Document ID: EPA-HQ-OAR-2021-0299-0041
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2023-02-10T05:00Z

DRF Work Practice Specific Items:
1. What components will FHR monitor when a PSL is generated? Will the monitoring focus only on traditional LDAR components first to identify a leak source? Question to EPA Team: Is more specificity needed from the request to reflect this? 
p. 14: FHR will monitor the following components when a PSL is generated:
 Agitator - FF
 Agitator - VV
 Agitator  -  HON
 Compressor  -  HON
 Compressor  -  non HON
 Compressor in Hydrogen Service
 Connector
 Pump  -  with permit specifying 500 ppm
 Pump  -  HON
 Pump  -  VV
 Relief Device
 Valve
 NDE Component
 Agitator hydrocarbon (HC) but non LDAR
 Compressor  -  HC but non LDAR
 Connector  -  HC but non LDAR
 Pump  -  HC but non LDAR
 Relief Device  -  HC but non LDAR
 Valve  -  HC but non LDAR
The monitoring will focus on both LDAR and non-LDAR component leaks.
2. Of the components monitored in the DRF, what monitoring instrument will be used to determine the source of the leak? Question to EPA Team: I believe we would want to specifically know what they are using, or at a minimum to know that they will always use Method 21. From a compliance perspective, is more specificity needed?
p. 13: Handheld portable equipment such as VOC analyzers, OGI, and other appropriate detectors will be used to determine the source of the leak. Once identified, the source is measured with calibrated M21-capable equipment to document the leak's maximum concentration value and initiate repair procedures.

3. What defines a leak under the DRF?  
4. Can FHR provide a listing by component type (valves, pumps, etc.) with the number of components subject to each specific leak definition in each applicable subpart separately for both the Meta-Xylene and Mid-Crude Units?

5. If using a combination of detection instruments, such as OGI and Method 21 instrument, will a visible leak with OGI be repaired regardless of the Method 21 ppm reading?
6. Will all leaks (as defined) that are found in the PSL be repaired? If not, what leaks would not be repaired?
7. Are categories of leaks defined within specific quantified ranges? If so, what are those ranges?
8. What leak identification commitments are FHR making for each category? For example, deploy the technicians within 24 hours of PSL generation for Category 1, and within 3 calendar days for Category 2 and 3.
      p. 12
      Category 1: Direct alarms for operators, for example phone notifications, and/or email notification to appropriate personnel. Facility personnel promptly take appropriate action to evaluate.
      Category 2 & 3: Notifications are accompanied by Potential Source Location (PSL). Facility personnel initiate investigation within 3 business days.

9. What is required by the DRF connected with timing creating enforceability concerns?  Is it one technician with an OGI first?  How many components within the PSL need to be monitored and by when?  With what equipment? There is some clarity as to when a leak is assumed to have been found, but what happens if that assumption is incorrect and the leak continues day after day?  What happens if the leak is not found?  Is there a point in time when all components must be monitored within the PSL?  What if all components are monitored and the leak continues? What is the obligation for repair if non-LDAR component or piece of equipment to which no leak standard applies is found to be the cause of the triggered DRF?  Provide a more clear proposal that addresses these enforceability concerns.

10. What is the maximum number of days FHR will investigate a PSL before assuming a leak has resolved if not found?
11. When does the 5/15 repair clock begin? Is it at PSL generation or at component-level identification?
12. What specific information will FHR keep in the record related to the DRF?
      p. 16-17
             Fugitive Emission Management Plan
             Sensor Selection
             Sensor Node Placement
             Sensor Initial Calibration and Quarterly Bump Tests
             Sensor Data
             Meteorological Data
             PSL Notifications and PSL Investigations

13. What specific information will FHR include in the semiannual reports related to the DRF?
      p. 13: FHR will continue to follow the currently applicable LDAR reporting requirements of 40 CFR 60 Subparts VV, VVa, GGG, GGGa, QQQ; 61 Subpart FF; 63 Subparts H and CC; 30 TAC 115 and 28VHP permit conditions. Where these rules specify reporting the number of each equipment type or the number of components monitored, a reasonable estimate may be used for areas covered by LDSN-DRF practices.
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LDSN Specific Items:
1. How will FHR clearly identify which components are not monitored by the LDSN, and thus continue to be subject to the Method 21 or AVO inspections?
      p. 6: FHR will maintain records to clearly demonstrate which portions of the facility are complying with M21 CWP, OGI AWP, and which are utilizing the LDSN-DRF AMEL. Each component covered by the LDSN-DRF is not required to be individually identified or listed.
2. How many sensors will FHR install in each of the 2 units included in the request? Question to EPA Team: Should they provide a count of sensors for the unit, or minimum number of sensors, before approval?
      p. 8-10: Figure 5 and Figure 6
3. The "black" box aspect of sensor location and density is problematic because we cannot determine if it is sufficient (Context: FHR has added sensors following output of "black box" algorithms). Related to #1, at best, it only is sufficient to the effectiveness of their current program, which is unknown.
      a. OECA staff would be interested in understanding what the limitations are to provide more sensors, such that discrete component monitoring, at the regulatory leak thresholds, can be enabled.
            i. Alternative to discrete component monitoring, can the baseline be lowered such that the LDSN can detect/locate leaks at lower detection thresholds. This could be middle ground between FHR's baseline and individual component monitoring since it can account for continuous monitoring.
      b. OECA staff also is interested in periodic "dosing" tests to ensure the monitors are picking up know standards.
      c. Information Needed: Inputs to "black box"
4. What specific information will FHR keep in the record related to the LDSN?
5. What specific information will FHR include in the semiannual reports related to the LDSN? Question to EPA Team: Should specific information related to the LDSN be included in the report?
      p. 16: FHR will continue to follow the currently applicable LDAR reporting requirements of 40 CFR 60 Subparts VV, VVa, GGG, GGGa, QQQ; 61 Subpart FF; 63 Subparts H and CC; 30 TAC 115 and 28VHP permit conditions. Where these rules specify reporting the number of each equipment type or the number of components monitored, a reasonable estimate may be used for areas covered by LDSN-DRF practices.
      
6. What is the timeframe for recalibrating or replacing a sensor that fails the responsivity test? What is the procedure for recalibration?
      p. 15: Repairs will be made as soon as practicable.
      p. 15: Continuous Sensor Check. The health of each sensor is continuously monitored for power outage, loss of data transmission, and sensor baseline levels. The current status of each sensor is available on mSyte. Historical data is also logged in the database. Any failure or significant deviation from preset threshold values will result in a notification being sent to appropriate facility personnel. Failed sensors will be reset, repaired, or replaced.
      
      p. 15: Periodic Responsivity Test. The sensitivity of each installed sensor will be measured and recorded at least quarterly by conducting a "bump test" using an isobutylene standard or other appropriate standard. A successful bump test is shown by a "Pass" message from the mobile app, which indicates the response of the sensor exceeds 50% of the nominal value of the standard. A bump test may be repeated up to two additional times if the first test is not successful. If the sensor continues to fail, it will be recalibrated or replaced with a pre-calibrated sensor.

7 Can FHR provide the manufacturer and model number with more details on principal of measurement, sensitivity, response factors, and more specific initial calibration and ongoing QA/QC requirements along with specific acceptability criteria for initial and ongoing calibration checks for the specific sensors proposed for use.

8. Is 10% downtime an average across sensors or is it an average per sensor? If it is an average across sensor, is there a maximum annual downtime per sensor?
      p. 15: The annual average of LDSN system operational downtime will be 10% or less.
9. How does DOR affect PSL generation and the ability to see additional leaks while a component is on DOR?
      p. 13: The DOR allowances of these rules still apply to leaks detected via LDSN-DRF.

10. The description of sensor selection/placement is very generic. This is a site-specific request and the information should be specific to the site (process unit). This reads more like a method or regulation aimed at a wide audience. 
11. Is there a need to review the sensor selection and node placement on some recurring basis based on process changes?
12. Can the baseline be lowered such that the LDSN can detect/locate leaks at lower detection thresholds?
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Equivalence Demonstration Specific Items:
1. Will FHR provide the LeakDAS database to OAQPS for verification of model results prior to release of the CRADA report?
2. What is the actual DT band and DTU identified during the pilot testing? How does this compare to the model inputs and results?
      p. A22: Cluster repair threshold  -  3000 ppm
      p. B10: Although the nominal leak average detection threshold (DTA) is 5000 ppm, several smaller leaks (500-5000 ppm) are predicted to be detected by the Molex LDSN due to peculiarities of leak-to-sensor distance distribution in an operating plant environment. All those "to be detected" leaks have significant impact on emission equivalency calculations.
3. What is the preset threshold criteria for the units in this request? At what level will they get an alert? How easily is this level adjusted or can it be fixed or monitored in order to record of how/if adjusted over time? The simulation is based on present threshold criteria; however, the request doesn't explain what this is or what will be used in practice if approved.
4. How will FHR prevent background creep  -  where the sensor baseline by which peaks are compared increases over time? Figure A-6 shows continued climb in emissions over time. Does this mean there is a point where the LDSN no longer performs equivalent or better? If so, what is the backstop?
5. What sensor density was modeled in the simulations? How does it compare to the sensor density that will be used in the actual process units?
6. For each future unit, will FHR be doing a similar simulation of historic data and sensor density to determine equivalence and DT band within the specific unit? How will we handle this? Will these need to be new AMEL requests for each individual unit?
7. The equivalency appears to be based on the effectiveness of FHR's program. How do we measure the effectiveness of that program? Provide full LDAR backup file (beginning where FHR established M21 program effectiveness through overlap of LDSN pilot).
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Other Items:
 Will FHR continue to document and investigate AVO that are identified during general operations, or will these be ignored unless the LDSN detects something in that area?
            
            p. A11: It is not uncommon for audio visual olfactory (AVO) leaks on LDAR components to be entered into databases such as LeakDAS. This approach allows the facility to follow the normal leak repair protocols and maintain records to show compliance with applicable regulations. When an AVO leak is found in the field by operations personnel, an initial repair attempt is conducted. If this corrects the AVO indications, the component is considered repaired. If the repair does not seem effective, then a monitoring technician is dispatched to conduct a M21 inspection to provide a M21 result for comparison with applicable leak definitions.

 Can FHR do periodic "dosing" tests to ensure the monitors are picking up the standards?

 If the program were designed for DTUs of 10,000 ppm, 2000 ppm, 1000 ppm and 500 ppm, provide the total installation cost of the system, estimated annual operating costs, and the projected emission reduction benefit at each DTU level separately for the Meta-Xylene Unit and Mid-Crude Unit.

 Provide a total installed cost and operating costs per sensor node for the specific sensor nodes proposed for use in the program.

 For the Meta-Xylene Unit and Mid-Crude Unit provide the annual average operating costs using traditional LDAR.

 On page 8 of the AMEL, the following statement appears: "In practice, the DRF process often identifies actionable leaks that are well below the DTU (> 500 ppm but less than the DTU)."  Please clarify what is intended by the parenthetical.  Do leaks below 500 ppm above baseline trigger a PSL investigation response or are they ignored?  Is a PSL triggered for any leak above baseline or is there a threshold (e. g. 500 ppm)?  How is the leak ppm level above baseline calculated?

 On Page 11 of the AMEL, the following statement appears: "Based on that analysis and the use of complex proprietary algorithms, target areas of interest are generated."  EPA cannot approve an AMEL that is based on what is essentially an undefined black box algorithm.  EPA must be provided with a better explanation of how the algorithm draws the PSL box based on the inputs in order to review and approve this AMEL.

 Please address the ongoing monitoring plan adjustments and calculations of the cumulative daily emissions for identified leaking components subject to delay of repair until next turnaround.

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