2006 Water Comprehensive Plan - City of Bellevue

needed to manage those assets at a very high level. There are also processes in place forassessing the condition of Bellevue’s buried assets. However, because of limited access to theseassets, these processes provide only limited information for use in making asset managementdecisions. Bellevue’s biggest challenge in this area is obtaining useful information on thecondition of its asbestos cement (AC) water pipe, which comprises 53% of the system. Bellevuecurrently runs a full range of tests on AC pipe that has appeared to fail due to age-relateddeterioration. So far the City has not obtained enough test data to establish a correlationbetween an easily performed test and the condition of the pipe.Determine Residual LifeThe residual life of an asset determines what the Utility has left to manage. It is also called theremaining effective or useful life. For the broad picture, Bellevue uses the age of the asset andestimates of average life expectancy of that class of asset to predict effective and residual life.To further refine the estimates, factors that increase or reduce effective life (such as soil type,presence of ground water, etc.) are also considered.Determine Life Cycle CostsEconomic, social, and environmental costs all affect decisions for management of assets. Assetlife cycle costs begin when a need for the asset is identified, and they accumulate throughout thelife of the asset, including needs justification, design, construction, operation, maintenance,condition assessment, risk management, renewal, replacement, and disposal. Risk managementincludes an evaluation of environmental and social costs which generally involve a disruption ofservice or impact to habitat. All costs must be accounted to determine the real cost of owningand operating assets. As part of the development of the AMP, Bellevue is developing a moreformalized process for determining life cycle costs.Set Target Level of ServiceBellevue has established various target levels of service. These levels of service representchoices made by the Utility to focus efforts and resources. They communicate Utilityunderstanding of customer expectations and regulator requirements. Target levels of service(LOS) are intended to balance expectations with the cost to provide that service. They affectasset inventory, residual life, life cycle costs, business risk exposure, maintenance activities, CIPproposals, and funding requirements.Determine Business Risk ExposureEvaluation of business risk exposure is a systematic identification of the likelihood andconsequences of an asset failing, and the development of appropriate strategies to minimize risk.Threats to an asset can be natural events, external impacts, or physical or operational failures.Economic, social, and environmental consequences are considered. Data on systemcharacteristics and condition is used to estimate useful life and probability of failure. Bellevuehas also identified various factors to be considered to rate how severe the consequence of anassets failure would be. The probability and consequence of failure are combined to determine7-3