What type of pipe is used in solvent welding for valve installation?

The correct answer is rigid plastic, which refers to materials such as PVC (polyvinyl chloride) and CPVC (chlorinated polyvinyl chloride). Solvent welding is a method used to join these types of pipes, where a solvent adhesive softens the pipe surface, allowing the two pieces to bond as they cure.

Rigid plastic will hold its shape under pressure and stress, making it suitable for plumbing applications, including valve installations where structural integrity and leak prevention are critical. This type of pipe is often favored for its resistance to corrosion, low weight, low cost, and ease of installation.

While flexible plastic might also be used in plumbing, it is not typically solvent welded in the same way that rigid options are. Metal pipes are generally joined using fittings, threads, or solder, not solvent welding, and thermal plastic broadly refers to various types of plastic that may not specifically align with the solvent welding process. Therefore, the use of rigid plastic is the most appropriate choice for this application.