Combustion
Furnace/dryer
The Combustion category of emission sources includes devices such as boilers, furnaces, space heaters, emergency or back-up generators, dryers, or incinerators. These devices are sources of air pollutants when they burn gaseous (natural gas), liquid (fuel oil) or solid (coal or wood) fuels.
You need to determine if you are exempt
Under the general exemptions, you will need to do more detailed calculations to determine if you are exempt. For the fuel burning emissions source types listed below, there are emission factors available from US EPA to calculate the emissions from your business.
(Click on the drop-down topic below to go to EPA's site for emission factors, then refer to the fact sheets that follow. Be sure to copy the emission factors for all pollutants listed in the section [vocs, particulate matter, SO2, nitrogen oxides, and hazardous air pollutants] to calculate for each exemption level.)
Topics with Links to Emission Factor Information
- External Combustion Furnaces including indirect malt dryers, heat treating furnaces, etc.
- Emergency Electric Generators and Other Internal Combustion Engines including engine test stands
- Equipment that Temporarily Increases Steam Electric Generation Capability
General Information
You can use the MTE Calculation Examples spreadsheet [EXCEL 54kb exit DNR] for help with calculating maximum theoretical emissions (MTE) and to see example calculations. (Save the file to your computer's hard drive after it opens.)
Calculations Fact Sheet
To get more details on how to calculate or determine your boiler rating, fuel heating value, fuel throughput and maximum theoretical emissions, please review this fact sheet on Combustion Sources and Air Pollution Construction Permits [PDF 77kb exit DNR] (while examples provided are for external combustion furnaces, the calculations for internal combustion engines with emission factors are basically the same).
If the calculations you performed here are the only ones at your facility for the specified pollutant, then you can compare the emissions rate for that pollutant with the general exemption levels to see if you are exempt so far.
(If you only have one boiler to provide heat and process steam at your plant, and have no other sources of dusts or fumes that would be considered particulate matter emissions, then you can compare your calculated emission rate for particulate matter from the boiler with the general exemption level of 5.7 lb/hr of particulate matter. If your calculated emission rate is below the exemption level, then so far so good. You will need to check the emission for other pollutants before determining if the whole construction project is exempt.)
Hazardous Air Pollutant Guidance
These processes will also have hazardous air pollutant emissions. Please review the following guidance on hazardous air pollutant emission calculations:
- Wisconsin's Air Toxics Program — A web site containing information about hazardous air pollutants and state regulations.
- Hazardous Air Pollutant List — An interactive Excel spreadsheet that can show you the thresholds in the state rule for each of the HAPs that you emit. Just place an X in the Select column, then choose the X option from the drop down menu in the top row of that column, and only the information on your HAPs should be shown. Save it to your hard drive as soon as the file opens.