Rules in 40 CFR 60 Subpart OOOO and OOOOa require routine visibility observation testing for enclosed combustion devices (e.g., ECD) and flares (open-tipped, candlestick flares).

Enclosed combustion devices and flares are required under NSPS OOOO and OOOOa to be operated with no visible smoke emissions, except for periods not to exceed a total of 1 minute during any 15-minute period. To demonstrate compliance, a visibility test known as EPA Method 22 is used.


EPA Test Method 22 Used

The EPA test method require can be found in 40 CFR 60, Appendix A-, “Test METHOD 22 Method 22 – Visual Determination of Fugitive Emissions from Material Sources and Smoke Emissions from Flares.” Section 11 of the method has the detailed procedure to follow. Note that the procedure was modified 8/3/2017.


Applicability of Method 22 Testing Requirements

This testing requirement only applies to enclosed combustors and flares that were installed to comply with NSPS OOOO and OOOOa.

Method 22 testing is not required for combustion devices and flares used to comply with State enforceable air permits such that NSPS OOOO and OOOOa do not apply. The only exception is if a State permitting agency requires such testing.


Frequency of Method 22 Testing

Perform the test once every calendar month, separated by at least 15 days between each test.

This applies to manufacturer tested enclosed combustor models and those that are field tested by the operator.


Test Procedure

Review the published Method 22 for detailed procedure.

Below is a summary of the procedure.

  1. Observer conducting the test should view the emission source from a position at least 15 feet, but not more than 400 m (0.25 miles) from the emission source. The position should be where the sunlight is not shining directly in the observer’s eyes.
  2. Record the following information on the field data sheet used (see sample form in Figure 1 below):
    1. Company name, facility name, observer name, observer affiliation, date of observation
    2. Combustor or flare identification name
    3. Observer’s name, observer’s affiliation, and date.
  3. Record estimated wind speed, wind direction, and sky conditions (clear, partly cloudy, cloudy) and any precipitation occurring during observation.
  4. Sketch the process unit being observed, and note the observer location relative to the source and the sun. Indicate the potential and actual emission points on the sketch.
  5. Record start and end time of observation with accumulated number of minutes of observation. Conduct observation for a minimum of 15 continuous minutes. The suggested maximum observation time without a break is 20 minutes.
  6. Record accumulated number of minutes where visible smoke emissions are observed.
  7. If no visible smoke emissions are observed during the 15-minute observation period, then the combustor or flare has passed the test. The exception to this is that if the cumulative total time of observed visible emissions is less than or equal to 1 minute, then the combustor or flare passed the test and no further actions required.
  8. A failure of the test occurs if the total cumulative observed visible smoke emissions exceed 1 minute in any 15-minute period.


What to do if fail Method 22 test?

If the enclosed combustor or flare fails the test, follow the manufacturer’s repair instructions or use best combustion engineering practice as outlined in the device’s inspection and maintenance plan to return the unit to compliant operation.

Record all repairs and maintenance activities for each device in a maintenance and repair log and ensure the records are available for inspection.

After a return of the device to operation from a maintenance or repair activity, conduct another Method 22 visual observation test to demonstrate compliance with the visible emissions standard.


Method 22 Training

No certification is required to conduct Method 22 testing. Method 22 is a simple method that only requires the observer to record the amount of time that emissions are observed. The observer must read and understand the requirements of Method 22 and document the observations.

For a link to EPA’s Method 22 training guidance and for a copy of the procedure, go to: LINK to Method 22

Training of observers that will conduct the test should include the following:

  1. Read and understand the EPA Method 22 procedure.
  2. Read and understand the Method 22 Question and Answer document from the EPA Air Toxics website
  3. Understand how to conduct the test and document the observations.
  4. Be sure to maintain records of Method 22 training for each observer conducting the testing.



Maintain copies of these observations either onsite or at the nearest local field office for at least 5 years.

Figure 1. Sample Method 22 Observation Form


Get Prepared and Stay in Compliance

Cimarron can assist your company with NSPS OOOO and OOOOa compliance. Our thorough understanding of oil and gas processes and expertise with storage tank emission controls (VRUs, VRTs, VCUs) and leak monitoring makes us a leader in providing certainty to your compliance needs.

Our services include Method 22 testing for your facilities.

Our IQR (Identify, Quantify and Rectify) services include fugitive leak monitoring (LDAR) that meets NSPS OOOOa requirements. Our IQR services can also assist with emission controls selection for your facility.

Contact us today at:
+1 (844) 746-1676

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