TECHNICAL SUPPORT DOCUMENT

Control of Air Pollution from Volatile Organic Compounds

Alternative Leak Detection and Repair (LDAR) Work Practice (AWP)

Docket ID: EPA-R06-OAR-2010-0611

December 2014

Revisions to 30 TAC Chapter 115 submitted July 2, 2010

No material in this submittal package was designated as Confidential Business Information.

FOR FURTHER INFORMATION CONTACT:

Jennifer Huser, United States Environmental Protection Agency Region 6, Air Permits Section 

(6PD-R), 1445 Ross Avenue, Suite 1200, Dallas, Texas 75202-2733, (214) 665-7347
Background

Under the Clean Air Act (CAA), EPA promulgated an 8-hour ozone standard of 0.08 parts per 

million (ppm), which is more protective than the previous 1-hour ozone standard (62 FR 38855, 

July 18, 1997). On April 30, 2004, EPA published designations and classifications for the 1997 

8-hour ozone standard (69 FR 23858). The Dallas-Fort Worth 1997 ozone nonattainment area 

(DFW area), which consists of Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, 

Rockwall and Tarrant Counties, was initially classified as a moderate ozone nonattainment area. 

The DFW area was reclassified as a serious ozone nonattainment for the 1997 ozone standard 

(75 FR 79302, December 20, 2010). The Houston-Galveston-Brazoria ozone nonattainment area 

(HGB area) consists of Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery 

and Waller counties. The HGB area is classified as a severe ozone nonattainment for the 1997 

ozone national ambient air quality standard (NAAQS). See 73 FR 56983, October 1, 2008. The 

Beaumont-Port Arthur area (BPA area) consists of Hardin, Jefferson, and Orange Counties and 

was redesignated to attainment for the 1997 ozone standard (75 FR 64675, October 20, 2010).

Volatile organic compounds (VOCs) and oxides of nitrogen (NOx) are known as “ozone 

precursors,” as they react with oxygen and sunlight to form ozone. Motor vehicle exhaust and 

industrial emissions, gasoline vapors and chemical solvents emit NOx and VOCs. Controlling 

sources of NOx and VOC emissions can lower ozone levels in the ambient air.

Sections 172(c)(1) and 182 of the CAA require ozone nonattainment areas that are classified as 

moderate or above for ozone nonattainment to adopt Reasonably Available Control Technology 

(RACT) requirements for sources that are subject to Control Techniques Guidelines (CTGs) 

issued by EPA and for “major sources” of VOCs and NOx. Major sources are defined as the 

following for each affected nonattainment area: in areas classified as moderate, are those

sources that have the potential to emit at least 100 tons per year of VOCs or NOx; for areas 

classified as serious, are those that have the potential to emit 50 tons per year (tpy) of VOCs or 

NOx; and in areas classified as severe, are those sources that have the potential to emit at least 25 

tons per year of VOCs or NOx (CAA § 182(c)). RACT is defined as the lowest emissions 

limitation that a particular source is capable of meeting by the application of control technology 

that is reasonably available considering technological and economic feasibility (44 FR 53762, 

September 17, 1979). As a part of the RACT requirements, EPA requires emission control 

techniques which are considered RACT. The techniques include work practice standards, such as 

leak detection and repair programs, which states are required to implement to ensure emissions 

from fugitive sources are identified through routine monitoring and reduced by timely repair of 

leaking equipment.

Leak Detection and Repair (LDAR) is a fundamental aspect of air pollution control by reducing 

fugitive emissions from leaking piping components and instrumentation. Unlike standard add on 

controls, the emission reductions achieved from an LDAR program are through timely

identification and repair of leaks. Certain industries are required to identify equipment leaks

pursuant to 40 CFR Parts 60, 61, 63, and 65. Method 21 is time-consuming and costly, since an 

individual must spend an average of 2-15 minutes per monitoring event per component, 

depending on its size, and larger petrochemical facilities can have upwards of 300,000 
components per site. Additionally, Method 21 requires the use of a monitor which meets specific

performance standards, and is based on technology that is twenty five years old. New technology 

has been developed which utilizes an optical gas imaging instrument, and is believed by EPA to 

provide equal, or better, environmental protection than that provided by the Method 21 work 

practice. On April 6, 2006, EPA proposed through notice and comment rulemaking a voluntary 

alternative work practice for leak detection and repair of fugitive emission sources using optical 

gas imaging, titled “Alternative Work Practice To Detect Leaks From Equipment.” See 71 FR 

17401. EPA’s final alternative work practice (AWP) rule was effective on the date of its 

publication in the Federal Register on December 22, 2008. See 73 FR 78200. This final 

rulemaking revised the General Provisions of 40 CFR Parts 60, 63, and 65, as well as any 

references to leak detection and repair throughout 40 CFR Parts 60, 61,63, and 65, to include the 

AWP. The final action also included a requirement to conduct instrument monitoring once per 

year using the current Method 21 leak detection instrument.

The optical gas imaging devices prescribed in the AWP are not capable of quantifying emissions, 

and the existing LDAR standards are based on a quantitative leak threshold. In the final federal 

AWP rule, EPA established through comparative bagging studies and modeling that using the 

AWP bimonthly, detecting a mass emission rate of 60 grams per hour, is equivalent to a Method 

21 leak detection level of 500 ppm. Because the modeling effort could not account for all of the 

uncertainties associated with equipment leaks, such as varying leak rates, and to address the 

potential for leaks to exist below the detection threshold of 60 grams per hour, EPA included the 

requirement to conduct an annual screening using Method 21. See 73 FR 78202.

The general VOC fugitive emission LDAR rules in 30 Texas Administrative Code (TAC), 

Chapter 115, Subchapter D, Divisions 2 and 3 were implemented to satisfy RACT requirements 

under the CAA (see 73 FR 10383, February 27, 2008 for Division 2; and 73 FR 40972, July 17, 

2008 for Division 3). The highly-reactive volatile organic compound (HRVOC) fugitive 

emissions LDAR rules are in 30 TAC Subchapter H, Division 3 and were implemented as part of 

the HGB attainment demonstration for the one-hour ozone NAAQS (71 FR 52655-56, 

September 6, 2006).

SIP Revision Adopted on June 2, 2010 and Submitted to EPA on July 2, 2010

On June 2, 2010, the Texas Commission on Environmental Quality (TCEQ) adopted revisions to 

the State Implementation Plan (SIP) that revise the LDAR rules to allow an optional AWP to 

detect fugitive emission leaks using optical gas imaging instruments. The adopted amendments 

revised 30 TAC Chapter 115.322 – 115.326, 115352 – 115.357, 115.781, 115.782, and 115.786 –

115.788 (denoted as 30 TAC 115) and added new 30 TAC 115.358 and 115.784. 30 TAC 115

addresses Control of Air Pollution from Volatile Organic Compounds. A discussion of the 

changes made by TCEQ can be found in Appendix A – Excerpt from June 18, 2010 Texas 

Register. The final adopted rule can be found in Appendix B – 30 TAC 115.322-115.326, 

Subchapter D (Petroleum Refining, Natural Gas Processing, and Petrochemical Processes), 

Division 2 (Fugitive Emission Control in Petroleum Refineries in Gregg, Nueces, and Victoria 
Counties), and 30 TAC 115.352-115.358, Division 3 (Fugitive Emission Control in Petroleum 

Refining, Natural Gas/Gasoline Processing, and Petrochemical Processes in Ozone 

Nonattainment Areas), and 30 TAC 115.781, 115.782, 115.784, 115.786-115.788, Subchapter H

(Highly-Reactive Volatile Organic Compounds), Division 3 (Fugitive Emissions).

Evaluation of SIP Revision

Review of the SIP Revision

Review of the SIP revision found the following amendments to the existing Chapter 115 rules:

 TCEQ adopted or incorporated by reference the requirements for the AWP promulgated 

by EPA in 40 CFR Part 60.18.

 TCEQ adopted additional requirements beyond those found in the federal AWP

published in 40 CFR Part 60.18 to provide for adequate enforceability and ensure that the 

AWP is at least as stringent as the existing SIP requirements.

 TCEQ included substantive additions to their LDAR rules that went beyond EPA’s final 

AWP rule. These additional requirements, outlined below, were included to ensure that 

personnel using optical gas imaging instruments have adequate training and to address 

quality assurance and enforcement concerns with the federal AWP as written in 40 CFR 

Part 60.18. The additional requirements include:

- Each person operating an optical gas imaging instrument for the purposes of 

the AWP will be required to conduct the daily instrument check. [30 TAC 

115.358(c)(2)]

- Owners or operators electing to use the AWP are required to submit 

notification to the appropriate Texas Commission on Environmental Quality 

(TCEQ) regional office at least 30 days prior to implementation. [30 TAC 

115.358(g)]

- Operator training is required for personnel performing the AWP. [30 TAC 

115.358(h)]

- A specific subset of components (e.g., blind flanges, heat exchanger heads, 

sight glasses, etc.) subject to 30 TAC 115.781(b)(3) may be sampled at 

alternative frequencies for the annual Method 21 test required under the AWP

if the components are not subject to a federal LDAR Method 21 requirements 

under 40 CFR Parts 60, 61, 63, or 65. [30 TAC 115.781(h)(6)]
 Because TCEQ currently implements specific LDAR requirements in the state’s LDAR 

rules in 30 TAC 115 Subchapter H, Division 3 (HRVOC rules), TCEQ included 

additional provisions to ensure the AWP would not result in backsliding under the CAA. 

These provisions include:

- For leaks more than 10,000 parts per million by volume (ppmv), rapid repair 

times are required under 30 TAC 115.782(b) and extraordinary efforts must be 

undertaken within a shorter time period to qualify for delay of repair under 30 

TAC 115.782(c). The rulemaking requires any leak detected using the AWP

to meet the more stringent repair time limits of 30 TAC 115.782(b) and (c) 

unless a Method 21 test is done to demonstrate the leak is 10,000 ppmv or 

less.

- The rule retains the third-party audit requirements of 30 TAC 115,788; 

however, an alternative audit procedure will be required if the company is 

using the AWP.

- Consistent with EPA guidance (Protocol for Equipment Leak Emission 

Estimates, EPA-453/R-95-017, November 1995), 30 TAC 115.782(c) requires 

companies to use EPA correlation equations for calculating emissions. For 

leaks detected using the AWP, a company will be required to use the 100,000 

ppmv pegged emission rates from the EPA guidance document.

 The AWP adopted by TCEQ is stated to be voluntary and optional, affording sites 

flexibility by not adopting an “all-in or all-out” approach, allowing companies to 

identify which components, even within a process unit, may be monitored with the 

AWP. This accounts for the fact that the optical gas imaging instrument is not capable of 

detecting all chemicals.

 TCEQ has stated that the rule revisions will not change a site’s applicable permits. If an 

owner or operator wants to use the AWP, they will still need to change the permit 

LDAR requirements through the state’s NSR permitting process. Implementation of the

AWP without a corresponding change to the permit LDAR requirements could be a 

violation of the permit and the SIP.

 TCEQ made the annual Method 21 monitoring optional for certain 

components regulated by Subchapter H, Division 3 (HRVOC) but not by a 

federal CAA LDAR regulation.

CAA 110(l) Analysis

The general VOC fugitive emission LDAR rules in 30 TAC 115 Subchapter D, Divisions 2 

and 3 were implemented to satisfy RACT requirements under the CAA. The HRVOC fugitive 

emissions LDAR rules are in 30 TAC 115, Subchapter H, Division 3 and were implemented as 

part of the HGB attainment demonstration for the one-hour ozone NAAQS. In finalizing the 

federal AWP, EPA indicated (73 FR 78202) that the leak threshold of 60 grams per hour (g/hr)

for the optical gas imaging was equivalent to the leak definition of 500 ppmv. The applicable 
leak definitions in Subchapter D division 2 is 10,000 ppmv; the applicable leak definition under 

Subchapter D, Division 3 is 10,000 ppmv for pump seals and compressor seals, and 500 ppmv 

for all other components subject to the division. For Subchapter H, Division 3, these LDAR rules 

were implemented as part of the HGB attainment demonstration for the one-hour ozone NAAQS. 

The applicable leak definition is 500 ppm, which is equivalent to the 60 g/hr threshold set by 

EPA for the AWP. TCEQ considered that while the method was determined to be equivalent to a 

leak detection limit of 500 ppmv, there are certain control requirements in the HRVOC fugitive 

rules that are not tied specifically to the leak definition.

CAA section 110(l) requires that a SIP revision submitted to EPA be adopted after 

reasonable notice and public hearing. Texas adopted the SIP revision after reasonable notice and 

public hearing. TCEQ received written comments from seven organizations/individuals, 

including EPA Region 6, on the proposed revisions to 30 TAC 115. EPA’s comment pertained to 

a clarification necessary in the preamble to the rule, and was addressed in the final rulemaking. 

TCEQ also held three public hearings: Irving, Texas (January 19, 2010), Austin, Texas (January 

20, 2010), and Houston, Texas (January 21, 2010). No comments were received during the 

public hearings.

Section 110(l) also requires that we not approve a SIP revision if the revision would interfere

with any applicable requirement concerning attainment and reasonable further progress, or any 

other applicable requirement of the CAA. The revisions are consistent with or incorporate 

verbatim EPA’s federal alternative work practice method for the detection of fugitive emissions. 

Further, the rule revision maintains all other LDAR RACT controls, therefore approval will not 

interfere with any applicable requirement of the CAA.

Recommendation

It is recommended that the revision to the Texas SIP be approved because:

• It improves upon the SIP-approved rules in that it provides for a voluntary alternative 

method for the detection of fugitive emissions from leaking components.

• Approval would not interfere with any applicable requirement concerning attainment and 

reasonable further progress or any other applicable requirement of the CAA.

• Is consistent with an EPA federal rule that provides an alternative to required monitoring 

for fugitive components to ensure facilities identify and repair leaking equipment in a 

timely and effective manner to reduce fugitive air emissions.