Maintenance is evolving.

The availability of new sensing technologies and products has enabled a move away from the older Reactive Maintenance (run to failure) and Preventive Maintenance (time based) approaches to the condition based strategy of Predictive Maintenance (PdM).

The rationale for PdM is that by carrying out maintenance only when it is required and by preventing machinery failures, costs are reduced and productive output is increased.

However, PdM requires upfront costs for the sensors and their installation. So, here are five things we feel support the case for condition monitoring and the return on investment it can offer.

1. Using case studies and cost justification exercises, the following comparative maintenance costs relating to power generation are;

• Reactive maintenance – $17.00
• Preventive maintenance – $13.00
• Predictive maintenance – $9.00

(costs in US$,per Horsepower per year – Source; The Electric Power Research Institute)

2. The following benefits have been attributed to condition monitoring;   

• Maintenance costs reduced by 50%
• A reduction of 55% in unexpected failures
• Repair and overhaul times down by 60%
• A reduction of 30% in the spare parts inventory
• The Mean Time Between Failures (MTBF) rate increased by 30%
• Uptime increased by 30%
  (‘Plant Engineer’s Handbook’ by Keith Mobley)

These figures may seem high, but in a typical manufacturing plant, a 10% reduction in maintenance costs has the same benefit to the bottom line as an increase in sales of 40%.  Additionally, studies have shown that a properly implemented Predictive Maintenance programme supported by condition monitoring can replace up to 30% of Preventative Maintenance tasks.

 3. Predictive Maintenance using one or more sensors is shown to decrease machine downtime four times more effectively than other methods. (Plant Engineering Magazine)

 4. The measurable benefits Predictive Maintenance programmes in the oil and gas industry have shown, on average, are;                        

• Return on Investment – 10 times
• Reduction in maintenance costs – 25 to 35%
• Elimination of breakdowns – 70 to 75%
• Reduction in downtime – 35 to 45%
• Increase in production – 20 to 25%
  (US Department of Energy)

 5. In relation to oil analysis as a condition monitoring technique-

     “6.3.5 Equipment Cost/Payback

For facilities utilising a large number of rotating machines that employ circulating lubricant, or for facilities with high dollar equipment using circulating lubricant, few predictive maintenance technologies can offer the opportunity of such a high return for dollars spent. Given the high equipment replacement cost, labour cost, and downtime cost involved with a bearing or gearbox failure, a single failure prevented by the performance of oil analysis can easily pay for a programme for several years.”
(US Department of Energy’s O&M Best Practices Guide Release 3.0)