4 The record articles

What Do You Need to Know About Starting a Stack Testing Program?

Posted: March 13th, 2023

Authors: Steve R. 

When your facility finds they need to do a stack test on a piece of equipment, there will be a number of questions thrown at you. Being proactive will go a long way toward having a smooth and positive experience. Here are some questions that you should ask.

Why are we testing?

Identifying why is essential. Is there a regulation or permit condition that requires a performance test? Is this a test to determine the peak performance of a unit and/or control device in terms of emissions? A pre-test for a compliance program to determine the optimal rates to run a unit? Answering these basic questions gives an idea of the length of time needed to test and the procedural obstacles that may arise. For example, a test protocol may need to be developed and submitted to the proper regulatory agency prior to any stack testing. The protocol will describe how you will run the unit during the test and how you will use the data gathered during the test. Protocol review takes time, and the reviewing agency may request changes to your test plan as a result of their review.

What pollutants and parameters are listed in the permit?

Once you know why you are testing, you will need to know what pollutants you are testing and how you will have to operate the unit during the testing. Knowing which pollutants and parameters are important, the emissions limits that apply, and how to set operating limits allows you to define the specifics of methods and implementation. The permit and any previous testing/sampling data provide the best information to define the testing scope.

What other information does the stack tester need before testing?

To successfully implement a stack testing program there are details that the stack testing company needs to be efficient and successful. Once the protocol/test plan is prepared, the stack tester will need more information on the source itself. Specifically, they will need at a minimum to know the stack dimensions and if the stack fits the needs of the testing methods. Does the stack meet the length requirements? Are the ports large enough to fit certain probes? Are there enough ports to fit each test method all at once or does the test program need to be split into test phases?

In addition, the stack testing firm will need to know some details about the facility. Will the test team be able to park a trailer near the unit or will they have to run sample lines several hundred feet away? Oftentimes the stack testing company will bring a lab trailer onsite that will need to be powered with a certain voltage. Some facilities have special welding outlets installed near where a stack testing laboratory trailer will be parked. Some trailers can only be powered by the high voltage outlets. Knowing what voltage is available to them prior to their arrival is important.

Another detail to consider – what are your facility’s safety requirements? Each facility is different, some have rigorous safety programs that can require lengthy training and require background checks and/or drug and alcohol screening before testing contractors are allowed to come onsite and do work. Some sites require specialized online training, online classes, or even ID badges before arriving on site. Having all the proverbial ducks in a row up can help prevent any delays to the start of the testing.

What process parameters need to be monitored during stack testing?

One of the trickiest things about stack testing is understanding the link between process operations during the test, permit limits, and how the process operates during non-testing days. Specific process conditions may be required to be maintained throughout the duration of the testing. Collection of data including certain temperatures, feed rates, or loads is often captured through a facility data system and may need to be recorded throughout the testing. However the process is to be run, and the process data is to be collected, details should be figured out prior to any test date, and reviewed the day(s) of the test. Making sure that all stakeholders (stack testers, unit operators, facility environmental team, etc.) are on the same page with how the process needs to be operating during the test, and the implications on operations after the test program, is a crucial part of stack testing and can make or break the success of the testing program. For example, oftentimes a process parameter rate is listed in a permit. If during a performance test that parameter is below the limit listed in that permit, then the regulating agency could either nullify the test or possibly limit the operation of the unit until the next performance test.

How can ALL4 help?

Stack testing is usually a periodic event. Facility test coordinators have a pivotal role in the success of the stack test. They have to meld together the following:

  • Permit requirements
  • Previous data
  • Current facility operations (and operating philosophy)
  • Site access
  • Stack testing requirements
  • Possible future operating limits

ALL4 can be a guide throughout the process of stack testing. It can be a daunting and strange process, but with some guidance, and the right questions, stack testing no longer needs to be a stressful event. Having us guide your facility through the environmental jargon and facilitate the many hurdles involved can relieve the stress stakeholders feel. Please reach out to me at 610-422-1169 or at srathfon@all4inc.com if you have any questions regarding this subject.


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