The fitting at the bottom of gravity tank discharge pipe is base elbow.

The fitting at the bottom of gravity tank discharge pipe is base elbow.

• A. Elbow
• B. Reducer
• C. Tee
• D. Base elbow

Answer: (D)

The main idea is that gravity tank discharge piping uses a fitting designed to sit at the base of the vertical outlet and direct the flow away from the tank. A base elbow is that specialized fitting: it has a base or mounting feature that ties directly into the bottom outlet of the tank, providing a secure, right‑angle change from vertical to horizontal while staying anchored at the tank base. This makes it the correct choice for the bottom discharge because it addresses both the direction of flow and the need for a stable, leak‑proof base connection. A plain elbow is just a bend without the base mounting requirement, a reducer changes pipe size, and a tee creates a branch—none of which specifically match the bottom‑of‑tank mounting situation.

The main idea is that gravity tank discharge piping uses a fitting designed to sit at the base of the vertical outlet and direct the flow away from the tank. A base elbow is that specialized fitting: it has a base or mounting feature that ties directly into the bottom outlet of the tank, providing a secure, right‑angle change from vertical to horizontal while staying anchored at the tank base. This makes it the correct choice for the bottom discharge because it addresses both the direction of flow and the need for a stable, leak‑proof base connection. A plain elbow is just a bend without the base mounting requirement, a reducer changes pipe size, and a tee creates a branch—none of which specifically match the bottom‑of‑tank mounting situation.