Leak Detection and Repair (LDAR) in the Valve Industry

In the heart of the industry, every hiss and puff from a leaky valve is more than just a technical snag – it is a sign of potential harm slipping into the air we share. Enter the world of Leak Detection and Repair (LDAR), the environmental safeguard where technicians and tools come together to hunt down these elusive leaks. This is not just about fixing what is broken; it is about preserving the quality of the environment and eliminating potential disasters. Welcome to the critical world of LDAR, where every sealed leak is a victory.

By Mike Dunn, Co-Owner – JS Machine and Valve Inc.

Leak Detection and Repair (LDAR) refers to the processes and practices used to identify and rectify unintentional leaks of volatile organic compounds (VOC’s) and hazardous air pollutants (HAPs) from industrial equipment. These leaks can arise from various sources, includ­ing valves, pumps, connections, and other equipment. LDAR programs aim to reduce the emissions of these harm­ful gases to ensure compliance with environmental regulations and reduce potential health risks.

Evolution and History

The need for LDAR emerged as a re­sponse to growing awareness of the environmental and health impacts as­sociated with VOCs and HAPs. As indus­tries expanded and chemical usage in­creased, the potential for leaks also rose. Recognizing the environmental implica­tions of these leaks, regulatory bodies established standards and guidelines to monitor and control emissions. This initiative prompted the U.S. Environmen­tal Protection Agency (EPA) to create Method 21. Certified inspectors use this method to identify potential VOC leaks in process equipment such as valves, flanges, and other related components, depending on the operation’s nature. The EPA has emphasized the importance of Method 21 in ensuring compliance with LDAR regulations. Non-compliance with Method 21 requirements has been identified as a significant issue, leading to increased VOC emissions.

VOC monitoring instruments must meet the following criteria under Method 21:

  1. The VOC instrument detector shall re­spond to the compounds being pro­cessed. Detector types that may meet this requirement include, but are not limited to, catalytic oxidation, flame ionization, infrared absorption, and photoionization.
  2. The instrument shall be capable of measuring the leak definition concen­tration specified in the regulations.
  3. The scale of the instrument meter shall be readable to ± 2.5% of the specified leak definition concentration.
  4. The instrument shall be equipped with an electrically-driven pump to ensure that the sample is provided to the detector at a constant flow rate. The nominal sample flow rate, as mea­sured at the sample probe tip, shall be 0.10 to 3.0 l/min when the probe is fitted with a glass wool plug or filter that may be used to prevent plugging of the instrument.
  5. The instrument shall be equipped with a probe or probe extension or sam­pling not to exceed ¼” in outside di­ameter, with a single end opening for admission of the sample.
  6. The instrument shall be intrinsically safe for operation in explosive atmo­spheres as defined by the National Electrical Code by the National Fire Prevention Association or other ap­plicable regulatory code for operation in any explosive atmospheres that may be encountered in its use. The instrument shall, at a minimum, be intrinsically safe for Class 1, Division 1 conditions, and Class 2, Division 1 conditions, as appropriate, as defined by the example code. The instruments shall not be operated with any safety device, such as an exhaust flame ar­restor, removed.

LDAR Walkthrough

LDAR technicians walk through a refin­ery using the appropriate equipment to discover a leak. Once a leak is discov­ered, several steps must be taken.

First, documentation of the leak: The technician records the leak details, in­cluding the location, equipment type (in this example, a valve), leak concen­tration (usually in parts per million or ppm), date, and time of detection. The technician tags the leaky valve with a unique identifier or label. This helps in tracking the leak for repair and verifi­cation purposes. The technician then informs the facility’s management or appropriate department about the de­tected leak. Based on the severity of the leak and regulatory requirements, re­pairs are scheduled. The determination of the timeframe to fix the leak is based on various factors, including the sever­ity of the leak, potential environmental impact, safety concerns, consent decree, and/or regulatory requirements.

According to the EPA’s Leak Detection and Repair guide, the following are gen­eral guidelines:

  • Immediate Repair: Leaks that pose an immediate danger to health, safety, or the environment; leaks that can result in significant loss of products; leaks that violate specific regulatory thresholds or limits.
  • Repair within 5 Days: Leaks that do not pose an immediate danger but need prompt attention; leaks that can result in a moderate environmental impact if not addressed promptly; leaks that are close to violating regulatory thresholds.
  • Repair within 15 Days: Leaks that have a minor impact and do not pose imme­diate health, safety, or environmental risks; leaks that are under regulatory thresholds but still need to be addressed; situations, where repair parts or specialized personnel, are needed and are not immediately available
  • Based on the classification and severity of the leak and regulatory requirements, repairs are scheduled.

Repairing the Leak

Maintenance personnel or specialized repair teams are responsible for addressing leaks, with specific actions based on the type of equipment. For valves, this may involve tightening a component, replacing a faulty part, or conducting a comprehensive overhaul of the valve. Authorized personnel will make and document a ‘first attempt’ at repair, which is the initial effort made to repair a leak after it has been identified. The purpose of documenting this first attempt is to ensure that facilities are proactive in addressing leaks. Even if the leak is not successfully repaired on the first attempt, the facility demonstrates its commitment to resolving the issue. Facilities document and date the first attempt, actions taken, and the results. This documentation can be crucial for regulatory compliance and for demonstrating to regulatory agencies that the facility is taking timely action to address leaks.

Following the repair, the LDAR technician then re-tests the valve to ensure the leak has been successfully resolved. If the repair is successful, the technician updates the records to indicate that the valve has been repaired, noting the date of repair, the actions taken, and the results of the post-repair verification.

Subsequently, the valve will be periodically monitored as part of the facility’s ongoing LDAR program to ensure no future leaks occur. Depending on regulatory requirements, the facility may need to report the detected leak, the actions taken, and the results of the repair to environmental agencies or other governing bodies. The facility may analyze the leak data over time to identify trends, recurrent issues, or areas of improvement. This can lead to proactive measures, equipment upgrades, or enhanced training for technicians to minimize future leaks.

If the first attempt successfully repairs the leak, the component continues to be monitored to ensure the leak has been effectively fixed. However, if the first attempt is unsuccessful, further actions or delay-of-repair procedures may be initiated. Delay of repair refers to situations where a known leak is not repaired within the regulatory timeframe due to specific and justifiable reasons.

Based on information from the Electronic Code of Federal Regulations for LDAR, a valve does not automatically go on ‘delay of repair’ simply because the first attempt was unsuccessful. The decision to place a valve on ‘delay of repair’ is based on specific criteria. Some reasons that a valve would go on ‘delay of repair’ would include:

  • Technical Feasibility: If repairing or replacing the valve is technically in- feasible without a process unit shut- down, then the valve can be placed on delay of repair. The repair should then be completed by the end of the next process unit shutdown.
  • Emissions Consideration: If the owner or operator determines that the emissions resulting from immediate repair would be greater than the fugitive emissions from delaying the repair, then a delay is allowed.
  • Supply Limitations: A delay of repair beyond a process unit shutdown will be allowed for a valve if valve assembly replacement is necessary during the process unit shutdown, valve assembly supplies have been depleted, and valve assembly supplies had been sufficiently stocked before the supplies were depleted. Delay of repair beyond the second process unit shutdown will not be allowed unless the third process unit shutdown occurs sooner than six months after the first process unit shut-down.

Economic Implications of LDAR

While the environmental benefits of LDAR are evident, its economic implications are equally significant. Unchecked leaks can result in substantial financial losses for industries. For instance, the loss of valuable products due to leaks can impact profitability. In addition, potential legal liabilities and penalties for non-compliance can lead to significant financial consequences. Therefore, implementing an effective LDAR program is not only an environmental necessity but also a sound economic decision.

Advanced Technologies in LDAR

The LDAR process has benefited immensely from technological advancements, including:

  • Drones: Equipped with sensors, drones can monitor large industrial areas, providing a bird’s eye view of the property and detecting leaks in hard-to-reach places.
  • Artificial Intelligence (AI): AI algorithms can analyze sensor data to predict potential leak points, allowing for proactive maintenance and repair.
  • Augmented Reality (AR): AR can assist technicians in precisely identifying- ing leak locations, enhancing the efficiency of the repair process.

Training and Skill Development in LDAR

The success of any LDAR program hinges on the skills and expertise of the technicians involved. Comprehensive training programs are essential to equip technicians with the knowledge and skills required to detect and repair leaks effectively. This includes understanding the intricacies of the equipment, inter- preting readings accurately, and taking appropriate corrective actions.

Community Engagement and LDAR

Community engagement is a crucial aspect of LDAR. Industrial and petrochemical companies often operate in close proximity to residential areas, and leaks can have direct implications on the health and well-being of the community. By actively engaging with the community, companies can foster trust and ensure that any concerns related to leaks and emissions are addressed promptly.

As the exploration of Leak Detection and Repair is concluded, it is evident that LDAR is more than a set of tasks – it is a vital practice that keeps the industrial gears turning smoothly. Beyond complex technology and meticulous regulations, the core of each plant is smoothly-running machinery, the cornerstone of industrial success. LDAR, with its arsenal of tools and techniques, is not just about fixing leaks; it ensures that factories and plants operate at peak efficiency. It is therefore important to re- member that LDAR is the silent guardian of operational integrity, making sure that every component, every valve, and every connection is sealed.


  1. U.S. Environmental Protection Agency (EPA),”Method 21 – Determination of Volatile Organic Compound Leaks”. www.epa.gov/sites/default/fi les/2017-08/ documents/method_21.pdf](www.epa.gov/sites/ default/fi les/2017-08/documents/method_21.pdf)
  2. U.S. Environmental Protection Agency (EPA), “Leak Detection and Repair: A Best Practices Guide” https://www.epa.gov/compliance/leak-detection- and-repair-best-practices-guide](https://www.epa. gov/compliance/leak-detection-and-repair-best- practices-guide)
  3. Electronic Code of Federal Regulations, “40 CFR 63.171 — Standards: Delay of repair”. This source was referenced in this article but a direct URL was not provided. It’s recommended to access the eCFR website to find the specific section.
ABOUT THE AUTHOR: Mike Dunn is an alumnus of Northeastern State University, receiving a Bachelor of Science in Management Information Systems. However, deviating from the most obvious professional path, Mike decided to uphold the family legacy and enter the illustrious valve repair industry. Almost two decades later, Mike is the co-owner of JS Machine and Valve Inc.
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