Enter the concentration of impurities at upstream point (ppm) and the concentration of impurities at downstream point (ppm) into the Purge Factor Calculator. The calculator will evaluate the Purge Factor.

## Purge Factor Formula

The following two example problems outline the steps and information needed to calculate the Purge Factor.

**PURF = IU / ID**

Variables:

- PURF is the Purge Factor ( )
- IU is the concentration of impurities at upstream point (ppm)
- ID is the concentration of impurities at downstream point (ppm)

## How to Calculate Purge Factor?

The following steps outline how to calculate the Purge Factor.

- First, determine the concentration of impurities at upstream point (ppm).
- Next, determine the concentration of impurities at downstream point (ppm).
- Next, gather the formula from above = PURF = IU / ID.
- Finally, calculate the Purge Factor.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

concentration of impurities at upstream point (ppm) = 50

concentration of impurities at downstream point (ppm) = 2

PURF = IU / ID** **= ?