Enter the atmospheric or vent pressure (Pa) and the absolute pressure used for the purge (Pa) into the Gas Purge Calculator. The calculator will evaluate the Gas Purge. 

Gas Purge Formula

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

GP = -4/log(Pa/Ph)

Variables:

  • GP is the Gas Purge (number of purge cycles)
  • Pa is the atmospheric or vent pressure (Pa) 
  • Ph is the absolute pressure used for the purge (Pa) 

To calculate the gas purge rate, divide negative 4 by the log of the ratio of the atmospheric vent pressure by the purge pressure.

How to Calculate Gas Purge?

The following steps outline how to calculate the Gas Purge.

  1. First, determine the atmospheric or vent pressure (Pa). 
  2. Next, determine the absolute pressure used for the purge (Pa). 
  3. Next, gather the formula from above = GP = -4/log10(Pa/Ph).
  4. Finally, calculate the Gas Purge.
  5. 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.

atmospheric or vent pressure (Pa) = 30

absolute pressure used for the purge (Pa) = 20

GP = -4/log10(Pa/Ph) = ?