Permit Appendix A: Source-Specific Calculations
A.1. Compliance Demonstration for Facilities without Records
Facilities With No Operating Records Prior to Issuance of this Permit: For emission limits based on a 12-month rolling sum, the Permittee does not have the data to calculate the 12-month rolling sum on a monthly basis. For the first 12 months of operation, the Permittee shall use the emission limits in Table A.1 below:
TABLE A.1 – Cumulative Pollutant Emission Limits During First 12 Months of Operation
Number of Months in Operation / Pollutants subject to25 tpy limits in the permit: PM, PM10, PM2.5, NOx, CO
(tons) / Pollutants subject to
5 tpy limits in the permit: Any single HAP
(tons) / Pollutants subject to
12.5 tpy limits in the permit: Total HAP
(tons)
1 / 5 / 0.5 / 1
2 / 7 / 0.9 / 2
3 / 9 / 1.3 / 3
4 / 11 / 1.7 / 4
5 / 13 / 2.1 / 5
6 / 15 / 2.5 / 6
7 / 17 / 2.9 / 7
8 / 19 / 3.4 / 8
9 / 21 / 3.9 / 9
10 / 23 / 4.3 / 10
11 / 24 / 4.7 / 11
12 / 25 / 5 / 12.5
A.2. Calculations for Combustion Sources
This includes Indirect and Direct Heating Sources and Internal Combustion Engines.
A.2.1 NOx and CO emissions limits ≤ 25 tons per year based on a 12-month rolling sum.
The emissions during a given month are calculated using Equation A2.1:
Equation A2.1 (emission in tons per month):
NOx (or CO), tons per month = 0.0005 x [( EF x Q)ng +(EF x Q)lpgb + (EF x Q)lpgp + (EF x Q)do/bio]ihs
+ [(EF x Q)ng + (EF x Q)do +( EF x Q)g ]rice
Where:
EF= emission factor for NOx (or CO) (see Tables A.2.1, A.2.2, and A.2.3)
Q= actual quantity of fuel purchased or used (whichever was stated in the permit application) per month (use the units that are appropriate to the emission factor for each fuel type)
ng= natural gas
lpgb= liquefied petroleum gas - butane
lpgp= liquefied petroleum gas - propane
do= distillate oil
bio= biodiesel
g= gasoline
hs= heating source – direct or indirect
rice= reciprocating internal combustion engines
0.0005 = conversion factor, ton/lb
Emission factors from Compilation of "Air Pollutant Emission Factors (AP-42) Fifth Edition, Emission Factor Listing for Criteria Air Pollutants" and “Emission Factors for Greenhouse Gas Inventories (April 2014, used in Table A.2.1, Table A.2.2, and Table A.2.3.
For engines that are model year 2007 or later, the Permittee may use emission factors which were certified by the engine manufacturer. Maintain at the facility a copy of the manufacturer’s certification with the emission factor identified.
Table A.2.1
Industrial/Commercial Direct and Indirect Heating Sources Emission Factors (EF)Pollutant / Natural Gas
(lb/MMft3) / LPG - Butane
(lb/1000 gal) / LPG - Propane
(lb/1000 gal) / Distillate Oil
(lb/1000 gal)
PM / 7.6 / 0.8 / 0.7 / 3.3
PM10 / 7.6 / 0.8 / 0.7 / 3.3
PM2.5 / 7.6 / 0.8 / 0.7 / 3.3
SOx / 0.6 / 0.09S / 0.10S / 144S
NOx / 100.0 / 15 / 13 / 20.0
VOC / 5.5 / 0.9 / 0.8 / 0.2
CO / 84.0 / 8.4 / 7.5 / 5.0
Pb / 0.0005 / - / - / 0.0
Table A.2.2
Stationary Internal Combustion Engines: Distillate Oil and BioDieselEmission Factor
Pollutant / Distillate Oil (Diesel)
(lb/MMBtu)
< 600 hp / BioDiesel
(lb/MMBtu)
2- and 4-Cycle Engines
PM / 0.31 / 0.30
PM10 / 0.31 / 0.30
PM2.5 / 0.31 / 0.30
SOx / 0.29 / 0.29
NOx / 4.41 / 4.45
VOC / 0.36 / 0.32
CO / 0.95 / 0.90
Pb / - / -
Table A.2.3
Stationary Internal Combustion Engines: Natural Gas CombustionEmission Factors
Pollutant / 2-SLB
(lb/MMBtu) / 4-SLB
(lb/MMBtu) / 4-SRB
(lb/MMBtu)
PM / 0.00991 / 0.00991 / 0.00991
PM10 / 0.0384 / 0.0000771 / 0.00950
PM2.5 / 0.0384 / 0.0000771 / 0.00950
SOx / 0.000588 / 0.000588 / 0.000588
NOx
(%Load) / 3.17
(90-105) / 1.94
(<90) / 3.17
(90-105) / 1.94
(<90) / 2.21
(90-105) / 2.27
(<90)
VOC / 0.120 / 0.118 / 0.00296
CO / 0.386
(90-105) / 0.353
(<90) / 3.17
(90-105) / 1.94
(<90) / 3.72
(90-105) / 3.51
(<90)
Pb / - / - / -
Notes:
(1)PM=Particulate Matter
PM10=Particulate Matter less than 10 microns in aerodynamic diameter
PM2.5=Particulate Matter less than 2.5 microns in aerodynamic diameter
SO2=Sulfur Dioxide
NOx=Oxides of Nitrogen
VOC=Volatile Organic Compounds
CO=Carbon Monoxide
Pb=Lead
MM=Million
Btu=British thermal unit
lbs=pounds
ft3=cubic feet
gal=gallons
hp= horsepower
(2)Natural Gas heating value is 1,050 Btu/standard cubic foot.
LPG- Butane heating value is 102,600 Btu/gal.
LPG- Propane heating value is 91,500 Btu/gal
Gasoline heating value is 130,000 Btu/gal.
Distillate Oil (Diesel) heating value is 140,000 Btu/gal
(3)S for Distillate Oil: Weight percent sulfur in oil. S indicates that the weight percent of sulfur in the oil should be multiplied by the value given. The maximum weight percent sulfur allowed in this permit is 0.0015%.
(4)S for LPG: Sulfur content expressed on grams/1,000 cubic foot gas vapor. S is assumed to be 0.15 grains/1,000 cubic feet vapor which is equivalent to 0.02% sulfur by weight.
(5)Biodiesel Emission Factors for criteria pollutants were taken from EPA document “Voluntary Diesel Retrofit Program”, and for GHG from EPA document “Emission Factors for Greenhouse Gas Inventories (April 2014,
Permittee With Operating Records Prior to Issuance of this Permit:
The Permittee shall not exceed emissions of 25 tons per year of CO calculated as a 12-month rolling sum. Each month’s CO emissions shall be calculated with Equation A1 above, and then added to the previous 11 months’ emissions.
The Permittee shall not exceed emissions of 25 tons per year of NOx calculated as a 12-month rolling sum. Each month’s NOx emissions shall be calculated with Equation A1 above, and then added to the previous 11 months’ emissions.
A.3. Calculations for Material Usage and Processing Operations
This includes use of paints, thinners, abrasive blasting material, etc. that can use the provided calculation methods.
Emission Units which qualify as insignificant activities or fugitive sources do not need to be included in the calculations.
A.3.1 Demonstration of Compliance with Permit Limits
Permittee With At Least 12 Months of Operating Records.Each month, the Permittee shall use the directions in this Appendix to calculate the 12-month rolling sum of the Particulate Matter, VOC, Total HAP, and Single HAPemissions from material usage and processing operations to demonstrate compliance with the limits of this permit. The Permittee shall use their actual operating history to calculate the 12-month rolling sum.
Permittee Without 12 Months of Operating Records.Each month, the Permittee shall use the directions in this Appendix to calculate the monthly emissions of the Particulate Matter, VOC, Total HAP, and Single HAPemissions in tons/month from material usage and processing operations to demonstrate compliance with the limits of this permit.The Permittee shall evaluate their compliance based on the months for which they have operating data. The Permittee must then use Table A.1 above to determine if they are under the applicable emission limit. For example, if the Permittee has 3 months of operating data, the Permittee shall sum the monthly emissions for the most recent month and the previous 2 months, and compare the resulting number to the applicable limit in row 3 of Table A.1. Once the Permittee has 12 months of data, then the Permittee must calculate the 12-month rolling sum of the emissions each month, as required above.
A.3.2 Material Content Identification
If the information is necessary for the Permittee’s calculation method, the material specifications (VOC content, Solids content etc.) shall be determined by the Safety Data Sheet (SDS), Material Safety Data Sheet (MSDS), or Certification of Analysis (COA) provided by the supplier. If a content range is given on the SDS, MSDS, or COA the highest number in the range shall be used for the compliance calculations. If there is information provided in the Regulatory Section of the SDS, the highest number in the range of that section may be used. Other alternative methods approved by the MPCA may be used to determine the material contents.
Considerations for Particulate Matter/Solids Contents
- Each month, identify the Particulate Matter (PM, PM<10 microns, and PM<2.5 microns) contents in coating materials and other material-usage operations in lbs of Particulate Matter (also known as Solids) per gallon of material, for each material used at the facility.
- When using the SDS or MSDS as the basis of this determination, the Permittee can assume that PM consists entirely of PM less than 2.5 microns, meaning PM=PM10=PM2.5.
- The Permittee may choose to assume that any or all materials used at their facility consist of 100% Solids/Particulate Matter, as long as the Permittee can remain under the limits of the permit while using that assumption.If a material is assumed to be 100% Solids, then the Solids content is the density of the material in lbs/gallon.
- For some material processing operations (blasting, sanding, grinding etc.) the material used or processed may be 100% Solids/Particulate Matter.
Considerations for VOC Contents
- Each month, identify the Volatile Organic Compound (also known as V.O.C. or VOC) contents in coating materials and other material-usage operations in lbs of VOC per gallon of material, for each material used at the facility.
- The Permittee may choose to assume that any or all materials used at their facility consist of 100% VOC, as long as the Permittee can remain under the limits of the permit while using that assumption.If a material is assumed to be 100% VOC, then the VOC content is the density of the material in lbs/gallon.
Considerations for HAP Contents
- For each month in which the Permittee determines that the 12-month sum of the VOC emissions is less than the single HAP limit (5 tons based on a 12-month rolling sum) as calculated in Section 3.4, the Permittee can choose to assume that the 12-month sum of the Total HAP and Single HAP emissions are also 5 tons. For that month the Total and Single HAP emissions calculation is not required.
- For each month in which the Permittee determines that the 12-month sum of the VOC emission is greater than 5 tons, the Permittee must determine the HAP content and calculate the HAP emissions as indicated below.
- For each month that the calculation is required, identify each individual Hazardous Air Pollutant (also known as HAP) content in each coating material or other material. Record the name of each individual HAP (such as toluene, xylene, ethyl benzene etc.) and the contents of that HAP in lbs of HAP per gallon of material, for each material used at the facility.
A.3.3 PM/PM10/PM2.5Emissions Based on a 12-month rolling sum
STEP 1: Calculation of Solids/Particulate Matter Used each Month (Solids Usage)
The Permittee shall calculate the total amount of Solids used or processed during a calendar month using records of hourly usage rate, daily material usage, hours of operations, purchase records, or any combination of methods as identified in the permit application or Compliance Management Plan. Depending on the calculation basis previously identified, the Permittee may use one or more of the following example calculation methods, or a similar method, to determine monthly usage in lbs Solids/month. Method 1 and 2 may be more useful for coating operations where the solids content in lbs/gallon is known. Methods 3 and 4 may be more useful for operations where a 100% Solids material is used, such as in abrasive blasting, and the weight of the material used or purchased hourly or daily is known.
Method 1: Solids Usage (S) based on hourly usage rate (such as spray gun capacity), hours of operation, and SDS/MSDS
Where:
S= Solids Usage in lbs Solids/month
A = rate of material usage (i.e. spray gun capacity) in gallons/hour
B = solids content of material from SDS or MSDS, as identified in Section A.3.2 (lb Solids/gallon of material)
C = actual hours of operation for the previous month
Method 2: Solids Usage based on gallons of material used or purchased each day, days of operation, and SDS/MSDS
Where:
S= Solids Usage in lbs Solids/month
A = average gallons of material used or purchased per day
B = solids content of material from SDS or MSDS, as identified in Section A.3.2 (lbs solids/gallon of material)
C = actual days of operation for the previous month
Method 3: Material Usage based on hourly usage or processing, hours of operation, and an Emission Factor (EF)
Where:
S= Solids Usage in lbs Solids/month
A = lb of material (i.e. abrasive) used per hour
EF = Emission Factor (lb PM/lb material) identified in permit application or Compliance Management Plan (see Table A.3.1 below for abrasive blasting EFs). The emission factors for PM, PM10and PM2.5may be pollutant specific.
C = actual hours of operation for the previous month
Method 4: Solids Usage based on material used or purchased each day, days of operation, and an Emission Factor (EF)
Where:
S= Solids Usage in lbs Solids/month
A = lb of material (i.e. abrasive) used or purchased per day
EF = Emission Factor (lb PM/lb material) identified in permit application or Compliance Plan (see Table A.3.1 below for abrasive blasting Emission Factors)
C = actual days of operation for the previous month
Table A.3.1
Emission FactorAbrasive / lb PM / lb abrasive / lb PM10/lb abrasive
Sand / 0.041 / 0.029
Grit / 0.010 / 0.0070
Steel Shot / 0.004 / 0.0034
Other / 0.010 / 0.00010
Emissions factors for PM/PM10/PM2.5 emissions from abrasive blasting obtained from Volume I of STAPPA-ALAPCO "Air Quality Permits". PM2.5 is assumed to be equivalent to PM10.
STEP 2: Identify Transfer Efficiency and Overall Control Efficiency as applicable
Transfer Efficiency
Select a Transfer Efficiency if one of the application methods in Table A.3.2 is used. These are the transfer efficiencies allowed by this permit for these application methods. Alternatively, the Permittee may choose to use a transfer efficiency of zero, as long as the Permittee can remain under the limits of the permit while using that assumption. For operations not identified in Table A.3.2, transfer efficiency is assumed to be zero.
Table A.3.2
Application Method / Transfer EfficiencyAir atomization spray / Not allowed
Airless spray / 0.45
Electrostatic/Air atomization / 0.70
Electrostatic/Airless / 0.75
High Volume Low Pressure / 0.75
Electrode deposition / 0.95
Powder / 0.95
Overall Control Efficiency
Calculate the Overall Control Efficiencyfor PM/PM10/PM2.5. This calculation shall be used as indicated in your Compliance Management Plan, if applicable.
Considerations for Overall Control Efficiency:
- The Permittee may choose to use an Overall Control Efficiency of zero, as long as the Permittee can remain under the limits of the permit while using that assumption.
- For operations that do not use control equipment, the Overall Control Efficiency is zero.
- For operations that are totally enclosed as defined in Section A of this permit, the Capture Efficiency (C) is 100%.
- For operations that are not totally enclosed, but are certified according to Minn. R. 7011.0072, the Capture Efficiency (C) is 80%.
- For operations that are not totally enclosed, and are not certified according to Minn. R. 7011.0072, the Overall Control Efficiency is zero.
- The Collection or Destruction Efficiency (D) used in this equation will depend on the type of control equipment used.
- The Control or Destruction Efficiency (D) for PM/PM10/PM2.5 as controlled by different types of control equipment are listed Minn. R. 7011.0070 and Section A of this permit.
- Note: If the Permittee accounts for control for PM then the PM, PM10, and PM2.5 emissions must be determined separately from this point on, since there are different control efficiencies for each type of particulate matter.
Where:
C= Capture efficiency (% capture).
D= Collection or Destruction efficiency (%Collection or %Destruction).
STEP 3: Calculate lb of Particulate Matter (PM/PM10/PM2.5) per month
This equation gives PM/PM10/PM2.5 emitted in lbs/month using the Solids/month (S) identified in STEP 1, and taking into account anytransfer efficiency or control efficiency identified in STEP 2.
Where:
Monthly Emissions= Particulate Matter(PM/PM10/PM2.5) emissions in lbs/month
S = lbs Solids/month as determined in STEP 1
Transfer Efficiency= Transfer Efficiency as identified in STEP 2 (this may be zero)
Overall Control Efficiency= % Overall Control Efficiency as identified in STEP 2 (this may be zero)
STEP 4: Determine the Total Monthly Emissions
If more than one Solids-emitting process, or materials with different solids contents, are used at the facility, and consequently more than one method was used to determined monthly emissions, at this point the monthly emission from each process or material should be summed to determine the Total monthly PM/PM10/PM2.5 emissions. If PM, PM10, and PM2.5 are not considered to be equal, then a total monthly emissions should be calculated separately for PM, PM10, and PM2.5.
STEP 5: Identify Material Shipped as Waste, as applicable
The Permittee may elect to obtain credit for solids shipped in waste materials by one of the following methods:
- The Permittee may analyze a composite sample of each waste shipment to determine the weight content of Solids in lbs/gallon.
- The Permittee may use supplier data for raw materials to determine the solids content of each waste shipment, using the same content data used to determine the content of raw materials. If the waste contains several materials, the content of mixed waste shall be assumed to be the lowest solids content of any of the materials.
Once Solids content is identified, use a calculation method to determine waste (W) in lbs Solids/month.
For example:
Where:
W = Waste shipped in lbs Solids/month
X = Solids content of the waste in lbs Solids/gallon
Y = Total amount of waste, in gallons, shipped that month
STEP 6: Calculate tons Particulate Matter (PM/PM10/PM2.5) per month
Where:
PM= Emission of Particulate Matter (PM/PM10/PM2.5) in tons/month
T= Total monthly emission of Particulate Matter in lb/month as determined in STEP 4
W=waste shipped in lbs Solids/month as determined in STEP 5 (if no waste credit is taken, this will be zero)
0.0005 = conversion factor; ton/pounds (ton/lbs)
STEP 7: Calculate the 12-month rolling sum of Particulate Matter
Each month, the Permittee shall calculate the 12-month rolling sum PM/PM10/PM2.5emissions for the previous 12-month period by summing the monthly PM emissions data, as calculated in STEP 6, for the previous 12 months.
A.3.4 VOC Emissions Based on a 12-month rolling sum
STEP 1: Calculation of Volatile Organic Carbon (VOC) Used Each Month
The Permittee shall calculate the total amount of VOCs used or processed during a calendar month using records of hourly usage rate, daily material usage, hours of operations, purchase records, or any combination of methods as identified in the permit application or Compliance Management Plan. Depending on the calculation basis previously identified, the Permittee may use one or more of the following example calculation methods, or a similar method, to determine monthly usage in lbs VOC/month.
Method 1: VOC Usage (V) based on hourly usage rate (such as spray gun capacity), hours of operation, and SDS/MSDS
Where:
V= VOC Usage in lbs VOC/month
A = rate of VOC-containing material usage (i.e. spray gun capacity) in gallons/hour
B = VOC content of material from SDS or MSDS, as identified in Section A.3.2 (lb VOC/gallon of material)
C = actual hours of operation for the previous month
Method 2: VOC Usage based on gallons of material used or purchased each day, days of operation, and SDS/MSDS