Skip to main content

Create an editable spreadsheet with the information indicated below. Each step in your calculations needs to be clear and easy to follow.

Facility information

Provide the facility ID, file number, and name as indicated on the Calculating emissions page. In addition, include:

  • Storage tank identification number (s) (TK# or EQUI#) found on GI-05C or similar form
  • Note any fuel-combusting heaters associated with tanks: how many, the fuels that can be used, and the total rated heat input of each heater. Calculate emissions for the heaters as external combustion units – see the Calculating emissions main page. Not applicable to electric heaters with no emissions.
  • For each tank, indicated tank type: Fixed roof tank (vertical or horizontal), internal floating roof tank, or external floating roof tank
  • Operating limitations, or the permit limits you propose to restrict your potential-to-emit – see Synthetic minor permit limits. Attach additional spreadsheets or other information, if needed. Cite any rules that apply. If you used vendor certification or stack test data to limit your potential-to-emit, the factor you used will become your permit limit. Include all proposed limits on Form CD-01.

Emissions calculations

Generally, you will list the pollutants your facility emits in the left column, and each calculation will be another column in your spreadsheet. Provide the formula or equation for each calculation. Use the equations and algorithms outlined in Chapter 7 of EPA’s AP-42: Compilation of Air Emission Factors.

The MPCA no longer accepts emissions data using TANKS Emissions Estimation Software, Version 4.09d in permit applications, but existing, permitted tanks using the TANKS software may continue.

Example spreadsheet format

Fixed roof tanks (vertical or horizontal)


Pollutant

Maximum
unlimited
emissions (lb/yr)

Maximum
unlimited
emissions (tpy)

Limited
emissions (tpy)

Actual
emissions (tpy)

Proposed
operating
limitations

VOC – Standing loss

 

 

 

 

 

VOC – Working loss

 

 

 

 

 

VOC – Total Loss

 

 

 

 

 

HAP 1 – Standing loss

 

 

 

 

 

Etc.

 

 

 

 

 

Internal floating roof tanks


Pollutant

Maximum Unlimited Emissions (lb/yr)

Maximum Unlimited Emissions (tpy)

Limited emissions (tpy)

Actual Emissions (tpy)

Proposed Operating Limitations

VOC – Rim Seal loss

 

 

 

 

 

VOC – Withdrawal loss

 

 

 

 

 

VOC – Deck Fitting Loss

 

 

 

 

 

VOC – Deck Seam Losses

 

 

 

 

 

VOC – Total Loss

 

 

 

 

 

HAP 1 – Rim Seal loss

 

 

 

 

 

Etc.

 

 

 

 

 

External floating roof tanks


Pollutant

Maximum Unlimited Emissions (lb/yr)

Maximum Unlimited Emissions (tpy)

Limited emissions (tpy)

Actual Emissions (tpy)

Proposed Operating Limitations

VOC – Rim Seal loss

 

 

 

 

 

VOC – Withdrawal loss

 

 

 

 

 

VOC – Deck Fitting Loss

 

 

 

 

 

VOC – Total Loss

 

 

 

 

 

HAP 1 – Rim Seal loss

 

 

 

 

 

Etc.

 

 

 

 

 
  • List the pollutants the process or unit emits.
    • Volatile organic compounds
    • Hazardous air pollutants (HAPs), listed individually
    • Total emissions from HAPs
    • For fixed roof tanks: Create rows for emissions from standing loss, working loss, and total loss for each pollutant.
    • For internal floating roof tanks: Create rows for emissions from rim seal loss, withdrawal loss, deck fitting loss, deck seam loss, and total loss.
    • For external floating roof tanks: Create rows for emissions from rim seal loss, withdrawal loss, deck fitting loss, and total loss
  • Calculate the potential uncontrolled emissions in pounds per year, using equations and algorithms referenced in Chapter 7 of AP-42 for:
    • Fixed room tanks: standing losses and working losses
    • Internal floating roof tanks: rim seal losses, withdrawal losses, deck fitting losses, and deck seam losses
    • External floating roof tanks: rim seal losses, withdrawal losses, and deck fitting losses
      Add the losses for each tank type to obtain total losses.
  • Calculate the potential uncontrolled emissions in tons per year by dividing maximum unlimited emissions (lb/yr) by 2000 lb/ton for:
    • Fixed room tanks: standing losses and working losses
    • Internal floating roof tanks: rim seal losses, withdrawal losses, deck fitting losses, and deck seam losses
    • External floating roof tanks: rim seal losses, withdrawal losses, and deck fitting losses
      Add the losses for each tank type to obtain total losses.
  • Find the limited controlled emissions (tons/year) by taking into account all your facility's operation limits, such as the amount of tank throughput. Skip this step is you are seeking a registration Option D permit. Using the equations and algorithms found in Chapter 7 of AP-42, calculate:
    • Fixed room tanks: limited standing losses and working losses
    • Internal floating roof tanks: rim seal losses, withdrawal losses, deck fitting losses, and deck seam losses
    • External floating roof tanks: rim seal losses, withdrawal losses, and deck fitting losses
      Add the losses for each tank type to obtain total losses.
  • Determine actual emissions (tons/yr) for existing units with historical records using the equations and algorithms in Chapter 7 of AP-42 and the average of the previous two calendar years of usage data. If this is a new unit or no records exist, use the equations and algorithms in AP-42 and a reasonable estimate of the tank’s actual throughput.
  • Find the potential-to-emit after permit limits using the operating limitations described above.