What is A Manhole: Components & Where Should be Provided

Manholes provide safe and efficient access to utilities and wastewater systems. They must be built to allow access to continuous subsurface storm sewers for inspection and maintenance. Not only living creatures have anatomy, but manholes also have anatomy. This article will discuss the anatomy of a manhole, highlighting the components and their functions. Apart from that, we also discuss where they must be provided.

Components of a manhole

The following are nine components that make up the anatomy of a manhole.

1. Manhole Cover

As the name suggests, this part protects the hole itself and prevents the entry of dirt or foreign objects from outside. This section has many benefits, including ensuring the safety of pedestrians or vehicles passing over it and preventing blockages. This part is easy to remove with a hook, making it easier for workers to access. This cover is usually made of cast iron, plastic, steel, or composite materials.

2. Manhole Frame

This is the part that supports the manhole cover. The role is to provide structural support to the cover so that the cover remains safely on the ground.

This part is usually a hollow cage, the frame is designed to fit over the hole opening. Apart from that, the shape of this frame also follows the shape of the cover, it can be square, circular, or rectangular.

3. Chimney

The chimney is a narrow path to the depths. This part is the top of the hole and resembles an upside-down funnel. The narrow shape leading downwards creates a transition to the wider area below.

4. Cone Section

This section is a path to the core. Below the chimney is a conical section that slopes outward. Apart from functioning as the main route, this route also directs access to the center of the manhole.

5. Barrel section

The barrel section is the part where the action occurs. It forms the main hole area, allowing important repair and maintenance work on utilities and wastewater systems.

6. Steps

Manholes are usually equipped with steps installed on the sides to facilitate safe movement for workers entering and exiting the hole.

7. Invert

This section refers to the bottom surface of the manhole and includes two important components: the bench and the channel.

8. Channel

Please note that manholes are not direct openings into the wastewater system. Under the concrete surface of the hole, there is a pipe or what is usually called a channel that carries wastewater. An opening in the center allows access for maintenance.

9. Bench

Benches are positioned above the duct and provide a stable platform for workers to stand on while performing duct-related tasks. This bench also helps prevent overflow during backup.

Where should manholes be provided?

The following are the locations where manholes must be provided:

1. Where two or more storm sewers converge.
2. At the storm sewer’s point of reverse curvature (PRC), as well as the start or finish of a curve (PC or PT).
3. Where the size of the pipe changes.
4. In the event of a sudden shift in alignment.
5. The location of the pipe slope changes.
6. At appropriate intervals in sewer portions that are straight.

A manhole is a complex structure that allows professionals to safely and efficiently access wastewater and utility systems to perform repairs and maintenance. The nine parts mentioned above are integral components that contribute to the function of the manhole.