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.