Approved Instrument Monitoring Method (AIMM) for oil & gas


An Approved Instrument Monitoring Method (AIMM) must be used to inspect components, storage tanks and natural gas-driven pneumatic controllers at well production facilities, natural gas compressor stations, and natural gas processing plants (storage tanks only) under the Leak Detection and Repair (LDAR), Storage Tank Emission Management (STEM) and Natural Gas-Actuated Pneumatic Controller requirements of Air Quality Control Commission (AQCC) Regulation 7.
AQCC Regulation 7 defines AIMM as an infrared (IR) camera, EPA Method 21, or other instrument based monitoring method or program approved in accordance with the requirements of Regulation 7, Part B, Section I.L.8 (“Alternative AIMM”).
Although Section I.L.8 is specific to the Ozone Control Area or Nonattainment Area (NAA), the Air Pollution Control Division (“Division”) will use the requirements in Section I.L.8. to evaluate all Alternative AIMM regardless of where the AIMM may be used in Colorado. However, an Alternative AIMM that requests to be used exclusively outside the NAA will not be subject to the public notice and EPA review and approval provisions of Section I.L.8.a.(iv).
For more information on public notice for Alternative AIMM, please see the Alternative AIMM Public Notices page.

Infrared camera

Regulation 7, Part B, Sections I.B.19. and II.A.18. define an IR camera as “an optical gas imaging instrument designed for and capable of detecting hydrocarbons.”

The following list provides examples of non-quantitative handheld and tripod-mounted IR cameras that meet the above noted definition:
  • FLIR models GF300, GF320, Gx320, GFx320, G620, GF620, Gx620
  • Opgal EyeCGas camera
  • Infrared Cameras Inc. (ICI) Gas DetectIR VOC
  • Konica Minolta Gas Camera System, Models: GMP01, GMP02
  • Ventus OGI-Camera MWIR Core installed in any unmanned aerial system or custom built handheld camera
NOTE: IR cameras that are optimized for the detection of methane but have reduced detection capabilities for total hydrocarbons including VOCs, such as uncooled long-wave infrared (LWIR) cameras, do not meet the definition of an IR camera under Regulation 7 and are required to obtain an Alternative AIMM approval prior to use for meeting Regulation 7 monitoring requirements. This is required because Regulation 7 applies to total hydrocarbons (methane + VOCs) for oil and gas. However, the Alternative AIMM provision in Regulation 7 allows for approval of monitoring technologies that are optimized or specific to methane if the Alternative AIMM requirements are met.
Additionally, an IR camera that offers or utilizes quantification capabilities that will be used for the determination of an emissions leak requiring repair will also need to obtain Alternative AIMM approval since Regulation 7 specifies that any emissions associated with a leak detected by an IR camera require leak repair. An Alternative AIMM approval, however, allows for the leak identification requiring repair to be established as set forth in the approval . 
For questions on whether a particular IR camera meets the definition of an IR camera in Regulation 7, please contact the AIMM Team at cdphe_aimm@state.co.us.
A non-handheld IR camera used in a mobile monitoring platform or deployment method (for example, vehicle-mounted or aerial) will be required to develop and implement a monitoring plan in order to be used for Regulation No. 7 monitoring requirements. Please see the Alternative AIMM Guidance & Procedures document for details regarding the monitoring plan.

EPA Method 21

EPA Method 21 states the instrument detector type is not specified, but it must meet the specifications and performance criteria in Section 6.0 of the method. Example instrument detector types for meeting EPA Method 21 criteria include flame ionization detectors (FID) and photo ionization detectors (PID).


Alternative AIMM

  • Alternative AIMM Guidance &, Procedures document, which provides information on the Alternative AIMM application process, as well as monitoring plan requirements for non-handheld IR cameras.
  • Submit completed Alternative AIMM application and supporting documentation to cdphe_aimm@state.co.us.
  • Alternative AIMM approved for use to meet Regulation 7 requirements will be issued an approval letter outlining the conditions of approval. An approved Alternative AIMM may be used by anyone to meet Regulation 7 requirements provided the approval conditions are met. Please see below for currently issued Alternative AIMM approval letters.

Alternative AIMM and Title V operating permits

If an approved Alternative AIMM will be used at a facility subject to Title V Operating Permit requirements, the Alternative AIMM must first be documented within the Title V Operating Permit. Please submit a complete Title V Operating Permit modification application or revise a previously submitted Title V Operating Permit application requesting use of the approved Alternative AIMM at a subject facility before implementation of the Alternative AIMM at the facility.


Please direct all questions and/or Alternative AIMM applications to cdphe_aimm@state.co.us.
Questions regarding Alternative AIMM may be submitted prior to submitting an application.