Smart LDAR —

More Cost-Effective?

Mike meister

managing Consultant—Corpus Christi

On December 19, 2008, EPA issued a final 

rule establishing a voluntary Alternative 

Work Practice (AWP) to detect leaks of 

volatile organic compounds (VOC) and 

hazardous air pollutants (HAP) from process 

equipment (FR Vol. 73, Number 246), 

thereby providing the regulated community 

additional flexibility in complying with leak 

detection and repair (LDAR) requirements. 

The AWP allows owners or operators of 

an affected facility to identify leaking 

equipment using an optical gas imaging 

instrument in lieu of a leak monitor as 

prescribed in Title 40, Code of Federal 

Regulations (40 CFR) Part 60, Appendix A 

(Method 21). The development of the AWP 

and its associated monitoring technologies 

are collectively referred to as “Smart LDAR.”

What is Smart LDAR?

Beginning in the 1980s, EPA called for 

the implementation of LDAR programs 

for control of fugitive VOC emissions (i.e., 

emissions from piping components such 

as flanges, connectors, valves, pumps, 

etc.). Therefore, LDAR requirements were 

initially promulgated in the New Source 

Performance Standards (NSPS) under 

40 CFR 60, Subpart VV. EPA went on to 

incorporate LDAR requirements in other 

NSPS and 40 CFR 61. These efforts were 

extended with the passage of the Clean Air 

Act Amendments of 1990, which resulted 

in the adoption of LDAR provisions into the 

Maximum Achievable Control Technology 

(MACT) rules under the National Emissions 

Standards for Hazardous Air Pollutants 

(NESHAP). More recently, the proposed 

mandatory Greenhouse Gas Reporting rule 

(40 CFR 98) contains fugitive monitoring 

provisions.

The current LDAR work practice requires the 

use of Method 21 to identify component 

leaks. Method 21 involves moving a gas 

sampling instrument probe around all leak 

interfaces (seals) and determining the highest 

VOC/HAP concentration. After determining 

the location of the highest concentration, 

the probe must remain at that location 

for two times the response time. The 

instrument 

readings are 

compared with 

levels established 

by EPA and/or the 

state air pollution 

regulatory agency 

to determine if the 

component leaks. 

If the measured 

VOC concentration 

at a component 

exceeds the leak 

definition (which 

typically varies 

from 500 parts per 

million by volume 

(ppmv) to 10,000 ppmv, depending on the 

type of component and specific subpart), 

the component must be repaired or 

replaced within a specified period of time. 

The repeated Method 21 measurement of 

emissions following such maintenance must 

be below the leak concentration level for 

the component to be considered repaired. 

In 1997, the American Petroleum Institute 

(API) conducted a study of 11.5 million 

monitored refinery components to 

determine if there was a correlation 

between component type or application 

and its potential to leak. The study showed 

that over 90 percent of the controllable 

fugitive emissions were attributed to 0.13 

percent of the components monitored, 

demonstrating that significant time and 

effort is spent monitoring components that, 

statistically, do not leak. Furthermore, after 

an LDAR program has been implemented 

at a site, the number of leaks detected 

during each subsequent monitoring period 

decreases because pre-existing leaks 

have been repaired and may not leak for 

regulatory update

4 Environmental Quarterly | Summer 2009

extended periods of time. Although repair 

costs decrease as the number of leaks is 

reduced, the costs of conducting Method 

21 monitoring is not always reduced in the 

same proportion. In some cases, the cost 

of conducting Method 21 monitoring may 

remain constant, resulting in a decrease in 

cost-effectiveness. 

Conceptually, the costs associated with the 

current work practice of monitoring each 

component at a site individually could be 

significantly reduced by implementing 

a method that more efficiently locates 

the high leaking components without 

monitoring each piping component in 

the plant using Method 21. This concept, 

dubbed “Smart LDAR,” could use newer 

technology to locate and repair the most 

significant leaking components more 

quickly and at less cost than the current 

work practice.

Technologies Evaluated

Remote sensing (i.e., the acquisition of data 

through the use of either recording or a 

real-time sensing device, such as imaging, 

that is not in direct physical contact with the 

object being monitored) and instantaneous 

detection capabilities of Smart LDAR 

technology can allow an operator to scan 

process areas containing tens to hundreds of 

components in real time. Significant leaks 

can be identified immediately, allowing 
Summer 2009 | Environmental Quarterly 5

quicker repair and ensuring efficient use 

of resources. In the development of the 

AWP, EPA researched multiple remote 

sensing technologies to measure pollutant 

concentrations, including the following:

n Ultra-Violet Differential Optical 

Absorption Spectra (UV- DOAS)

n Open-Path Fourier Transform Infrared 

Spectroscopy (OP-FTIR)

n Rama-Spectroscopy

n Tunable Diode Laser (TDL)

n Differential Absorption Light Detection 

and Ranging (DIAL/LIDAR) 

n Optical Gas Imaging 

To date, the only technology that has been 

approved and implemented as an AWP is 

optical gas imaging. Due to issues such 

as excess expense, technical limitations 

of the number and type of chemical 

species detected, interference from nontarget emissions, and required expertise 

for calibration and operation, the other 

technologies have not been approved as 

an AWP. However, LIDAR, which utilizes 

laser absorption and reflection to generate 

a differential signal that can be used to 

calculate the concentration of the target 

compound, is currently in use in both 

ground-level and airborne applications 

by EPA and a number of state agencies to 

create concentration contouring of various 

chemicals and to validate emission factors. 

Two types of optical gas imaging cameras 

are available for use as an AWP, the basic 

operation of which are explained below:

n Active Optical Gas Imaging - utilizes a 

laser beam reflected (backscattered) by 

the background to detect the chemical 

present. The optical image is produced 

by the reflected light with a light 

wavelength strongly absorbed by the 

gas cloud. The image is displayed realtime on the screen of the gas imaging 

camera.

n Passive Optical Gas Imaging - a passive 

technology that records the difference 

in absorption of specific infrared (IR) 

wavelengths in the field of vision and 

produces the appearance of a cloud 

where the chemical is present. The 

technology uses different combinations 

of lenses, detectors and filters for 

detecting different pollutants. The 

optical lens of a passive gas imaging 

camera can be tuned to illuminate 

target compounds (a principle similar to 

that used in “night-vision” equipment) to 

detect leaks. 

Optical gas imaging technology offers 

several advantages from the perspective 

of Smart LDAR implementation. It meets 

the Smart LDAR requirements of providing 

efficient real-time leak analysis while also 

being lightweight, compact, and robust, 

thereby allowing a single operator to easily 

transport the equipment for use under field 

conditions. In addition, since the cameras 

can be used to detect leaks from a distance, 

they provide a greater element of operator 

safety over the current work practice using 

Method 21.

The chief limitation of optical gas imaging is 

related to calibration of the camera. Each 

camera is calibrated based on the required 

detection limits of compounds that possess 

a specific range of absorption and reflection 

wavelengths. If a site is required to monitor 

pollutants whose ranges do not overlap, the 

camera must be recalibrated for the second 

group of pollutants or another camera 

used. Other issues that may be considered 

roadblocks to implementation include the 

requirement for daily instrument checks, the 

potential requirement by state agencies that 

operators must undergo accredited formal 

training, and the high initial equipment 

costs (currently available cameras carry 

a price tag of approximately $85,000.) 

However, these disadvantages may not 

necessarily preclude the implementation of 

optical gas imaging technology as an AWP, 

particularly for larger sites.

Smart LDAR Implementation

Passive optical gas imaging cameras are 

being widely used throughout industry 

for leak detection. State agencies are now 

using this technology in statewide fugitive 

emissions reduction initiatives (e.g., the 

Texas Commission on Environmental 

Quality’s “Find-It-and Fix-It” program and 

aircraft overflights over industrial areas such 

as the Houston Ship Channel). Optical gas 

imaging cameras have been used to detect 

the presence of unburned hydrocarbons in 

flare plumes outside of the flame and to 

determine combustion efficiency in various 

combustion sources. Besides industrial 

applications, optical gas imaging was used 

by EPA and the Louisiana Department of 

Environmental Quality in detecting leaks 

and other sources of air pollutants, post 

Hurricane Katrina. The table on page 6 

is a partial list of local, state, and federal 

agencies that currently operate optical 

gas imaging cameras for the purpose 

of performing various surveillance and 

compliance investigations. 

In addition to being implemented into LDAR 

programs as an AWP, optical gas imaging 

cameras may be utilized in the future 

by industry and regulatory agencies for 

various other tasks, such as safety and risk 

mitigation applications, sulfur hexafluoride 

(SF6

) detection as part of the collaborative 

effort between EPA and the electric power 

industry to reduce greenhouse gas emissions 

(the SF6

 Emission Reduction Partnership), 

and the quantification of emissions, once 

the technology is further developed.

Considerations

There are several key points to consider 

before implementing an optical gas imaging 

camera for fugitive gas leak detection.

n The definition of a leak is any visual 

indication whether seen via camera or 

naked eye, which is a departure/

additional to existing work practice 

standard. For instance, visual 

indications of a leak from a gas/vapor or 

light liquid service valve are not 

addressed in current work practice 

standard. Visual indications of a leak 

from a valve in heavy liquid service 

would be considered a potential leak. 

The facility can then decide to eliminate 
6 Environmental Quarterly | Summer 2009

Additionally, weekly visual inspections 

of affected pump/agitator components 

may still be required, as prescribed

under the current LDAR program, if a 

site plans to adopt the AWP.

n Smart LDAR does not allow for decrease 

in monitoring frequency due to “good 

behavior,” as does the current work practice. 

Thus, the cost savings realized due to 

decreased monitoring frequencies when 

using Method 21 do not apply to the AWP. 

n After detecting leaks analogous to the 

existing work practice standard, owners 

or operators must re-check the repaired 

equipment for further leaks with the 

same gas imaging camera or they may 

use Method 21 to confirm that the leak 

has been repaired.

n Owners or operators must perform the 

specified daily calibration checks to 

ensure proper operation.

n Owners or operators should be aware 

of the high initial cost of the equipment 

and are advised to perform a cost-benefit 

analysis before purchasing and 

implementing optical gas imaging 

equipment. In general, the company 

would realize a greater benefit in the 

long run, due to a reduction in labor cost. 

Additionally, some companies have taken 

the approach of purchasing one camera 

for multiple sites to minimize the cost per

site. Another option for managing cost is 

to contract the testing from a firm that 

specializes in air quality compliance, 

fugitive leak monitoring, and stack testing.

It is important to note that current optical 

gas imaging technology cannot quantify or 

speciate individual chemical compounds 

although there are efforts currently 

underway to adapt the technology to 

such applications. These enhancements 

include development of software that may 

interpret gross emission rate based on 

video imagery. Once the technology is fully 

realized, industry and agencies alike may 

be able to quickly and accurately determine 

compliance for other air emissionsrelated parameters, such control device 

performance and emissions limits, in 

real-time with the click of a button. t

the potential leak or conduct Method 21 

monitoring to determine if it meets the 

leak definition. Visual indications from 

a pump (except for pumps addressed 

under the Hazardous Organic NESHAP 

[HON] rule) are considered potential 

leaks; however, under AWP they would 

be considered leaks.

n When the AWP is used, owners/operators 

must also perform annual monitoring 

using the Method 21 instrument and 

provide all the Method 21 monitoring 

results to EPA via email. Therefore, 

owners or operators who are only 

required to conduct annual monitoring 

as part of their LDAR program would not 

benefit from implementing the AWP. 

regulatory update

Local, State, and Federal Agencies Using Official Gas Imaging 

Cameras for Fugitive Leak Detection

Level Agency 

Federal U.S. Environmental Protection Agency (EPA)

U.S. Department of Interior - Mineral Management Service (MMS)

State California - Bay Area Air Quality Management District (BAAQMD)

California - South Coast Air Quality Management District (SCAQMD)

Delaware - Department of Natural Resources and Environmental 

Control (DNREC)

Illinois - Environmental Protection Agency (IEPA)

Louisiana - Department of Environmental Quality (LDEQ)

Montana - Department of Environmental Quality (MODEQ)

New Jersey - Department of Environmental Protection (NJDEP)

Texas - Commission on Environmental Quality (TCEQ) 

Municipalities City of Houston - Bureau of Air Quality Control (BAQC)

City of Philadelphia - Air Management Services (AMS)

Kansas Environmental Conference

August 18-20 Wichita, KS

MCIC - EHS Safety School

August 24-25 Raleigh, NC

NCASI Western Regional Meeting 

September 1 Portland, OR

Drop by the Trinity booth at any of these upcoming conferences. We look forward to seeing you!

See You on the Road

TCEQ Advanced Air Permitting Seminar

September 29-30 Austin, TX

Environmental Federation of Oklahoma’s 

17th Annual Meeting

October 1 Tulsa, OK

Iowa-Illinois Safety Council’s 23rd Annual 

Environmental Conference & Expo 

October 1 Davenport, IA
Summer 2009 | Environmental Quarterly 7

Q. George, how would you describe your role at Trinity?

A. That’s an interesting question. Trinity is certainly well 

known for its air modeling prowess and I have worked for a 

number of years performing similarly challenging modeling 

work. My internal role here at Trinity is one of providing 

senior experience and mentoring due to the sheer number and 

variety of modeling scenarios in which I been involved over 

the years from my EPA experience to consulting. I like to 

share that experience however possible through instruction, 

project participation, project management, leadership roles 

in outside organizations, and through company pow-wows 

that focus on everything from the most sophisticated, new 

modeling techniques to the everyday task of interpreting the 

results. Externally, I continue to be focused on applying 

strategic modeling and regulatory analyses to assist clients in 

meeting their air quality challenges.

Q. What are the most pressing environmental challenges 

your clients seem to be facing in 2009?

A. In 2009, clients are facing a number of environmental 

challenges. First and foremost will be maintaining continued 

compliance while trimming environmental budgets and 

staff. Most companies want to maintain operations to the 

extent possible in spite of the economic downturn. Once the 

economy begins to recover, companies want to have their staff 

and resources intact, and their operations poised to respond. 

Another important challenge for companies in this new era is 

to have a plan for sustainability and low impact while leaning 

to green in terms of resource use, emissions, and overall 

impact on the environment. Energy and resource conservation 

were not high priorities until the last decade when we realized 

this approach saves money, saves resources, and makes sense. 

It’s exciting to be working with clients on meeting these 

challenges.

staff spotlight

Atmospheric Scientist Tackles 

Complex Air Quality Issues

George Schewe, a Certified Consulting Meteorologist and Qualified Environmental 

Professional, joined Trinity’s Covington, Kentucky office in 2008. A veteran of EPA with 

nearly three decades of consulting experience, George is well-versed in air quality 

regulatory requirements and a master in complex air dispersion modeling analyses. 

Here is George’s take on his role and current environmental issues.

Q. How are you supporting clients in addressing 

these issues?

A. One way we are trying to address client needs in this 

challenging economic environment is to provide alternatives 

for consideration in terms of facility actions, plans, and 

subsequent subjectivity to applicable regulations. Initial 

screening modeling that identifies relative impacts of various 

control strategies, facility layouts, operational changes, 

time-of-day operations, etc. can go a long way to reducing 

emissions, reducing impacts, minimizing modeling costs, and 

revealing culpable sources where emphasis can then be placed. 

I believe we can offer a quality product for a reduced cost to 

the client by using a strategic approach that includes initial 

discussions and meetings with the client and with regulatory 

agencies when possible to clarify how the modeling should 

proceed. This is consistent with our client service model 

always but is particularly important in today’s environment.

Q. How do you anticipate the environmental field 

(issues) changing over the next decade?

A. I expect more regulations on everything but still a big 

emphasis on the big sources such as power plants. Who 

would have thought 20 years ago that lawn mowers, chain 

saws, and barbecue grills would be regulated, not to mention 

wood burning stoves? As we enter a new era in energy 

production—more wind turbines, solar, nuclear, and the swing 

toward sustainability and environmentally safe technologies, 

I anticipate more integration of industry and green 

technologies. Ultimately, I hope successful integration will 

lead to a cleaner environment supported by more sustainable 

technologies that are cost-effective for industry. t

Contact George at (859) 341-8100 or at 

gschewe@trinityconsultants.com.