Claire Weatheritt is the Global Manager for John Crane’s Business Solutions PMO, responsible for delivering Reliability, Condition Monitoring and Maintenance Engineering projects for our customers globally. With over 20 years of experience in machinery diagnostics and condition monitoring, she spent the first 15 years of her career in the North Sea oil rigs, working with some of the top operators to achieve best-in-class performance and has applied the same principles to help plants in the Gulf Coast Region improve their reliability. She is a Chartered Engineer with the Engineering Council, a Prince2 practitioner and has an MEng degree (Electrical and Mechanical Engineering) from the University of Strathclyde.
Condition-based Maintenance (CBM) and Condition Monitoring (CM) may look similar and are often used interchangeably. However, these two aspects of maximizing plant uptime and reducing risk are different. We have created a five-part series to help you learn more about CBM and CM and their essential role in helping you increase reliability, reduce maintenance costs and lower the total cost of ownership.Condition Monitoring and Condition-based Maintenance Defined
CM is a range of activities undertaken to determine the condition of an asset. Correctly applied, this supports the identification of faults ahead of failures.
On the other hand, CBM is the philosophy of maintaining equipment based on its condition rather than on a fixed schedule or allowing it to run to failure and is dependent on effective CM. CBM should be applied strategically to ensure the correct monitoring techniques are used on the proper schedule and the measurements are correctly set up.
Where technically and economically feasible, CBM strategies offer the lowest lifecycle cost by maximizing plant uptime and reducing risk.Strategy
A strategic mix of reactive, time-based monitoring and CBM is typically applied across a plant. Determining the strategy is generally based on the asset register, the criticality of the machines, the failure modes and the detectability of those failure modes.
Under a CBM strategy, the goal is to intervene at the right time – not too early or too late. The aim is to monitor the parameters that warn of unsatisfactory operating conditions or equipment deterioration so maintenance actions can be taken before unwanted consequences occur.Running a CM Program
Depending on the techniques selected, the data collection will be done manually, wirelessly or continuously online. This will help identify any anomalies and provide a warning if the equipment is operating incorrectly or if a potential failure can occur. If the program is well-established, corrective action or maintenance needs can be promptly addressed when issues are detected.
No matter how detailed the analysis used in the strategy assignment, data feedback from the operation is a necessary part of the control loop on the management controls. This enables the program manager to either keep doing what works or make a change.
CM can involve combining techniques, including observations from operator rounds, lubricant analysis and performance monitoring. Whatever method is selected must be technically feasible, detect the failure modes to be defended against, meet the organization’s requirements and be economically justified. If it does not do that, the strategy must be revisited. For example, when an unexpected failure occurs, it is vital to examine the following:
- Was it detected?
- Could it have been detected with different techniques?
- Was the correct strategy applied?
- If it was detected, why wasn’t it addressed?
An effective CBM program should be used to support reliability improvement and can help the site team to:
- Minimize the downtime of equipment to avoid exposure to the risk of plant downtime, improving uptime and reducing costs
- Eliminate root causes of failure, inefficiency, waste and excessive costs
- Prioritize the maintenance of assets
- Manage its spare parts
- Ensure each unit runs to its fullest expectable Mean Time Between Overhauls (MTBO)
- Assist in assessing realistic MTBOs
- Reduced insurance premiums
- Assurance that operations can be continued safely
Many plants succeed in attaining improvements by embedding CBM in the culture. Others have failed to succeed, even with a highly competent CM program.Experience in CM and CBM
John Crane's CM services can enable you to address potential problems before they negatively impact your operations. In close collaboration with you, we will develop a reliability-based maintenance strategy for cost-effective operation and increased reliability based on your plant requirements. Learn more here.