What is commonly used for connecting plastic pipes?

Solvent cement is commonly used for connecting plastic pipes, especially those made from materials like PVC (polyvinyl chloride) and CPVC (chlorinated polyvinyl chloride). This method involves applying a special solvent-based adhesive that chemically softens the surfaces of the plastic pipes, allowing them to bond together as the solvent evaporates. This creates a strong and secure joint that is capable of withstanding both pressure and temperature variations.

The advantage of using solvent cement lies in its ability to create seamless connections without the need for additional mechanical fasteners, which can be prone to leaks and failure. Solvent cement joints are integral across various plumbing applications, from residential to commercial systems, particularly where plastic piping is utilized due to its lightweight, corrosion-resistant, and cost-effective properties.

Welded joints, compression fittings, and threaded fittings are typically used for joining other types of materials, such as metals. These methods do not provide the same level of effectiveness and reliability when it comes to plastic plumbing connections. Thus, for plastic pipes, solvent cement is the standard and most reliable choice.