Probabilistic Life Assessment

Probabilistic Assessment - providing realistic estimates of component remaining life

In the increasingly cost-competitive market, accurate and timely information on equipment condition is vital for input into repair/replacement strategies and associated costs. This results in an increased need for more reliable and realistic life prediction methods, particularly for aged equipment/plant. 

Existing remaining life evaluation techniques and defect assessment procedures are deterministic, in that they require specific data input. In most practical situations, the key inputs to a deterministic life assessment are not single valued but distributed - through spatial changes (e.g. thickness, temperature, stress, etc) or temporal variability (e.g. operating conditions, ageing, etc) through the imprecision of measurements and scatter in the data (e.g. inspection, on-line monitoring data, materials data, etc.) 

To take into account these uncertainties/variations, the deterministic assessment is based on the “worst-case scenario” and conservative values/bounds for the inputs are used in the analysis. However, this generally provides an overly conservative and unrealistic result. 

One way to provide a more realistic estimate of the component remaining life is to use a Probabilistic Approach that enables statistical quantification of the variation in the key inputs in terms of a nominal value and the scatter or drift around this value.

Click here to access any of ETD's downloadable service brochures, including P91 & P92 Inspection.

For more information on Probabilistic Life Assessment please contact us.

Comparison of the deterministic and probabilistic approaches to life assessment, showing that the probabilistic approach allows longer component operation