Which type of pipe is specifically designed to maintain structural integrity underground?

Cast-iron pipe is specifically designed to maintain structural integrity underground due to its robust and durable nature. This type of pipe can withstand high pressures and the weight of the surrounding soil, making it suitable for underground applications. Its resistance to corrosion and ability to handle heavy loads without deformation ensures that it can maintain its structural integrity over long periods, which is critical in plumbing systems that are buried underground.

In addition to these features, cast-iron pipes also have excellent sound-dampening properties, reducing the noise of flowing water. This makes them a preferred choice in urban environments where noise pollution can be a concern. The longevity and reliability of cast-iron pipes are well-documented, further solidifying their role in underground plumbing infrastructure.

While other materials such as copper, plastic, and PVC serve specific functions and have their own advantages, they do not offer the same level of strength and durability for underground installations as cast-iron pipes do.