reliability Centered Maintenance (RCM)

shops and tools

stores and spare parts

Prime conditions for precise functioning of a system integrating the above elements are:

– defining and establishing the work flow, including defining the roles and responsibilities of the various team members.

– management commitment to improve maintenance.

Planning

Planning is used to reduce labour and material waste as much as possible. The goal of planning is to prepare the jobs to reduce delays and increase labour productivity. To quote Plato [2]: “…the beginning of every task is the most important part …”

The following guidelines will help secure precise planning:

1. Planner in group separate from trades.

2. Planner concentrates on future work.

3. Planner maintains file system based on equipment tags.

4. Planner develops work plans to anticipate delays, safety or quality problems.

5. Planner recognizes the skills of the trades people.

6. GLP is the top level Key Performance Indicator (KPI) used to measure efficiency and planning / scheduling effectiveness

Precise planning also calls for adopting rigour and discipline in developing and using the planning system. This means that the planning process must be accurately documented, practiced and periodically revised as part of a continuous improvement initiative. The work order form, which is the main vehicle used to carry the information at each step of the process (request, approve, plan, schedule, execute, close) needs to be simple and accurate, regardless of whether it is in paper or electronic format.

The planning system, which partly depends on the work order form, also includes:

equipment coding, using a deficiency tag and priority codes that are the result of a joint definition effort between maintenance and production.

developing a critical equipment list that will help secure precision in the equipment files by identifying the equipment that require additional information.

a file system that enables the planner to use equipment data and information attained on previous jobs for developing and improving work plans.

the inventory planning and control are essential for parts availability, and call for rigorous attention paid to the planning-store interface.

The planner needs to apply the planning principles, process and system when planning work orders. The process begins with the work scope definition that includes the requirements definition illustrated in Figure 2 and the development of a draft job plan shown in Figure 3.

As the planner works through these steps, he uses two main types of estimates: the scoping estimate and the detailed estimate. He can apply various techniques to determine his estimate. Interfacing with area and shop supervisors will improve the quality of estimates and simplify the jobs of both the supervisor and the planner.

The first draft of the job plan is further refined, and special attention is given to the guidelines that relate to developing the planned level of detail, sketching and drawing, trade skill level, estimating work hours and job duration, parts, tools, estimating job cost and safety.

With regard to ensuring the safe operation and maintenance of a plant, the job plan must include:

1. Equipment isolation procedures.

2. Standard procedures for hazardous jobs.

3. Safety review meetings prior to major overhauls.

4. Safety induction for new and all contract workers.

5. Quality assurance review of all new and reconditioned parts.

6. Updates of drawings and manuals if the plant is modified.

7. Equipment history reminders and analyses to anticipate potential safety problems.

As the planning process evolves and matures, it is only natural that some jobs will be performed more often than others. Frequently performed jobs are excellent candidates for developing a standard job plan.

Scheduling

The planning process provides the maintenance supervisor the necessary tool to manage how much work an entire maintenance crew needs to accomplish. The basics of scheduling are centered on giving enough work to the crew to fill up the forecast of hours available.

An advance schedule will:

set goals

ensure a sufficient amount of work

allow material staging

allow inter-trade co-ordination as well as co-ordination with production

ensure sufficient proactive work to prevent further breakdowns

If the goal of planning is to increase GLP, then its primary objective is to prepare the jobs to increase maintenance productivity. Scheduling helps allocate the jobs necessary for completion. Scheduling forms an integral part of planning. Plant shutdowns benefit from having set
schedules and so does routine maintenance.

Precision in scheduling involves these key principles:

1. Work packages are essential for weekly scheduling and contain all the required information.

2. Weekly and daily schedules have to be adhered to as closely as possible.

3. The maintenance supervisor develops a one-week schedule for each crew based on the trade hours available forecast.

4. The one-week schedule provides work for every available work hour.

5. The maintenance supervisor develops the daily schedule one day in advance.

6. GLP is the top level Key Performance Indicator (KPI) used to measure efficiency and planning / scheduling effectiveness.

The scheduling process comes alive when the team members start to perform their respective tasks. Driven by the maintenance supervisor, the scheduling process is guided by the maintenance management reference plan that establishes the long-term direction. The scheduling process includes an interface with the production supervisor who provides the necessary input with respect to the availability of the equipment for maintenance work. The maintenance supervisor is assisted by the maintenance planner. The trades people receive the scheduling output from the maintenance supervisor.

The work schedule is the main tool used to communicate information. Communication takes place at different stages during specific meetings that are essential for scheduling to be effective. There are three types of work schedules: for the long term, the schedule of shutdowns is used while routine maintenance appears on the weekly schedule with jobs being ultimately distributed to trades people using the daily schedule.

Jobs planned with priorities and timing identified, time and material estimates, and procurement process complete are accumulated in the work backlog. This includes routine and preventive maintenance. The information contained in the backlog defines the workload of the maintenance department. A minimum backlog level is necessary to ensure a good occupation rate of maintenance personnel. At the other extreme, too high a backlog level will compromise the plant equipment availability. The backlog should be monitored globally by management as well as by specialized personnel (electricians, mechanics). When the backlog level reaches high or low levels certain actions need to take place. Figure 4 illustrates the backlog measurement and control.

Work control

Plant maintenance activities are complex and involve many employees. Resources to support activities should be coordinated in a timely, controlled manner to ensure that they are ready to support the schedule. The resources that should be taken into consideration include personnel, material, expendable supplies, special tools, and services.

Since the quality of maintenance activities directly impacts the plant’s reliability, helping the workforce to achieve quality workmanship while maximizing productivity requires close control by the maintenance manager and supervisors.

Material availability is an important element to a successful maintenance program. Many items call for long lead times, particularly materials needed for modifications and repair parts for older equipment. These items need to be identified and ordered well in advance and tracked to delivery to ensure that they will be available at the job site when needed.

Daily meetings with team members, should be conducted to help monitor the progress of key jobs and to provide short-range coordination of scheduled activities. Meetings need to be managed so that the time of the managers and supervisors is used efficiently, the redirection of work in progress is minimized, and delays of oncoming work shifts are prevented. Care should be taken to ensure that meetings focus on problems and their solutions.

Performance measures of the rate of activity completion, schedule adherence, productivity, and progress toward meeting plant maintenance goals, must be developed. These measures need to be checked periodically for validity and used by maintenance management to monitor performance.

Finally, feedback from trades people about the work performed is required to build history and to help the supervisor and planner analyze the work orders upon closure and improve the work packages.

Precision in work control implies the observance of the following principles:

1. Work planner and supervisor have trade skills and experience.

2. Training and support are provided to planner and supervisor.

3. Trades people provide feedback to Supervisor during and after work execution to update the maintenance management system database.

4. Planner analyzes work orders upon closure.

5. Measures are used for each phase of work control process.

6. GLP is the top level Key Performance Indicator (KPI) used to measure efficiency and planning / scheduling effectiveness.

A case study

The mill used in this example operates two paper recycling plants and a paperboard machine. ABB has been responsible for all maintenance since the late 1990s.

Significant cost savings and machine performance gains were obtained by focusing on equipment maintenance performance. One major driver was improved maintenance planning, scheduling and work control. Applying the above principles has led to boosting time efficiencies as well as the overall equipment effectiveness.

Figure 5 illustrates the percentage of man-hours spent on corrective unplanned work which decreased from a level of 30% to less than 10% in approximately 18 months and then stabilized in the 5-10% range thereafter.

Not shown in Figure 5 is the corresponding increase in preventive maintenance that initially had to be forced. It then became easier as the maintenance GLP was increasing, thus actually freeing up personnel which subsequently helped in the improvement activities. A sharp decrease in maintenance personnel overtime was also noted.

Conclusion

The maintenance business includes various inter-dependent aspects that are integrated into a single system. Having highly skilled workers with no tools or under-skilled workers who have tools does not help matters. Using the planning, scheduling and work control maintenance management tools with precision is necessary but not enough to optimize maintenance. The lessons learnt in the above-mentioned case study suggest that in addition to planning, scheduling and work control, precision is also required in identifying simple and consistent contract drivers that are aligned to production, clear lines of responsibility and accountability, using a partnership approach as opposed to the traditional supplier-customer relationship, adequate management tools (e.g. computerized maintenance management system, cost management system, RCM), appropriate resources and management support to drive change.

Bibliography

Directly referred to in this article:

[1] Bricteux, J.P., Tuomela, J. “Improving maintenance performance in pulp and paper mills”. Pulp & Paper Canada 104 (March 2003), pp. 20-23

[2] Plato – Republic, II, 377a-377d

Other source:

[3] Palmer, R.D., “Maintenance Planning and Scheduling Handbook”, McGraw-Hill, New York, NY, (1999)P&PC

Jean-Pierre Bricteux is Maintenance Engineering Manager for ABB Inc. He can be contacted at: jean-pierre.f.bricteux@ca.abb.com#text2#