The scheduled down period is called different names by different industries. Whether it's called a shutdown, shut-in, down-turn, turnaround, or outage, it can be the time when the maintenance department shines, or reveals its functional failings. This is the reason some maintenance managers dread these down periods. All eyes are focused on the work they do.

Scheduled shutdowns, however, can provide unique opportunities to a maintenance department not normally available during standard operation or even during short shutdown periods. Lost capacity can be restored to an overtaxed facility during an extended shutdown. Major equipment overhauls can be performed to help prevent future unscheduled shutdowns. Government mandated inspections and repairs can be accomplished during a shutdown, bringing a plant into better compliance.

Critical Path Method

Although historically applied to engineering and construction work, the process of project management is easily adaptable to a maintenance shutdown. One tool used extensively in project management is the critical path method (CPM). CPM was developed in the 1950s by U.S. government contractors to speed the construction of the first nuclear powered submarine, the Nautilus. Over 3,000 contractor and subcontractor companies had to be coordinated to develop the submarine. Traditionally, a Gantt chart (or bar chart, as it was commonly called) was used to lay out the tasks to be performed on a timeline. Each bar represented a task and its length represented the elapsed time required to complete the task. Gantt charts failed to meet the needs of very large projects because they did not clearly show the interdependency between different tasks.

The critical path method takes the interdependency of jobs into account. In a common shutdown, some jobs must follow other jobs, some jobs must precede other jobs, and some jobs can be performed concurrently with other jobs. Although it may at first seem difficult to determine all these relationships for each job in a shutdown, the task can be greatly simplified by asking one question of each job. That question is, "Which activity or activities must immediately precede this activity" The result of this exercise will reveal the true relationship of all jobs in the shutdown.

Assume you have the following list of jobs:

The precedent question was asked of all the activities in the list to identify the corresponding precedent activities. This questioning process is referred to as determining the precedent logic. These activities can be tied together graphically as shown in this diagram.

The resultant diagram is called a logic network or a PERT (Project Evaluation and Review Technique) diagram. This diagram not only shows the relationship activities have with preceding activities, but also the succeeding and concurrent activities. It should be noted that this was all accomplished by determining the precedent logic only.

The critical path (or sometimes paths) is the one which defines the shortest period of time in which the project can be completed. As such, it is the series of interrelated jobs which add up to the longest period time. All other concurrent paths usually have float or slack time.

Refer back to logic network example. The path which adds up to the longest total duration consists of activities A, C, D, E, G and H, for a total of 63 hours. This is also the shortest period of time in which the total project can be completed.

Knowing the critical path is helpful, but knowing the jobs with float or slack is equally helpful. Activities B and F are non-critical jobs totaling 8 hours. Activities D and E are critical jobs totaling 28 hours and can be performed concurrently with B and F. The difference in duration between these two paths is 20 hours. This is called the float or slack. Either B or F can be delayed 20 hours, or both jobs can be delayed any combination which totals 20 hours without extending the project.

Assume the same crew will have to be used to perform activity D and activity F. They obviously cannot be performed at the same time with this limitation on resources. The diagram and float calculation show that activity F can start 24 hours after the start of activity D is begun (4 hour duration of activity B plus 20 hours of float) without extending the duration of the shutdown.

It is important to make the distinction between what facility personnel may consider to be critical jobs and jobs which fall on the critical path. In reality they may not be the same. Its all a matter of definition. The job plant personnel feel is important during the shutdown may require the most resources or may be the most technically challenging. This job may can be a not be on the critical path. The critical path method works under the assumption that the project must be completed in the shortest period of time. If a critical path job is ignored and allowed to extend beyond its scheduled duration, the duration of the total project will be extended. This may be more devastating to the operation of the plant than the extension of a non-critical, albeit technically challenging.

Project Management Software

The project status should be updated continuously during the execution phase of a shutdown. This means redrawing the logic network and resulting Gantt charts to show delays and extended job durations as they occur. A new critical path may develop so formally non-critical jobs can become critical.

Building and updating a large project manually can be a daunting task that few would consider practicable. CPM computer programs were developed to solve these problems in the early 1950s however, these programs were only developed on mainframe computers for a select few organizations. Project management software for the PC, developed and improved over the last 10 years, has made project management more accessible. These programs can help the user organize interdependent tasks using precedent logic. Resources with different working hours, schedules and costs can be assigned to these tasks and the results can be viewed on screen or printed. These software tools are also helpful in analyzing and communicating project activity. The progress of the shutdown can be tracked and updated using these programs and the associated costs can be monitored.

Choosing the Right Program

Complex and sophisticated programs are, and have been, available for years. However, the simpler the program, the quicker someone can start receiving the benefit.

It's a good idea to try a few programs out to see which one is best for you. Low end programs are inexpensive, usually under $600 US., while high end programs can range from $4000 to $12,000 US. Low end programs are sufficient if you are looking to get a fast start with computerized project management software. Intelligent, on-line, support is available in some programs. This feature can lead a novice through the process of project management without much difficulty.

Most project management programs are designed for general business applications and not maintenance. However, many offer the ability to customize the program to your specific needs. Customized fields can be added for entry of work order numbers or equipment numbers. These fields can be sorted, filtered, or searched quickly if the need arises. Most can import a simple ASCII or spreadsheet file. If a computerized maintenance management system (CMMS) can export to these formats (and most can), then the need for double entry is eliminated.

Much of the work of a shutdown coordinator requires communicating with other people about a shutdown in progress. Project management programs can make this task easy too. Logic network diagrams and Gantt charts can be printed on demand. Although almost any printer can be used, this is best accomplished using a color printer or plotter as the output device. Tasks in the critical path can be displayed in a different color than the other tasks on a logic diagram. These charts can be annotated by the user to highlight certain sections.

Reports can be customized to present project information the way the user wants it to be presented. Common canned reports available are baseline-to-actual, resource allocation, cost distribution, earned value analysis, and actual to budget. Most users feel a need to modify the output of these reports in a word processing program.

File import and export capability is built into most of the programs. Not only can reports be sent to a word processing file, data can be transferred between different formats. Many of the common formats such as ASCII comma separated text (.CSV), dBase (.DBF), Lotus 1-2-3 (.WK?), or Excel (.XLS), are available. It also possible to just cut and paste data between spreadsheets and softwar programs. Additionally, Microsoft Project can be transferred between many programs through a format called MS Project Exchange (.MPX) format.

All popular programs operate in a LAN or a client server environment, so project information can be updated by more than one user. Some programs allow the user to send project via e-mail to inform project members and update the project data files. The process is called "distributed or workgroup project management".

Not only can multiple resources and levels of resource be identified, but each resource can have its own individual calendar. These calendars indicate the working days and hours for each resource or resource group. The duration of a project can be extended if insufficient resources are available. Some programs have difficulty dealing with shift schedules for resources. If this is a major requirement, consider some of the high-end programs.

Multiple projects can be worked and managed simultaneously using most project software. Multiple projects can use the same people or other resources with overlapping assignments. Handling more than one project with a single project software file helps to sort out these situations. Some programs feature the ability to draw resources from a common pool for all projects and improves the ability to level resources between these projects.

Getting the Most from Project Software

Some people's initial forays into using project programs were tainted by the limitations of early software programs, such as the inability to handle part of an hour or restrictions on the number of resources which could be defined. Unfortunately, sometimes it was the limited knowledge of project management methods by the user that led to the initial frustration with the programs. Many of the software limitations cited in the early days have been eliminated. The following rules should be followed to get the most out of project programs.

Identify jobs by duration. Maintenance planners ordinarily identify job labor requirements in terms of total labor hours and the craft required to complete the job. Project management programs require that labor requirements be identified as elapsed time, resource type, and quantity of the resource. This distinction allows the software to determine the optimum resource level required to perform concurrent jobs on the critical and non-critical paths. A process called resource leveling is employed to delay the start time of non-critical jobs within float or slack to limit the peak requirements.

Expand your idea of resources. Most people think of a resource as the technical labor required, such as mechanics and electricians. Inspectors, safety personnel, engineers, and operations personnel should also be included as a resource on jobs. Nonhuman resources in short supply, such as cranes, tools, and laser alignment instruments, should be considered as well. The process of load leveling will reveal any conflicts with these resources so the shutdown coordinator can deal with them ahead of time.

Include operations activities. Maintenance people usually only think of the work that the maintenance department has to do during a shutdown. Often operations is involved in the preliminary stages to shut down, cool down, decontaminate, and lock out equipment. All these activities take time during the shutdown, so get estimates from operations and add these tasks to the project.

Break larger jobs into smaller segments to separate out the resources required. For example, an eight hour job may require a mechanic and an operations person. The mechanic will be involved in the entire job, from start to finish. The operations person will only be involved in the initial shutdown of equipment, lock outs, issuing safety permits, and startup. These activities may only take the first half hour and last half hour of the shutdown. When using some project programs it is important to break this job into segments so it is clear the operations person is not required for the entire duration of the job. This distinction comes in handy during the load leveling process.

Don't assign start times and/or end times when initially entering project data. Let the project program determine the logical start time from the precedent logic. Only make a change it if the resultant start time does not correspond to a convenient time for your shutdown.

Don't limit the number of resources when you initially enter data into a project management program. The critical path method provides optimal results when an assumption is made that resources are unlimited. Let load leveling determine which jobs can be delayed to optimize the use of resources. The needed delay may be accomplished within the float or slack time available and not effect the project duration. If some resources are not lowered to the available level, the duration of the shutdown may have to be extended as a last resort.