Confronting the Tsunami - A New Approach to Renewal Planning

Eric Skowron (ProjectMax Limited)

If your renewal plan shows a backlog of $30M and $150M of renewals over the next three years, will you be spending $180M over that time? Certainly! We have a graph and some numbers to prove it! In reality, perhaps yes, but quite likely, probably not. 

If we knew the condition and thus remaining life of all of our underground assets, renewal planning would be easy. The next best thing is to predict a likely condition of those assets so we can prioritise those to inspect and those most likely to fail. 'Install date' coupled with a formula for 'Expected life' based on material is typically used to establish a 'Renewal Date'. This approach can provide some useful insights, but unless backed with relevant fault records, observed condition evaluation and testing and/or other reality-based information, it may be best to leave the diggers in the yard for now and be bit more strategic with renewal planning first.

Every renewal decision must have a clear justification, which shouldn’t be ‘the pipe has reached the end of its predicted life'. For example, the average life expectancy for a male in New Zealand is approximately 80 years, (similar to that of AC pipe). Does that mean every male born in 1943 will die this year? Certainly not, and pipes are no different.

While renewal planning based on material and installation date can provide a good estimate of potential longevity, it can also be misleading as pipes can perform differently in different environments and under different operating conditions. Short-term and long-term renewal plans generated from these inputs are often not representative of the condition of pipe assets or the likely timing of renewal.

An improved approach integrates asset data with data confidence assessment and asset condition assessment to better understand what is known, what is not, why and how it impacts short-term and long-term planning outcomes.

By approaching renewal planning in this way, we can make better and more effective decisions on how our communities' infrastructure is managed and how financial resources are used.

This paper will describe how implementation of renewal strategies create better and more financially sustainable short-term and long-term asset renewal programs. It will highlight how integrating these approaches can yield improved results with more confidence and a greater understanding of risk. It will summarise how limited budgets can therefore be more effectively used to address critical vulnerabilities while reducing the likelihood of replacing assets that aren't quite ready for the bone yard yet.

A case study will highlight a renewal planning strategy developed and applied, methodology adopted, time taken to produce renewal predictions (weeks rather than years) across 7,500km of network assets. Both short-term and long-term results will be summarised with discussion of how they are being applied. The paper will conclude with discussion of how this approach could be applied to the proposed water service entities and benefits that could be expected.


386 KB
22 Feb 2024

1400 Eric Skowron - Oct-17-2023 2pm Matiu Mr Eric Skowron.pdf

2 MB
22 Feb 2024