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Regulation 3 Changes for Internal Combustion Engines


What's New?

Businesses that operate Internal Combustion Engines (ICE) that were once exempt from submitting an Air Pollutant Emission Notice (APEN) to the Division now may be subject to reporting.  In previous years, Regulation No. 3 listed specific exemptions from APEN reporting requirements for select engines under a certain horsepower and hours of operation.  However, these specific exemptions have been removed from Regulation No. 3 (previously found in Reg. 3 Part A, Sections II.d.1.sss. and ttt.).  On October 3, 2011, the EPA published in the Federal Register a final action partially approving and partially disapproving Colorado’s SIP revisions, which revised APEN and permitting exemptions that the Air Quality Control Commission (AQCC) submitted to EPA in September 1997, June 2003, July 2005, August 2006, and August 2007.  EPA commented that the APEN exemption should require recordkeeping and reporting.  The Division opted to propose to repeal the APEN exemption and revise the permit exemption to be consistent with current SIP approved language instead of requiring additional recordkeeping and reporting. While the categorical exemptions have been repealed, sources may still utilize the general one and two ton APEN exemptions found in Part A, Section II.D.1.a. of Regulation No. 3.

If you own an engine that was exempt from the APEN submittal based on size (horse power) and hours of operation, you must now calculate your emissions and report them to the Division if they are above APEN reporting levels. Regulated engines may include, but are not limited to, small diesel engines, emergency engines for back-up power at a building, and small water pump engines.

Steps to determine if you need to report your engine to the Division:

Step #1- Determine if your engine is subject to New Source Performance Standard (NSPS) IIII

If your engines is subject to NSPS IIII, then you are required to report that engine and the emissions to the Division.  Use the following checklist and guidance documents to determine if your engine is subject to NSPS IIII.  If your engine is subject to a NSPS that has been incorporated by reference into AQCC Regulation 6 Part A, exemptions for reporting and permitting do not apply pursuant to AQCC Regulation No. 3, Part A, Section II.D.1 and Part B, Section II.D. 

If you purchase an engine from outside of Colorado or if you relocate your engine, refer to PS Memo 10-03 to determine if you may have tripped NSPS regulations.


Step #2- Calculating emissions for your internal combustion engine

The following spreadsheets use accepted methods to calculate emissions from internal combustion engines.  The preferred method is to use manufacturer' emission factors in grams per horse power hour (g/hp-hr), but if these factors can not be obtained, than use the appropriate emission factors from EPA's AP-42, Sections 3.3 and 3.4.  Select the appropriate excel spreadsheet below to generally estimate your emissions: *Note these spreadsheets are conservative and are used to generally estimate emissions.  You may more accurately estimate emissions using manufacturer emissions factors and site specific operated data for each engine in question.


Step #3- Determine if your emissions are at reportable levels


Step #4- Report your emissions to the Division

If you have question contact the Small Business Assistance Program at: 303-692-3148 or 3175