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Preparing for Subpart MM 2020 Performance Testing

Posted: April 18th, 2019

Authors: Lindsey K. 

40 CFR Part 63, Subpart MM (National Emission Standards for Hazardous Air Pollutants for Chemical Recovery Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills) was amended in October 2017.  The amendments include a periodic performance testing provision, the first of which is required by October 13, 2020.  As with any performance test, preparation well in advance of the test date is the key to success.  Here’s what you need to know.


Most mills will conduct a performance test for particulate matter (PM), and specifically filterable PM, as a surrogate for hazardous air pollutant (HAP) metals from the recovery furnace, smelt dissolving tank, and lime kiln.  New kraft and soda recovery furnaces and sulfite combustion units will also need to test for gaseous HAP.  A summary of the applicable emissions limits is provided below:

Testing Conditions

Pursuant to 40 CFR §63.865, “Performance tests shall be conducted based on representative performance (i.e., performance based on normal operating conditions) of the affected source for the period being tested,” which excludes periods of startup, shutdown, and malfunction.  During the test, you’ll need to establish operating parameter limits, as applicable to your mill’s control configuration.  If you’ve already established operating parameter limits prior to the amendments, you’ll need to confirm or reestablish the limits during the performance test.

Should you prefer monitoring an alternative parameter pursuant to 40 CFR §63.864(e)(13) or the use of a control device other than an electrostatic precipitator (ESP), wet scrubber, regenerative thermal oxidizer (RTO), or fabric filter pursuant to 40 CFR §63.864(e)(14), written approval is required and should be obtained prior to the performance test, since the approval will include the “manner in which the operating limit is to be set.”

Should you wish to comply with an overall PM emissions limit pursuant to 40 CFR §63.862(a)(1)(ii), you’ll need to establish this limit during the performance test as well.  If you’ve previously established an overall PM emissions limit, you only need to reestablish the limit if an applicable air pollution control system is modified or replaced (for example, your recovery furnace ESP is upgraded), or if an applicable source is shut down for more than 60 consecutive days.

When is a performance test not just a performance test?

There is more to a performance test than just measuring emissions at the stack.  Don’t forget about the performance evaluations for continuous monitoring systems (CMS)!  Ongoing compliance with emissions limits after the performance test is based on continuous compliance with the operating parameter limits established during the performance test, such as scrubber pressure drop and liquid flow rate.  The purpose of CMS performance evaluations is to demonstrate that the continuous monitoring data used to establish those limits are valid.  For example, a performance evaluation may involve independently measuring the scrubber liquid flow rate and comparing it to the values obtained by the inline flowmeter to verify its accuracy.

Depending on your mill’s control configuration, performance evaluations may be required for the following CMS:

To Whom It May Concern

Notification requirements for the performance test and performance evaluation(s) are specified in the General Provisions under 40 CFR §§63.7 and 63.8, respectively.  Notification of the performance test is required at least 60 days in advance of the scheduled test date, and notification of the performance evaluation should be submitted simultaneously.  The notifications should be sent to the appropriate U.S. EPA Regional Office and your local regulatory agency.

Test Plans

A performance test plan and performance evaluation test plan must be developed in advance of the tests.  Although not required to be submitted, U.S. EPA may request to see either plan in advance of the testing, so it’s wise to have them prepared by the time of the 60-day notification.  Pursuant to 40 CFR §63.7(c)(2)(i) and (ii) for performance test plans and §63.8(e)(3)(i) and (ii) for performance evaluation test plans, the test plans must include the following components:

  • Program objectives
  • Program summary
  • Schedule
  • Data quality objectives (i.e., pre-test/evaluation expectations of precision, accuracy, and completeness of data)
  • Internal QA program (i.e., the activities planned by routine operators and analysts to provide an assessment of test data precision for performance tests and CMS performance for performance evaluations)
  • External QA program (i.e., for performance evaluations, systems audits that include the opportunity for on-site evaluation by the Administrator of instrument calibration, data validation, sample logging, and documentation of quality control data and field maintenance activities)


As with other recently updated rules, test results will need to be submitted via U.S. EPA’s Compliance and Emissions Data Reporting Interface (CEDRI) in a format generated using U.S. EPA’s Electronic Reporting Tool (ERT).  The results are due within 60 days of completing the performance test.  Plan for a little extra time if you’ve never entered results via CEDRI!

20-20 Hindsight Foresight

With testing due by October 2020, this may not be the first thing on your mind.  But, your mill likely has other testing obligations, so don’t forget to consider how this testing deadline aligns with your routine testing schedule.  It may make sense for you to test early.

They say hindsight is 20-20, but hopefully this blogpost helps you see 20-20 before 2020 testing!  Feel free to contact me at lkroos@all4inc.com or 610.933.5246 x122 with any questions!


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