Probability of failure

(initial estimate)

Consequences of failure

Level of risk


Cost of replacement


By consideration of the cost of replacement and level of acceptable risk (probability of failure), a CAPEX program can be determined for replacement/rehabilitation of an existing main.

capital expenditure

Example of CAPEX output for System of pipelines

The economic lifetime of any pipe system can be optimised by targeting the areas of critical mains most likely to fail and prioritising their proposed rehabilitation or replacement cost. The result is to reduce expenditure on mains failure risk while maintaining customer supply. Thus, a tool for quantifying risk and replacement can be given to the owner of the asset to
match risk against budget.

Savings in capital expenditure can be channelled into an increased level of pipeline monitoring which can fine tune the inputs into the above model. Comprehensive telemetry linked to integrated asset management systems are one example of this, expert diagnosis of failure sites and mechanisms is another. An increased understanding of acquired data leads to accuracy in
assigning failures to known strata which can effectively target resources to replace and rehabilitate appropriate lengths of pipe. Compiling a reliable database of overall inputs can facilitate future pipeline assessment strategies.