What is the first component to assemble when connecting fixture drains?

The first component to assemble when connecting fixture drains is the sanitary tee. This fitting is crucial because it serves as the junction point for the drain line from the fixture and the vent line, which helps maintain proper pressure and allows sewer gases to escape. When installing drainage systems, starting with the sanitary tee ensures that the flow from the fixture can head towards the building sewer while also correctly connecting to the venting system.

When installing a drainage system, assembly typically begins at the fixture and works its way down to the building sewer. Since the sanitary tee is designed to facilitate both drainage and venting, it is positioned right at the start to ensure that the system is balanced and functions appropriately, making it essential to prioritize this component first. This method also aids in maintaining a clear and efficient pathway for wastewater, which is fundamental for proper plumbing installation.