Maintenance and Reliability Best Practices. Ramesh Gulati
Читать онлайн книгу.
A group of people (or an individual) that has its own functions with responsibilities and relationships to achieve its objectives. The organization includes, but is not limited to, sole trader, company, corporation, enterprise, department, plant or factory, partnership, charity or institution, or part or combination thereof.
Reliability
The probability that an asset or item will perform its required functions for a specific period under stated conditions. It is usually expressed as a percentage and calculated using mean time between failures (MTBF).
What Do Best Practices Have to Do with Maintenance and Reliability?
In any organization, assets are needed to produce products or provide services. An item or asset, as defined here, could be an electrical/electronic or mechanical hardware component or device, a building, a software product, or a manufacturing system or process.
A well-designed, robust M&R program is required to ensure that assets are available and cost-effectively performing to their designed capacity when needed in an organization. The performance of an asset is based on three factors (see Figure 1.1):
1. Inherent reliability—how it was designed
2. Operating environment—how it will be operated
3. Maintenance plan—how it will be maintained
FIGURE 1.1 Asset Performance
Usually, assets are designed with a certain level of reliability. This designed-in (or built-in) reliability—inherent reliability, the first factor in the list above—is the result of the individual components’ reliability and the way they are configured. We cannot change or improve the reliability of an asset after it has been installed unless we replace or modify it with better and improved components (with the exception of redesigning it).
The second factor, the asset’s operating environment, considers both the operating conditions under which the asset has to operate and the operator’s skills. Several studies have indicated that 40% or more of all failures are the result of operational errors or lack of understanding. Organizations need to ensure that operators are appropriately educated and trained in operating these assets without causing operational errors that lead to failures. In fact, operators should be the first line of defense both in monitoring the asset’s performance and any abnormal conditions and in initiating timely corrective actions.
The third factor is a maintenance plan that defines how the asset will be maintained. The objective of a good maintenance plan is to sustain asset reliability and to improve its availability. The plan should include the necessary maintenance and service-type actions needed to detect potential failures before they lead to unscheduled downtime.
Reasons for Not Implementing Best Practices
Over the years, the author has conducted many maintenance and reliability best practices workshops and has discussed failures of implementing best practices with hundreds of participants. These discussions concluded that the top 10 excuses or reasons for failure in implementing best practices are:
1. We thought we had a better way.
2. Our current process was working—why change?
3. We tried this before, and it didn’t work.
4. It was too hard.
5. We didn’t understand why it was necessary.
6. We didn’t trust our system vendor.
7. The vendor told us it was not necessary.
8. Our company (our process) is different (unique).
9. We could not afford it.
10. We did not have the time.
Examining these excuses, we can derive these four fundamental reasons not to implement best practices:
• Failure to understand the business operational risks
• Inability to correlate best practice cause and effect
• Fear of change
• Budget and schedule constraints
So what do best practices have to do with these principles of maintenance and reliability? Throughout the many years of the maintenance and reliability industry, good and bad practices have been identified. These practices, both the good and the bad, have been brought up in briefings at national and international conferences, discussed in person and over the airwaves, and written about in magazines, books, websites,and blogs. The best of these practices are now becoming more accepted and more widely published at the local, national, and international level,becoming the benchmarks that companies seek to achieve. Throughout this book, we will be discussing best practices related to maintenance,reliability, and asset management and how they can be implemented effectively to improve asset performance and reduce the overall cost of asset ownership.
Examples of Maintenanceand Reliability Benchmarks
What are the best practices in the maintenance and reliability field, and how can they be implemented to get better results? M&R best practicesare practices that have been demonstrated by organizations that are leaders in their industry. These companies are the quality producers with very competitive costs, usually the lowest in their industry. Figure 1.2 lists a few examples (by no means an exhaustive list) of maintenance and reliability best practice benchmarks along with their related typical world-class values. Benchmarks are discussed in more detail in Chapter 9.
The first value shown in Figure 1.2, maintenance cost as a percentage of replacement asset value (RAV), is a maintenance performance measure used extensively as a benchmark for evaluating best practices. We can immediately identify the cost differences between companies that are typical and companies that are world class or best in class. However, typical companies are likely to spend more to build up their maintenance and reliability program. Then, once they have achieved the desired level of reliability and availability, they should be able to reduce the maintenance cost by continuing to apply the best practices.
FIGURE 1.2 Comparing Best Practices Benchmark
We need to be very diligent in using these benchmarks for comparative purposes because definitions of these benchmarks can vary from one organization to another. It is significantly important to ensure that the terms used by the two organizations have the same meaning. The performance measures in Figure 1.2 have been included to demonstrate this.
Note: The Society for Maintenance & Reliability Professionals (SMRP) has done an excellent job defining and standardizing many of these benchmark metrics. The author has been involved with that effort for many years.
The details of a few maintenance and reliability best practice benchmarks along with their related typical world-class values as shown in Figure 1.2 are as follows:
1. Maintenance cost as a percentage of RAV. This measure is calculated as maintenance cost divided by the replacement asset value. In this benchmark, two factors must be defined in order to ensure a comparison is accurate:
a. Maintenance cost. This cost of maintenance for a plant or facility includes maintenance labor, maintenance