Repair work is usually the most difficult task to define and estimate. Repair work is usually identified after inspections of the equipment. Some repairs are known beforehand, from previous shutdowns or from inspections while the plant is operating (infrared, ultrasonic, etc.).

Often we can estimate the extent of the repairs based on the history (previous inspection reports, repairs) and the type of service for a particular piece of equipment. After the equipment is inspected and repairs are recommended and approved, then we can revise the original estimates as necessary.

Of all of the possible repairs, the most difficult to estimate is refractory work. Even after refractory repairs are underway, the extent or scope of these repairs usually change. It is best to have several activities defining refractory work, each dealing with a specific area or part of the equipment. For example:

• Repair refractory at plenum
• Repair cyclone refractory
• Repair north wall refractory
• Repair bottom head refractory

Of course, "repair refractory" is not a very good definition of the work. Refractory repairs should always be detailed showing all necessary steps:

• Erecting scaffolding
• Chipping out the old refractory
• Removing the old hex steel or bad order anchors
• Sandblasting or grinding the walls
• Cleaning out the debris
• Installing new hex steel or anchors
• Installing the new refractory
• Removing scaffolds
• Refractory curing time
• Clean up

Even if you decide not to include any repair estimates in your work order, you should at least have an activity labeled "MISCELLANEOUS REPAIRS" with no manpower. This way you can later add duration and manpower, and it will help in reminding you to be alert for the inspection reports, so that the repairs won’t be overlooked.

Of course, some prefer to include a time duration to provide a convenient time span in case repairs are needed. This also works well. The method you choose will depend upon the prevailing philosophy within your organization.

It is important to keep all estimates (particularly repair work estimates) current. The reason is that the estimates will establish the required manpower staffing and the remaining schedule time span to get the work accomplished. Otherwise both budget and schedule will be overrun.