In our always growing cities some civil engineering systems becomes extremely important, as the cities’ functioning depends on it. Among those key systems, the Water Distribution Network (WDN) is crucial for the residents, cities’ services, and industry.

The water distribution network  can be considered a system, as it is composed by a great number of pipe diameters, junctions between those pipes, and can also be decomposed in primary main pipes and secondary ones.

Subsystem : Water Main Pipe

Water mains are probably the most important component of a water distribution system. This particular pipe will conduct the water from the water treatment plants to other secondary pipes of branch networks. A failure on a water main means a failure of the whole water distribution network. For its evident importance, it is necessary already on the design phase to choose the right pipe type.

In the latest assignment, we could compare three design solutions for a water main pipe. The three solutions are considered to have the same function, since the nominal diameter of the pipe and thus the water flow capacity is equivalent for every design option. The options were (1) PVC Pipe, (2) Reinforced Concrete Pipe and (3) Steel Pipe.

After considering the different maintenance timelines for every option as well as the defining the Life Cycle Inventory. We defined a Goal and Scope of our LCA, choosing the the following environmental performance indicators for the analysis:

• Energy Consumption (MJ)
• Water Consumption (m³)
• CO₂ Emission (kg eq. CO₂)
• SO₂ Emission (kg eq. SO₂)

This first LCA results can already give us the information that the Option 2 (Reinforced Concrete Pipe) is the more adequate choice within our design options.

Another useful tool to decide which design option is the best one is the Multi-Criteria Decision Method called Analytic Hierarchy Process (AHP). Using this method we could compare pairwise every design option with regard of the performance indicators chosen in the LCA.

Analytical Hierarchy Process applied to the design decision

Usind the AHP Method we find again that the Reinforced Concrete Pipe is still the design option with best performance and thus will be the water pipe type applied to the integrated systems assignment.

[1] https://lcrws.org/system-construction/raw-water-pipeline/

 

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