Multi-Objective Design Optimization of Branched Pipeline Systems: Analytical Probabilistic Assessment of Fire Flow Failure

This paper develops a multi-objective optimization approach that incorporates the probability of fire flow failure in branched water distribution networks. An analytical probabilistic model is developed to quantify the probability of fire flow failure in branched networks and incorporated into the non-dominated sorting genetic algorithm (NSGA-II). The optimization approach seeks to minimize two conflicting objectives: capital cost and the probability of fire flow failure. Capital cost and fire flow failure probability are balanced through the selection of the pipe diameters and the number of pumps in the system. The probability of hydraulic failure under fire flow conditions is solved analytically in a branched network. The non-dominated sorting genetic algorithm is used to produce a set of Pareto-optimal solutions in the objective space of pipe and pump cost and fire flow failure probability.