In this action, the EPA is finalizing a protocol for the use of OGI as appendix K to 40 CFR part 60. The EPA notes that while this protocol is being finalized in this action, the applicability of the protocol is broader. The protocol is applicable to facilities when specified in a referencing subpart to help determine the presence and location of leaks; it is not currently applicable for use in direct emission rate measurements from sources.
The protocol does not on its own apply to any sources; it applies only where a specific rule subpart incorporates it by reference and specifies the sources to which it applies. In this case, we are finalizing the use of the protocol only for implementing the standards for process units at natural gas processing plants that are being finalized in this action. Once incorporated into a subpart, the protocol would only be applicable for surveys of process equipment using OGI cameras where the majority of compounds (> 75 percent by weight) in the emissions streams have a response factor of at least 0.25 when compared to the response factor of propane.
This is the first time that EPA publish a method using MWIR OGI for LDAR survey. Although attached to this methane reduction rule finalized, it may be applicable for any future source rule that emits plumes with majority of VOCs gases (response factor requirement). Opgal’s EyeCGas Multi cooled MWIR Optical Gas Imaging Camera has RF greater than 0.25 for methane and all relevant VOC gases for both relevant filters.
Additionally, the OGI camera used for surveying must also be capable of detecting (or producing a detectable image of) methane emissions of 19 g/hr (0.14 g/hr for methane Opgal EyeCGas Multi OGI camera with standard filter for this laboratory set of conditions, which is 140 times lower than the required detection) and either butane emissions of 29 g/hr (0.11 g/hr for butane with the Opgal EyeCGas Multi camera with standard filter for this laboratory set of conditions, which is 260 times lower than the required detection) or propane emissions of 22 g/hr (0.10 g/hr for propane with Opgal EyeCGas Multi OGI camera with standard filter for this laboratory set of conditions, which is 210 times lower than the required detection) at a viewing distance of 2.0 meters and a delta-T of 5.0 °C in an environment of calm wind conditions around 1.0 meter per second or less.
Verification that the OGI camera meets these criteria may be performed by the owner or operator, the camera manufacturer, or a third party.
The results above for Opgal’s EyeCGas Multi OGI camera with the standard filter, are the results of performance tests at the above laboratory conditions.
Field conditions, such as the viewing distance to the component to be monitored, wind speed, ambient air temperature, and the background temperature, have the potential to impact the ability of the OGI camera operator to detect a leak. Because it is important that the OGI camera has been tested under the full range of expected field conditions in which the OGI camera will be used, an operating envelope must be established for field use of the OGI camera. Imaging must not be performed when the conditions are outside of the developed operating envelope. Operating envelopes are specific to each model of OGI camera and can be developed by the owner or operator, the camera manufacturer, or a third party. To develop the operating envelope, methane gas is released at a set mass rate and wind speed, viewing distance, and delta-T (the temperature differential of the background and the released gas) are all varied to determine the conditions under which a leak can be imaged. For purposes of developing the operating envelope, a leak is considered able to be imaged if three out of four observers can see the leak. Once the operating envelope is developed using methane, the testing is repeated with either butane or propane gas.
Opgal develops operating envelope for each of the 3 gases and both relevant filters, and will publish it soon for the convenience of the owner. EyeCGas Multi OGI camera set of operating envelopes is expected to be the least restrictive as the camera mass flow detection limits (MFDLs) is more than 2 order of magnitude lower than the detection requirements (e.g. 140 time for methane).
The operating envelope for the OGI camera is the more restrictive operating envelope developed between the different test gases.
The most restrictive operating envelope is expected to be for methane as it has the highest MFDL out of the 3 gases and the lowest detection requirement in Appendix K.
The operating envelope must be confirmed for all potential configurations that could impact the detection limit of the OGI camera. In cases where an operating envelope has not yet been established for an OGI camera model or an OGI camera operator needs to expand an operating envelope to account for site[1]specific conditions, the OGI camera operator can conduct a daily field check for maximum viewing distance prior to conducting the monitoring survey. The daily field check must be conducted for each OGI camera operator who will conduct the monitoring survey using the OGI camera (and each camera configuration) they will use to complete the monitoring survey. The daily field check must be performed using the same gases and flow rates used for setting the operating envelope and initial verification check. The maximum viewing distance for the day for the OGI camera operator will be the farthest viewing distance where the OGI camera operator is able to visualize a leak of both test gases. A complete video record, as well as documentation of the delta-T, wind speed, ad viewing distance, must be retained for the daily field check. If the delta-T in the field decreases below the delta-T that was recorded for the daily field check or if the wind speed increases above the wind speed recorded for the daily field check, the maximum viewing distance determination must be repeated for the new delta-T and wind speed conditions.
The final NSPS OOOOb also includes provisions for the use of
dvanced methane detection technologies that allow for periodic screening or continuous monitoring for fugitive emissions and emissions from covers and closed vent systems (CVS) used to route emissions to control devices.
EyeCGas 24/7 PRO and EyeCGas Fly along with EyeCGas Multi (portable solution) can be added under this rule as advanced methane detection technologies.
These advanced methane detection technologies could also be used to identify super-emitter emissions events sooner and outside the normal periodic OGI monitoring for fugitive emissions, control devices, covers on storage vessels, and CVS. Therefore, the EPA is finalizing a Super Emitter Program where an owner or operator must investigate, and if necessary, take steps to ensure compliance with the applicable regulation(s) upon receiving certified notifications of detected emissions that are 100 kilograms per hour (kg/hr) of methane or greater. The final EG OOOOc also includes the same provisions described for NSPS OOOOb that allow for the use of alternative test methods using advanced methane detection technologies for periodic screening or continuous monitoring for fugitive emissions and emissions from covers and CVS used to route emissions to control devices. Finally, the EPA is also finalizing in the final EG OOOOc presumptive requirements for state plans to include a Super Emitter Program, where an owner or operator must investigate, and if necessary, take steps to ensure compliance with the applicable regulation(s) upon receiving certified notifications of detected emissions that are 100 kilograms per hour (kg/hr) of methane or greater.
