What are the two types of drop manholes?

What are the two types of drop manholes?

• A. Inside Drop and Main Drop
• B. Vertical Drop and Horizontal Drop
• C. Inside Drop and Outside Drop
• D. Top Drop and Bottom Drop

Answer: (C)

Two types of drop manholes are inside drop and outside drop. This classification shows where the vertical drop between the upstream and downstream pipes occurs relative to the manhole interior. In an inside drop, the drop tube or chute is inside the manhole chamber, so the flow from the higher inlet falls inside the manhole and meets the downstream pipe already inside the chamber. In an outside drop, the vertical reduction happens outside the chamber, using a drop pipe that carries the flow down to the level of the downstream line before it enters the manhole or connects to it from the side. This distinction explains why the terms inside drop and outside drop are the standard, practical names. Other terms like vertical/horizontal, main, or top/bottom drops aren’t used to describe this classification.

Two types of drop manholes are inside drop and outside drop. This classification shows where the vertical drop between the upstream and downstream pipes occurs relative to the manhole interior. In an inside drop, the drop tube or chute is inside the manhole chamber, so the flow from the higher inlet falls inside the manhole and meets the downstream pipe already inside the chamber. In an outside drop, the vertical reduction happens outside the chamber, using a drop pipe that carries the flow down to the level of the downstream line before it enters the manhole or connects to it from the side. This distinction explains why the terms inside drop and outside drop are the standard, practical names. Other terms like vertical/horizontal, main, or top/bottom drops aren’t used to describe this classification.