Which type of piping should be laid so that they are compressed longitudinally?

The correct choice indicates that mechanically coupled piping should be installed in such a way that it is compressed longitudinally. This approach allows for the accommodation of thermal expansion and contraction that naturally occur due to temperature variations. By ensuring a longitudinal compression, the mechanically coupled joints can maintain their integrity and minimize the risk of separation or leakage.

In the context of pipeline engineering, mechanically coupled pipes utilize fittings and connectors that are designed to create a strong and flexible connection. This method provides some advantages over other types of piping systems when it comes to handling dynamic stresses and movements, ensuring both safety and reliability in pipeline operations.

Seamless piping is typically known for its strength and ability to handle high pressures but does not inherently require longitudinal compression upon installation. Welded piping creates a continuous structure but does not have the flexibility needed to accommodate down-the-line stresses associated with thermal changes without specific design considerations. Screw-threaded pipes are less commonly used in long conducts for pressure applications and typically do not rely on compression in the same manner as mechanically coupled options. Thus, the practice of laying mechanically coupled piping under compression enhances durability and operational efficacy.