Regulations to further reduce methane and VOC emissions affect the operations of oil and gas (O&G) production facilities and equipment. Existing and proposed regulations require Leak Detection and Repair (LDAR) at O&G production facilities. For many years now, federal and state regulations have required LDAR at chemical plants, refineries and gas processing facilities and for monitoring for leaks from emission control equipment.
Typically, O&G production facilities upstream of gas processing facilities have been exempt from formal LDAR program on a facility-wide basis. This is expected to change based on proposed modifications to NSPS OOOOa.
HY-BON/EDI IR camera user conduction IQR survey for leaks.
Reasons for LDAR
Some reasons to monitor for leaks include:
- Safety considerations to minimize leaks of flammable gases, H2S and other potentially harmful hazardous air pollutants such as benzene.
- Ensure leak free operation of the closed vent system (piping) serving emission control systems (e.g., vapor recovery unit, vapor combustion units). NSPS OOOO has requirements to monitor emission control closed vent systems for storage tanks.
- Regulatory requirements for mandatory leak detection monitoring programs. Note that proposed changes to NSPS OOOO require LDAR programs for new oil and gas production facilities.
- Obtain emission reduction credits based on using emission factors that are lower than facilities not using a LDAR program. The Texas Commission on Environmental Quality (TCEQ) has a model Emission Reduction Credit Program for ozone nonattainment areas that includes LDAR for reducing fugitive leaks.
- Minimize wasteful leaks and increase product sent to sales
- Minimize odors from impacting nearby public areas and landowners
Component Types Covered under LDAR
LDAR programs typically apply to equipment in VOC service, such as:
- Storage tanks
- Connectors and flanges,
- Open-ended lines.
- Instruments, meters
- Pressure relief devices
- Sampling connections
LDAR Program Requirements
Most LDAR requirements will include:
- Approved methods for detecting natural gas leaks
- Definition of a leak – typically in gas parts per million by volume (ppmv) limit – if use VOA meter. The concentration varies from a VOA meter reading of 500 ppmv to 10,000 ppmv depending on the regulation.
- Equipment and components required to be monitored
- Monitoring frequency (e.g., monthly, quarterly, semiannually, annually)
- Leak repair requirements
- Recordkeeping and reporting
Regulations and Programs for LDAR
Examples of regulations and programs that require, may require or encourage the use of LDAR for O&G production facilities upstream of gas processing facilities include:
40 CFR 60 Subpart OOOO – tank hatches and closed vent system for storage tank emission controls.
- Proposed rules in 40 CFR 60 Subpart OOOOa (proposed in Sept 2015, final expected in 2016).
- 40 CFR 98 Subpart W – Mandatory Greenhouse Gas (GHG) Reporting rule.
- Texas Commission on Environmental Quality (TCEQ) oil and gas Standard Permits and Permits by Rule (PBR).
- Colorado Department of Health and Environment – CDPHE Regulation 7
- Pennsylvania Department of Environmental Protection (DEP) Exemption Category No. 38 and GP-5 LDAR program
- Center for Sustainable Shale Development (CSSD) voluntary program
Typical and New Monitoring Methods for Leaks
Some typical and developing leak monitoring method are listed below. Always review the regulatory requirements to determine the approved leak detection methods.
- Audio, visual, olfactory (AVO) for certain components – no instrument required.
- EPA Method 21 using volatile organic analyzer (VOA) meter reading in parts per million by volume (ppmv)
- Optical gas imaging (OGI) using “InfraRed Cameras” such as FLIR, Rebellion OGI, Picarro Surveyor.
- Hand held sensors
- Land vehicle mounted sensors
- Unmanned aerial vehicle (UAV) or “drone” mounted sensors
- UWSTM Hatch Sense System – wireless sensor is designed to monitor whether a hatch cover is open or closed.
Definition of a Leak
Leaks are normally defined in terms of leak thresholds. The leak threshold depends on the method used to survey for leaks. Existing and past regulations have required fugitive emissions to be monitored using sensory monitoring (e.g., audio, visual, olfactory) or EPA Method 21 meters to determine if a leak exceeded a set threshold (e.g., the leak concentration was greater than the leak definition for the component).
For audio, visual, olfactory (AVO) methods a leak is typically considered any detectable emissions.
- EPA Method 21 monitoring has leak thresholds ranging from 500-10,000 ppm. Proposed NSPS OOOOa is considering leak thresholds of 500 ppm, 2,500 ppm and 10,000 ppm.
- For OGI cameras, the leak threshold is normally considered to be detection of visible emissions (i.e., emissions that can be seen using OGI cameras).
LDAR Monitoring Frequency
Monitoring frequency varies depending on the regulatory programs. This can include:
- Weekly audio, visual, olfactory (AVO) methods
- Quarterly, semiannual or annual monitoring using Method 21 or OGI camera.
- Operators may reduce monitoring frequency if the leak rates are less than a set percentage of the total number of components. This can vary from 2% to 5% of the total.
- For most programs, if the monitored leak percentage is below the set percentage, the operator can skip a monitoring period; skipping monitoring normally will only reduce the frequency to an annual basis – provided the leak percentage stays below the set percentage. If leaks are detected over the set percentage, then the monitoring frequency can increase – depending on regulatory or program requirements.
Monitoring records must be kept on location or other approved location and available for inspection by the regulatory agency. Typical recordkeeping includes all monitoring records such as:
- Monitoring dates
- Monitoring equipment used
- Calibration records
- Listing of components monitored
- Number of leaks detected
- Date(s) of successful repair of the leak(s)
- Deviations from the monitoring plan
Most programs do not require copies of the LDAR monitoring to be reported to the regulatory agency. The proposed NSPS OOOOa has a requirement to submit LDAR reports the EPA or delegated state agency.
HY-BON IQR Services
Let HY-BON/EDI assist your company your LDAR needs. Our Identify, Quantify and Rectify (IQR) your facility emissions. Using our IQR services and our ongoing Vent Gas Management (VGM) system we can assist you stay in compliance with LDAR requirements and make your company money. HY-BON/EDI’s vent gas management (VGM) system is a cost effective way to take this issue off of your plate. We use “best in class” vapor recovery units (VRU), Vapor Recovery Towers (VRT) and enclosed combustion units (ECU) to comply with storage tank emission control requirements.
Avoid regulatory compliance issues by remotely monitoring the state of tank hatches, gates, valves, and other mechanisms. HY-BON/EDI’s. Hatch Sense is the only safe, wireless thief hatch alert system with monitoring capabilities. Since we meet the UL Class 1 Div 1 requirements for intrinsically safe equipment Hatch Sense can be deployed now at your production facilities and solve problems. Operators can use Hatch Sense to demonstrate to regulators their proactive approach to minimizing leaks and increasing compliance.