Which type of joints should be used in drainage systems according to plumbing standards?

Mechanical joints are specifically designed for drainage systems due to their ability to accommodate movement and provide a secure seal. These types of joints are typically easy to assemble and disassemble, which allows for maintenance and repairs in drainage systems without the need for specialized tools or skills. They ensure leak-tight connections that can handle variations in temperature and other conditions, making them particularly suitable for flexible applications.

In contrast, soldered joints are commonly seen in water supply systems but may not be as effective in drainage systems where flexibility and movement are necessary. Movable joints, while allowing for some motion, may not provide the same level of sealing required in drainage applications. Welded joints are often permanent and can be difficult to separate for maintenance, making them less practical for drainage systems where access is key. Therefore, mechanical joints are the appropriate choice for ensuring reliable and maintainable drainage systems according to plumbing standards.