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Minnesota rules require many facilities that produce air emissions to conduct performance testing (also called "stack testing") that:

  • quantifies facility emissions.
  • determines the physical, chemical, or aesthetic properties of the emissions.
  • in some cases, measures the performance of emission-control equipment.

Performance tests are performed by independent testing companies with testing expertise. A list of testing companies is available from the Source Evaluation Society.

Most permits require recurring performance tests on a set schedule. Before 2019, facilities had to submit test frequency plans to the MPCA. The agency now sets a test schedule with permit issuance based on factors such as compliance history, previous test results, applicable requirements, stringency of limit, use of emission factor, etc. If warranted, the frequency may be reset after a test by compliance staff in the Notice of Compliance or Notice of Verification. That test frequency becomes effective upon issuance of the review letter and will be incorporated in the facility’s permit.

Facilities subject to performance-testing requirements must:

  • Provide notification and a test plan to the MPCA at least 30 days before the scheduled test unless required otherwise. A test plan details what will be tested, the methods used, and how equipment will be operated during the test. Submit test plans electronically (via email) to SubmitStackTest.PCA@state.mn.us as well as your assigned stack test staff member (if known).
  • Arrange for a pretest meeting with MPCA staff at least seven days before the test. We'll discuss the test plan with you and your consultant to ensure procedural and technical requirements will be met, as well as answer questions. Pretest meetings are typically held over the phone.
  • Submit a test report to the MPCA no later than 45 days after the test.

Note: If you can't meet these deadlines, or need to reschedule after the test plan has been approved, it is your responsibility to contact MPCA staff and discuss the situation. Do not test prior to having approval.

Test plans

Your test plan must be complete and accurate, and approved by the MPCA prior to testing. If the submitted test plan is missing necessary information, the MPCA will request a revised plan. Once satisfied, the agency will provide written approval of the plan that may include clarifications or modifications. Use this completeness checklist to ensure you include all required information.

Test methods

The U.S. EPA's Air Emission Measurement Center lists the test methods available for emission measurement.

Test reports

You must submit a complete and accurate test report meeting all requirements of Minn. Rule 7017.2035. Use the completeness checklist to ensure you include all required information. Performance test reports must be certified using this certification form.

Submit the appropriate operating data form as part of a complete test report; it provides a summary of the operating conditions during the test and verification that it was completed at worst case conditions. Tests not completed at worst case typically have limits set on production and control equipment operations.

In addition to the summary form, emission unit and control equipment operating conditions must be recorded for each run and averaged over three runs to provide a final average value for the test. Readings of discrete data from monitoring instruments must be recorded at least every 15 minutes, or other reasonable time interval as approved, during the test. Strip charts or retrieved electronic data from continuous monitors or rates recorded manually must be included in the test report and summarized on one of these forms:

Submitting test reports

Send stack tests reports (in a PDF format only) attached to an email to: SubmitStackTest.PCA@state.mn.us. The email message body must include:

  1. Name of regulated party (and facility name if different)
  2. Facility contact
  3. Agency Interest ID number or permit number
  4. Date of performance or certification test
  5. Name of MPCA staff who sent approval
  6. Date of submission

Noncompliance reporting

All periods of noncompliance with emission or other limits — even during engineering tests — must be reported to the MPCA. Operating at a rate other than that allowed by the current air permit must also be reported.

Send routine compliance reports to AQRoutineReport.PCA@state.mn.us.

Air permit compliance forms

Submitting routine compliance reports

Include the submission date and a brief description as part of the routine report document title:

  • Example: 1-28-16, DRF-1, DRF-2, CR-04
  • Example: 1-28-16, Pt 60 MM Compliance Report
  • Example: 1-28-16, DRF-1 and EU001 NOx

Frequently asked questions about reporting test results

Am I required to submit the results of an engineering performance test that I conduct for my own information?
If an engineering test indicates noncompliance with a limit, the company must inform the MPCA. Generally, the pollutant, emissions, and operating conditions can be summarized and reported in place of a complete report, unless a more detailed report is requested. Results of a compliant engineering test need not be provided, unless requested by the MPCA. All periods of noncompliance with emission or other limits must be reported to the MPCA.

If early results indicate a test failure, can I stop the test and try again later?
Each performance test must consist of at least three separate test runs. If after conducting one or more test runs, the company determines that an emission limit has been exceeded, the MPCA should be contacted for further guidance. A detailed description of sampling or other problems experienced during the test should be included in the executive summary of the test report. Regardless of the number or length of test runs, data from an aborted emissions test may be used to establish violations.

What if my test results indicate noncompliance?
The unit must be retested within 30 days of the MPCA notice of noncompliance, unless a compliance plan is submitted and approved by the MPCA. The period of noncompliance begins at the date of the initial noncompliant test. Therefore, you should take immediate measures to minimize emissions without waiting for the formal notification from the MPCA.

Can I use the data from my test report for emission fee inventory purposes?
Yes. Minnesota rules require the calculation of emissions based on an established hierarchy. In the absence of continuous emission monitor data, the next method of calculation, a performance test, must be used. When a performance test for PM, PM10, PM2.5, CO, NOx, SOx, VOC or Pb is conducted and meets the requirements of Minn. R. 7017.2001-7017.2060, the results must be used to calculate emissions, unless specified otherwise by Minn. R. 7019.3000-7019.3100. It is the company’s responsibility to ensure the results of performance tests are accounted for in their annual emission inventory. The final decision to approve the emission factor for any given inventory year will be made by the Emission Inventory Coordinator.

How do I submit confidential information as part of a test report?
Claims of confidentiality for test report information must have a statutory basis and be included in a cover letter that accompanies the test report. See Minn. R. 7000.1300 and Minn. Stat. § 13.37 and 116.075 to determine whether your information meets the criteria. In the cover letter, identify the confidential information and explain the statutory basis for the claim. Provide both a public and a confidential copy of the test report.