What does 1 in 80 fall on drainage pipe?

A 1 in 80 fall on a drainage pipe refers to the slope or gradient of the pipe, indicating that for every 80 units of horizontal distance, the pipe drops by 1 unit vertically. This slope is essential for ensuring proper drainage by allowing gravity to facilitate the flow of wastewater. A 1 in 80 fall is a relatively gentle slope, typically used in drainage systems to prevent blockages and ensure efficient drainage without excessive velocity.