Condition-Based Maintenance

What is Condition-Based Maintenance?

Condition-based maintenance (also known as CBM) is maintenance done when the condition of an asset indicates that it is needed. With this approach, maintenance teams regularly check the condition of their equipment. When they find signs of wear and tear, a preventive maintenance task is scheduled to avoid a breakdown.

The condition of an asset can be checked with:

• Visual inspections
• Non-destructive (NDT) tests
• Data gathered by different sensors or tools

Condition-based maintenance vs predictive maintenance

It is easy to confuse CBM with predictive maintenance. They share a similar approach. But predictive maintenance or PdM combines condition-based monitoring (measuring vibrations, temperature, pressure, and other things that have a predictable pattern) with formulas and algorithms that predict when a piece of equipment might fail.

CBM on the other hand, uses measurements of things like pressure or temperature to trigger work orders. CBM does not use complicated formulas to find patterns or make predictions.

What is the goal of CBM?

The main goal of condition-based maintenance is to make the most of your maintenance resources by performing work only when an asset’s condition requires it.

Instead of triggering a PM based on time or usage intervals, CBM goes one step further, triggering work based on condition. For this reason, CBM helps make sure your team performs maintenance only when an asset truly needs it.

Table of Contents

Measuring asset condition with condition monitoring
Downsides of condition-based maintenance
Requirements for implementing CBM
Conclusion

Measuring asset condition with condition monitoring

Condition monitoring is the process of measuring an asset’s condition regularly. This helps teams identify changes or wear and tear in an asset that might need maintenance. Unusual measurements may also indicate that a failure is about to happen. 

There are many different kinds of measurements used to detect maintenance needs. Teams choose methods based on an asset’s design and function. Here are a few of the most common. 

Vibration analysis

Vibration analysis is used for rotating equipment like compressors, centrifugal pumps, and motors. Vibration monitoring sensors installed on equipment measure axial, vertical, or horizontal movement, and trigger work when vibration levels become too high.

Lubricant analysis

Lubricant or oil analysis is a non-invasive technique for assessing the condition of a machine. It works by analyzing the viscosity of lubricants and the number and size of particles (debris) such as iron, silicon, aluminum silicate, etc. in oil samples to determine wear and tear.

Infrared thermography

Radiation and temperature are invisible to the human eye but easily and quickly detected by infrared cameras. These cameras watch for temperature changes in equipment that may be a sign of deterioration.

Ultrasonic analysis

Malfunctioning equipment makes a sound that ultrasonic sensors can hear but humans cannot. These sensors can be applied to a very wide range of machinery. They quickly alert operators about issues like deep subsurface defects and corrosion, leaking gases, and over or under lubricated bearings. This method is also ideal for ensuring safety in some electrical inspections, especially in situations involving closed gears.

While these are the most commonly used methods, this is not an exhaustive list. Other methods include corrosion monitoring, pressure analysis, motor current analysis, visual inspections, and more. For a deep dive, check out this in-depth list of condition monitoring techniques.

Benefits of condition-based maintenance

All proactive maintenance strategies have similar advantages. They include:

• Reduced number of unplanned asset failures and downtime incidents.
• Improved equipment availability, reliability, and worker safety.
• More efficient PM scheduling that avoids peak production times.
• Increased asset lifespan.
• Improved equipment performance.

Advantages of CBM over basic preventive maintenance 

Because of the special equipment and techniques involved, there can be a higher upfront cost to using condition-based maintenance. 

So what makes that cost worthwhile? The biggest benefit of CBM over other kinds of PM is the increased accuracy of planning maintenance work. Here are some practical ways that can impact your asset management program: 

• Minimizing labor costs by eliminating unnecessary maintenance.
• Minimizing PM or downtime service interruptions on your most critical assets.
• Improving inventory management by having (only) the parts on hand that you need.
• Reducing response time by monitoring conditions in real-time.

Downsides of condition-based maintenance

The key to getting any maintenance program right is striking the balance between cost and benefit. That balance will be different for every organization. 

Make sure to consider the downsides or costs of any maintenance strategy. This will help you make sure it is a worthwhile fit for your organization. 

Here are some things to consider if you are thinking about implementing CBM. 

• Condition monitor tools can be expensive to purchase and install. 
• Choosing the right sensors takes time, research, and expertise.
• Training your team to use CBM technology effectively requires an investment of its own.  
• Harsh or extreme working conditions may damage sensors, or make it difficult for them to work properly, especially when trying to detect fatigue damage.
• Waiting until conditions warrant maintenance may mean that you have less control over when to perform it, and multiple assets requiring maintenance at the same time can strain your team. 

In many organizations, the potential to reduce maintenance costs will outweigh these considerations. If so, CBM is a great option.

Requirements for implementing CBM

If you have considered all the benefits and costs of CBM and decided it is the right method for you, the next step is making sure your team is ready.

Here are some basic requirements that will ensure CBM is a success. 

• Condition monitoring sensors installed on applicable equipment. 
• Condition monitoring tools needed to take condition measurements.
• Staff properly trained in reading and using CBM technology for measurement, data analysis, and scheduling.
• A maintenance team willing to learn and adapt to changes in their workflow.
• A CMMS software or other software to collect data from CM sensors. 

For an in-depth look at what a CMMS is, check out our What is a CMMS System and How Does it Work guide.