Risk management for maintenance of district heating networks

Abstract

Underground infrastructure such as buried district heating pipes are difficult to inspect. The methods available to assess the status of the district heating pipes are often both expensive and do not provide enough evidence to determine the condition of the pipelines. This paper discusses how utilities systematically can work with risk assessments and risk classification to plan the maintenance and renewal of district heating networks. The results were based on interviews with a selection of Swedish district heating companies that were already using risk and vulnerability analysis as a tool for maintenance and renewal of their networks, as well as on a literature study of methods for risk and vulnerability analysis. The study showed that a rather limited number of methods were used by the selected utilities, mainly those based on risk matrices. Risk classification of pipes were carried out based on age, type and dimensions of pipes, identification of pipes to customers with greater need for security of supply, history of damages on the pipes and statistics over probability of damage for different kind of pipes, working environment and safety. Personnel involved in the management and maintenance planning of reinvestment in the district heating network emphasized that strategic work with risk management really can aid the foreseeing of coming needs for reinvestments and planning of maintenance. The study rendered in advices and a checklist for how district heating companies can start working with the area of risk management.