potential failure are also treated as CM work. It really doesn’t matter how we classify the work as long as we know what goes in each bucket/box and it is done the same way every time.
Subject-matter experts and authors classify maintenance practices in different ways based on their experiences. Each practice can be effective based on the work environment and how we apply it.
Here are examples of ways to classify maintenance practices:
Classification A
Broadly speaking, maintenance can be classified into two major categories (Figure 3.2):
1. Preventive maintenance—what we do to prevent failure before it occurs
2. Corrective maintenance—what we do after a failure to bring it back to operation
FIGURE 3.2 Maintenance Practices—Classification A
The effectiveness of these tasks, whether preventive or corrective,greatly depends on how we execute them. If they are completed in a planned and scheduled manner, they are much more cost-effective than if they are completed in unscheduled mode. Task execution will be discussedfurther in Chapter 4, “Work Management: Planning and Scheduling.”
Classification B
In this classification, tasks are further divided into PM (TBM and RBM), CBM, OBM/TPM (operator-performed), CM (planned; all work resulting from PM, CBM, and OBM), and breakdowns (reactive), as shown in Figure 3.3.
FIGURE 3.3 Maintenance Practices—Classification B
Classification C
Some subject-matter experts classify these categories as shown in Figure 3.4.
These classifications of maintenance approaches are just a few examples. It ultimately doesn’t matter how we classify them. What’s more important is that the right data is collected and analyzed to make improvements. Our objective is to:
• Conduct more and effective PM and CBM to catch the problems before they turn into failures.
• Find problems and issues during PM and CBM tasks and get them fixed cost-effectively.
• Minimize failures and breakdowns.
• Get an asset fixed, if and when it fails, as quickly as possible,but safely.
Maintenance practices can be used not only to form a more structured maintenance program, but also to define an organization’s program. One key practice that companies use to effectively execute their maintenance program is related to operator-based maintenance, including the use of operators in designing for maintenance and reliability.
FIGURE 3.4 Maintenance Practices: Classification C
Operator-Based Maintenance
Unlike what is typically assumed, the operator is actually one of the most important members of the maintenance team. Well-informed,trained, and responsible operators will ensure that assets are being kept in good working order.
Operators are the first line of defense against unplanned asset downtime. Operator-based maintenance (OBM) assumes that operators who are in daily contact with the assets can use their knowledge and skills to predict and prevent breakdowns and other losses.
The main objective of an operator’s maintenance program (aka an autonomous maintenance program) is to equip operators with the following asset-related skills:
• Ability to detect abnormalities
• Ability to correct minor abnormalities and restore function if they can
• Ability to set optimal asset conditions
• Ability to maintain optimal equipment conditions
Autonomous maintenance is one of the basic pillars of total productive maintenance (TPM). TPM is a Japanese maintenance philosophy that involves operators performing some basic maintenance activities. This practice will be discussed further in Chapter 7, “Operator-Driven Reliability.”
The operators learn the maintenance skills they need through a training program. They then perform the following tasks:
• Conduct general inspection.
• Keep assets clean and all areas accessible.
• Identify and eliminate problem sources.
• Support and create cleaning and lubricating standards and procedures.
• Standardize through visual workplace management.
• Implement autonomous asset management.
• Perform minor maintenance and service items, e.g., replacing filters, lubricating, and changing the oil.
• Work with the maintenance team to repair what they are unable to perform.
The operators use the following four sensory tools to identify problem areas, then either fix them or get help to repair the problems before they turn into major failures:
1. Look for any abnormalities—clean, in place, accessible.
2. Listen for abnormal noises, vibrations, leaks.
3. Feel for abnormal hot or cold surfaces.
4. Smell abnormal burning or unusual odors.
The following suggested measures could help in achieving that goal.
Operator Involvement
Operators can detect any abnormalities and symptoms at an early stage and correct them before they turn into major failures. O&M personnel can ensure that all the assets are properly secured and bolted. The support structures—piping, hoses, guards, etc.—should not be loose or vibrating; they should be properly fastened.
Cleaning
Cleaning leads to inspection and timely detection of any incipient failures like cracks and damaged belts. Dirt and dust conceal small cracks and leaks. If an asset is clean, we could assess if things are not working right, e.g., leaking, rubbing, and bolt loosening, which may be an indication of incipient failure.
Keep assets and the surrounding area clean. A clean asset creates a good feeling and improves employee safety and morale.
Lubricating
Lubrication helps to slow down wear and tear. Check if components are being lubricated properly with the correct type of lubricants and if oil is being changed at the proper frequencies. Don’t overlubricate; use the right amount. Ultrasonic guns can be used to ensure the required amount of lubricant is used. Apply 5S plus or 6S practices to have a lubrication plan, with pictures identifying all lube points and the type of lubricant to be used.
Operating Procedures
All operating procedures available at the site should be current. Are these procedures easily understood? Do operators know how to shut