HAZard and OPerability (HAZOP) analysis for identification of information requirements for sewer asset management

Asset management is a prerequisite for maintaining the required level of serviceability of urban drainage systems. The required asset management effort to achieve a certain level of service is unclear due to limited knowledge on sewer systems process and structure complexity. Sewer failure mechanisms explain the structural/operational failures of sewer elements. This paper describes a method for assessing sewer failure mechanisms as a first step to identify information needed for sewer asset management. In order to be able to identify the main processes and defects responsible for the structural/operational failures of sewer elements, as well as the possibility of obtaining the information about them, a HAZard and OPerability (HAZOP) approach was applied. HAZOP results were, due to the nature of the analysis, rearranged in such a way that they can be applied in Failure-Tree Analysis (FTA) for the purpose of further risk estimation.