Condition-Based Maintenance (CBM) Explained

Imagine a world where production lines run smoothly at optimal levels all the time. A few days before a critical asset fails, a notification is sent to your maintenance team alerting them to the impending problem, giving them adequate notice to schedule downtime and perform the service or repair.

Ideally, that’s the world a condition-based maintenance program creates for today’s manufacturing and production businesses. Understanding the concept, benefits, challenges, applications, and strategies can help companies select the best assets for condition-based maintenance. The following guide is designed to help you get started.

What Is Condition-Based Maintenance?

According to Reliable Plant, “condition-based maintenance is a maintenance strategy that monitors the real-time condition of an asset to determine what maintenance needs to be performed.”

Condition-based maintenance may be performed using predictive maintenance tools like sensors that provide around-the-clock monitoring of critically important performance data such as the temperature of a commercial freezer for a food manufacturer. Conditions like pressure, humidity, vibration, and others may all be indicators of potential problems and impending failures. In addition, periodic tests or visual inspections can also trigger condition-based maintenance work orders.

Part of a complete maintenance program, condition-based maintenance works hand-in-hand with other maintenance strategies including preventive maintenance that focuses on performing inspections, work based on a calendar or usage schedule, or run-to-failure maintenance that waits for non-critical components to break down before replacing or repairing.

Types of Condition-Based Maintenance

Given the variety of assets and equipment used in today’s manufacturing and production world, many types of condition-based maintenance exist. Some of the most common include:

Vibration Monitoring

By measuring the levels of vibration and frequencies of equipment, maintenance teams can determine the condition and performance of different assets and their components. This information can help technicians spot pre-failure issues such as worn out bearings, resonance, imbalance, components that have become loose, and damaged shafts.

For example, rotating equipment tends to vibrate more as it ages, potentially affecting its performance, overall lifespan, and safety of operators. Vibration may become louder, more frequent, or faster before complete failure or a dangerous scenario occurs. Thus, vibration analysis can help spot issues such as these before major problems or damage happens.

An article by Reliability Maintenance Solutions advises, “when gathering data, you want to ensure you’re gathering the complete data set. In other words, you need to get a full vibration signature for the vertical, axial, and horizontal axes on the driven equipment as well as both ends of the motor. And ensure that you will be able to resolve any indications of failure from the components within the asset.”

Infrared Thermography

This type of condition-based maintenance uses a thermal imager that simply measures the amount of heat produced by a component or machine and visually displays that data for analysis. Ideally, a maintenance team has established baseline temperature levels for all critical assets, which can then be used to compare ongoing measurements. When a machine is overheated, this level will then clearly exceed the baseline, alerting the team of potential problems.

Several different types of infrared thermometers can be useful in various applications:

• Pyrometers. Also known as spot infrared thermometers, pyrometers are handheld radar guns that can check the temperature of a particular item. They work well for hard-to-reach assets such as bearings and belts, electrical room components, fluid-handling systems, or rotating motors. Pyrometers use a field of view and distance-to-spot ratio.
• Scanning Systems. Unlike spot thermometers, infrared scanning systems can monitor larger areas such as the area over a conveyor belt for heat changes.
• Imaging Cameras. By checking heat at various points within a larger area, these cameras can deliver a two-dimensional picture for further analysis.

Ultrasonic Analysis

Instead of using heat as infrared thermography does, ultrasonic analysis puts sound to work. These measurement tools can convert high-frequency tones to actionable data. For example, an organization may use contact or structure-dependent collection to detect potential problems in bearings, gears, or pumps, which will produce a high-frequency sound before failure. In addition, non-contact or airborne measurements can detect vacuum or pressure leaks within electrical or compressed gas systems.

Oil Monitoring

Oil is often known as the lifeblood of equipment as it courses through critical components of a machine. It stands to reason then that analyzing that oil can provide insight to the asset’s performance and trigger condition-based maintenance activities. When checked regularly, oil can indicate whether an asset is performing optimally, if additives are depleted, and whether contaminants are present. By checking oil properties and viscosity, a maintenance team can study which elements may be caused by corrosion or other mechanical degradation.

Electrical Analysis

Machinery tends to pull different amounts of electricity throughout its performance, and conducting a thorough electrical analysis can be another useful tool in a condition-based maintenance program. This tool can check the quality of incoming power by taking the current readings from a motor using ammeters, which then alerts maintenance technicians which equipment is pulling an unusually high amount of electricity.

Pressure Monitoring

Poor pressure within assets that require gas, air, or fluid to move throughout their system means suboptimal performance, while abnormally high pressure can cause employee safety issues. Sensors that can monitor pressure around the clock means that alerts can be sent immediately when pressure ranges are not met so appropriate repairs can be performed before major failure or injury occurs.

When to Use Condition-Based Maintenance

Maintenance programs are diverse, and it’s important that organizations select the right balance of different types of maintenance to be most effective. Condition-based maintenance has its strengths and is best for applications that require constant or regular monitoring of a factor that can reliably alert technicians to impending failures. These should be critical assets required for optimal production line performance or employee safety. The most common applications are:

Temperature-Sensitive Assets. Temperature is a significant and easily measured indicator of equipment performance. It can be applied in a wide variety of situations. For example, ensuring a freezer remains within safe temperature ranges guarantees quality and safety in the food industry, keeping a motor within acceptable temperature ranges prevents overheating, and monitoring building temperatures can keep employees comfortable while conserving energy.

Pressure-Sensitive Applications. Sensors that can take continuous pressure readings do a great service to organizations that depend on assets using pressured air, water, or gas for their operations. Not only can tiny leaks be detected immediately using drops in pressure, but major damage and employee injury can be prevented if high-pressure situations can be mitigated as soon as they occur.

Oil-Reliant Equipment. The most common assets that benefit from oil analysis condition-based maintenance are vehicles. Just like your personal car requires regular oil changes, fleet equipment or other transport equipment do as well. Instead of basing these oil changes on time or usage, analyzing the oil viscosity and particles can help better predict the life of the oil and when it requires replacement for optimal performance.

Benefits of Condition-Based Maintenance

Implementing a condition-based maintenance component within your overall maintenance program can generate a great deal of benefits for your organization. Some key benefits include:

Increased Reliability. When your assets can essentially “tell” you when they are about to fail, you’ll be able to experience much higher equipment reliability.

Decreased Downtime. This, in turn, decreases downtime, which means your operators stay busy during their shifts and your equipment works at optimal levels.

Higher Productivity. Long-term, this means higher productivity. More quality products can come off your lines, keeping customers happy and revenue climbing.

Reduced Maintenance Costs. Keeping your assets running smoothly is important, but too much unneeded maintenance can be costly. Condition-based maintenance means you are zeroing in on the problems that need to be fixed immediately, maximizing those maintenance dollars.

Rapid Failure Identification. Since potential failures can be triggered by temperature or pressure sensors, you’ll be notified quickly of problems.

Reduced Unplanned Failures. As a result, you can generate work orders for scheduled downtimes instead of shutting down a line for emergency maintenance.

Improved Safety. Since condition-based maintenance can “catch” problems before they become significant issues, you’ll be able to keep employees safer.

Increased Asset Lifespan. Small problems in equipment, left unchecked, can not only cause bigger problems but can result in further damage and larger, more expensive repairs. Condition-based maintenance can mean adding years of life to critical assets.

Challenges of Condition-Based Maintenance

Before implementing condition-based maintenance, it’s important to understand that typical challenges will often arise. Here are the most common.

High Initial Investment. Starting off on the right foot with selecting critical assets, establishing baseline measurements, and purchasing and implementing appropriate sensors and analysis programs can be expensive. You’ll also need significant human resources to do the initial work of collecting data and prioritizing assets in establishing a condition-based maintenance program.

Ongoing Training. Once you’ve selected the best assets for condition-based maintenance and invested in sensors to monitor key performance factors, you’ll need trained technicians and employees to properly analyze and understand the alerts and data. The maintenance team will need to understand what each alert means and how quickly work orders must be completed to prevent complete failure, further expensive damage, or an accident or injury. Although training will require additional resources, both in costs of the training itself and the time required to receive the training, it is imperative to a successful, sustainable condition-based maintenance program.

Managing Harsh Environments. Often sensors need to operate in harsh or sub-optimal working conditions, making it potentially more difficult to obtain accurate data. Selecting the right kind of sensors to monitor your equipment will be key to reliable readings and alerts.

Uncertain Maintenance Planning. Although it’s always desirable to understand what a technician’s day will look like in terms of maintenance tasks, condition-based maintenance by nature is unpredictable. As soon as a sensor is triggered by a factor falling out of range, the maintenance team may need to shift gears, depending on the severity of the problem. This can disrupt the workflow for the day as well as cause unexpected and irregular budgetary expenses.

Technology Support. Since condition-based maintenance requires a massive amount of data, potentially collected from multiple sensors on various pieces of equipment, you’ll need a technology and software system to support, organize, capture, manage, and analyze all this information. Selecting the right partner and program can require additional time and resources.

How to Optimize Condition-Based Maintenance

Now that you understand the basics of condition-based maintenance, it’s time to take the next step and learn how to optimize it for your organization. Incorporating condition-based maintenance into an overall asset operations management (AOM) program will ensure your investment is well-spent with the people, processes, and technology aligned to optimize its benefits.

Find Your Baseline

It’s pretty much impossible to measure improvement if you don’t know where you’re starting. That’s why it’s important to intimately know your critical assets, the things you can measure for optimal performance, and your failure modes. Once you have that data, you will be able to accurately calibrate your sensors and other analysis efforts to alert you to any potential failures as soon as they occur, allowing you to address them as soon as possible.

Start by identifying which assets are the strongest candidates for condition-based maintenance. Ideal assets can be monitored effectively by one or more of the methods previously defined and can alert the maintenance team of potential problems with enough time to take action in a cost-effective manner.

Begin by establishing the baseline performance or acceptable ranges for the factors that you’ll be monitoring such as minimum and maximum temperatures, frequencies, or pressures. You may want to check the manufacturer recommendations for certain assets or look at historical data for that piece of equipment to set appropriate baselines. Once those are determined, implement the sensors or analysis programs you’ll use for monitoring.

Create a P-F Curve

Since the potential failure or P-F curve was created in the 1970s for United Airlines and the U.S. Department of Defense to help reduce losses and downtime, organizations have been using this tool to help visualize the health of assets over time.

Using an X-Y axis, this curve shows a relationship between equipment deterioration, cost, and prevention. Toward the beginning of the curve, an asset may still be functioning fine but in the early stages of breakdown, which may trigger certain behavior or cues. As time marches on, the chance or severity of failure becomes greater and the cues or triggers may become more frequent until the asset actually stops working all together. 

The time interval between potential and predicted failure is where your condition-based maintenance must occur in order to be effective, forming the crux of a successful condition-based maintenance program.

Implement AOM Technology

AOM technology pulls together the best of maintenance, operations, and reliability data and processes to help organizations make the smartest business decisions with complete visibility across the entire lifecycle of maintenance, asset management, and operations. 

By utilizing AOM, companies are able to take manufacturer guidelines along with performance and historic repair data to decide what maintenance tasks need to be performed and how frequently. Then, an AOM software solution records sensor data, initiates necessary work orders, facilitates repairs, and logs completed work for an accurate asset history.

All this information is readily available to the entire organization so further analysis and asset-based decisions can be made on an ongoing basis.

When AOM and condition-based maintenance work together, an organization can ensure the right parts are available on time and that work is performed before major problems ensue, but not so frequently that precious resources are wasted.

Build the Right Culture

For AOM technology and condition-based maintenance to be sustainable and successful for the long-run, you need to create the right culture and offer ongoing training to staff, technicians, and all employees. Technicians who understand their actions and attitude about the value they individually contribute are an important component of condition-based maintenance success. Not only will they be more effective in using the tools, but they will seek opportunities to improve the entire process.

Training should be thorough and ongoing including an explanation of the different ways condition-based monitoring can be done. Employees should understand how this concept applies to all critical assets, what they need to do to ensure data is logged properly, and how important timely repairs are to prevent complete failure.

Conclusion

Condition-based maintenance is a key component of any overall maintenance program. For certain assets that have specific measurable factors such as temperature or pressure readings that can signal potential failure, condition-based maintenance can be an excellent way to optimize maintenance activities to prevent complete failure while minimizing overall maintenance costs.