Maintenance Matters Focus on: Condition Monitoring 14 | Plant & Works Engineering www.pwemag.co.uk October/November 2026 The business case for condition monitoring is strongest when framed around financial impact rather than technology. Its value lies in reducing both the likelihood of failure and the severity of its consequences. In many cases, avoiding a single major failure is enough to recover the full cost of the monitoring system. A practical way to understand this value is through risk, which can be expressed as the product of consequence and likelihood. If a compressor failure results in £500,000 of combined production loss, labour and spare parts, and it occurs once every ten years, the annualised risk is £50,000. If the same failure occurs every two years, the annual risk increases to £250,000. When a condition monitoring system detects early signs of failure and allows corrective action before damage occurs, that risk is either reduced or eliminated. The resulting financial benefit translates directly into ROI. Assessing ROI ROI is typically assessed using two measures: the payback period, which describes how quickly the investment is recovered, and the ROI ratio or percentage, which compares the benefits achieved over a defined period against the total cost of ownership. To produce a credible ROI calculation, both benefits and limitations of condition monitoring must be considered. Failure consequences vary significantly in severity and must be evaluated accordingly. At the lowest level are normal losses, which include production losses and maintenance costs during planned shutdowns. More severe are probable maximum losses, such as major repairs or full machine replacement combined with extended downtime. At the extreme are maximum possible losses, which may involve catastrophic equipment damage, safety or environmental incidents, fires, or prolonged business interruption. Condition monitoring delivers value by reducing the frequency of these events and by limiting their escalation. The largest contributor to ROI is typically reduced lost production. Preventing unplanned downtime improves availability, which often accounts for the majority of financial savings. For example, avoiding five hours of downtime on a machine producing £10,000 per hour results in £50,000 of preserved output. Alongside availability, labour savings are achieved through fewer emergency repairs, reduced overtime and more efficient maintenance planning. Maintenance records provide a reliable baseline for estimating these savings. Spare parts costs also decline as maintenance becomes more targeted. Early fault detection prevents secondary damage and avoids replacing components that are still in good condition. Energy consumption, while more difficult to quantify, can also be reduced. Machines operating in poor mechanical condition often consume more power, Making the business case for condition monitoring As production plants push existing assets harder and rely on machines that were once considered redundant, reliability has become a direct financial concern. With limited backup capacity, equipment failures now lead immediately to lost production, higher maintenance costs and increased operational risk. In this environment, condition monitoring is no longer justified primarily on technical grounds, but on its ability to deliver a measurable return on investment (ROI). James Donnelly* explains further.
RkJQdWJsaXNoZXIy MjQ0NzM=