Which formula is used to calculate fall in a piping installation?

The formula used to calculate the fall in a piping installation is the product of the grade and the run. This calculation is essential in plumbing as it ensures proper drainage by determining how much the pipe slopes over a given horizontal distance.

The grade of a pipe typically refers to the slope expressed as a ratio or percentage (for example, a 2% grade means a fall of 2 units vertically for every 100 units horizontally). By multiplying this grade by the run, which is the horizontal distance the pipe covers, you can find the necessary vertical drop, or fall, required for effective drainage. This calculation helps prevent blockages and ensures that wastewater flows correctly through the plumbing system, avoiding issues such as backflow or stagnation.

Understanding how to calculate fall is crucial for ensuring that installations are compliant with plumbing codes and effective in their operation.