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The operation of a water supply system (WSS) is inextricably linked with the possibility of different types of failure. It is very common for these failures to be random in nature. The results of reliability studies carried out in many water supply systems revealed, for example, the possibility of incidental water pollution, power supply issues, failure in machinery, damage to water plants, or natural disasters. As a result of the WSS failure, we deal with a state of threat to safety (TSS) or a state of loss of safety (LSS). Using Markov processes, we developed a failure model of the WSS to determine the possibility that the system may find itself in different states of safety. As a result, a mathematical model using Markov processes has been proposed for each of these distinct states of safety (complete safety state—CSS; threat to safety state—TSS; and loss of safety state—LSS). The proposed approach in the water supply system will limit emergency states by optimizing working and repair times. Reducing losses in the water supply system is crucial to reduce and optimize energy consumption for water production and distribution. [ABSTRACT FROM AUTHOR]

The continuity of gas-supply service is a major concern for all gas-supply operators. A safety review of a gas-supply system could help to mitigate the potential repercussions of supply disruptions. Disruptions occur at random due to systemic failures in gas distribution networks. Assessing the operational safety of gas distribution networks is challenging and complex, especially when operational data are limited or associated with high uncertainty. This paper focuses on gas leak incidents. Natural gas leaks disrupt the production process and endanger the ecosystem. Mechanically originated damage in pipelines is found to be the major cause of leaks, according to our investigations. This paper proposes a three-parameter risk matrix to be used in the safety analysis of gas-supply systems. This paper then raises the possibility of using grey-system theory. Grey-system theory has been used to overcome the limitations of the conventional matrix method. This choice is motivated by two facts: our data are heterogeneous with a high level of uncertainty, and some of the data are based on experts' judgement and maintenance reports using qualitative metrics. It is underlined how GST provides insight for the decision-making process, even in the absence of complete information sets. The method developed here is advocated in the context of procedures ensuring the safety and the supply continuity of gas-supply systems. [ABSTRACT FROM AUTHOR]

Within the frame of upgrading and modernisation of the Water Supply System (WSS), our work is focussing on the safety systems/devices implemented or that should be implemented in the WSS. The implementation of safety systems is supposed to reduce hazard occurrence and hazardous consequences in case of a WSS unsafe disruption. To assess this reduction, we preconise the use of the safety integrity levels standards. The implementation of the safety systems/devices is undertaken on the ground of the multi-barriers safeguard approach. The "Water Contamination Hazard" is considered in the paper. A case study is presented, assessed and conclusions are drawn. The methodology presented in the paper and the results of the case study assessment will contribute to the decision-making regarding the upgrading of the safety and the performance of the WSS. [ABSTRACT FROM AUTHOR]

The development of appropriate methods by which to assess the functioning of gas pipelines helps limits the consequences of disasters, in that way protecting users better. Assessment methods of this kind are presented in this paper, which advocates the integrated risk area identification method. The risk taken account of is understood to be a function of the probability or frequency of occurrence of undesirable events, and comes with parameters defining the consequences of these events, should they arise, in terms of their magnitude. The level of system vulnerability to events of these types is a factor considered, and the risk calculation is of a kind that encompasses both quantitative and qualitative aspects. The approach taken is regarded as a quick and simple risk-assessment tool applicable to the daily operation of gas networks for a gas company. Specifically, the framework of the research carried out extends to: (1) Estimation of the average cost of failure of gas pipelines in the case of an urban agglomeration in SE Poland; (2) assessment of the level of integrated risk facing the gas-supply subsystem, by reference to the risk area identification method; (3) failure forecasting by way of regressions with delay; and (4) conclusions regarding failure risk assessment in a gas-supply network, as well as a consideration of prospects. The framework referred here, thus constitutes the basis for both analysis and assessment of the safety of a gas-supply system. [ABSTRACT FROM AUTHOR]