GHD Inc., 16451 Scientific Way, Irvine, CA 92618, USA.
Water Sci Technol. 2013;67(6):1302-9. doi: 10.2166/wst.2013.003.
For effective management of water and wastewater infrastructure, the United States Environmental Protection Agency (US-EPA) has long emphasized the significant role of risk in prioritizing and optimizing asset management decisions. High risk assets are defined as assets with a high probability of failure (e.g. soon to fail, old, poor condition) and high consequences of failure (e.g. environmental impact, high expense, safety concerns, social disruption). In practice, the consequences of failure are often estimated by experts through a Delphi method. However, the estimation of the probability of failure has been challenging as it requires the thorough analysis of the historical condition assessment data, repair and replacement records, and other factors influencing the deterioration of the asset. The most common predictor in estimating the probability of failure is calendar age. However, a simple reliance on calendar age as a basis for estimating the asset's deterioration pattern completely ignores the different aging characteristics influenced by various operational and environmental conditions. This paper introduces a new approach of using 'real age' in estimating the probability of failure. Unlike the traditional calendar age method, the real age represents the adjusted age based on the unique operational and environmental conditions of the asset. Depending on the individual deterioration pattern, the real age could be higher or lower than its calendar age. Using the concept of real age, the probability of failure of an asset can be more accurately estimated.
为了有效管理水和废水基础设施，美国环境保护署（US-EPA）长期以来一直强调风险在确定和优化资产管理决策方面的重要作用。高风险资产是指具有高故障概率（例如即将发生故障、陈旧、状况不佳）和高故障后果（例如环境影响、高费用、安全问题、社会混乱）的资产。在实践中，失败的后果通常由专家通过德尔菲法进行估计。然而，由于需要对历史状况评估数据、维修和更换记录以及影响资产恶化的其他因素进行彻底分析，因此故障概率的估计一直具有挑战性。在估计故障概率时，最常用的预测因子是日历年龄。然而，简单地依赖日历年龄作为估计资产恶化模式的基础，完全忽略了不同的老化特征，这些特征受到各种操作和环境条件的影响。本文引入了一种使用“实际年龄”估计故障概率的新方法。与传统的日历年龄方法不同，实际年龄表示根据资产独特的操作和环境条件进行调整的年龄。根据个别恶化模式，实际年龄可能高于或低于其日历年龄。使用实际年龄的概念，可以更准确地估计资产的故障概率。
