3.11 Condition Assessment Information
Pipe network
The pipe network renewals investment profile is driven by age-based information. The concept being
that the older the pipe the poorer the condition with the risk of failure and service interruptions
increasing as they reach or exceed their expected useful life. Using this approach, we have prepared
a condition assessment against the IIMM framework for each specific pipe in the networks. The
condition ratings used are as per the IPWEA International Infrastructure Management Manual
(IIMM) as follows.
Confidence
Condition description
Age assumptions
Rating 1
Very good condition
> 75% remaining life
2
Good Condition – minor defects only
50-74% remaining life
Fair or moderate condition – maintenance
3
25-49% remaining life
required to return to accepted level of service
4
Poor condition – consider renewal
3-24% of remaining life
Less than 3% remaining life
5
Very poor condition – approach unserviceable
including backlog
The condition rating is theoretical, there could be pipes that are rated at 5 that remain serviceable
and vice versa. Actual renewals are prioritised and programmed based on risk. This is using the asset
criticality level and the evidence of the asset being unserviceable (operational evidence, condition
assessments). Renewals are programmed to fill the available funding per annum.