Enhanced Leak Detection and Repair (LDAR) programs (ELP) began to appear in consent decrees in the early 2000s for refineries and in 2009 for chemical plants — they promise to become the norm in cases where the U.S. Environmental Protection Agency (EPA) takes issue with the effectiveness of standard LDAR programs. Designed to systematically improve the quality and effectiveness of industrial sites' efforts, ELP is considered by both the Justice Department and EPA to be appropriate injunctive relief in LDAR enforcement cases.
Significantly, LDAR itself is a National Air Toxics Enforcement priority: "Leaking equipment, such as valves, pumps and connectors, are the largest source of emissions of volatile organic compounds (VOC) and volatile hazardous air pollutants (VHAP) from petroleum refineries and chemical manufacturing facilities… With the large universe of sources subject to LDAR requirements and the high level of non-compliance, EPA will continue to focus on LDAR in the FY 2008–10 air/toxics strategy" . With so many sites still to be inspected, the proposed priorities for 2011–2013 remain the same.
The U.S. government's involvement in environmental issues dates back to the 1955 enactment of the Air Pollution Control Act. Publication of Rachel Carson's "Silent Spring" in 1962 marked the beginning of the environmental movement and helped spur the Clean Air Act of 1963. In 1970 that act was amended to include motor vehicle emissions. The Clean Air Act of 1990 imposed additional regulations regarding emission levels and permits, and introduced LDAR programs to a growing list of compliance criteria.
By 1998, the EPA had realized that LDAR programs weren't having the desired effect. Investigations into fugitive emissions from refineries revealed that actual leak and emission rates were two or more times higher than those reported . The findings prompted the EPA and Justice Department to focus on these facilities and pursue consent decrees.
When the EPA and Justice Department bring suit against a facility based on the EPA's investigative and enforcement arm findings, the parties negotiate a consent decree that may require specific actions to settle the charges. These actions may include equipment and system upgrades, special projects furthering use of new technologies, and implementation of an ELP.
An ELP begins with defining specific items such as an open-ended line, certified low-leaking valves and packings, and covered equipment and processes. Based on 2009 settlements and EPA presentations, a typical ELP contains 14 parts that vary by site and consent decree.
Part B addresses monitoring frequency, which can be monthly, quarterly or annually, depending upon component. Existing regulations that require more frequent monitoring obviously take precedence. Pumps and agitators must be monitored monthly, valves and closure devices for open-ended lines quarterly, and connectors annually. Failure to meet the higher performance standards for new and repacked equipment will require more frequent monitoring and associated record-keeping and reporting. Equipment replaced or repacked (per Part G) must be monitored monthly for 12 months after which monitoring frequency can be increased to annually.
After two years of component compliance, a site may be eligible for extended monitoring intervals — for example, checking valves and closure devices annually and connectors every two years. However, if any component leaks during this extended period, it will be subject to monthly monitoring until it complies and then for 12 months thereafter.
Part C mandates use of Method 21 (for determination of VOC leaks) with a toxic vapor analyzer and data logger (Figure 1). If the analyzer is found to undergo calibration drift, components measured by the instrument must be remonitored according to established criteria.
Part D addresses LDAR action levels, including ELP-defined leakage rates shown in Table 1. Any time a leak is detected by audio, visual or olfactory sensing, it must be repaired according to the standard schedule at the time it's discovered.
Part E deals with leak repairs — the first attempt at a repair must be made within five days and the final attempt within 15 days of detection (Figure 3). The component must be monitored within one business day of any attempted repair. The objective of this exercise is to achieve the best repair resulting in the lowest possible rate of emission. Only if a component such as a valve can't be repaired into compliance or removed from service would it be drilled and tapped, unless this method of repair is precluded by valid safety, mechanical, quality or environmental factors. At this point or after two unsuccessful drill-and-tap attempts, the component may be put on a delay-of-repair (DOR) list. Part F is dedicated to DOR.
Part G is by far the most progressive and demanding part of an ELP. It addresses equipment upgrades, encompassing three possible alternatives covering preventive actions program/leak trend analysis, equipment replacement/improvement, and more stringent equipment replacement/ improvement. As such, it pushes LDAR to a more proactively preventive level, raising the bar above the norm for monitoring, corrective action and reporting, and exemplifies the spirit of enhanced LDAR. This is the first time this degree of definition and prescriptive action has been targeted toward valve leaks, and requires the use of certified low-leak technologies (Figure 2).
Equipment replacement/improvement, which was included in two consent decrees in 2009, is the most prescriptive and detailed of the three alternatives. Designed to improve emissions performance of valves and connectors, it requires compiling a list of all valves in the covered process units. Any new valve must be certified as low-leak and fitted with certified low-leak packing.
Low-leak valve and packing certification requires a written guarantee by the manufacturer that the valve will maintain a rate of leakage not to exceed 100 ppm for five years, or documentation that the valve has been tested not to exceed this rate. Documentation of guarantees from each vendor is required and must be retained on-site as proof of compliance.
Any valve with stem seals leaking at or above 250 ppm must be replaced with a certified low-leak valve or repacked with certified low-leak packing within 30 days. Corrective action that requires a unit shutdown may be deferred to the first scheduled maintenance shutdown.
Valves found to be leaking between 100 ppm and 250 ppm must be noted, listed and prioritized in order of magnitude of leakage and the number of times they were found to be leaking.
The list is used to determine how many valves must be replaced or repacked. This is done by taking 10% of the valves leaking between 100 ppm and 250 ppm, less the number of DOR valves, those previously fitted with low-leak packing and those scheduled for replacement or repair in the next scheduled shutdown:
VTBRR = 0.10 (VT - VDOR - VPRR - VPR)
where VTBRR is the number of valves leaking at a rate of 100–250 ppm to be replaced or repacked in the maintenance shutdown, VT is the total number of valves in the covered process unit at the time of the shutdown, VDOR is the number of DOR valves to be replaced or repacked in the shutdown, VPRR is the number of valves previously replaced or repacked with certified low-leak technology and VPR is the number of valves awaiting replacement or repacking prior to shutdown.
The more stringent alternative of Part G requires that 20% of valves leaking between 100 ppm and 250 ppm be replaced or repacked. Optionally, valves emitting HAPs can be eliminated from service — but their removal mustn't introduce other potential points of leakage. The number of such valves may be credited toward the calculated number of valves requiring replacement or repacking.
If a certified low-leak valve or packing isn't commercially available, the site must submit a report, identifying each affected valve, vendors contacted and written documentation from each such vendor that a certified remedy is unavailable.
Flanged, threaded, compression, cam-lock and quick-connect-type connectors also are subject to repair, replacement and improvement. Any connector found to be leaking at or above 250 ppm must be repaired with technology that in the plant's judgment will attain a level of leakage below 250 ppm. As with valves, a successful repair must be made within 30 days of detection. Connectors are subject to the same post-replacement/repair monitoring requirements as valves. Connectors eliminated or replaced by welded joints or pipe are considered to be repaired or improved.
The site must report all equipment replacements, improvements and eliminations, identifying the relevant equipment, describing the action taken for compliance with Part G equipment upgrades and scheduling of future replacements and upgrades.
Part H deals with change management. All equipment added to or removed from a plant must be recorded and evaluated with regard to applicable LDAR requirements; documents must be retained. In addition, all personnel and contractors responsible for monitoring, equipment maintenance and repairs, and other LDAR-related activities must be trained — per Part I, which stipulates the training must commence within six months of initiation of an ELP, and refreshers must be conducted annually.
Part J sets forth requirements for quality assurance and control. It calls for LDAR technicians to certify on a daily basis that monitoring data are accurate and have been properly collected. Records of the LDAR department must be internally audited on a quarterly basis by a non-technician but LDAR-trained employee. The audits must include a review of equipment that isn't now but should be covered by the ELP, records documenting monitoring frequency, all sign-offs, repair documents, monitoring data versus equipment count, calibration and monitoring equipment maintenance records, and field observation of equipment monitoring. In addition, yearly third-party audits are required.
Part M requires retention of all original records, including copies of every LDAR audit and documentation of prescribed ELP compliance. The plant must retain monitoring data, leak repair, training and audit records for five years and calibration equipment records for one year. Electronic records of monitoring data must be retained for the duration of the consent decree.
Part N stipulates that compliance status reports must be filed at intervals specified by the consent decree. The reports must detail the personnel assigned to LDAR activities, percentage of their time devoted to these functions, all instances of non-compliances, problems encountered in the process of compliance, training requirements, quality-assurance/quality-control deviations and corrective actions, and provide a summary of LDAR audit results. The plant manager and an environmental or engineering management official must sign and certify the reports to be true.
Enhanced LDAR takes standard LDAR to a higher level of compliance, mandating the use of certified low-leak valves and packings, and aligning the regulations with the best available technologies and practices.
Jim Drago, P.E., is manager, business development and market research, for Garlock Sealing Technologies, Palmyra, N.Y. E-mail him at email@example.com.
1. "FY08–FY10 Compliance and Enforcement National Priority: Clean Air Act, Air Toxics," U.S. EPA, Washington, D.C. (Oct. 2007).
2. "Leak Detection and Repair — A Best Practices Guide," Appendix E, "Enforcement Alert —Proper Monitoring Essential to Reducing 'Fugitive Emissions' Under Leak Detection and Repair Programs," U.S. EPA, Washington, D.C. (2007).