Storage Tank Emissions Calculation Tool

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DEQ has developed a tool for estimating emissions from working and breathing losses from volatile organic liquid storage tanks. The tool is based off EPA’s updated AP-42 calculation method, which also replaces the outdated TANKS emissions estimation software. The new AP-42 method corrects errors for more accurate estimates.

You may use the tool below or download it as a standalone .zip file (Updated October 22, 2021). The tool opens in a compatible browser but does not require an internet connection. This release of the tool only includes calculations for fixed roof and horizontal tanks. Floating roof tanks, landing, and cleaning calculations will be addressed in a future release. For any questions or comments, please contact Richard Kienlen / Phillip Fielder.

Release Notes
Version 21294 – Released October 22, 2021

  • Clarifying how to address flashing.  This includes considerations for tank which are manifolded together with a shared vapor headspace.
  • Added a tooltip regarding our current produced water policy.
  • Added additional flexibility for users manually entering liquid properties and using Antoine’s Equation coefficients.  The user may now enter coefficients based on various temperatures and pressures.
  • Included guidance for how to calculate speciated emissions after running the tool.
  • The output report clearly indicates when the user manually entered liquid properties.
  • Added the ability for a user to give a manually entered liquid a name.
  • Corrected several typos and added various minor clarifications.