LDAR Glossary

LDAR (Leak Detection and Repair)

A regulatory program designed to detect and minimize emissions from industrial equipment.

Method 21

A technique used to detect volatile organic compound (VOC) leaks from process equipment using a portable gas analyzer.

Optical Gas Imaging (OGI)

An advanced leak detection method that uses infrared cameras to identify gas leaks invisible to the human eye.

Volatile Organic Compounds (VOCs)

Organic chemicals that evaporate at room temperature and contribute to air pollution.

Hazardous Air Pollutants (HAPs)

Toxic air pollutants known to cause serious health effects, including cancer and respiratory issues.

Fugitive Emissions

Uncontrolled gas or vapor emissions from equipment leaks, valves, and storage tanks.

Leak Definition

The concentration of a gas leak, typically measured in parts per million (ppm), that requires corrective action under LDAR regulations.

Background Level

The natural concentration of VOCs or HAPs in the air, measured before testing for leaks to ensure accurate readings.

Drift Test

A calibration test performed to verify the accuracy of a gas analyzer before and after LDAR monitoring.

Bagging Technique

A method used to enclose a leaking component in a sealed bag to measure emissions more accurately.

Repair Verification Monitoring

A follow-up test conducted after a leak repair to confirm that the component no longer emits beyond the allowable threshold.

Delay of Repair (DOR)

A status applied when a leaking component cannot be repaired immediately due to operational constraints. A plan must be in place for repair at the next available shutdown.

Low-Leak Technology

Equipment designed to minimize emissions, such as low-leak valves and gaskets.

Maximum Allowable Emission Limit (MAEL)

The highest permissible emission level for a facility or component, as defined by regulatory agencies.

Portable Gas Analyzer

A handheld device used in LDAR programs to measure gas concentrations around components for leak detection.

Consent Decree

A legally binding agreement between a facility and regulatory agencies that enforces compliance with LDAR regulations.

Enforcement Action

A legal or regulatory response to LDAR noncompliance, which may include fines, penalties, or required corrective measures.

Environmental Protection Agency (EPA)

The U.S. agency responsible for enforcing environmental regulations, including LDAR requirements.

Clean Air Act (CAA)

A U.S. law regulating air emissions to reduce pollution and protect public health.

El Paso Testing

A specialized emissions testing method used to assess compliance with both local and federal regulations.

Component

Any piece of equipment (such as valves, pumps, or connectors) that can potentially leak and must be monitored under LDAR regulations.

Leak Rate

The speed at which a gas leak occurs, typically expressed in parts per million per second (ppm/s) or mass flow rate.

Bar Leak

A leak from a pressurized system that occurs at the interface of two components, such as gaskets or seals.

Facility Response Plan (FRP)

A comprehensive plan required by regulatory agencies to address emissions control and emergency response for leaks.

Supervisory Control and Data Acquisition (SCADA)

A system used to monitor and control industrial processes, including emissions tracking in LDAR programs.

Flange

A mechanical joint used to connect pipes, valves, and other components in industrial systems. Often monitored for leaks in LDAR programs.

Pump Seal

A sealing mechanism used to prevent leakage from rotating pump shafts, commonly inspected in LDAR programs.

First Attempt at Repair

An initial effort to correct a detected leak before requiring a full shutdown or major maintenance.

Facility Monitoring Plan

A site-specific plan outlining the methods and frequency of LDAR inspections required to maintain compliance.

Alternative Work Practice (AWP)

A method approved by regulatory agencies that allows facilities to use advanced technologies, such as Optical Gas Imaging, instead of Method 21.

Leak Threshold

The predefined concentration level of a gas leak that triggers mandatory repair under LDAR regulations.

Turnaround

A scheduled shutdown of industrial operations for maintenance, including leak repairs and LDAR program evaluations.

Natural Gas Liquids (NGLs)

Hydrocarbon-based liquids extracted from natural gas that may contribute to fugitive emissions.

Infrared Spectroscopy

An analytical technique used in OGI to detect and identify gas leaks based on their infrared absorption characteristics.

Directed Inspection and Maintenance (DI&M)

A targeted approach to LDAR that prioritizes high-risk components for inspection and repair.

Fenceline Monitoring

Air quality monitoring conducted at the perimeter of an industrial facility to detect fugitive emissions.

Hydrocarbon Analyzer

A device used to measure the concentration of hydrocarbons in emissions, often utilized in LDAR programs.

Quarterly Monitoring

Routine LDAR inspections conducted every three months to detect and repair leaks in compliance with regulations.

Self-Audit

An internal review conducted by a facility to assess compliance with LDAR regulations before external inspections.

Leak Repair Protocol

A standardized procedure for repairing and verifying leaks in industrial equipment.

Subpart W

A section of the EPA’s Greenhouse Gas Reporting Program that covers fugitive emissions from the petroleum and natural gas industry.

Non-Methane Organic Compounds (NMOCs)

Organic compounds, excluding methane, that contribute to air pollution and are regulated under LDAR programs.