The Environmental Protection Agency (EPA) regulation of fugitive volatile organic compounds (VOC) emissions, or leaks, arose out of the research projects conducted between the 1950s and 1980s at several facilities throughout the United States. The research concluded the cumulative effect of all the leaking components may present environmental and health problems to the surrounding area. The research also concluded when most components leak, they do so at very low levels, thus a majority of fugitive emissions come from a very small percentage (not exceeding 10 percent) of high leaking components. The need for fugitive VOC emissions was also necessitated by the fact that approximately 70 percent of total VOC emissions from facilities engaging in processing of gases and light liquids arose from uncontrolled emissions.

Leak detection and repair (LDAR) is governed by several different forms of federal regulation. These regulations include National Emission Standards for Hazardous Air Pollutant (NESHAPs), New Source Performance Standards (NSPS), the Hazardous Organic NESHAP (HON), Maximum Achievable Control Technology (MACT) and Consent Decrees.

Subpart VV (40 CFR 60.480) serves as the backbone for most fugitive VOC emissions monitoring as required by various forms of federal regulations. Most state LDAR programs that exist draw heavily from Subpart VV because it is so effective in marrying work practice standards with equipment modification requirements. Subpart VV includes implementation of LDAR monitoring for processes and components in liquid service, repair attempts, as well as reporting and recordkeeping requirements. LDAR programs at source facilities typically have a mix of LDAR requirements including: Subpart VV, HON units, MACT Hazardous Air Pollutant (HAP) streams and consent decrees. Each of these rules provides different leak definitions, repair times, overall applicability, reporting and recordkeeping.

Implementation of various federal LDAR regulations has been difficult as many sources have erroneously reported fugitive emissions or missed the emissions altogether. The EPA has estimated that during a five year period up to 80,000,000 pounds of VOC emissions were missed as a result of poorly implemented or non-existent LDAR programs. The EPA also has stated average leak rates at several facilities are up to five times greater than what had been reported by LDAR regulated sources.

LDAR programs are required by federal regulations for facilities found throughout the United States are based on EPAs Method 21, Determination of Volatile Organic Compound Leaks. EPA Method 21 serves as formalized guidance for the monitoring and screening of fugitive VOC emissions. Method 21 provides instruction on monitoring techniques, analyzer specification and selection, analyzer calibration and sample collection.

Even with Method 21, there are several common pitfalls most sources experience when implementing an LDAR program. One major problem typically experienced is not calibrating instruments as they are to be used in LDAR monitoring and screening procedures. Other common mistakes include using expired calibration gas, using calibration gas with inappropriate concentration levels and not performing calibration drift checks at appropriate frequencies. Calibration drift assessment should take place at the end of each day of monitoring; however, recommended best practices dictate a drift assessment should be calculated after approximately half way through the completion of monitoring, especially if the monitoring occurs over a seven or eight-hour period.

Another common problem is a failure to survey the equipment component as close to the interface as possible. Greater distance between the probe and monitored component allows leak gas concentrations to dissipate, lowering the number of leaks corrected to be identified. Monitoring potentially leaking components too quickly can also lead to fewer leak determinations and misidentified components.

Other problems often associated with LDAR program include: missing repair timeframes, not conducting appropriate maintenance on leaking components as well as failure to maintain an appropriate LDAR database and leak log. Deficient leak logs and LDAR database entries also can lead to insufficient repair records and failures in successfully re-monitoring repaired components.

The final significant pitfall of LDAR monitoring programs is providing misplaced performance incentives to LDAR department staff. These types of incentives generally involve rewarding employees who monitor the most components over a designated time period or rewarding those monitors who detect the fewest leaks. LDAR program with incentives should focus more on those employees who survey carefully and try to ensure monitoring quality.

In order for LDAR programs to be successful at any facility, a complete and accurate applicability determination must be made. It is important for all facilities holding gaseous or liquid components and transporting them on-site to determine what aspects of LDAR monitoring are applicable to them and begin to manage implementation of the overall LDAR program. A properly managed LDAR program will help protect the local environment and prevent deviations EPA may scrutinize.