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UDC 628.1/.3.196

GALPERIN E. M.

# The complexity of the reliability index of water and wastewater facilities

(to be discussed)

### Summary

Reliability has been the most important feature of water and wastewater facilities. However no clear consistent definition of this notion and the procedure of calculating its indicators have been formulated so far. At present it can be done only with use the mathematical tool of the reliability theory. Most of the published editions on that subject offer one of the failure-free performance parameters as a reliability index without considering the fact that water and wastewater facilities are maintainable. Hereof it follows the need of using the integrated reliability index that takes into account both failure-free performance and maintainability. For the calculation of this index Markov model with continuous-time discrete state is used.

Key words

repairability , water and wastewater systems , Markov model , failure-free performance , integrated reliability index , simple index