Sometimes plugs are used with a female adapter to create an opening that can be closed off and re-opened if needed. Plugs can also be used to close off just one end of a fitting. Most PVC or CPVC plugs have a specially molded top that is ridged to assist in installation or removal. The molded design allows for use of a wrench or tool.
Why choose schedule 80 CPVC over PVC? CPVC is known for having a higher max temperature (200F). It is also different chemically which makes it resistant to a different set of media. Generally speaking, CPVC is usually found in more commercial and industrial settings as opposed to consumer or residential. CPVC is often used in laboratories, processing plants and more.