It can be a main gas line or pipes for water supply to the house and used for drain-waste ventilation (DWV). PVC pipes will work well for natural gas lines and water supply. They are usually available in 10 foot and 20 foot sizes, and come in different diameters. The size ranges from ½ inch to 6 inch to choose one depending on the purpose.
PVC cannot be used for natural gas. It will be risky to install the PVC pipe for the natural gas lines. For example, when a gas with tiny atoms, melted gasoline gas, is sent in a plastic hose, gas particles can enter through the hose.