Leak Detection and Repair (LDAR) is a program implemented to comply with environmental regulations for reducing the fugitive emissions of targeted chemicals into the environment. Several standards such as Maximum Achievable Control Technology (MACT) standards, New Source Performance Standards (NSPS), and National Emissions Standards for Hazardous Air Pollutants (NESHAP) require the monitoring and reporting of these fugitive emissions from process equipment. Process components subject to LDAR are periodically monitored to detect the leaks which are required to be repaired within a predefined time period.

This means that chemical plants, hazardous waste facilities, and refineries, among others, are subject to LDAR services for all of their valves, pumps, and flanges.

The environmental regulations that prescribe LDAR programs as a means of reducing emissions have very specific standards that must be applied to a monitoring and repair program. These LDAR standards normally define the:

• Chemical streams that must be monitored
• Types of components (pumps, valves, connectors, etc.) to be monitored
• Measured concentration in PPM that indicates a leak
• Frequency of monitoring
• Method of monitoring
• Actions to be taken if a leak is discovered
• Length of time in which an initial attempt to repair the leak must be performed
• Length of time in which an effective repair of the leak must be made
• Actions that must be taken if a leak cannot be repaired within guidelines
• Record-keeping and reporting requirements

There are many federal, state, and sometimes local regulations that may apply to leak monitoring. Each component class may have different leak definitions or monitoring frequencies. This makes manual scheduling of component monitoring very difficult. Sometimes more than one regulation (with different standards) may apply to the same component at the same time. This requires more than one set of monitoring standards, record-keeping and reporting requirements to be applied to the same component for each standard that applies. An average-sized manufacturing plant may have from 3,000 to 30,000 components to be monitored, and large facilities may have well over 100,000 components on various monitoring schedules, with various standards applied for compliance with environmental regulations.