A reliability-centric organization makes reliability the focus of the maintenance and operations departments. The company must have a strong, independent reliability leader, but fixing and replacing equipment are still part of the equation. Part III of this multi-part series explains how to handles repairs and spares.
Precision, high-quality repairs are required to achieve high performance in machinery, which is defined as more than 80 months in general-purpose equipment or no unscheduled downtime in special-purpose equipment. Precision repairs are a result of skilled craftsmen, quality parts, quality repair standards, quality assurance/quality control (QA/QC) processes, and proper documentation.
The personnel, whether company employees or hired contractors, must be highly skilled craftsmen. Reliability department engineers must work with the maintenance department to determine the skills required of the workforce, develop training for the craftsmen, and regularly test/qualify them. For example, the plant machinery specialist should develop, train, and test the craftsmen on the skills required to work in the plant. Figure 1 shows an example of a list of required machinery skills. Each asset should develop its own list based on the plant’s core tasks and skills required to complete those tasks. Each task should have a defined set of steps, conditions, and standards, and these should be taught to the personnel and repeated over a three-year cycle. This list should be a living document in that the list of tasks will change based on the plant’s evolution over time.
Figure 1. Each asset should have its own list based on the plant’s core tasks and skills required to complete those tasks.
An additional benefit of a craft training program is that it can be used as part of an apprentice training program. The current demographics of the workforce dictate that a plant must be able to develop its own skilled workforce, which is essential for ensuring quality repairs in the plant. If a company does not grow its own skilled in-house workforce, the company will have to spend time and effort finding and qualifying outside craftsmen, be prepared to pay a higher premium for such skills, and accept the risk of inconsistent repairs resulting from high contractor turnover. In-house skilled craftsmen are, in the long term, a cheaper and more effective workforce.
Fix it right
The spare-parts process plays an important role in achieving quality and timely repairs. All equipment must have complete bills of materials (BOMs) set up in the asset’s CMMS system with the correct parts stocked so they can be located quickly and easily. The spare-parts process for special-purpose equipment is critical; the right process can cut repair times in half, contributing to profits by increasing production uptime. A good process will also reduce the costs associated with labor and expediting parts and will avoid issues associated with non-conforming spare parts.
Quality spare parts are critical for maintenance employees to perform their jobs and ensure reliable operations after an overhaul.
Organizing your critical spares is an enormous undertaking, but with excellent rewards, including cutting repair times in half, increasing the quality of the repairs, and lowering the repair costs. When faced with decisions of faster, better, or cheaper, most organizations settle for two of the three, but spare parts organization is clearly a way to achieve all three simultaneously.
The process requires developing several processes, including:
- creating standard BOMs for the equipment
- developing inspection and testing plans for all parts
- implementing a QA/QC process and using QM in your CMMS
- reviewing existing spare parts per the inspection and testing plans
- ordering all parts to complete the BOMs
- kitting the parts per machine, which includes kitting the specialty tools
- implementing a process to control the kits, inspect them, and review them periodically
- developing a process of repairing parts and replenishing the kits.
Each part of the process is critical and must be performed by a dedicated machinery specialist, not only to set up but also to maintain the process. Adding the above responsibility to existing personnel will result in marginal results or failure of the process. If your organization does not have enough equipment to justify a dedicated machinery specialist, then your site may consider using a corporate employee to set up and review the process for multiple assets and a local machinery specialist to maintain the program.
Inspecting spare parts
Why is it important to inspect your incoming spare parts? To show the importance of QA/QC for all parts coming into your warehouse, consider the three-year summary of OEM compressor parts coming into an asset, shown in Figure 2.
Figure 2. The scorecard tracks quality of OEM compressor parts.
The data show an improvement from 93% to 95% over three years, but the asset was still receiving 5% bad parts from OEMs that knew full well that their parts were being inspected. This asset might consider dropping Vendor A or at least having a serious discussion with its management to improve the quality of their product.
If poor quality parts are arriving when vendors know you are inspecting the parts, imagine what kind of quality you are getting and installing in your equipment if vendors know you are not inspecting parts upon arrival. This QA/QC process will cut repair times in half, because you have all the right parts on hand. You won't have to stop production while looking for parts, expedite shipping of parts due to unavailability, or find out you have the wrong part during the overhaul. The savings on repair times will justify the cost of kitting the materials; plus you will have increased production from getting the equipment back on-line in half the time.
Quality repair procedures must be documented and taught to repair personnel. General-purpose equipment repair procedures should specify all the requirements for repairing the equipment to OEM specifications or better. Repair sheets should be used to document the as-found and as-left condition of the equipment so the organization can understand the history of the repairs for troubleshooting "bad actors." These sheets can range between four to eight pages of information and must be filled out as applicable.
For special-purpose equipment, detailed, specific equipment repair procedures should be developed for the equipment from pre-planning to post-repair, and it should include the same requirements for documenting as-found and as-left conditions. These specific equipment plans need to be written with such detail that an engineer right out of school can read, understand, and plan an overhaul or repair for any of the plant’s critical equipment. Such plans eliminate the total reliance on any one person who has the most knowledge about a particular machine. The equipment seems to know when that person is on vacation and purposely decides to act up.
Clean room justified
Sometimes a clean room is needed, especially for precision repairs. For example, a certain Gulf Coast plant's pump repair shop did not use a clean room for assembly. The shop was a metal building with no air filtration, and workers knew that dust was getting into the equipment during pump repairs, no matter how much they tried to keep it out during the re-assembly process.
A study of that plant's pump failures over an 18-month period found that 13% of the failures were early bearing failures. Most of those had early bearing faults, and more than half were attributed to contaminated repairs, after ruling out contaminated lube oil. Such a high pump-failure rate more than justified the capital required for installation of a clean assembly room for repairing the machinery. Rather than accepting 80+ months pump MTBR as good enough, the reliability-centric organization looked for additional ways to improve, and installation of the clean room had the potential to make a step change in the MTBR of the plant.
Startup after repair
|Craig D. Cotter, PE, CMRP, is a maintenance specialist with 21 years of experience in refining, chemical, and E&P organizations in the areas of reliability engineering and maintenance management. He’s a member of SMRP and the Vibration Institute with a Category III certification. Contact him at (281) 413-9475 or [email protected].|
Once the equipment is repaired, startup assistance from engineering and maintenance ensures that the equipment is returned to service properly without undue stresses on the unit. A detailed startup checklist must be used each time the equipment is started up following maintenance and should also be used when performing monthly equipment swapping. The first phase of implementing such a program includes preparing this checklist and training personnel on its use and implementation. Initially, machinery engineering personnel should be present for the equipment startup while operations staff can use the checklist to start the equipment, and then reliability personnel confirm the equipment status and assist in the startup operations. As the organization matures, operations personnel can start up the equipment without the assistance of the reliability department, but operations must ensure compliance of the process through audits.
As a best practice, all startup and equipment swaps should occur during the day when maintenance and reliability personnel are in the plant. The old saying, “Nothing good happens after midnight,” applies to equipment startups. However, there are times when equipment must be started on an emergency basis, and operators properly trained on the checklists can make the off-hour startups much more effective.
With the equipment repaired properly by maintenance, and the unit restarted by operations, the organization is on the right path to becoming reliability-centric. However, sometimes equipment is misapplied, and often plant conditions change, causing the equipment to operate outside its design parameters. In these cases, even the best operators and the best repair technicians will not get these bad actors to perform at a level that meets the business unit’s operational goals, and this is where reliability engineering comes into play.