How are old pipes typically replaced in a distribution system?

Replacing old pipes in a distribution system can be accomplished through excavation or trenchless technology, making this the correct approach.

Excavation involves digging up the ground to access the old pipes, allowing for their removal and replacement with new ones. This method is effective, especially in situations where the pipe layout is straightforward or where the soil conditions allow for easy digging.

Trenchless technology, on the other hand, offers modern advantages by minimizing surface disruption. It utilizes techniques like horizontal directional drilling, which enables new pipes to be installed alongside or in place of old ones without the need for extensive digging. This method reduces damage to roads, landscaping, and existing infrastructure, making it a popular choice in urban environments where disruption needs to be minimized.

Other methods, like placing new pipes over old ones, can lead to issues such as inadequate flow capacity, increased pressure on existing infrastructure, and potential complications during maintenance. Similarly, relying solely on trenching methods limits the efficiency and adaptability of modern pipe replacement projects. Chemical degradation is not a viable replacement method; it pertains to the breakdown of materials instead of the installation of new pipes. Thus, the combination of excavation and trenchless technology is the best practice for old pipe replacement in water distribution systems.