What is a double sanitary tee used for?

A double sanitary tee is specifically designed to connect horizontal pipes and vent stacks within drainage systems, facilitating the proper flow of wastewater and venting gases. This fitting is crucial in ensuring that the drainage system operates efficiently, allowing waste to be transported without causing blockages or backpressure, which could lead to drainage issues.

The design of the double sanitary tee helps maintain smooth flow paths while also allowing for the escape of gases that might build up in the drainage system. This characteristic makes it especially important in residential and commercial plumbing, where proper drainage and air circulation are essential for hygiene and comfort.

Other options presented do not accurately represent the purpose of a double sanitary tee. For instance, while connecting various sizes of pipes could involve different types of fittings, the double sanitary tee is not specifically intended for that function. Similarly, diverting rainwater runoff typically involves different types of plumbing fittings, such as gutter systems, rather than a sanitary tee. Connecting multiple sinks to a single drain can also be accomplished with other fittings, such as standard sanitary tees or wyes, but the double sanitary tee excels in its application related to drainage and venting, reinforcing why the correct choice pertains to connecting horizontal pipes and vent stacks.