Technical Support Document 

March 2010 

Regulations to Control Volatile Organic Compound Emissions from VOC Storage 

Tanks, Transport Vessels and Marine Vessels in the Houston/Galveston/Brazoria 

(HGB) 1997 8-Hour Ozone Nonattainment Area 

Background 

Under the Clean Air Act (CAA) EPA promulgated, on July 18, 1997, 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). On April 30, 2004, EPA published designations 

and classifications for the 1997 8-hour ozone standard (69 FR 23858). The HGB area, 

which consists of Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, 

Montgomery and Waller counties was classified as a moderate ozone nonattainment 

area, with an attainment date no later than June 15, 2010. On October 1, 2008, at the 

request of the Governor of Texas, we reclassified the area as a severe ozone 

nonattainment area with an attainment date no later than June 15, 2019 (73 FR 56983). 

Volatile organic compounds (VOC) 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 Clean Air Act 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 

volatile organic compounds (VOCs) and nitrogen oxides (NOx). 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). EPA previously 

approved the Texas VOC regulations as meeting RACT requirements for Storage of 

VOCs (30 TAC 115, Subchapter B, Division 1) and Degassing or Cleaning of Stationary, 

Marine and Transport Vessels (30 TAC 115, Subchapter F, Division 3), (February 27, 

2008 Federal Register, 73 FR 10383). 

The Texas Commission on Environmental Quality (TCEQ) reported that studies with 

their research partners found that certain types of VOC storage tank emissions, 

including degassing, flash, and floating roof landing loss emissions, have been 

unreported or underreported in the HGB area (June 8, 2007 Texas Register, 32 TexReg 

3178). Degassing emissions occur when gas or vapor is removed from a storage tank. 

Flash gas emissions are VOC emissions to the atmosphere from depressurization of 

crude oil or condensate when it is transferred from a higher pressure to a lower 

pressure tank, reservoir, or other container. Floating roof landing loss emissions occur 
when the liquid level in a floating roof tank is lowered and the roof rests (lands) on the 

legs, or supports, rather than on the liquid, severely limiting the control efficiency of the 

floating roof. 

These emissions could total several thousand tons per year. It was estimated that 

unreported or underreported floating roof landing loss emissions alone in the HGB area 

totaled approximately 7,250 tons in 2003. As a result, the State revised its VOC control 

regulations to help reduce emissions from these sources in the HGB area. The State of 

Texas adopted the revision to the SIP on May 23, 2007 and submitted it to EPA on June 

13, 2007. 

Two public hearings for the proposed revision were held on January 29, 2007 in 

Houston. The State also received comments from EPA and others. EPA’s comment 

letter of February 12, 2007 was supportive of the proposed changes. Comments from 

EPA and others and the State’s response to the comments can be found in the State 

submittal to EPA. The State submittal can be found in the electronic docket (Docket 

number EPA-R06-OAR-2007-0526). 

Requirements to Control VOC Emissions 

The revision adds additional requirements to control VOC emissions from VOC storage 

tanks, transport vessels and marine vessels in the HGB area. These tanks and vessels 

store volatile organic liquids at petroleum refineries, chemical plants, gasoline storage 

terminals, bulk terminals, pipeline breakout stations, and oil and natural gas production 

sites. The revision amended Chapter 115 of Title 30 of the Texas Administrative Code 

(30 TAC 115), Subchapter B Division 1 (Storage of Volatile Organic Compounds) and 

Subchapter F Division 3 (Degassing or Cleaning of Stationary, Marine and Transport 

Vessels) by adding a new section 115.110 and revising sections 115.112-115.117, 

115.119, 115.541-115.547 and 115.549. 

Specifically the revision: 

• Requires more stringent controls for tank fittings on floating roof tanks to prevent the 

direct contact of stored VOCs with ambient air; 

• Limits the circumstances under which floating roof tank landings are allowed to times 

when the landing is necessary in order to carry out inspections or maintenance or to 

support a change in service to a liquid that is incompatible with the previously stored 

liquid. Convenience landings would not be allowed unless vapors are routed to a control 

device during the landing, are authorized under an emission limit or cap in a permit 

issued under 30 TAC Chapter 116, or fall within a 25 tpy exemption level. 

• Requires routing of VOC flash emissions to a vapor recovery system or control device 

for crude oil and condensate storage tanks at oil and gas exploration and production 

sites and pipeline breakout stations with uncontrolled flash emissions greater than 25 

tons per year; 

• Requires use of a vapor control system to control VOC emissions from the degassing 

of storage tanks with a nominal capacity of 250,000 gallons or more, or with a nominal 
capacity of 75,000 gallons or more storing liquids with a true vapor pressure greater 

than 2.6 pounds per square inch absolute (psia); 

• Require degassing vapors from storage vessels, transport vessels, and marine 

vessels in the HGB area to be vented to a control device until the VOC concentration of 

the vapors is reduced to less than 34,000 parts per million by volume as methane; 

• Require VOC monitoring during the degassing process using an appropriate 

monitoring device; and 

• Require additional recordkeeping to validate compliance. The revision also provides 

options for estimating uncontrolled flash emissions. 

Table 1 is a summary of the revision by section. 

Table 1. Summary of Revision to 30 TAC 115 

Subchapter B, Division 1, Storage of Volatile Organic Compounds 

Section 

Revised

Revision Reason Revision is Approvable

115.110 

Definitions 

 

Definitions added for Deck cover, 

Flexible enclosure system, 

Incompatible liquid, Internal 

sleeve emission control system, 

Pipeline breakout station, Pole 

float, Pole sleeve, Pole wiper, 

Slotted guidepole and Tank 

battery. 

The revision helps define the 

requirements. 

115.112 

Control 

Requirements 

Provides additional requirements 

for tank fittings on floating roof 

tanks and restrictions on tank 

landings (115.112(d)(2)). The 

additional requirements for 

floating tank roof fittings are as 

follows: 

• Openings in an internal floating 

cover or external floating roof 

must provide a projection below 

the liquid surface, except for 

automatic bleeder vents and rim 

space vents (115.112(d)(2)(A)). 

• Automatic bleeder vents and rim 

space vents must be closed 

except when required to be open 

to relieve excess pressure or 

vacuum (115.112(d)(2)(B)). 

• Roof drains that empty into 

stored liquids, (except for stub 

drains on internal floating roof 

tanks), must have a slotted 

The requirements will help 

prevent VOC emissions from 

storage tanks by preventing the 

direct contact of the stored liquid 

with ambient air. 
membrane fabric cover that 

covers at least 90% of the area of 

the opening or an equivalent 

control that must be kept in a 

closed (i.e., no gap of more than 

1/8 inch) position at all times 

except when the drain is in actual 

use (115.112(d)(2)(D)). 

• Visible holes, tears, or other 

openings in any seal or seal fabric 

are prohibited (115.112(d)(2)(E)). 

Secondary seals for external 

floating roof storage tanks must 

be the rim-mounted type and the 

accumulated area of gaps that 

exceed 1/8 inch (0.32 centimeter) 

in width between the secondary 

seal and tank wall must be no 

greater than 1.0 square inch per 

foot of tank 

diameter(115.112(d)(2)(F)). 

• Opening for a slotted guidepole 

in an external floating roof tank 

must be equipped with one of the 

following control device 

configurations: 

(i) A pole wiper and a pole float. 

The wiper or seal of the pole float 

must be at or above the height of 

the pole wiper 

(ii) A pole wiper and a pole sleeve 

(iii) An internal sleeve emission 

control system 

(iv) Retrofit to a solid guidepole 

system 

(v) A flexible enclosure system 

(vi) A cover on an external floating 

roof tank . 

(115.112(d)(2)(G)). 

Floating roof tank landings are 

limited to times when the landing 

is necessary in order to carry out 

inspections or maintenance or to 

support a change in service to a 

liquid that is incompatible with the 

As landings severely limit the 

control efficiency of floating roofs, 

limiting landings will reduce VOC 

emissions. 

Controlling these emissions will 

reduce VOC emissions. 
previously stored liquid. 

Convenience landings would not 

be allowed unless vapors are 

routed to a control device during 

the landing, are authorized under 

an emission limit or cap in a 

permit issued under 30 TAC 

Chapter 116, or fall within a 25 tpy 

exemption (155.122(d)(2)(H)). 

Provides controls on flash 

emissions from tanks at upstream 

oil or gas production sites or 

midstream pipeline breakout 

station if the potential for VOC 

emissions would be greater than 

25 tpy (115.112(d)(4) and (5)). 

Flash emissions from these tanks 

are controlled by routing flashed 

gases to a vapor recovery system 

or control device. 

115.113 

Alternate 

Control 

Requirements 

Adds the phrase “(relating to 

Storage of Volatile Organic 

Compounds)”. 

Minor editorial change. 

115.114 

Inspection 

Requirements 

Adds references to 30 TAC 

115.112(d)(2)(E) and (F) and 

makes some minor editorial 

changes. 

Updates the section to reference 

the new section being adopted. 

115.115 

Approved Test 

Methods 

Monitoring for determining flash 

emissions if the owner or operator 

chooses to demonstrate 

compliance with the 25 tpy limit by 

direct measurement (115.115(c)). 

Assists with implementation. 

115.116 

Monitoring and 

Recordkeeping 

Requirements 

Recordkeeping to document 

exemptions. 

Assists with implementation. 

115.117 

Exemptions 

Removal of exemption for the 

storage of crude oil and 

condensate prior to custody 

transfer in tanks with capacity less 

than 210,000 gallons in the HGB 

area from the control 

requirements of Subchapter B, 

Division 1 (115.117(a)(2)). 

Removing exemption allows for 

more VOC emission reductions. 
115.119 

Counties and 

Compliance 

Schedules 

Sets a compliance date of 

January 1, 2009, unless 

compliance with the new 

requirements would necessitate 

emptying and degassing the tank. 

Then compliance would not be 

required until the next time the 

tank is emptied or degassed but 

not later than January 1, 2017 

(115.119(c)). 

Provides adequate time for 

implementing the revised 

requirements. 

Subchapter F, Division 3, Degassing or Cleaning of Stationary, Marine and 

Transport Vessels 

Section 

Revised

Revision Reason Revision is Approvable

115.541 

Emission 

Specifications 

Revises degassing control 

requirements to storage tanks in 

the HGB area with a nominal 

capacity of 75,000 gallons or 

greater storing materials with a 

true vapor pressure greater than 

2.6 psia or to storage tanks with a 

nominal capacity of 250,000 

gallons or more storing material 

with a true vapor pressure of 0.5 

psia or greater. Previously 

degassing controls applied only to 

storage tanks with a nominal 

capacity of one million gallons or 

more. 

Lowering the threshold for 

storage tanks that are subject to 

VOC emission control means that 

additional tanks will be required 

to control VOC emissions. These 

storage tanks are those in the 

HGB area storage tanks with a 

nominal capacity of less than one 

million gallons, but more than 

75,000 gallons. The revision now 

requires venting of vapors to a 

control device when these 

storage tanks are degassed. 

Providing control requirements 

for additional storage tanks will 

allow for more VOC emission 

reductions. 

115.542 

Control 

Requirements 

Revises criteria for control of 

degassing vapors from storage 

tanks, transport vessels and 

marine vessels in the HGB area. 

Vapors are required be vented to 

a control device until the VOC 

concentration of the vapors is 

reduced to less than 34,000 ppm 

by volume (ppmv) as methane or 

to less than 50% of the lower 

explosive limit (LEL). Previous 

requirements specified the 34,000 

ppmv concentration (or 20% of 

the LEL for marine vessels) as 

criteria for determining when 

Removing the option to vent after 

a turnover of four vapor space 

volumes has occurred will help to 

ensure that VOC concentrations 

are low and could lead to 

additional VOC emission 

reductions. 
vapors can be vented to the 

atmosphere but also allow venting 

after a turnover of four vapor 

space volumes has occurred. 

The revision removes the option 

to vent to atmosphere after a 

turnover of four vapor space 

volumes has occurred. 

Concentrations must be 

rechecked periodically while the 

tank is vented to the atmosphere 

to ensure that it remains below 

34,000 ppmv or 50% LEL. If 

ventilation is continuous, the 

concentration must be measured 

at least once every 12 hours. If 

ventilation ceases for more than 

four hours, the concentration must 

be rechecked before the tank is 

reopened. The VOC 

concentration equivalent to 50% 

LEL is less than 34,000 ppmv. 

Additionally, concentration 

measurements are no longer 

required after five consecutive 

readings less than 34,000 ppmv 

or less than 50% LEL have been 

obtained 

115.543 

Alternate 

Control 

Requirements 

Changed “Houston/Galveston” to 

“Houston/Galveston/Brazoria”. 

Minor change. Under 30 TAC 

115.10 (19) “Houston/Galveston” 

or “Houston/Galveston/Brazoria” 

are both defined as Brazoria, 

Chambers, Fort Bend, Galveston, 

Harris, Liberty, Montgomery, and 

Waller Counties. 

115.544 

Inspection 

Requirements 

Changed “Houston/Galveston” to 

“Houston/Galveston/Brazoria”. 

Minor change. 

115.545 

Approved Test 

Methods 

Adds requirements for measuring 

VOC concentration of the storage 

vessels, transport vessels, or 

marine vessels to determine when 

the vapors can be vented to the 

atmosphere instead of to a control 

device. Measurements should be 

made at the head space of the 

The additional requirements will 

help to ensure that VOC 

concentrations are low before 

venting to the ambient air. 
vessel, as close as possible to the 

tank bottom to ensure that the 

concentration measurement is 

representative of actual 

conditions, but the measurements 

should be made at a safe location.

115.546 

Monitoring and 

Recordkeeping 

Requirements 

Additional records are to be kept 

to document that degassing 

vapors are routed to a control 

device until they reach the criteria 

to be released to the atmosphere. 

Requiring additional records will 

assist with implementation by 

providing documentation that 

VOC emissions are sufficiently 

controlled. This will help validate 

compliance. 

115.547 

Exemptions 

Exemptions were revised so that 

storage tanks in the HGB area 

with a nominal capacity of less 

than one million gallons but 

greater than or equal to 250,000 

gallons or with a nominal capacity 

of greater than or equal to 75,000 

gallons storing material with vapor 

pressure greater than 2.6 psia are 

no longer exempt from the 

requirements to control degassing 

emissions. 

Providing control requirements 

for additional storage tanks will 

allow for more VOC emission 

reductions. 

115.549 

Counties and 

Compliance 

Schedules 

January 1, 2009 is set as the 

compliance date for the revision. 

Allows time for compliance. Date 

has already passed. 

For more information on the requirements please see the appendices or 30 TAC 115, 

Subchapter B, Division 1 (Storage of Volatile Organic Compounds) and Subchapter F, 

Division 3 (Degassing or Cleaning of Stationary, Marine and Transport Vessels). 

Appendix 1 is excerpted from the June 8, 2007 Texas Register. The Texas Register 

can be accessed through the internet at http://texinfo.library.unt.edu/texasregister/ . 

The Texas Administrative Code rules can be accessed through the internet at: 

www.tceq.state.tx.us/rules/indxpdf.html . 

Evaluation of Revision 

EPA has evaluated the Chapter 115 revision and finds they enhance the SIP by 

reducing emissions from VOC storage tanks, transport vessels and marine vessels in 

Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery and Waller 

counties by requiring additional controls on VOC emissions from these sources as 

discussed above. These reduced emissions will help lower ozone levels in the HGB 

area. The rulemaking subjects owners or operators of VOC storage tanks, transport 
vessels, and marine vessels located in the HGB 1997 8-hour ozone nonattainment area 

to more stringent control, monitoring, and recordkeeping requirements. 

As shown in the table 1, these revisions improve TCEQs rules. These rules were 

previously approved by EPA as meeting the Act’s RACT requirements most recently in 

2008. With these improvements, the rules will continue to insure the Act’s requirements 

are met. Under CAA section 110(l) EPA may not approve a SIP revision if the revision 

would interfere with any applicable requirement concerning attainment or any other 

applicable requirement of the CAA. EPA approval of the revision will not interfere with 

any applicable requirement concerning attainment or any other applicable requirement 

of the CAA including RACT requirements. 

Recommendation 

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

revisions improve the rules that were previously approved resulting in additional VOC 

reductions and insuring that RACT is still met for these source categories. 
Appendices 

Appendix 1 – Excerpt from the June 8, 2007 Texas Register (32 TexReg 3178) 

Appendix 2 – Title 30 of the Texas Administrative Code (30 TAC 115), Subchapter B 

Division 1 (Storage of Volatile Organic Compounds) 

Appendix 3 – Title 30 of the Texas Administrative Code Subchapter F (Miscellaneous 

Industrial Sources) 
Appendix 1 – Excerpt from the June 8, 2007 Texas Register (32 TexReg 3178) 

Chapter 115. CONTROL OF AIR POLLUTION FROM VOLATILE ORGANIC 

COMPOUNDS 

The Texas Commission on Environmental Quality (TCEQ or commission) adopts new 

§115.110 and amendments to §§115.112 - 115.117, 115.119, 115.541 - 115.547, and 

115.549. New §115.110 and amendments to §§115.112, 115.115 - 115.117, 115.119, 

and 115.541 - 115.547 are adopted with changes to the proposed text as published in 

the December 29, 2006, issue of the Texas Register (31 TexReg 10525). Amendments 

to §§115.113, 115.114, and 115.549 are adopted without changes and will not be 

republished. 

The amendments will be submitted to the United States Environmental Protection 

Agency (EPA) as a revision to the state implementation plan (SIP). 

BACKGROUND AND SUMMARY OF THE FACTUAL BASIS FOR THE ADOPTED 

RULES 

On June 15, 2004, the Houston-Galveston-Brazoria (HGB) ozone nonattainment area 

was classified as a moderate nonattainment area under the eight-hour national ambient 

air quality standard (NAAQS) under the Federal Clean Air Act (FCAA) Amendments of 

1990 (42 United States Code (USC), §§7401 et seq.). For the HGB area, defined by 

Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller 

Counties, the TCEQ has developed this eight-hour ozone SIP revision in accordance 

with 42 USC, §7410. Hence, this rulemaking and HGB SIP revision is part of the first 

step in addressing the eight-hour ozone standard for the area. 

The one-hour ozone NAAQS, which preceded the eight-hour ozone standard, was 

revoked June 15, 2005 (69 FR 23951). However, the one-hour ozone control strategies 

in the HGB area will remain in place. This set of strategies will continue to reduce the 

amount of ozone precursors and ozone in the HGB airshed. On September 6, 2006 (71 

FR 52656), EPA published approval of the HGB nonattainment area's one-hour ozone 

attainment demonstration and associated rules. The approval was published in six 

parts, covering the rules for the control of highly-reactive volatile organic compounds 

(HRVOC), the HRVOC emission cap and trade (HECT) program, the mass emission 

cap and trade (MECT) program for nitrogen oxides (NOx), the one-hour ozone 

attainment plan, the emissions credit banking and trading program, and the discrete 

emission credit banking and trading program. For a more complete background on the 

one-hour ozone SIP revisions please refer to Chapter 1 of the eight-hour SIP revision 

that has been submitted for adoption concurrent with this rule package (Project Number 

2006-027-SIP-NR). 
The rulemaking subjects owners or operators of volatile organic compound (VOC) 

storage tanks, transport vessels, and marine vessels located in the HGB eight-hour 

ozone nonattainment area to more stringent control, monitoring, recordkeeping, and 

reporting requirements. The revised requirements have been developed to reduce VOC 

emissions that have previously been underreported in emissions inventories (EI). 

The first Texas Air Quality Study (TexAQS 2000) measured ambient VOC 

concentrations in the Houston Ship Channel to be in greater proportions to NOx 

emissions than what would be expected based on the reported point source emissions 

inventories. Therefore, when TCEQ and its research partners began TexAQS II in May 

2005, one of the study's primary goals was to identify VOC emission sources that have 

been historically unreported or underreported in the EI and could potentially be 

contributing to the discrepancy between measured ambient concentrations and reported 

point source emissions. 

TexAQS II remote sensing VOC project results indicate that certain types of storage 

tank emissions, including degassing, flash, and floating roof landing loss emissions, 

generally have been unreported in the EI. Recent data analysis, a floating roof landing 

loss emissions survey, and other TCEQ studies indicate that these unreported 

emissions could total several thousand tons per year (tpy); unreported or underreported 

floating roof landing loss emissions alone in the HGB area totaled approximately 7,250 

tons in 2003. The rulemaking will help reduce emissions from these sources as well as 

other sources of potentially unreported tank emissions, such as slotted guidepoles and 

other tank fittings. 

SECTION BY SECTION DISCUSSION 

Grammatical, style, and other non-substantive corrections are made throughout the 

rulemaking to be consistent with Texas Register requirements, to improve readability, 

and to conform to the drafting standards in the Texas Legislative Drafting Manual, 

August 2006. Such changes include appropriate and consistent use of acronyms, 

section references, and certain terminology such as "that" and "which" and "shall" and 

"must." These changes are not discussed further. 

Subchapter B, General Volatile Organic Compound Sources 

Division 1, Storage of Volatile Organic Compounds 
Adopted §115.110 adds ten definitions used in regulatory text. Adopted §115.110(3) 

defines Incompatible liquid as the term is used in §115.112(d)(2)(H)(ii). The definition is 

intended to allow tank landings when necessary for change of service to a material that 

would be contaminated by the previously stored material. For example, a change in 

service to gasoline with a lower Reid vapor pressure (RVP) that must be performed to 

comply with applicable fuel requirements is considered an incompatible liquid. The 

definition has been revised in response to comments to specify that different chemical 

mixtures and different grades of liquid material would also be considered incompatible 

liquids if the liquid being introduced into the tank would be made unusable for its 

intended purpose due to contamination from the previously stored liquid. Adopted 

§115.110(10) defines Tank battery as the term is used in §115.112(d)(4) and (d)(5). In 

response to comments, the definition has been modified to clarify that a collection of 

tanks at a pipeline breakout station, petroleum refinery, or petrochemical plant is not 

considered to be a tank battery. In response to comments, definitions have been added 

for the terms deck cover, pole float, pole sleeve, pole wiper, slotted guidepole, internal 

sleeve emission control system, and flexible enclosure system. These definitions have 

been added to clarify additional options for controlling emissions from slotted guidepoles 

that have been incorporated into §115.112(d)(2)(G). The commission has also added a 

definition for pipeline breakout station because the term is used in clarifying the 

applicability of requirements for control of flash emissions in §115.112(d)(4) and (5). 

Adopted changes to §115.112 amend §115.112(a) to specify that the existing 

requirements apply to the HGB area until January 1, 2009. Adopted changes also add 

subsection (d) to specify additional requirements for storage vessels in the HGB area 

that will take effect on January 1, 2009. In response to comment, the phrase "beginning 

January 1, 2009," has been added to clarify when the new requirements take effect. 

Adopted §115.112(d)(1) specifies the tank size and vapor pressure criteria that 

determine control requirements for tanks. These are the same criteria and control 

requirements that are now effective in the HGB area. These requirements are being 

moved to subsection (d) to be at the same location as new provisions that will apply to 

tanks in the HGB area. 

Adopted §115.112(d)(2) changes the control requirements for tank fittings. In response 

to comments, rule language has been changed to be more consistent with language in 

the EPA regulations in 40 CFR Part 63, Subpart WW, National Emission Standards for 

Storage Vessels (Tanks) Control Level 2. 

The proposed requirement in §115.112(d)(2)(A) that all openings in an internal or 

external floating roof except for automatic bleeder vents, rim space vents, and roof 

drains must provide a projection below the liquid surface and be equipped with a cover, 

seal, or lid has been modified. The requirements for all openings except automatic 

bleeder vents (vacuum breaker vents) and rim space vents to provide a projection 
below the liquid surface is separate from the requirement for all openings except 

automatic bleeder vents (vacuum breaker vents), rim space vents, leg sleeves, and roof 

drains to be equipped with a cover. The proposed wording would have incorrectly 

required the use of covers on fixed roof support columns. The proposed wording that 

the cover, seal, or lid must be equipped with a working gasket and kept in a closed 

position (with no visible gaps) at all times except when the opening is in actual use has 

been revised in response to comments to specify that required deck covers must be 

closed (with no gap of more than 1/8 inch) at all time, except when they must be opened 

for access. 

Adopted §115.112(d)(2)(B) specifies that automatic bleeder vents (also known as 

vacuum breaker vents) and rim space vents must be equipped with a gasketed lid, 

pallet, flapper, or other closure device and must be closed at all times except when 

required to be open to relieve excess pressure or vacuum, in accordance with the 

manufacturer's design. The current rule requires only that the automatic bleeder vents 

and rim space vents be closed. In response to comments, the language has been 

changed to allow use of a gasketed lid, pallet, flapper, or other closure device instead of 

a working gasket. Also in response to comments, language allowing automatic bleeder 

vents to open in accordance with the manufacturer's design has been added. For 

convenience, the requirements for automatic bleeder vents and rim space vents have 

been combined in §115.112(d)(2)(B). 

Section 115.112(d)(2)(C) has been revised in response to comments to allow openings 

for fixed roof support columns to be equipped with flexible fabric sleeve seals instead of 

deck covers. Adopted §115.112(d)(2)(D) requires that any roof drain that empties into 

the stored liquid must be equipped with a slotted membrane fabric cover or equivalent 

control. The current rule specifies the use of the slotted membrane fabric cover; the 

adopted rule allows the use of other controls. EPA regulations allow controls other than 

slotted membrane fabric covers. Other controls can provide equivalent or superior 

emission reduction performance. Examples include weighted ball or ball in cage type 

controls. The adopted rule also specifies that the requirement does not apply to stub 

drains on internal floating roof tanks. Stub drains are found on internal floating roof 

tanks that have bolted decks. Their purpose is to allow stored liquid that collects on the 

roof to drain back into the tank. Covers or other controls on these stub drains would 

provide minimal, if any, reduction in VOC emissions. In response to comments, the 

phrase "no visible gap" has been changed to "no gap of more than 1/8 inch." 

Adopted §115.112(d)(2)(E) states that there must be no visible holes, tears, or other 

openings in any seal or seal fabric. Adopted §115.112(d)(2)(F) states that secondary 

seals on external floating roof tanks must be rim-mounted and specifies a maximum 

allowable area of gaps between the secondary seal and the tank wall. In response to 

comments, the phrase "with the exception of gaps that do not exceed the following 

specification" has been added to clarify that a limited gap area is allowed. 
Adopted §115.112(d)(2)(G) requires each slotted guidepole well to be controlled. The 

quantities of emissions reduced would depend on various factors including the tank size 

and material stored. As an example, a 100-foot diameter external floating roof tank with 

4,000,000-gallon capacity that stores gasoline with an RVP of 9 pounds per square inch 

absolute (psia) and has 25 turnovers per year with an uncontrolled slotted guidepole 

would emit 11.85 tpy VOC from the guidepole alone and 14 tpy total VOC from the tank. 

The same tank with a controlled slotted guidepole would have 4.5 tpy VOC from the 

guidepole alone and 6.6 tons tpy total VOC emissions. For this case, controlling the 

slotted guidepole would result in a 62% decrease in annual VOC emissions from the 

guidepole and a 53% decrease in total annual tank VOC emissions. In response to 

comments, the wording has been changed to allow additional control options for slotted 

guidepoles consistent with the EPA regulations for tanks in 40 CFR Part 63, Subpart 

WW, and the Storage Tank Emissions Reduction Partnership Program (STERPP). 

These additional controls include a pole wiper and a pole float, a pole wiper and a pole 

sleeve, an internal sleeve emission control system, retrofit to a solid guidepole system, 

a flexible enclosure system, and a cover over the external floating roof. Emission 

calculations using the EPA TANKS program indicate that emissions from a slotted 

guidepole in a tank storing gasoline with an RVP of 10 psia could be reduced from 13.5 

tpy down to 0.2 tpy by installing a cover over the roof. The language in 

§115.112(d)(2)(G) has also been revised to qualify that the controls for slotted 

guidepoles are only required for external floating roof tanks. Based on the emission 

calculations, emissions from slotted guidepoles in internal floating roof tanks or domed 

external floating roof tanks would be equivalent to emissions expected by installing 

slotted guidepole controls on external floating roof tanks. 

Adopted §115.112(d)(2)(H) specifies that a floating roof must be kept floating on the 

liquid surface at all times except when it must be supported by leg supports during initial 

fill and other limited circumstances. Instances when the roof is supported by its legs are 

referred to as "landings." Adopted §115.112(d)(2)(H) limits the circumstances under 

which tank landings are allowed to times when the landing is necessary either to carry 

out inspections or maintenance, or to support a change in service to a liquid that is 

incompatible with the previously stored liquid. Change in service to gasoline with a 

lower RVP that must be performed to comply with applicable fuel requirements is 

considered a change to a liquid that is incompatible with the previously stored liquid and 

would be allowed. Different chemical mixtures and different grades of liquid material 

would also be considered incompatible liquids if the liquid being introduced into the tank 

would be made unusable for its intended purpose due to contamination from the 

previously stored liquid. Tank landings for the purposes of inventory control (also known 

as convenience landings) would not be allowed unless vapors are routed to a control 

device during the time that the roof is landed, or landing emissions are within an 

emissions limit or cap established under a 30 TAC Chapter 116 permit. Convenience 

landings would also be allowed if sitewide landing emissions are less than 25 tpy. 

Emissions from tank landings are higher than those that would occur while the roof is 
floating and have generally not been included in EI. A recent survey by the Air Quality 

Division's Industrial Emissions Assessment Section indicates that an additional 7,250 

tons from tank landings should have been reported in 2003. The adopted rule helps to 

reduce these previously unreported emissions. Storage tanks with a capacity less than 

25,000 gallons and those storing material with a vapor pressure less than 1.5 psia are 

not subject to the control requirements because such tanks are not required to be 

equipped with floating roofs. As an alternative to the adopted requirements of 

§115.112(d)(2)(H)(i) - (iv), §115.112(d)(2)(H)(v) provides a compliance option where a 

floating roof storage tank emissions limit or cap could be established in permits issued 

under 30 TAC Chapter 116 to control floating roof tank landing emissions along with 

standing and working loss emissions from the tank. The commission has recently 

established enforceable storage tank emission caps with several independent, for-hire 

petroleum and bulk liquid terminals in the HGB region and will allow operation under 

these caps to demonstrate compliance with the rules for reducing emissions from tank 

landings. The emission limits or caps enable these terminals to reduce landing 

emissions through a combination of measures, including operational roof landing 

restrictions where feasible, lowering of leg position to minimize vapor space, restricting 

landed tank refill rates, degassing with controls following landings, and new and 

emerging control techniques. In response to comments, the proposed restriction 

specifying the cap could not include any increase in emissions due to tank landings that 

would otherwise be prohibited under §115.112(d)(2)(H)(i) - (iv) has been deleted. Also 

in response to comments, §115.112(d)(2)(H)(vi) has been added to allow facilities with 

sitewide landing emissions less than 25 tpy to be exempt from the restrictions on tank 

landings. The meaning of "initial fill" in §115.112(d)(2)(H) has been clarified in response 

to comments to indicate that refilling a tank that has been emptied, degassed, and 

cleaned according to the provisions of Chapter 115, Subchapter F, Division 3, is 

allowed. The word "required" has been deleted from §115.112(d)(2)(H)(i) in response to 

comments to clarify that landings are allowed for maintenance performed according to 

company or site maintenance plans and not just in response to regulatory requirements. 

The wording in §115.112(d)(2)(H)(ii) has been revised in response to comments to use 

the term "incompatible liquid" in §115.110. Also in response to comments, 

§115.112(d)(2)(H)(iv) has been changed to require control of VOC emissions until the 

roof is within 10% by volume of being refloated, instead of until the roof is completely 

refloated. Commenters expressed concern that requiring control until the roof was 

completely refloated could result in liquids being drawn into the control device and 

causing damage. 

Adopted §115.112(d)(3) specifies that vapor recovery systems used as a control device 

must maintain a minimum control efficiency of 90%. This is the same requirement that 

currently applies. 

Adopted §115.112(d)(4) specifies that flash emissions from condensate storage tanks 

must be controlled if condensate throughput for an individual tank or the collection of 

tanks in a tank battery prior to custody transfer is greater than 1,500 barrels (63,000 
gallons) per year, unless the owner or operator demonstrates that the emissions from 

the individual tank or the collection of tanks in the tank battery are less than 25 tpy. 

Adopted §115.112(d)(5) specifies that flash emissions from crude oil or condensate 

storage tanks must be controlled if uncontrolled VOC emissions from an individual tank 

at an upstream oil or gas production site or a midstream pipeline breakout station, or 

collectively from a tank battery at an upstream oil or gas production site, would be 

greater than 25 tpy. This limit was proposed as §115.112(d)(4). The throughput limit for 

condensate was added to the adopted rule as §115.112(d)(4) for ease of enforcement. 

Using default emission factors described later in this preamble, a throughput of 1,500 

barrels per year of condensate would be expected to have 25 tpy of VOC emissions. If 

an owner or operator can demonstrate that a condensate tank with throughput greater 

than 1,500 barrels per year would have emissions less than 25 tpy, the tank would not 

be subject to the flash emission controls, as allowed under the new exemption in 

§115.117(a)(9). Crude oil and condensate typically contain dissolved gases that flash as 

the pressure on the liquid is reduced. For example, flashing occurs when the liquids are 

routed from a separator or other pressurized vessel to an atmospheric storage tank. 

The flashed gases may contain VOC in addition to methane and ethane, and may also 

entrain VOC from the stored liquid. In many cases, these gases can be economically 

routed to a vapor recovery device so that the energy content can be recovered for use 

at the production site or the gas can be compressed and routed to the sales line. If the 

volume of gas is sufficient, the capital cost for these vapor recovery devices can be 

repaid in a short time because of the high economic value of the recovered gas. The 25 

tpy threshold for control was chosen because it defines the major source level for 

severe nonattainment areas. The HGB area was classified as severe under the onehour ozone standard before the one-hour standard was replaced with the eight-hour 

standard. The adopted 25 tpy threshold also represents the maximum emission rate 

that a site would be authorized to operate under a permit by rule (PBR). The 25 tpy 

threshold applies to an individual tank or to an aggregation of tanks in a tank battery at 

an oil and gas exploration and production site. Because flash emissions could occur 

from any of the connected tanks, the adopted rule requires that the total emissions from 

all connected tanks be considered in determining whether the 25 tpy threshold is met. In 

response to comments, the commission has specified that the requirements for 

controlling flash emissions apply only to tanks and tank batteries storing crude oil and 

condensate prior to custody transfer at exploration and production sites and to individual 

tanks at midstream pipeline breakout stations. Crude oil and condensate stored at 

downstream sites such as pipeline terminals, refineries, or petrochemical plants may be 

a source of flash emissions, but in response to comments, the commission has decided 

not to subject these downstream sites to the new rule at this time because the test data 

and test methods in support of the rule were designed to be used at oil and gas 

production sites. The commission will continue to evaluate the extent of flash emissions 

at downstream sites and may regulate such emissions in the future. The adopted rule 

gives several options for estimating the uncontrolled flash emissions. The methods are 

based on estimating an emission factor in terms of pounds of VOC emitted per barrel 

(lb/bbl) of crude oil or condensate produced. Railroad Commission regulations in 16 

TAC §3.58(b) require producers to file a monthly report of the amount of oil, casing 

head gas, natural gas, and condensate produced during the month. Owners or 
operators can use these production records for the previous 12 months (rolling) along 

with the emission factor to estimate the total VOC emissions. The emission factor can 

be determined by direct measurement of the gas over a 24-hour period. Gas volume 

can be measured by manifolding all of the tanks together and using a device such as a 

mass flow meter or positive displacement meter. A sample of the gas can be analyzed 

using Gas Processors Association Method 2286, Tentative Method of Extended 

Analysis for Natural Gas and Similar Mixtures by Temperature Programmed Gas 

Chromatography, or accepted EPA methods to measure the composition of the flashed 

vapors. These measurements can be used to calculate the pounds of VOC emitted over 

the 24-hour measurement period. The pounds of VOC can then be divided by the oil or 

condensate production rate in barrels to determine the emission rate in pounds of VOC 

per barrel. Instead of making direct measurements, the owner or operator can use 

default emission factors of 33.3 lb/bbl of condensate or 1.6 lb/bbl of crude. These 

factors were determined in a study titled VOC Emissions from Oil and Condensate 

Storage Tanks. This study, conducted in 2006, was sponsored by the TCEQ and the 

Houston Advanced Research Center (HARC) and is identified as project H51C. For 

crude oil, owners or operators can use a chart found as Exhibit 2 of the EPA publication 

Lessons Learned from Natural Gas STAR Partners: Installing Vapor Recovery Units on 

Crude Oil Storage Tanks, October 2003, to estimate the volume of flash gas per barrel 

of oil. The VOC mass emission rate can then be determined by assuming that the 

hydrocarbon vapors have a molecular weight of 34 pounds per pound mole and are 

48% by weight VOC. These values came from the HARC H51C study. Finally, the 

owner or operator can use a computer simulation or other method approved by the 

executive director to estimate flash emissions. These options are specified to minimize 

the burden on owners and operators to make direct measurements or complex 

calculations. If the regulated entity chooses to make direct measurements and they 

yield emission rates that are higher than those determined by the default emission 

factors, EPA chart, or simulation, or if computer simulation yields results higher than the 

default emission factors or chart, the higher rates must be used. In response to 

comments, rule language has been added to §115.112(d)(5) to specify that the higher 

rates must be used. The proposed rule only noted this restriction in the preamble. The 

commission has deleted the proposed §115.112(d)(4)(E) and combined the option to 

use a computer simulation with the option to use another method approved by the 

executive director. This language was previously in §115.112(d)(4)(F). The accuracy of 

computer simulations is entirely dependent on the accuracy of the inputs and the use of 

appropriate model parameters. Regulated entities will still have the option to use a 

computer simulation to estimate flash emissions, but the use must be pre-approved by 

the executive director to ensure that the results are accurate. Staff of the Industrial 

Emissions Assessment Section who review such calculations for EI reporting will review 

the simulation use. 

Nothing in the adopted rule implies authorization of flash emissions. All emissions must 

be authorized according to a permit or other authorization under 30 TAC Chapters 106 

or 116. The adopted rule regulates flash emissions from crude oil and condensate 

storage at oil or gas production sites and pipeline terminals. Flash emissions may also 
occur at storage terminals, refineries, and petrochemical plants, and crude oil and 

condensate are not the only sources of flash emissions. Processes in petroleum 

refineries and chemical plants can generate liquids containing dissolved gases that will 

flash when the liquid is routed from higher pressure equipment to an atmospheric 

storage tank. Although flash emissions from these other liquids are not regulated under 

the adopted rule, the commission is not implying that these emissions are authorized. 

Methods specified in the EPA Compilation of Air Pollutant Emission Factors (AP-42) to 

calculate emissions from storage tanks do not include emissions from flash. Unless 

these flash emissions have been separately estimated and included in best available 

control technology (BACT) and health effects reviews during permitting, the emissions 

are not authorized even if they are not expressly prohibited by regulation in Chapter 

115. 

Adopted §115.115(c) specifies appropriate measuring instruments and test methods for 

determining flash emissions if the owner or operator chooses to demonstrate 

compliance with the 25 tpy limit by direct measurement. The use of a mass flow meter, 

positive displacement meter, or similar device must be used for determining flash gas 

flow rate. Conventional pitot tube or orifice plate techniques may not be appropriate for 

the relatively low flow rates from oil and condensate storage tanks. Flow measurements 

must be made over a 24-hour period representative of normal operation to make sure 

that the measurements capture emissions during a typical working cycle including 

pumping into and out of the tanks. The language in §115.115(c) has been changed to 

specify that at oil and gas production sites, flow measurements must be made while the 

producing wells are operational. The proposed rule listed this requirement, but the 

adopted language has been changed to clarify that it applies to measurements made at 

oil and gas production sites and not to measurements made at pipeline breakout 

stations that could be at some distance from the producing wells. Gas composition must 

be determined using Gas Processors Association Method 2286, Tentative Method of 

Extended Analysis for Natural Gas and Similar Mixtures by Temperature Programmed 

Gas Chromatography, or approved EPA test methods. The listed test methods have 

been changed since proposal to include standard EPA test methods for the 

determination of VOC composition in addition to the Gas Processors Association 

Method 2286. 

In response to comments, the term "reportable emissions" in §115.116(a) has been 

replaced with the term "emissions inventory reportable emissions" to avoid confusion 

with the use of the term "reportable emissions" as used in the general air quality rules in 

30 TAC Chapter 101. 

Adopted §115.116(c)(1) specifies that owners or operators of storage tanks that are not 

required to be equipped with a floating roof or vapor recovery system because the vapor 

pressure of the stored material is less than 1.5 psia shall keep records of the material 

stored and the vapor pressure. These records are necessary to document that material 
stored in fixed roof tanks meets the criteria for exemption from control requirements. In 

response to comments, the wording "length of time material is stored" has been 

replaced with the more precise wording "starting and ending dates when the material is 

stored." Commenters had expressed confusion over the meaning of the phrase. 

Adopted §115.116(c)(2) specifies that owners or operators of crude oil or condensate 

storage tanks with flash emissions shall keep records to verify that emissions from 

these tanks are below the 25 tpy criteria for exemption from control requirements. 

Records must be sufficient to allow investigators to determine whether flash emissions 

have been calculated by an appropriate method. If a computer simulation is used, 

records of the input and output must be retained. In response to comments, the wording 

has been changed to clarify that the requirements apply only to tanks or tank batteries 

at exploration and production sites or to tanks at pipeline breakout stations. Also in 

response to comments, the requirement to project emissions for the next year upon 

request has been deleted. 

The adopted amendment to §115.117(a)(2) specifies that in the HGB area, the storage 

of crude oil and condensate prior to custody transfer in tanks with capacity less than 

210,000 gallons will no longer be exempt from the control requirements of Subchapter 

B, Division 1 after January 1, 2009. The VOC emissions from such tanks at oil and gas 

production sites (especially emissions arising from flashed gases) have been found to 

be a significant source of VOC emissions and have previously not been reported. 

A new exemption §115.117(a)(9) has been added to specify that if an owner or operator 

can demonstrate that a condensate tank with throughput greater than 1,500 barrels per 

year would have emissions less than 25 tpy, then the tank would not be subject to the 

flash emission controls in §115.112(d)(4). 

Adopted §115.119(c) specifies that compliance with the requirements of §§115.112(d), 

115.115(c), and 115.116(c) must occur by January 1, 2009, as part of the effort to 

address the eight-hour ozone standard for the HGB area. However, if compliance with 

the new requirements would necessitate emptying and degassing the tank, compliance 

would not be required until the next time the tank is emptied or degassed but not later 

than January 1, 2017. Additional emissions that would arise from emptying and 

degassing a tank could negate the benefit of the emission controls and so would not be 

required solely for the purpose of installing controls. Because tanks are generally taken 

out of service at least once every ten years, the controls must be installed no later than 

ten years from the date these rules are adopted. The delay in compliance would apply 

only to the installation of equipment; monitoring and recordkeeping requirements must 

be observed beginning January 1, 2009. Regulated entities that use the delay of 

compliance provision should be prepared to justify why tank emptying and degassing 

was necessary to comply with the rules. Tanks with a nominal capacity less than 
210,000 gallons (794,850 liters) storing crude oil and condensate prior to custody 

transfer that were previously exempt must comply by January 1, 2009. Since proposal, 

wording has been added to clarify that these tanks must comply by January 1, 2009, 

regardless if compliance would require emptying and degassing the tank. 

Subchapter F, Miscellaneous Industrial Sources 

Division 3, Degassing or Cleaning of Stationary, Marine, and Transport Vessels 

The adopted change to §115.541(a)(1) specifies that after January 1, 2009, the 

degassing control requirements will apply to storage tanks in the HGB area with a 

nominal capacity of 75,000 gallons or greater storing materials with a true vapor 

pressure greater than 2.6 psia or to storage tanks with a nominal capacity of 250,000 

gallons or more storing material with a true vapor pressure of 0.5 psia or greater. The 

current rule mandates degassing controls only to storage tanks with a nominal capacity 

of one million gallons or more. The EI database has records of more than 950 floating 

roof storage tanks with capacity between 75,000 and one million gallon capacity that 

could be required to employ vapor recovery during tank degassing under the adopted 

rule. There are also more than 3,000 fixed roof storage tanks in this size range, but an 

unknown number of these storage tanks store materials with a vapor pressure less than 

2.6 or 0.5 psia and will not be subject to the adopted degassing requirement. Degassing 

emissions from these smaller storage tanks can be abated with technology similar to 

that used for larger tanks. The size and vapor pressure criteria for determining which 

storage tanks are subject to the degassing control requirements were changed since 

proposal in response to comments and subsequent cost effectiveness calculations by 

staff. 

The adopted change to §115.542(a)(5) specifies that the current control requirements 

apply in the HGB area only until January 1, 2009. Adopted §115.542(a)(6) specifies new 

criteria for control of degassing vapors from storage tanks and transport vessels in the 

HGB area. The change requires that vapors be vented to a control device until the VOC 

concentration of the vapors is reduced to less than 34,000 ppm by volume (ppmv) as 

methane or to less than 50% of the lower explosive limit (LEL). The current rules specify 

the 34,000 ppmv concentration as one criterion for determining when vapors can be 

vented to the atmosphere but also allow venting after a turnover of four vapor space 

volumes has occurred. If the storage tanks are drained dry and if the flow of 

displacement gases is measured properly, four turnovers would generally be sufficient 

to reduce VOC concentrations to less than 34,000 ppmv. If liquid remains in the bottom 

of the storage tank or transport vessel, as commonly occurs due to irregularities in the 

vessel surface, the remaining liquid would continue to be a source of VOC emissions 

after the four turnover criterion has been satisfied. The adopted rules remove the option 

to vent to atmosphere after a turnover of four vapor space volumes has occurred. 
Dilution from ventilation gas used to sweep the vapor space within the vessel could also 

cause a reading of 34,000 ppmv VOC to be reached temporarily, but if liquid remains in 

the storage tank the concentration could again rise when the flow of ventilation gas 

ceases. The adopted revision requires continued control of the vapors until the VOC 

concentration decreases to below 34,000 ppmv or a reading of less than 50% is 

obtained on an LEL meter. The concentration must be rechecked periodically while the 

tank is vented to the atmosphere to ensure that it remains below 34,000 ppmv or 50% 

LEL. If ventilation is continuous, the concentration must be measured at least once 

every 12 hours. If ventilation ceases for more than four hours, the concentration must 

be rechecked before the tank is reopened. The 50% LEL criterion was added in 

response to comments. The VOC concentration equivalent to 50% LEL is less than 

34,000 ppmv and therefore is an acceptable criterion to determine when degassing 

vapors can be emitted to atmosphere. Also in response to comments, language has 

been added to specify that the concentration measurements are no longer required after 

five consecutive readings less than 34,000 ppmv or less than 50% LEL have been 

obtained. 

The adopted change to §115.542(b)(4) specifies that the stated control requirements 

apply in the HGB area only until January 1, 2009. Adopted §115.542(b)(5) specifies new 

criteria for control of degassing vapors from marine vessels in the HGB area. The 

change requires vapors to be vented to a control device until the VOC concentration of 

the vapors is reduced to less than 34,000 ppmv as methane or 50% LEL. The current 

rules specify this concentration as one criterion for determining when vapors may be 

vented to the atmosphere but also allow venting after a turnover of four vapor space 

volumes has occurred. The adopted rules remove the option to vent to atmosphere after 

a turnover of four vapor space volumes has occurred. This change is being adopted for 

degassing vapors from marine vessels for the same reasons discussed for the adopted 

§115.542(a)(6) for storage tanks and transport vessels. The 50% LEL criterion has been 

added to the rule because the commission has specified that an equivalent LEL 

percentage can be used to determine when degassing need no longer be controlled for 

storage tanks. The current rule in §115.542(b)(4) uses 20% of the LEL as one of the 

criteria for when marine vessels may be vented to the atmosphere. This requirement 

was not changed because it applies to sources in the Beaumont-Port Arthur area as 

well as (until January 1, 2009) sources in the HGB area. The revised §115.542(b)(5) 

specifies 50% of the LEL to be consistent with the value used in §115.542(a)(6) for 

storage tanks and transport vessels. Because the LEL criterion is an option to allow 

flexibility in measurement methods, using 50% instead of 20% in §115.142(b)(5) will not 

allow an increase in VOC emissions over those allowed under §115.542(b)(4). 

Adopted §115.545(11) specifies the methods that must be used to measure the VOC 

concentration of the storage vessels, transport vessels, or marine vessels to determine 

when the vapors can be vented to the atmosphere instead of to a control device. In 

response to comments, several additional analytical methods have been specified to 

allow flexibility for the concentration measurements. However, the large potential 
variability in chemical composition of stored liquids necessitates carefully selecting and 

implementing the analytical method according to the precise chemical and physical 

circumstances occurring at the time of the measurement. Thus, the commission 

requires that sufficient records and other information be maintained to show that the 

alternative method used completely meet the needs of the specific instance. Examples 

of such records are maintenance and calibration records of all equipment, training 

records of equipment operators, and a written sampling plan for each instance complete 

with data quality objectives and QA/QC measurement parameters. The measurement 

should be made at the head space of the vessel, as close as possible to the tank 

bottom to ensure that the concentration measurement is representative of actual 

conditions, but the measurements should be made at a safe location. 

Adopted §115.546(1)(D) specifies that records of the VOC concentration measurements 

required by §115.542(a)(6) and (b)(5) must be maintained. The records are necessary 

to document that degassing vapors are routed to a control device until they reach the 

criteria to be released to the atmosphere. 

A change to §115.547(2) is adopted to state that after January 1, 2009, storage tanks in 

the HGB area with a nominal capacity of less than one million gallons but greater than 

or equal to 250,000 gallons or with a nominal capacity of greater than or equal to 75,000 

gallons storing material with vapor pressure greater than 2.6 psia will no longer be 

exempt from the requirements to control degassing emissions. As discussed earlier in 

this preamble, degassing emissions from these smaller tanks can be controlled with 

technology similar to that used to control degassing emissions from the larger tanks. 

The commission revised the exemption level in response to public comments. 

The words "causes" and "prevents" are added to §115.547(4) so that the text more 

clearly expresses the intended meaning of the exemption. 

Adopted §115.549(d) specifies that compliance with the new and revised requirements 

must occur by January 1, 2009, as part of the effort to address the eight-hour ozone 

standard for the HGB area. 
Texas Commission on Environmental Quality Page 1 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER B: GENERAL VOLATILE ORGANIC COMPOUND SOURCES 

DIVISION 1: STORAGE OF VOLATILE ORGANIC COMPOUNDS 

§§115.110, 115.112 - 115.117, 115.119 

Effective June 14, 2007

§115.110. Definitions. 

The following words and terms, when used in this division (relating to Storage of Volatile 

Organic Compounds), have the following meanings, unless the context clearly indicates otherwise. 

Additional definitions for terms used in this division are found in §§3.2, 101.1, and 115.10 of this title 

(relating to Definitions). 

(1) Deck cover--A device that covers an opening in a floating roof deck. Some deck 

covers move horizontally relative to the deck (i.e., a sliding cover). 

(2) Flexible enclosure system--A system that includes all of the following: a flexible 

device that completely encloses the slotted guidepole and eliminates the hydrocarbon vapor emission 

pathway from inside the tank through the guidepole slots to the outside air; a guidepole cover at the top 

of the guidepole; and a well cover positioned at the top of the guidepole well that seals any openings 

between the well cover and the guidepole (e.g. pole wiper), any openings between the well cover and 

any other objects that pass through the well cover, and any other openings in the top of the guidepole 

well. 

(3) Incompatible liquid--A liquid that is a different chemical compound, a different 

chemical mixture, a different grade of liquid material, or a fuel with different regulatory specifications 

provided that the chemical compound, chemical mixture, grade of liquid material, or fuel would be 

unusable for its intended purpose due to contamination from the previously stored liquid. 

(4) Internal sleeve emission control system--An emissions control system that 

includes all of the following: an internal guidepole sleeve that eliminates the hydrocarbon vapor 

emission pathway from inside the tank through the guidepole slots to the outside air; a guidepole cover 

at the top of the guidepole; and a well cover positioned at the top of the guidepole well that seals any 

openings between the well cover and the guidepole (e.g. pole wiper), any openings between the well 

cover and any other objects that pass through the well cover, and any other openings in the top of the 

guidepole well. 

(5) Pipeline breakout station--A facility along a pipeline containing storage vessels 

used to relieve surges or receive and store crude oil or condensate from the pipeline for reinjection into 

the pipeline and continued transportation by pipeline or to other facilities. 

(6) Pole float--A float located inside a guidepole that floats on the surface of the stored 

liquid. The rim of the float has a wiper or seal that extends to the inner surface of the pole. 
Texas Commission on Environmental Quality Page 2 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(7) Pole sleeve--A device that extends from either the cover or the rim of an opening in 

a floating roof deck to the outer surface of a pole that passes through the opening. The sleeve extends 

into the stored liquid. 

(8) Pole wiper--A seal that extends from either the cover or the rim of an opening in a 

floating roof deck to the outer surface of a pole that passes through the opening. 

(9) Slotted guidepole--A guidepole or gaugepole that has slots or holes through the 

wall of the pole. The slots or holes allow the stored liquid to flow into the pole at liquid levels above 

the lowest operating level. 

(10) Tank battery--A collection of equipment used to separate, treat, store, and 

transfer crude oil, condensate, natural gas, and produced water. A tank battery typically receives crude 

oil, condensate, natural gas, or some combination of these extracted products from several production 

wells for accumulation and separation prior to transmission to a natural gas plant or petroleum refinery. 

A collection of storage tanks at a pipeline breakout station, petroleum refinery, or petrochemical plant 

is not considered to be a tank battery. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.112. Control Requirements. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and until January 

1, 2009, in the Houston/Galveston/Brazoria areas as defined in §115.10 of this title (relating to 

Definitions), the following requirements apply. 

(1) No person shall place, store, or hold in any stationary tank, reservoir, or other 

container any volatile organic compound (VOC) unless such container is capable of maintaining 

working pressure sufficient at all times to prevent any vapor or gas loss to the atmosphere, or is 

equipped with at least the control device specified in Table I(a) of this paragraph for VOC other than 

crude oil and condensate, or Table II(a) of this paragraph for crude oil and condensate. 

Table I(a) 

REQUIRED CONTROL FOR STORAGE TANKS FOR 

VOC OTHER THAN CRUDE OIL AND CONDENSATE 

True Vapor Pressure 

of Compound at Storage Conditions 

Nominal Storage 

Capacity 

Emission Control 

Requirements 

< 1.5 psia* (10.3 kPa*) Any None 

�1,000 gal* (3,785 L*) None 

> 1,000 gal (3,785 L) Submerged fill pipe 

and or 
Texas Commission on Environmental Quality Page 3 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

� 25,000 gal (94,635 L) vapor recovery system 

> 25,000 gal (94,635 L) 

and 

� 40,000 gal (151,416 L) 

Internal or external floating 

roof (any type) 

or 

vapor recovery system 

� 1.5 psia (10.3 kPa) 

and 

< 11 psia (75.8 kPa) 

> 40,000 gal (151,416 

L) 

Internal floating roof 

or 

External floating roof with 

primary seal (any type) and 

secondary seal 

or 

vapor recovery system 

� 1,000 gal (3,785 L) None 

> 1,000 gal (3,785 L) 

and 

� 25,000 gal (94,635 L) 

Submerged fill pipe 

or 

� 11 psia (75.8 kPa) vapor recovery system

> 25,000 gal (94,635 L) 

Submerged fill pipe 

and 

vapor recovery system 

*psia=pounds per square inch absolute, *kPa=kilo Pascals, *gal=gallon, *L=Liter 

Table II(a) 

REQUIRED CONTROL DEVICES FOR STORAGE TANKS FOR 

CRUDE OIL AND CONDENSATE 

True Vapor Pressure 

of Compound at Storage Conditions 

Nominal Storage 

Capacity 

Emission Control 

Requirements 

< 1.5 psia* (10.3 kPa*) Any None 

� 1,000 gal* (3,785 L*) None 

> 1,000 gal (3,785 L) 

and 

� 40,000 gal (151,416 L) 

Submerged fill pipe 

or 

vapor recovery system 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

� 1.5 psia (10.3 kPa) 

and 

< 11 psia (75.8 kPa) 

> 40,000 gal (151,416 L) 

Internal floating roof 

or 

External floating roof with 

primary seal (any type) and 

secondary seal 

or 

vapor recovery system 

� 1,000 gal (3,785 L) None 

> 1,000 gal (3,785 L) 

and 

� 40,000 gal (151,416 L) 

Submerged fill pipe 

or 

� 11 psia (75.8 kPa) vapor recovery system

> 40,000 gal (151,416 L) 

Submerged fill pipe 

and 

vapor recovery system 

*psia=Pounds per square inch absolute, *kPa=kilo Pascals, *gal=Gallon, *L=Liter 

(2) For floating roof storage tanks subject to the provisions of paragraph (1) of this 

subsection, the following requirements apply. 

(A) All openings in an internal or external floating roof except for automatic 

bleeder vents (vacuum breaker vents) and rim space vents must provide a projection below the liquid 

surface or be equipped with a cover, seal, or lid. Any cover, seal, or lid must be in a closed (i.e., no 

visible gap) position at all times except when the device is in actual use. 

(B) Automatic bleeder vents (vacuum breaker vents) must be closed at all times 

except when the roof is being floated off or landed on the roof leg supports. 

(C) Rim vents, if provided, must be set to open only when the roof is being 

floated off the roof leg supports or at the manufacturer's recommended setting. 

(D) Any roof drain that empties into the stored liquid must be equipped with a 

slotted membrane fabric cover that covers at least 90% of the area of the opening. 

(E) There must be no visible holes, tears, or other openings in any seal or seal 

fabric. 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(F) For external floating roof storage tanks, secondary seals must be the rimmounted type (the seal must be continuous from the floating roof to the tank wall). The accumulated 

area of gaps that exceed 1/8 inch (0.32 centimeter) in width between the secondary seal and tank wall 

must be no greater than 1.0 square inch per foot (21 square centimeters permeter) of tank diameter. 

(3) Vapor recovery systems used as a control device on any stationary tank, reservoir, 

or other container must maintain a minimum control efficiency of 90%. 

(b) For all persons in Gregg, Nueces, and Victoria Counties, the following requirements shall 

apply: 

(1) No person shall place, store, or hold in any stationary tank, reservoir, or other 

container any volatile organic compound (VOC), unless such container is capable of maintaining 

working pressure sufficient at all times to prevent any vapor or gas loss to the atmosphere, or is 

equipped with at least the control device specified in Table I(a) for VOC other than crude oil and 

condensate or Table II(a) for crude oil and condensate. 

(2) For floating roof storage tanks subject to the provisions of paragraph (1) of this 

subsection, the following requirements shall apply 

. 

(A) All openings in an internal or external floating roof, except for automatic 

bleeder vents (vacuum breaker vents) and rim space vents, must provide a projection below the liquid 

surface or be equipped with a cover, seal, or lid. Any cover, seal, or lid must be in a closed (i.e., no 

visible gap) position at all times, except when the device is in actual use. 

(B) Automatic bleeder vents (vacuum breaker vents) are to be closed at all 

times except when the roof is being floated off or landed on the roof leg supports. 

(C) Rim vents, if provided, are to be set to open only when the roof is being 

floated off the roof leg supports or at the manufacturer's recommended setting. 

(D) Any roof drain that empties into the stored liquid shall be equipped with a 

slotted membrane fabric cover that covers at least 90% of the area of the opening. 

(E) There shall be no visible holes, tears, or other openings in any seal or seal 

fabric. 

(F) For external floating roof storage tanks, secondary seals shall be the rimmounted type (the seal shall be continuous from the floating roof to the tank wall). The accumulated 

area of gaps that exceed 1/8 inch (0.32 centimeter) in width between the secondary seal and tank wall 

shall be no greater than 1.0 square inch per foot (21 square centimeters/meter) of tank diameter. 

(c) For all persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

the following requirements shall apply. 

(1) No person may place, store, or hold in any stationary tank, reservoir, or other 

container any VOC, other than crude oil or condensate, unless such container is capable of maintaining 

working pressure sufficient at all times to prevent any vapor or gas loss to the atmosphere, or is 

designed and equipped with at least the control device specified in Table I(b) for VOC other than crude 

oil and condensate. 

Table I(b) 

REQUIRED CONTROL DEVICES FOR STORAGE TANKS FOR 

VOC OTHER THAN CRUDE OIL AND CONDENSATE 

True Vapor Pressure 

of Compound at Storage Conditions 

Nominal Storage 

Capacity 

Emission Control 

Requirements 

< 1.5 psia (10.3 kPa) Any None 

� 1,000 gal (3,785 L*) None 

> 1,000 gal (3,785 L) None 

> 1,000 gal (3,785 L) 

and 

� 25,000 gal (94,635 L) 

Submerged fill pipe 

or 

vapor recovery system 

� 1.5 psia (10.3 kPa) 

and 

< 11 psia (75.8 kPa) 

> 25,000 gal (94,635 L) 

Internal or external floating 

roof (any type) 

or 

vapor recovery system 

� 1,000 gal (3,785 L) None 

> 1,000 gal (3,785 L) 

and 

� 25,000 gal (94,635 L) 

Submerged fill pipe 

or 

� 11 psia (75.8 kPa) vapor recovery system

> 25,000 gal (94,635 L) 

Submerged fill pipe 

and 

vapor recovery system 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

*L=Liter 

(2) For floating roof storage tanks subject to the provisions of paragraph (1) of this 

subsection, the following requirements shall apply. 

(A) There shall be no visible holes, tears, or other openings in any seal or seal 

fabric. 

(B) All tank gauging and sampling devices shall be vapor-tight except when 

gauging and sampling is taking place. 

(3) No person in Matagorda or San Patricio Counties shall place, store, or hold crude 

oil or condensate in any stationary tank, reservoir, or other container, unless such tank, reservoir, or 

other container is a pressure tank capable of maintaining working pressures sufficient at all times to 

prevent vapor or gas loss to the atmosphere or is equipped with one of the following vapor-loss control 

devices, properly maintained and operated: 

(A) an internal floating cover or external floating roof as defined in §115.10 of 

this title (relating to Definitions). This control equipment shall not be permitted if the VOC has a true 

vapor pressure of 11.0 psia (75.8 kPa) or greater. All tank-gauging and tank-sampling devices shall be 

vapor-tight, except when gauging or sampling is taking place; or 

(B) a vapor recovery system as defined in §115.10 of this title (relating to 

Definitions). 

(d) For all persons in the Houston/Galveston/Brazoria area the following requirements apply 

beginning January 1, 2009. 

(1) No person shall place, store, or hold in any stationary tank, reservoir, or other 

container any VOC unless such container is capable of maintaining working pressure sufficient at all 

times to prevent any vapor or gas loss to the atmosphere, or is equipped with at least the control device 

specified in either Table I(a) of subsection (a)(1) of this section for VOC other than crude oil and 

condensate, or Table II(a) of subsection (a)(1) of this section for crude oil and condensate. 

(2) For floating roof storage tanks subject to the provisions of paragraph (1) of this 

subsection, the following requirements apply. 

(A) All openings in an internal floating cover or external floating roof as 

defined in §115.10 of this title (relating to Definitions) except for automatic bleeder vents (vacuum 

breaker vents), and rim space vents must provide a projection below the liquid surface. All openings in 

an internal floating cover or external floating roof except for automatic bleeder vents (vacuum breaker 

vents), rim space vents, leg sleeves, and roof drains must be equipped with a deck cover. The deck 

cover must be equipped with a gasket in good operating condition between the cover and the deck. The 
Texas Commission on Environmental Quality Page 8 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

deck cover must be closed (i.e. no gap of more than 1/8 inch) at all times, except when the cover must 

be open for access. 

(B) Automatic bleeder vents (vacuum breaker vents) and rim space vents must 

be equipped with a gasketed lid, pallet, flapper, or other closure device and must be closed (i.e. no gap 

of more than 1/8 inch) at all times except when required to be open to relieve excess pressure or 

vacuum, in accordance with the manufacturer’s design. 

(C) Each opening into the internal floating cover for a fixed roof support 

column may be equipped with a flexible fabric sleeve seal instead of a deck cover. 

(D) Any roof drain that empties into the stored liquid must be equipped with a 

slotted membrane fabric cover that covers at least 90% of the area of the opening or an equivalent 

control that must be kept in a closed (i.e., no gap of more than 1/8 inch) position at all times except 

when the drain is in actual use . Stub drains on internal floating roof tanks are not subject to this 

requirement. 

(E) There must be no visible holes, tears, or other openings in any seal or seal 

fabric. 

(F) For external floating roof storage tanks, secondary seals must be the rimmounted type (the seal must be continuous from the floating roof to the tank wall with the exception of 

gaps that do not exceed the following specification). The accumulated area of gaps that exceed 1/8 inch 

(0.32 centimeter) in width between the secondary seal and tank wall must be no greater than 1.0 square 

inch per foot (21 square centimeters per meter) of tank diameter. 

(G) Each opening for a slotted guidepole in an external floating roof tank must 

be equipped with one of the control device configurations specified in clauses (i) - (vi) of this 

subparagraph. 

(i) A pole wiper and a pole float. The wiper or seal of the pole float 

must be at or above the height of the pole wiper. 

(ii) A pole wiper and a pole sleeve. 

(iii) An internal sleeve emission control system. 

(iv) Retrofit to a solid guidepole system. 

(v) A flexible enclosure system. 

(vi) A cover on an external floating roof tank 

. 

(H) The floating roof must be floating on the liquid surface at all times except 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

when the floating roof is supported by the leg supports or other support devices (e.g., hangers from the 

fixed roof) during the initial fill (including refill after the tank has been degassed and cleaned in 

accordance with §§115.541 – 115.547 of this title (relating to Degassing or Cleaning of Stationary, 

Marine, and Transport Vessels) or as allowed under the following circumstances: 

(i) when necessary for maintenance or inspection; 

(ii) when necessary for supporting a change in service to an 

incompatible liquid); 

(iii) when the storage tank has a capacity of less than 25,000 gallons or 

the vapor pressure of the material stored is less than 1.5 psia; 

(iv) when the vapors are routed to a control device from the time the 

floating roof is landed until the floating roof is within ten percent by volume of being refloated; 

(v) when all emissions from the tank, including emissions from roof 

landings, have been included in a floating roof storage tank emissions limit or cap approved under 

Chapter 116 of this title (relating to Control of Air Pollution by Permits for New Construction or 

Modification); or 

(vi) when all emissions from floating roof landings at the regulated 

entity as defined in §101.1 of this title (relating to Definitions) are less than 25 tons per year. 

(3) Vapor recovery systems used as a control device on any stationary tank, reservoir, 

or other container must maintain a minimum control efficiency of 90%. 

(4) Storage tanks storing condensate prior to custody transfer must route flashed gases 

to a vapor recovery system or control device if the liquid throughput through an individual tank or the 

aggregate of tanks in a tank battery exceeds 1,500 barrels (63,000 gallons) per year. 

(5) Storage tanks storing crude oil or condensate prior to custody transfer or at a 

pipeline breakout station must route flashed gases to a vapor recovery system or control device if the 

uncontrolled VOC emissions from an individual storage tank, or from the aggregate of tanks in a tank 

battery, have the potential to equal or exceed 25 tons per year on a rolling 12-month basis. 

Uncontrolled emissions must be estimated by one of the following methods; however, if emissions 

determined using direct measurements or other methods approved by the executive director under 

subparagraphs (A) or (D) of this paragraph are higher than emissions estimated using the default factors 

or charts in subparagraphs (B) or (C) of this paragraph, the higher values must be used: 

(A) direct measurement using the measuring instruments and methods 

specified in §115.115 of this title (relating to Approved Test Methods); 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(B) using a factor of 33.3 pounds of VOC per barrel (42 gallons) of condensate 

produced or 1.6 pounds of VOC per barrel (42 gallons) of oil produced; 

(C) for crude oil storage only, using the chart in Exhibit 2 of the United States 

Environmental Protection Agency publication Lessons Learned from Natural Gas STAR Partners: 

Installing Vapor Recovery Units on Crude Oil Storage Tanks, October 2003, and assuming that the 

hydrocarbon vapors have a molecular weight of 34 pounds per pound mole and are 48% by weight 

VOC; or 

(D) other test method or computer simulation approved by the executive 

director. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.113. Alternate Control Requirements. 

Alternate methods of demonstrating and documenting continuous compliance with the applicable 

control requirements or exemption criteria in this division (relating to Storage of Volatile Organic 

Compounds) may be approved by the executive director in accordance with §115.910 of this title 

(relating to Availability of Alternate Means of Control) if emission reductions are demonstrated to be 

substantially equivalent. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.114. Inspection Requirements. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas, the following inspection requirements apply. 

(1) For internal floating roof storage tanks, the internal floating roof and the primary 

seal or the secondary seal (if one is in service) must be visually inspected through a fixed roof 

inspection hatch at least once every 12 months. If the internal floating roof is not resting on the surface 

of the volatile organic compounds (VOC) inside the storage tank and is not resting on the leg supports; 

or liquid has accumulated on the internal floating roof; or the seal is detached; or there are holes or 

tears in the seal fabric; or there are visible gaps between the seal and the wall of the storage tank, 

within 60 days of the inspection the owner or operator shall repair the items or shall empty and degas 

the storage tank in accordance with §§115.541 - 115.547 of this title (relating to Degassing or Cleaning 

of Stationary, Marine, and Transport Vessels). If a failure cannot be repaired within 60 days and if the 

storage tank cannot be emptied within 60 days, the owner or operator may submit written requests for 

up to two extensions of up to 30 additional days each to the appropriate regional office. The owner or 

operator shall submit a copy to any local air pollution control program with jurisdiction. Each request 

for an extension must include a statement that alternate storage capacity is unavailable and a schedule 

that will assure that the repairs will be completed as soon as possible. 
Texas Commission on Environmental Quality Page 11 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(2) For external floating roof storage tanks, the secondary seal gap must be physically 

measured at least once every 12 months to insure compliance with §115.112(a)(2)(F) and 

§115.112(d)(2)(F) of this title (relating to Control Requirements). If the secondary seal gap exceeds the 

limitations specified by §115.112(a)(2)(F) or §115.112(d)(2)(F) of this title, within 60 days of the 

inspection the owner or operator shall repair the items or shall empty and degas the storage tank in 

accordance with §§115.541 - 115.547 of this title. If a failure cannot be repaired within 60 days and if 

the storage tank cannot be emptied within 60 days, the owner or operator may submit written requests 

for up to two extensions of up to 30 additional days each to the appropriate regional office. The owner 

or operator shall submit a copy to any local air pollution control program with jurisdiction. Each 

request for an extension must include a statement that alternate storage capacity is unavailable and a 

schedule that will assure that the repairs will be completed as soon as possible. 

(3) If the tank is equipped with a mechanical shoe or liquid-mounted primary seal, 

compliance with §115.112(a)(2)(F) and §115.112(d)(2)(F) of this title can be determined by visual 

inspection. 

(4) For external floating roof storage tanks, the secondary seal must be visually 

inspected at least once every six months to ensure compliance with §115.112(a)(2)(E) and (F) and 

§115.112(d)(2)(E) and (F) of this title. If the external floating roof is not resting on the surface of the 

VOC inside the storage tank and is not resting on the leg supports; or liquid has accumulated on the 

external floating roof; or the seal is detached; or there are holes or tears in the seal fabric; or there are 

visible gaps between the seal and the wall of the storage tank, within 60 days of the inspection the 

owner or operator shall repair the items or shall empty and degas the storage tank in accordance with 

§§115.541 - 115.547 of this title. If a failure cannot be repaired within 60 days and if the storage tank 

cannot be emptied within 60 days, the owner or operator may submit written requests for up to two 

extensions of up to 30 additional days each to the appropriate regional office. The owner or operator 

shall submit a copy to any local air pollution control program with jurisdiction. Each request for an 

extension must include a statement that alternate storage capacity is unavailable and a schedule that will 

assure that the repairs will be completed as soon as possible 

. 

(b) For all persons in Gregg, Nueces, and Victoria Counties, the following inspection 

requirements shall apply. 

(1) If during an inspection of an internal floating roof storage tank, the internal floating 

roof is not resting on the surface of the VOC inside the storage tank and is not resting on the leg 

supports; or liquid has accumulated on the internal floating roof; or the seal is detached; or there are 

holes or tears in the seal fabric; or there are visible gaps between the seal and the wall of the storage 

tank, within 60 days of the inspection the owner or operator shall repair the items or shall empty and 

degas the storage tank. If a failure cannot be repaired within 60 days and if the storage tank cannot be 

emptied within 60 days, the owner or operator may submit written requests for up to two extensions of 

up to 30 additional days each to the appropriate regional office. The owner or operator shall submit a 

copy to any local air pollution control program with jurisdiction. Each request for an extension shall 

include a statement that alternate storage capacity is unavailable and a schedule that will assure that the 

repairs will be completed as soon as possible. 
Texas Commission on Environmental Quality Page 12 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(2) For external floating roof storage tanks, the secondary seal gap shall be physically 

measured at least once every 12 months to insure compliance with §115.112(b)(2)(F) of this title. If the 

secondary seal gap exceeds the limitations specified by §115.112(b)(2)(F) of this title, within 60 days of 

the inspection the owner or operator shall repair the items or shall empty and degas the storage tank. If 

a failure cannot be repaired within 60 days and if the storage tank cannot be emptied within 60 days, the 

owner or operator may submit written requests for up to two extensions of up to 30 additional days each 

to the appropriate regional office. The owner or operator shall submit a copy to any local air pollution 

control program with jurisdiction. Each request for an extension shall include a statement that alternate 

storage capacity is unavailable and a schedule that will assure that the repairs will be completed as soon 

as possible. 

(3) If the tank is equipped with a mechanical shoe or liquid-mounted primary seal, 

compliance with §115.112(b)(2)(F) of this title can be determined by visual inspection. 

(4) For external floating roof storage tanks, the secondary seal shall be visually 

inspected at least once every 12 months to insure compliance with §115.112(b)(2)(E) - (F) of this title. 

If the external floating roof is not resting on the surface of the VOC inside the storage tank and is not 

resting on the leg supports; or liquid has accumulated on the external floating roof; or the seal is 

detached; or there are holes or tears in the seal fabric; or there are visible gaps between the seal and the 

wall of the storage tank, within 60 days of the inspection the owner or operator shall repair the items or 

shall empty and degas the storage tank. If a failure cannot be repaired within 60 days and if the storage 

tank cannot be emptied within 60 days, the owner or operator may submit written requests for up to two 

extensions of up to 30 additional days each to the appropriate regional office . The owner or operator 

shall submit a copy to any local air pollution control program with jurisdiction. Each request for an 

extension shall include a statement that alternate storage capacity is unavailable and a schedule that will 

assure that the repairs will be completed as soon as possible. 

(c) For all persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 

the following inspection requirements shall apply. 

(1) If during an inspection of an internal floating roof storage tank, the internal floating 

roof is not resting on the surface of the VOC inside the storage tank and is not resting on the leg 

supports; or liquid has accumulated on the internal floating roof; or the seal is detached; or there are 

holes or tears in the seal fabric; or there are visible gaps between the seal and the wall of the storage 

tank, within 60 days of the inspection the owner or operator shall repair the items or shall empty and 

degas the storage tank. If a failure cannot be repaired within 60 days and if the storage tank cannot be 

emptied within 60 days, the owner or operator may submit written requests for up to two extensions of 

up to 30 additional days each to the appropriate regional office. The owner or operator shall submit a 

copy to any local air pollution control program with jurisdiction. Each request for an extension shall 

include a statement that alternate storage capacity is unavailable and a schedule that will assure that the 

repairs will be completed as soon as possible. 

(2) If during an inspection of an external floating roof storage tank, the external 

floating roof is not resting on the surface of the VOC inside the storage tank and is not resting on the 
Texas Commission on Environmental Quality Page 13 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

leg supports; or liquid has accumulated on the external floating roof; or the seal is detached; or there 

are holes or tears in the seal fabric; or there are visible gaps between the seal and the wall of the 

storage tank, within 60 days of the inspection the owner or operator shall repair the items or shall 

empty and degas the storage tank. If a failure cannot be repaired within 60 days and if the storage tank 

cannot be emptied within 60 days, the owner or operator may submit written requests for up to two 

extensions of up to 30 additional days each to the appropriate regional office. The owner or operator 

shall submit a copy to any local air pollution control program with jurisdiction. Each request for an 

extension shall include a statement that alternate storage capacity is unavailable and a schedule that will 

assure that the repairs will be completed as soon as possible. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.115. Approved Test Methods. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas, compliance with §115.112(a) and (d) of this title (relating to Control 

Requirements) must be determined by applying the following test methods, as appropriate: 

(1) Test Methods 1-4 (40 Code of Federal Regulations (CFR) Part 60, Appendix A) for 

determining flow rates, as necessary; 

(2) Test Method 18 (40 CFR Part 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(3) Test Method 22 (40 CFR Part 60, Appendix A) for visual determination of fugitive 

emissions from material sources and smoke emissions from flares; 

(4) Test Method 25 (40 CFR Part 60, Appendix A) for determining total gaseous 

nonmethane organic emissions as carbon; 

(5) Test Methods 25A or 25B (40 CFR Part 60, Appendix A) for determining total 

gaseous organic concentrations using flame ionization or nondispersive infrared analysis; 

(6) test method described in 40 CFR §60.113a(a)(1)(ii) (effective April 8, 1987) for 

measurement of storage tank seal gap; 

(7) determination of true vapor pressure using American Society for Testing and 

Materials (ASTM) Test Methods D323-89, D2879, D4953, D5190, or D5191 for the measurement of 

Reid vapor pressure; or 

(8) minor modifications to these test methods approved by the executive director. 

(b) For Gregg, Nueces, and Victoria Counties, compliance with §115.112(b) of this title shall 

be determined by applying the following test methods, as appropriate: 
Texas Commission on Environmental Quality Page 14 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) Test Methods 1-4 (40 Code of Federal Regulations 60, Appendix A) for 

determining flow rates, as necessary; 

(2) Test Method 18 (40 Code of Federal Regulations 60, Appendix A) for determining 

gaseous organic compound emissions by gas chromatography; 

(3) Test Method 22 (40 Code of Federal Regulations 60, Appendix A) for visual 

determination of fugitive emissions from material sources and smoke emissions from flares; 

(4) Test Method 25 (40 Code of Federal Regulations 60, Appendix A) for determining 

total gaseous nonmethane organic emissions as carbon; 

(5) Test Methods 25A or 25B (40 Code of Federal Regulations 60, Appendix A) for 

determining total gaseous organic concentrations using flame ionization or nondispersive infrared 

analysis; 

(6) test method described in 40 CFR 60.113a(a)(1)(ii) (effective April 8, 1987) for 

measurement of storage tank seal gap; 

(7) determination of true vapor pressure using ASTM Test Methods D323-89, D2879, 

D4953, D5190, or D5191 for the measurement of Reid vapor pressure; or 

(8) minor modifications to these test methods approved by the executive director. 

(c) For the Houston/Galveston/Brazoria area, compliance with §115.112(d)(5) of this title may 

be determined by using the following measurement instruments or applying the following test methods, 

as appropriate: 

(1) mass flow meter, positive displacement meter, or similar device over a 24-hour 

period representative of normal operation for flow measurements of flash gases. For crude oil and 

natural gas production sites, the flow measurements must be made while the producing wells are 

operational; and 

(2) test methods referenced in subsection (a)(2), (4), and (5) of this section or Gas 

Processors Association Method 2286, Tentative Method of Extended Analysis for Natural Gas and 

Similar Mixtures by Temperature Programmed Gas Chromatography, to measure the concentration of 

VOC in the flashed gases; or 

(3) minor modifications to these test methods approved by the executive director. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.116. Monitoring and Recordkeeping Requirements. 
Texas Commission on Environmental Quality Page 15 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas, the following recordkeeping requirements apply. 

(1) The owner or operator of any storage vessel with an external floating roof that is 

exempted from the requirement for a secondary seal as specified in §115.117(a)(1), (6), and (7) of this 

title (relating to Exemptions) and is used to store volatile organic compounds (VOC) with a true vapor 

pressure greater than 1.0 pounds per square inch absolute (psia) (6.9 kilo Pascals (kPa)) at storage 

conditions shall maintain records of the type of VOC stored and the average monthly true vapor 

pressure of the stored liquid. 

(2) The results of inspections required by §115.114(a) of this title (relating to 

Inspection Requirements) must be recorded. For secondary seal gaps that are required to be physically 

measured during inspection, these records must include a calculation of emissions for all secondary seal 

gaps that exceed 1/8 inch (0.32 centimeter) where the accumulated area of such gaps is greater than 1.0 

square inch per foot (21 square centimeters per meter) of tank diameter. These calculated emissions 

inventory reportable emissions (Tr) must be reported in the annual emissions inventory submittal 

required by §101.10 of this title (relating to Emissions Inventory Requirements). The emissions must 

be calculated using the following methodology: 

(A) Allowable Seal Gap (greater than 1/8 inch wide): As (square inches) = 1 

square inch per tank diameter foot x tank diameter. 

(B) Measured Seal Gap: Ms (square inches). 

(C) Reportable Seal Gap Area: Rs = Ms - As in square inches. 

(D) Reportable Seal Gap/Allowable Ratio: RRs = Rs divided by As. 

(E) Tank Circumference: Tc (feet). 

(F) Reportable Seal Gap Length (total linear feet of seal gap greater than 1/8 

inch gap width): Rl. 

(G) Reportable Seal Gap Length/Tank Circumference Ratio: RRl = Rl/Tc. 

(H) Tank Emissions (with good single seal): Ts = Compilation of Air 

Pollutant Emission Factors (AP-42) Calculation (convert to pounds/day). 

(I) Tank Emissions (with two good seals): Tss = AP-42 Calculation (convert 

to pounds/day). Note: Use maximum local monthly average ambient temperature as reported by the 

National Weather Service to calculate true vapor pressure. 

(J) Emissions Inventory Reportable emissions: Tr (pounds) = (Ts - Tss) x 

RRs x RRl x 90 days. Note: In no case should Tr be greater than (Ts - Tss). 
Texas Commission on Environmental Quality Page 16 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(3) Affected persons shall install and maintain monitors to continuously measure and 

record operational parameters of any of the following emission control devices installed to meet 

applicable control requirements . Such records must be sufficient to demonstrate proper functioning of 

those devices to design specifications, including: 

(A) the exhaust gas temperature immediately downstream of a direct-flame 

incinerator; 

(B) the inlet and outlet gas temperature of a chiller or catalytic incinerator; and 

(C) the exhaust gas VOC concentration of any carbon adsorption system, as 

defined in §115.10 of this title (relating to Definitions), to determine if breakthrough has occurred. 

(4) The results of any testing conducted in accordance with the provisions specified in 

§115.115(a) of this title (relating to Approved Test Methods) must be maintained at an affected facility. 

(5) All records must be maintained for two years and be made available for review 

upon request by authorized representatives of the executive director, the United States Environmental 

Protection Agency (EPA), or local air pollution control agencies with jurisdiction. 

(b) For all persons in Gregg, Nueces, and Victoria Counties, the following recordkeeping 

requirements shall apply. 

(1) The owner or operator of any storage vessel with an external floating roof which is 

exempted from the requirement for a secondary seal as specified in §115.117(b)(1), (6), and (7) of this 

title and used to store VOC with a true vapor pressure greater than 1.0 psia (6.9 kPa) at storage 

conditions shall maintain records of the type of VOC stored and the average monthly true vapor 

pressure of the stored liquid. 

(2) The results of inspections required by §115.114(b) of this title shall be recorded. 

(3) In Victoria County, affected persons shall install and maintain monitors to 

continuously measure and record operational parameters of any of the following emission control 

devices installed to meet applicable control requirements. Such records must be sufficient to 

demonstrate proper functioning of those devices to design specifications, including: 

(A) the exhaust gas temperature immediately downstream of a direct-flame 

incinerator; 

(B) the inlet and outlet gas temperature of a chiller or catalytic incinerator; and 

(C) the exhaust gas VOC concentration of any carbon adsorption system, as 

defined in §115.10 of this title, to determine if breakthrough has occurred. 
Texas Commission on Environmental Quality Page 17 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(4) The results of any testing conducted in accordance with the provisions specified in 

§115.115(b) of this title shall be maintained at an affected facility. 

(5) All records shall be maintained for two years and be made available for review 

upon request by authorized representatives of the executive director, EPA, or local air pollution control 

agencies. 

(c) For all persons in the Houston/Galveston/Brazoria area, the following recordkeeping 

requirements apply in addition to those specified in subsection (a) of this section. 

(1) The owner or operator of any stationary tank, reservoir, or container with a fixed 

roof that is not required to be equipped with a floating roof or vapor recovery system, as specified in 

either Table I(a) or Table II(a) of §115.112(a)(1) of this title (relating to Control Requirements), shall 

maintain records of the type of VOC stored, the starting and ending dates when the material is stored, 

and the true vapor pressure at the average monthly storage temperature of the stored liquid. This 

requirement does not apply to storage tanks with nominal storage capacity of 25,000 gallons or less 

storing volatile organic liquids other than crude oil or condensate, or to storage tanks with nominal 

storage capacity of 40,000 gallons or less storing crude oil or condensate. 

(2) The owner or operator of any storage tank that stores crude oil or condensate prior 

to custody transfer or at a pipeline breakout station and is not equipped with vapor recovery shall 

maintain records of the estimated annual emissions from the storage tank to document that the 

uncontrolled emissions are less than 25 tons per year. The records must be updated annually and must 

be made available for review within 72 hours upon request by authorized representatives of the 

executive director, the EPA, or local air pollution control agencies with jurisdiction. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.117. Exemptions. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas, the following exemptions apply. 

(1) Except as provided in §115.116 of this title (relating to Monitoring and 

Recordkeeping Requirements), any volatile organic compound (VOC) with a true vapor pressure less 

than 1.5 pounds per square inch absolute (psia) (10.3 kilo Pascals (kPa)) at storage conditions is exempt 

from the requirements of this division (relating to Storage of Volatile Organic Compounds). 

(2) Crude oil and condensate stored in tanks with a nominal capacity less than 210,000 

gallons (794,850 liters), prior to custody transfer, is exempt from the requirements of this division. 

After January 1, 2009, this exemption no longer applies in the Houston/Galveston/Brazoria area. 

(3) Storage containers that have a capacity of less than 25,000 gallons (94,625 liters) 

located at motor vehicle fuel dispensing facilities are exempt from the requirements of this division. 
Texas Commission on Environmental Quality Page 18 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(4) A welded tank with a mechanical shoe primary seal that has a secondary seal from 

the top of the shoe seal to the tank wall (a shoe-mounted secondary seal) is exempt from the 

requirement for retrofitting with a rim-mounted secondary seal if the shoe-mounted secondary seal was 

installed or scheduled for installation before August 22, 1980. 

(5) External floating roof tanks storing waxy, high pour point crude oils are exempt 

from any secondary seal requirements of §115.112(a) of this title (relating to Control Requirements). 

(6) Any welded tank storing VOC having a true vapor pressure less than 4.0 psia (27.6 

kPa) is exempt from any external floating roof secondary seal requirement if any of the following types 

of primary seals have been installed before August 22, 1980: 

(A) a mechanical shoe seal; 

(B) a liquid-mounted foam seal; or 

(C) a liquid-mounted liquid filled type seal. 

(7) Any welded tank storing crude oil having a true vapor pressure equal to or greater 

than 4.0 psia (27.6 kPa) and less than 6.0 psia (41.4 kPa) at storage conditions is exempt from any 

external floating roof secondary seal requirement if any of the following types of primary seals have 

been installed before December 10, 1982: 

(A) a mechanical shoe seal; 

(B) a liquid-mounted foam seal; or 

(C) a liquid-mounted liquid filled type seal. 

(8) Storage containers that have a capacity of no more than 1,000 gallons are exempt 

from the requirements of this division. 

(9) Condensate storage tanks or tank batteries with a throughput exceeding 1,500 

barrels (63,000 gallons) per year are exempt from the requirement in §115.112(d)(4) of this title to 

route flashed gases to a vapor recovery system or control device if the owner or operator demonstrates 

using test methods specified in §115.115(c) of this title, that uncontrolled VOC emissions from the 

individual tank, or from the aggregate of storage tanks in a tank battery, are less than 25 tons per year 

on a rolling 12-month basis. 

(b) For all persons in Gregg, Nueces, and Victoria Counties, the following exemptions apply. 

(1) Except as provided in §115.116 of this title, any VOC with a true vapor pressure 

less than 1.5 psia (10.3 kPa) at storage conditions is exempt from the requirements of this division. 

(2) Crude oil and condensate stored in tanks with a nominal capacity less than 210,000 
Texas Commission on Environmental Quality Page 19 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

gallons (794,850 liters), prior to custody transfer, is exempt from the requirements of this division. 

(3) Storage containers which have a capacity of less than 25,000 gallons (94,625 liters) 

located at motor vehicle fuel dispensing facilities are exempt from the requirements of this division. 

(4) A welded tank with a mechanical shoe primary seal which has a secondary seal 

from the top of the shoe seal to the tank wall (a shoe-mounted secondary seal) is exempt from the 

requirement for retrofitting with a rim-mounted secondary seal if the shoe-mounted secondary seal was 

installed or scheduled for installation before August 22, 1980. 

(5) External floating roof tanks storing waxy, high pour point crude oils are exempt 

from any secondary seal requirements of §115.112(b) of this title. 

(6) Any welded tank storing VOC having a true vapor pressure less than 4.0 psia (27.6 

kPa) is exempt from any external secondary seal requirement if any of the following types of primary 

seals have been installed before August 22, 1980: 

(A) a mechanical shoe seal; 

(B) a liquid-mounted foam seal; or 

(C) a liquid-mounted liquid filled type seal. 

(7) Any welded tank storing crude oil having a true vapor pressure equal to or greater 

than 4.0 psia (27.6 kPa) and less than 6.0 psia (41.4 kPa) at storage conditions is exempt from any 

external secondary seal requirement if any of the following types of primary seals have been installed 

before December 10, 1982: 

(A) a mechanical shoe seal; 

(B) a liquid-mounted foam seal; or 

(C) a liquid-mounted liquid filled type seal. 

(8) Storage containers which have a capacity of no more than 1,000 gallons are exempt 

from the requirements of this division. 

(c) For all persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 

the following exemptions apply. 

(1) Any VOC with a true vapor pressure less than 1.5 psia (10.3 kPa) at storage 

conditions is exempt from the requirements of this division. 

(2) Slotted sampling and gauge pipes installed in any floating roof storage tank are 

exempt from the provisions of §115.112(c) of this title. 
Texas Commission on Environmental Quality Page 20 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(3) Storage tanks with nominal capacities between 1,000 gallons (3,785 liters) and 

25,000 gallons (94,625 liters) are exempt from the requirements of §115.112(c)(1) of this title if 

construction began before May 12, 1973. 

(4) Storage tanks with a nominal capacity of 420,000 gallons (1,589,700 liters) or less 

are exempt from the requirements of §115.112(c)(3) of this title 

. 

(5) Storage containers which have a capacity of no more than 1,000 gallons are exempt 

from the requirements of this division. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.119. Counties and Compliance Schedules. 

(a) The owner or operator of each stationary tank, reservoir, or other container in which any 

volatile organic compound (VOC) is placed, stored, or held in Brazoria, Chambers, Collin, Dallas, 

Denton, El Paso, Fort Bend, Galveston, Hardin, Harris, Jefferson, Liberty, Montgomery, Orange, 

Tarrant, and Waller Counties shall continue to comply with this division (relating to Storage of Volatile 

Organic Compounds) as required by §115.930 of this title (relating to Compliance Dates). 

(b) The owner or operator of each stationary tank, reservoir, or other container in which any 

VOC is placed, stored, or held in Ellis, Johnson, Kaufman, Parker, and Rockwall Counties shall 

comply with this division as soon as practicable, but no later than March 1, 2009. 

(c) The owner or operator of each stationary tank, reservoir, or other container in which any 

VOC is placed, stored, or held in Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, 

Montgomery, and Waller Counties shall comply with the requirements of §§115.112(d), 115.115(c), 

and 115.116(c) of this title (relating to Control Requirements; Approved Test Methods; and Monitoring 

and Recordkeeping Requirements) as soon as practicable, but no later than January 1, 2009. If 

compliance with these requirements would require emptying and degassing of the stationary tank, 

reservoir, or container, compliance is not required until the next time the stationary tank, reservoir, or 

container is emptied or degassed but no later than January 1, 2017. The owner or operator of each 

stationary tank, reservoir, or container with a nominal capacity less than 210,000 gallons (794,850 

liters) storing crude oil and condensate prior to custody transfer in Brazoria, Chambers, Fort Bend, 

Galveston, Harris, Liberty, Montgomery, and Waller Counties shall comply with the requirements of 

this division as soon as practicable but no later than January 1, 2009, regardless if compliance with 

these requirements would require emptying and degassing of the stationary tank, reservoir, or 

container. 

Adopted May 23, 2007 Effective June 14, 2007 
Texas Commission on Environmental Quality Page 21 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER B: GENERAL VOLATILE ORGANIC COMPOUND SOURCES 

DIVISION 2: VENT GAS CONTROL 

''115.120 - 115.123, 115.125 - 115.127, 115.129 

Effective December 7, 2006 

'115.120. Vent Gas Definitions. 

The following words and terms, when used in this division (relating to Vent Gas Control), shall 

have the following meanings, unless the context clearly indicates otherwise. Additional definitions for 

terms used in this division are found in ''3.2, 101.1, and 115.10 of this title (relating to Definitions). 

(1) Bakery oven - An oven for baking bread or any other yeast-leavened products. 

(2) Synthetic Organic Chemical Manufacturing Industry (SOCMI) batch 

distillation operation - A SOCMI noncontinuous distillation operation in which a discrete quantity or 

batch of liquid feed is charged into a distillation unit and distilled at one time. After the initial charging 

of the liquid feed, no additional liquid is added during the distillation operation. 

(3) Synthetic Organic Chemical Manufacturing Industry (SOCMI) batch process -

Any SOCMI noncontinuous reactor process which is not characterized by steady-state conditions, and in 

which reactants are not added and products are not removed simultaneously. 

(4) Synthetic Organic Chemical Manufacturing Industry (SOCMI) distillation 

operation - A SOCMI operation separating one or more feed stream(s) into two or more exit streams, 

each exit stream having component concentrations different from those in the feed stream(s). The 

separation is achieved by the redistribution of the components between the liquid and vapor-phase as 

they approach equilibrium within the distillation unit. 

(5) Synthetic Organic Chemical Manufacturing Industry (SOCMI) distillation unit 

- A SOCMI device or vessel in which distillation operations occur, including all associated internals 

(including, but not limited to, trays and packing), accessories (including, but not limited to, reboilers, 

condensers, vacuum pumps, and steam jets), and recovery devices (such as absorbers, carbon 

adsorbers, and condensers) which are capable of, and used for, recovering chemicals for use, reuse, or 

sale. 

(6) Synthetic Organic Chemical Manufacturing Industry (SOCMI) reactor process 

- A SOCMI unit operation in which one or more chemicals, or reactants other than air, are combined or 

decomposed in such a way that their molecular structures are altered and one or more new organic 

compounds are formed. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.121. Emission Specifications. 
Texas Commission on Environmental Quality Page 22 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston areas, as defined in '115.10 of this title (relating to Definitions), the following 

emission specifications shall apply. 

(1) No person may allow a vent gas stream containing volatile organic compounds 

(VOC) to be emitted from any process vent, unless the vent gas stream is controlled properly in 

accordance with '115.122(a)(1) of this title (relating to Control Requirements). 

(2) No person may allow a vent gas stream to be emitted from the following processes 

unless the vent gas stream is controlled properly in accordance with '115.122(a)(2) of this title: 

(A) any synthetic organic chemical manufacturing industry reactor process or 

distillation operation; 

(B) any air oxidation synthetic organic chemical manufacturing process; 

(C) any liquid phase polypropylene manufacturing process; 

(D) any liquid phase slurry high-density polyethylene manufacturing process; 

or 

(E) any continuous polystyrene manufacturing process. 

(3) In the Dallas/Fort Worth, El Paso, and Houston/Galveston areas, VOC emissions 

from bakery ovens, as defined in '115.10 of this title, shall be controlled properly in accordance with 

'115.122(a)(3) of this title. 

(4) Any vent gas stream in the Houston/Galveston area which includes a HRVOC, as 

defined in '115.10 of this title, is subject to the requirements of Subchapter H of this chapter (relating 

to Highly-Reactive Volatile Organic Compounds) in addition to the applicable requirements of this 

division (relating to Vent Gas Control). 

(b) In Nueces and Victoria Counties, no person may allow a vent gas stream to be emitted 

from any process vent containing one or more of the following VOC or classes of VOC, unless the vent 

gas stream is controlled properly in accordance with '115.122(b) of this title: 

(1) emissions of ethylene associated with the formation, handling, and storage of 

solidified low-density polyethylene; 

(2) emissions of the following specific VOC: ethylene, butadiene, isobutylene, 

styrene, isoprene, propylene, methylstyrene; and 

(3) emissions of specified classes of VOC, including aldehydes, alcohols, aromatics, 

ethers, olefins, peroxides, amines, acids, esters, ketones, sulfides, and branched chain hydrocarbons 
Texas Commission on Environmental Quality Page 23 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(C8 and above). 

(c) For persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 

the following emission specifications shall apply. 

(1) No person may allow a vent gas stream to be emitted from any process vent 

containing one or more of the following VOC or classes of VOC, unless the vent gas stream is 

controlled properly in accordance with '115.122(c)(1) of this title: 

(A) emissions of ethylene associated with the formation, handling, and storage 

of solidified low-density polyethylene; 

(B) emissions of the following specific VOC: ethylene, butadiene, 

isobutylene, styrene, isoprene, propylene, and methylstyrene; and 

(C) emissions of specified classes of VOC, including aldehydes, alcohols, 

aromatics, ethers, olefins, peroxides, amines, acids, esters, ketones, sulfides, and branched chain 

hydrocarbons (C8 and above). 

(2) No person may allow a vent gas stream to be emitted from any catalyst 

regeneration of a petroleum or chemical process system, basic oxygen furnace, or fluid coking unit into 

the atmosphere, unless the vent gas stream is properly controlled in accordance with '115.122(c)(2) of 

this title. 

(3) No person may allow a vent gas stream to be emitted from any iron cupola into the 

atmosphere, unless the vent gas stream is properly controlled in accordance with '115.122(c)(3) of this 

title. 

(4) Vent gas streams from blast furnaces shall be controlled properly in accordance 

with '115.122(c)(4) of this title. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.122. Control Requirements. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston areas, the following control requirements shall apply. 

(1) Any vent gas streams affected by '115.121(a)(1) of this title (relating to Emission 

Specifications) must be controlled properly with a control efficiency of at least 90% or to a volatile 

organic compound (VOC) concentration of no more than 20 parts per million by volume (ppmv) (on a 

dry basis corrected to 3.0% oxygen for combustion devices): 

(A) in a direct-flame incinerator at a temperature equal to or greater than 1,300 

degrees Fahrenheit (704 degrees Celsius); 
Texas Commission on Environmental Quality Page 24 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(B) in a smokeless flare; or 

(C) by any other vapor control system, as defined in '115.10 of this title 

(relating to Definitions). 

(2) Any vent gas streams affected by '115.121(a)(2) of this title must be controlled 

properly with a control efficiency of at least 98% or to a VOC concentration of no more than 20 ppmv 

(on a dry basis corrected to 3.0% oxygen for combustion devices): 

(A) in a smokeless flare; or 

(B) by any other vapor control system, as defined in '115.10 of this title. 

(3) For the Dallas/Fort Worth, El Paso, and Houston/Galveston areas, VOC emissions 

from each bakery with a bakery oven vent gas stream(s) affected by '115.121(a)(3) of this title shall be 

reduced as follows. 

(A) Each bakery in the Houston/Galveston area with a total weight of VOC 

emitted from all bakery ovens on the property, when uncontrolled, equal to or greater than 25 tons per 

calendar year shall ensure that the overall emission reduction from the uncontrolled VOC emission rate 

of the oven(s) is at least 80%. 

(B) Each bakery in the Dallas/Fort Worth area with a total weight of VOC 

emitted from all bakery ovens on the property, when uncontrolled, equal to or greater than 50 tons per 

calendar year, shall ensure that the overall emission reduction from the uncontrolled VOC emission rate 

of the oven(s) is at least 80%. 

(C) Each bakery in the Dallas/Fort Worth area with a total weight of VOC 

emitted from all bakery ovens on the property, when uncontrolled, equal to or greater than 25 tons per 

calendar year, but less than 50 tons per calendar year, shall reduce total VOC emissions by at least 30% 

from the bakery's 1990 emissions inventory in accordance with the schedule specified in '115.129(d) of 

this title (relating to Counties and Compliance Schedules). 

(D) Each bakery in the El Paso area with a total weight of VOC emitted from 

all bakery ovens on the property, when uncontrolled, equal to or greater than 25 tons per calendar year 

shall reduce total VOC emissions by at least 30% from the bakery's 1990 emissions inventory in 

accordance with the schedule specified in '115.129(e) of this title. 

(E) Emission reductions in the 30% to 90% range are not creditable under 

Chapter 101, Subchapter H, Division 1 of this title (relating to Emission Credit Banking and Trading) 

for the following bakeries: 

(i) each bakery in the Houston/Galveston area with a total weight of 
Texas Commission on Environmental Quality Page 25 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

VOC emitted from all bakery ovens on the property, when uncontrolled, equal to or greater than 25 

tons per calendar year; 

(ii) each bakery in the Dallas/Fort Worth area with a total weight of 

VOC emitted from all bakery ovens on the property, when uncontrolled, equal to or greater than 50 

tons per calendar year; 

(iii) each bakery in the El Paso area with a total weight of VOC 

emitted from all bakery ovens on the property, when uncontrolled, equal to or greater than 50 tons per 

calendar year. 

(4) Any vent gas stream that becomes subject to the provisions of paragraphs (1), (2), 

or (3) of this subsection by exceeding provisions of '115.127(a) of this title (relating to Exemptions) 

shall remain subject to the provisions of this subsection, even if throughput or emissions later fall below 

the exemption limits unless and until emissions are reduced to no more than the controlled emissions 

level existing before implementation of the project by which throughput or emission rate was reduced to 

less than the applicable exemption limits in '115.127(a) of this title; and: 

(A) the project by which throughput or emission rate was reduced is authorized 

by any permit or permit amendment or standard permit or permit by rule required by Chapter 116 or 

Chapter 106 of this title (relating to Control of Air Pollution by Permits for New Construction or 

Modification; and Permits by Rule). If a permit by rule is available for the project, compliance with 

this subsection must be maintained for 30 days after the filing of documentation of compliance with that 

permit by rule; or 

(B) if authorization by permit, permit amendment, standard permit, or permit 

by rule is not required for the project, the owner or operator has given the executive director 30 days' 

notice of the project in writing. 

(b) For all persons in Nueces and Victoria Counties, any vent gas streams affected by 

'115.121(b) of this title must be controlled properly with a control efficiency of at least 90% or to a 

VOC concentration of no more than 20 ppmv (on a dry basis corrected to 3.0% oxygen for combustion 

devices): 

(1) in a direct-flame incinerator at a temperature equal to or greater than 1,300 degrees 

Fahrenheit (704 degrees Celsius); 

(2) in a smokeless flare; or 

(3) by any other vapor control system, as defined in '115.10 of this title. 

(c) For all persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 

the following control requirements shall apply 

. 
Texas Commission on Environmental Quality Page 26 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) Any vent gas streams affected by '115.121(c)(1) of this title must be controlled 

properly: 

(A) in a direct-flame incinerator at a temperature equal to or greater than 1,300 

degrees Fahrenheit (704 degrees Celsius); 

(B) in a smokeless flare; or 

(C) by any other vapor control system, as defined in '115.10 of this title, with 

a control efficiency of at least 90% or to a VOC concentration of no more than 20 ppmv (on a dry basis 

corrected to 3.0% oxygen for combustion devices). 

(2) Any vent gas streams affected by '115.121(c)(2) of this title must be controlled 

properly: 

(A) in a direct-flame incinerator or boiler at a temperature equal to or greater 

than 1,300 degrees Fahrenheit (704 degrees Celsius); or 

(B) by any other vapor control system, as defined in '115.10 of this title, with 

a control efficiency of at least 90% or to a VOC concentration of no more than 20 ppmv (on a dry basis 

corrected to 3.0% oxygen for combustion devices). 

(3) Any vent gas streams affected by '115.121(c)(3) of this title must be controlled 

properly: 

(A) at a temperature equal to or greater than 1,300 degrees Fahrenheit (704 

degrees Celsius) in an afterburner having a retention time of at least one-fourth of a second, and having 

a steady flame that is not affected by the cupola charge and relights automatically if extinguished; or 

(B) by any other vapor control system, as defined in '115.10 of this title, with 

a control efficiency of at least 90% or to a VOC concentration of no more than 20 ppmv (on a dry basis 

corrected to 3.0% oxygen for combustion devices). 

(4) Any vent gas streams affected by '115.121(c)(4) of this title must be controlled 

properly: 

(A) in a smokeless flare or in a combustion device used in a heating process 

associated with the operation of a blast furnace; or 

(B) by any other vapor control system, as defined in '115.10 of this title, with 

a control efficiency of at least 90% or to a VOC concentration of no more than 20 ppmv (on a dry basis 

corrected to 3.0% oxygen for combustion devices). 

Adopted December 13, 2002 Effective January 17, 2003 
Texas Commission on Environmental Quality Page 27 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

'115.123. Alternate Control Requirements. 

(a) The alternate control requirements for vent gas streams in the Beaumont/Port Arthur, 

Dallas/Fort Worth, El Paso, and Houston/Galveston areas are as follows. 

(1) Alternate methods of demonstrating and documenting continuous compliance with 

the applicable control requirements or exemption criteria in this division (relating to Vent Gas Control) 

may be approved by the executive director in accordance with '115.910 of this title (relating to 

Availability of Alternate Means of Control) if emission reductions are demonstrated to be substantially 

equivalent. 

(2) The owner or operator of a synthetic organic chemical manufacturing industry 

(SOCMI) reactor process or distillation operation in which vent gas stream emissions are controlled by 

a control device with a control efficiency of at least 90% which was installed before December 3, 1993 

may request an alternate reasonably available control technology (ARACT) determination. The 

executive director may approve the ARACT if it is determined to be economically unreasonable to 

replace the control device with a new control device meeting the requirements of '115.122(a)(2) of this 

title (relating to Control Requirements). Each ARACT approved by the executive director shall include 

a requirement that the control device be operated at its maximum efficiency. Each ARACT shall only 

be valid until the control device undergoes a replacement, a modification as defined in 40 Code of 

Federal Regulations (CFR) '60.14 (October 17, 2000), or a reconstruction as defined in 40 CFR 

'60.15 (December 16, 1975), at which time the replacement, modified, or reconstructed control device 

shall meet the requirements of '115.122(a)(2) of this title. Any request for an ARACT determination 

shall be submitted to the executive director in writing no later than May 31, 1994. The executive 

director may direct the holder of an ARACT to reapply for an ARACT if it is more than ten years since 

the date of installation of the control device and there is good cause to believe that it is now 

economically reasonable to meet the requirements of '115.122(a)(2) of this title. Within three months 

of an executive director request, the holder of an ARACT shall reapply for an ARACT. If the 

reapplication for an ARACT is denied, the holder of the ARACT shall meet the requirements of 

'115.122(a)(2) of this title as soon as practicable, but no later than two years from the date of the 

executive director's written notification of denial. 

(b) For all persons in Nueces and Victoria Counties, alternate methods of demonstrating and 

documenting continuous compliance with the applicable control requirements or exemption criteria in 

this division may be approved by the executive director in accordance with '115.910 of this title if 

emission reductions are demonstrated to be substantially equivalent. 

(c) For all persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 

alternate methods of demonstrating and documenting continuous compliance with the applicable control 

requirements or exemption criteria in this division may be approved by the executive director in 

accordance with '115.910 of this title if emission reductions are demonstrated to be substantially 

equivalent. 
Texas Commission on Environmental Quality Page 28 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Adopted December 13, 2002 Effective January 17, 2003 

'115.125. Testing Requirements. 

Compliance with the emission specifications, vapor control system efficiency, and certain 

control requirements and exemption criteria of ''115.121 - 115.123 and 115.127 of this title (relating 

to Emission Specifications; Control Requirements; Alternate Control Requirements; and Exemptions) 

shall be determined by applying one or more of the following test methods and procedures, as 

appropriate, when specifically required within this division (relating to Vent Gas Control), when 

required by the executive director under '101.8 of this title (relating to Sampling), or when the owner 

or operator elects to conduct testing of one or more vent gas streams. 

(1) Flow rate. Test Methods 1-4 (40 Code of Federal Regulations (CFR) 60, 

Appendix A) are used for determining flow rates, as necessary. 

(2) Concentration of volatile organic compounds (VOC). 

(A) Test Method 18 (40 CFR 60, Appendix A) is used for determining gaseous 

organic compound emissions by gas chromatography. 

(B) Test Method 25 (40 CFR 60, Appendix A) is used for determining total 

gaseous nonmethane organic emissions as carbon. 

(C) Test Methods 25A or 25B (40 CFR 60, Appendix A) are used for 

determining total gaseous organic concentrations using flame ionization or nondispersive infrared 

analysis. 

(3) Performance requirements for flares and vapor combustors. 

(A) For flares, Test Method 22 (40 CFR 60, Appendix A) is used for visual 

determination of fugitive emissions from material sources and smoke emissions. 

(B) For flares, additional test method requirements are described in 40 CFR 

60.18(f), unless EPA or the executive director has granted a waiver from such testing requirements. 

(C) Flares in the Beaumont/Port Arthur, Dallas/Fort Worth, and 

Houston/Galveston areas shall comply with the performance test requirements of 40 CFR 60.18(b), 

unless EPA or the executive director has granted a waiver from such testing requirements. 

(D) For vapor combustors, the owner or operator may consider the unit to be a 

flare. Each vapor combustor in Victoria County and the Beaumont/Port Arthur, Dallas/Fort Worth, El 

Paso, and Houston/Galveston areas which the owner or operator elected to consider as a flare shall 

meet the performance test requirements of 40 CFR 60.18(b) in lieu of any testing under paragraphs (1) 

and (2) of this section. 
Texas Commission on Environmental Quality Page 29 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(E) Compliance with the requirements of 40 CFR 60.18(b) will be considered 

to demonstrate compliance with the emission specifications and control efficiency requirements of 

'115.121 and '115.122 of this title. 

(4) Minor modifications. Minor modifications to these test methods may be used, if 

approved by the executive director. 

(5) Alternate test methods. Test methods other than those specified in paragraphs (1) - 

(3) of this section may be used if validated by 40 CFR 63, Appendix A, Test Method 301 (effective 

December 29, 1992). For the purposes of this paragraph, substitute Aexecutive director@ each place that 

Test Method 301 references Aadministrator.@

Adopted December 6, 2000 Effective January 18, 2001 

'115.126. Monitoring and Recordkeeping Requirements. 

The owner or operator of any facility which emits volatile organic compounds (VOC) through a 

stationary vent in Aransas, Bexar, Calhoun, Matagorda, Nueces, San Patricio, Travis, and Victoria 

Counties or in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas 

shall maintain the following information at the facility for at least five years, except that the five-year 

record retention requirement does not apply to records generated before December 31, 2000. The 

owner or operator shall make the information available upon request to representatives of the executive 

director, EPA, or any local air pollution control agency having jurisdiction in the area. 

(1) Vapor control systems. For vapor control systems used to control emissions in 

Victoria County and in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston 

areas from vents subject to the provisions of '115.121 of this title (relating to Emission Specifications), 

records of appropriate parameters to demonstrate compliance, including: 

(A) continuous monitoring and recording of: 

(i) the exhaust gas temperature immediately downstream of a 

direct-flame incinerator; 

(ii) the inlet and outlet gas temperatures of a catalytic incinerator or 

chiller; 

(iii) the exhaust gas VOC concentration of any carbon adsorption 

system, as defined in '101.1 of this title (relating to Definitions); and 

(iv) the exhaust gas temperature immediately downstream of a vapor 

combustor. Alternatively, the owner or operator of a vapor combustor may consider the unit to be a 

flare and meet the requirements specified in 40 Code of Federal Regulations (CFR) '60.18(b) and 
Texas Commission on Environmental Quality Page 30 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Chapter 111 of this title (relating to Control of Air Pollution from Visible Emissions and Particulate 

Matter) for flares; 

(B) in the Beaumont/Port Arthur, Dallas/Fort Worth, and Houston/Galveston 

areas, the requirements specified in 40 CFR '60.18(b) and Chapter 111 of this title for flares; and 

(C) for vapor control systems other than those specified in subparagraphs (A) 

and (B) of this paragraph, records of appropriate operating parameters. 

(2) Test results. A record of the results of any testing conducted in accordance with 

'115.125 of this title (relating to Testing Requirements). 

(3) Records for exempted vents. Records for each vent exempted from control 

requirements in accordance with '115.127 of this title (relating to Exemptions) shall be sufficient to 

demonstrate compliance with the applicable exemption limit, including the following, as appropriate: 

(A) the pounds of ethylene emitted per 1,000 pounds of low-density 

polyethylene produced; 

(B) the combined weight of VOC of each vent gas stream on a daily basis; 

(C) the concentration of VOC in each vent gas stream on a daily basis; 

(D) the maximum design flow rate or VOC concentration of each vent gas 

stream exempt under '115.127(a)(4)(C) of this title; and 

(E) the total design capacity of process units exempt under '115.127(a)(4)(B) 

of this title. 

(4) Alternative records for exempted vents. As an alternative to the requirements of 

paragraph (3)(B) and (C) of this section, records for each vent exempted from control requirements in 

accordance with '115.127 of this title and having a VOC emission rate or concentration less than the 

applicable exemption limits at maximum actual operating conditions shall be sufficient to demonstrate 

continuous compliance with the applicable exemption limit. These records shall include complete 

information from either test results or appropriate calculations which clearly documents that the 

emission characteristics at maximum actual operating conditions are less than the applicable exemption 

limit. This documentation shall include the operating parameter levels that occurred during any testing, 

and the maximum levels feasible (either VOC concentration or mass emission rate) for the process. 

(5) Bakeries. For bakeries subject to '115.122(a)(3)(A) - (B) of this title (relating to 

Control Requirements), the following additional requirements apply. 

(A) The owner or operator of each bakery in the Houston/Galveston area with 

a total weight of VOC emitted from all bakery ovens on the property, when uncontrolled, equal to or 
Texas Commission on Environmental Quality Page 31 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

greater than 25 tons per calendar year, shall submit a control plan no later than March 31, 2001, to the 

executive director, the appropriate regional office, and any local air pollution control program with 

jurisdiction. The plan shall demonstrate that the overall emission reduction from the uncontrolled VOC 

emission rate of the oven(s) will be at least 80% by December 31, 2001. At a minimum, the control 

plan shall include the emission point number (EPN) and the facility identification number (FIN) of each 

bakery oven and any associated control device, a plot plan showing the location, EPN, and FIN of each 

bakery oven and any associated control device, and the 2000 VOC emission rates (consistent with the 

bakery's 2000 emissions inventory). The projected 2002 VOC emission rates shall be calculated in a 

manner consistent with the 2000 emissions inventory. 

(B) All representations in control plans become enforceable conditions. It shall 

be unlawful for any person to vary from such representations if the variation will cause a change in the 

identity of the specific emission sources being controlled or the method of control of emissions unless 

the owner or operator of the bakery submits a revised control plan to the executive director, the 

appropriate regional office, and any local air pollution control program with jurisdiction within 30 days 

of the change. All control plans shall include documentation that the overall emission reduction from 

the uncontrolled VOC emission rate of the bakery's oven(s) continues to be at least the specified 

percentage reduction. The emission rates shall be calculated in a manner consistent with the most 

recent emissions inventory. 

(6) Bakeries (contingency measures). For bakeries subject to '115.122(a)(3)(C) and 

(D) of this title, the following additional requirements apply. 

(A) No later than six months after the commission publishes notification in the 

Texas Register as specified in '115.129(d) or (e) of this title (relating to Counties and Compliance 

Schedules), the owner or operator of each bakery shall submit an initial control plan to the executive 

director, the appropriate regional office, and any local air pollution control program with jurisdiction 

which demonstrates that the overall reduction of VOC emissions from the bakery's 1990 emissions 

inventory will be at least 30%. At a minimum, the control plan shall include the EPN and the FIN of 

each bakery oven and any associated control device, a plot plan showing the location, EPN, and FIN of 

each bakery oven and any associated control device, and the 1990 VOC emission rates (consistent with 

the bakery's 1990 emissions inventory). The projected VOC emission rates shall be calculated in a 

manner consistent with the 1990 emissions inventory. 

(B) In order to document continued compliance with '115.122(a)(3) of this 

title, the owner or operator of each bakery shall submit an annual report no later than March 31 of each 

year to the executive director, the appropriate regional office, and any local air pollution control 

program with jurisdiction which demonstrates that the overall reduction of VOC emissions from the 

bakery's 1990 emissions inventory during the preceding calendar year is at least 30%. At a minimum, 

the report shall include the EPN and FIN of each bakery oven and any associated control device, a plot 

plan showing the location, EPN, and FIN of each bakery oven and any associated control device, and 

the VOC emission rates. The emission rates for the proceeding calendar year shall be calculated in a 

manner consistent with the 1990 emissions inventory. 

(C) All representations in control plans and annual reports become enforceable 
Texas Commission on Environmental Quality Page 32 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

conditions. It shall be unlawful for any person to vary from such representations if the variation will 

cause a change in the identity of the specific emission sources being controlled or the method of control 

of emissions unless the owner or operator of the bakery submits a revised control plan to the executive 

director, the appropriate regional office, and any local air pollution control program with jurisdiction 

within 30 days of the change. All control plans and reports shall include documentation that the overall 

reduction of VOC emissions from the bakery's 1990 emissions inventory continues to be at least 30%. 

The emission rates shall be calculated in a manner consistent with the 1990 emissions inventory. 

(7) Additional flare requirements. The owner or operator of a facility that uses a flare 

to meet the requirements of '115.122(a)(2) of this title shall install, calibrate, maintain, and operate 

according to the manufacturer's specifications, a heat-sensing device, such as an ultraviolet beam sensor 

or thermocouple, at the pilot light to indicate continuous presence of a flame. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.127. Exemptions. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston areas, the following exemptions apply. 

(1) A vent gas stream from a low-density polyethylene plant is exempt from the 

requirements of '115.121(a)(1) of this title (relating to Emission Specifications) if no more than 1.1 

pounds of ethylene per 1,000 pounds (1.1 kg/1,000 kg) of product are emitted from all the vent gas 

streams associated with the formation, handling, and storage of solidified product. 

(2) The following vent gas streams are exempt from the requirements of 

'115.121(a)(1) of this title: 

(A) a vent gas stream having a combined weight of volatile organic compounds 

(VOC) equal to or less than 100 pounds (45.4 kg) in any continuous 24-hour period; 

(B) a vent gas stream specified in '115.121(a)(1) of this title with a 

concentration of VOC less than 612 parts per million by volume (ppmv); 

(C) a vent gas stream which is subject to '115.121(a)(2) or (3) of this title; and 

(D) a vent gas stream which qualifies for exemption under paragraphs (3), 

(4)(B), (4)(C), (4)(D), (4)(E), or (5) of this subsection. 

(3) The following vent gas streams are exempt from the requirements of 

'115.121(a)(2)(B) - (E) of this title: 

(A) a vent gas stream having a combined weight of VOC equal to or less than 

100 pounds (45.4 kilograms) in any continuous 24-hour period; 
Texas Commission on Environmental Quality Page 33 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(B) a vent gas stream from any air oxidation synthetic organic chemical 

manufacturing process with a concentration of VOC less than 612 ppmv; and 

(C) a vent gas stream from any liquid phase polypropylene manufacturing 

process, any liquid phase slurry high-density polyethylene manufacturing process, and any continuous 

polystyrene manufacturing process with a concentration of VOC less than 408 ppmv. 

(4) For synthetic organic chemical manufacturing industry (SOCMI) reactor processes 

and distillation operations, the following exemptions apply. 

(A) Any reactor process or distillation operation that is designed and operated 

in a batch mode is exempt from the requirements of '115.121(a)(2)(A) of this title. For the purposes of 

this subparagraph, batch mode means any noncontinuous reactor process or distillation operation which 

is not characterized by steady-state conditions, and in which the addition of reactants does not occur 

simultaneously with the removal of products. 

(B) Any reactor process or distillation operation operating in a process unit 

with a total design capacity of less than 1,100 tons per year, for all chemicals produced within that unit, 

is exempt from the requirements of '115.121(a)(2)(A) of this title. 

(C) Any reactor process or distillation operation vent gas stream with a flow 

rate less than 0.011 standard cubic meters per minute or a VOC concentration less than 500 ppmv is 

exempt from the requirements of '115.121(a)(2)(A) of this title. 

(D) Any distillation operation vent gas stream which meets the requirements of 

40 Code of Federal Regulations (CFR) '60.660(c)(4) or '60.662(c) (concerning Subpart 

NNN--Standards of Performance for VOC Emissions From SOCMI Distillation Operations, December 

14, 2000) is exempt from the requirements of '115.121(a)(2)(A) of this title. 

(E) Any reactor process vent gas stream which meets the requirements of 40 

CFR '60.700(c)(2) or '60.702(c) (concerning Subpart RRR--Standards of Performance for VOC 

Emissions From SOCMI Reactor Processes, December 14, 2000) is exempt from the requirements of 

'115.121(a)(2)(A) of this title. 

(5) Bakeries are exempt from the requirements of '115.121(a)(3) and '115.122(a)(3) 

of this title (relating to Emission Specifications and Control Requirements) if the total weight of VOC 

emitted from all bakery ovens on the property, when uncontrolled, is less than 25 tons per calendar 

year. 

(6) A vent gas stream is exempt from this division (relating to Vent Gas Control) if all 

of the VOCs in the vent gas stream originate from a source(s) for which another division within Chapter 

115 (for example, Storage of Volatile Organic Compounds) has established a control requirement(s), 

emission specification(s), or exemption(s) which applies to that VOC source category in that county. 
Texas Commission on Environmental Quality Page 34 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(7) A combustion unit exhaust stream is exempt from this division provided that the 

unit is not being used as a control device for any vent gas stream which is subject to this division and 

which originates from a non-combustion source. 

(8) As an alternative to complying with the requirements of this division (or, in the 

case of bakeries, as an alternative to complying with the requirements of '115.121(a)(1) and 

'115.122(a)(1) of this title) for a source that is addressed by a Chapter 115 contingency rule (i.e., one 

in which Chapter 115 requirements are triggered for that source by the commission publishing 

notification in the Texas Register that implementation of the contingency rule is necessary), the owner 

or operator of that source may instead choose to comply with the requirements of the contingency rule 

as though the contingency rule already had been implemented for that source. The owner or operator of 

each source choosing this option shall submit written notification to the executive director and any local 

air pollution control program with jurisdiction. When the executive director and the local program (if 

any) receive such notification, the source will then be considered subject to the contingency rule as 

though the contingency rule already had been implemented for that source. 

(b) For all persons in Nueces and Victoria Counties, the following exemptions apply. 

(1) A vent gas stream from a low-density polyethylene plant is exempt from the 

requirements of '115.121(b)(1) of this title if no more than 1.1 pounds of ethylene per 1,000 pounds 

(1.1 kg/1,000 kg) of product are emitted from all the vent gas streams associated with the formation, 

handling, and storage of the solidified product. 

(2) The following vent gas streams are exempt from the requirements of '115.121(b) 

of this title: 

(A) a vent gas stream having a combined weight of the VOC or classes of 

compounds specified in '115.121(b)(2) and (3) of this title equal to or less than 100 pounds (45.4 kg) in 

any continuous 24-hour period; and 

(B) a vent gas stream with a concentration of the VOC or classes of 

compounds specified in '115.121(b)(2) and (3) of this title less than 30,000 ppmv. 

(3) A vent gas stream is exempt from this division if all of the VOCs in the vent gas 

stream originate from a source(s) for which another division within Chapter 115 (for example, Storage 

of Volatile Organic Compounds) has established a control requirement(s), emission specification(s), or 

exemption(s) which applies to that VOC source category in that county. 

(4) A combustion unit exhaust stream is exempt from this division provided that the 

unit is not being used as a control device for any vent gas stream which is subject to this division and 

which originates from a non-combustion source. 

(c) For all persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 

the following exemptions apply. 
Texas Commission on Environmental Quality Page 35 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) The following vent gas streams are exempt from the requirements of 

'115.121(c)(1) of this title: 

(A) a vent gas stream from a low-density polyethylene plant provided that no 

more than 1.1 pounds of ethylene per 1,000 pounds (1.1 kg/1,000 kg) of product are emitted from all 

the vent gas streams associated with the formation, handling, and storage of solidified product; 

(B) a vent gas stream having a combined weight of the VOC or classes of 

compounds specified in '115.121(c)(1)(B) - (C) of this title equal to or less than 100 pounds (45.4 kg) 

in any continuous 24-hour period; and 

(C) a vent gas stream having a concentration of the VOC specified in 

'115.121(c)(1)(B) and (C) of this title less than 30,000 ppmv. 

(2) A vent gas stream specified in '115.121(c)(2) of this title which emits less than or 

equal to five tons (4,536 kg) of total uncontrolled VOC in any one calendar year is exempt from the 

requirements of '115.121(c)(2) of this title. 

(3) A vent gas stream is exempt from this division if all of the VOCs in the vent gas 

stream originate from a source(s) for which another division within Chapter 115 (for example, Storage 

of Volatile Organic Compounds) has established a control requirement(s), emission specification(s), or 

exemption(s) which applies to that VOC source category in that county. 

(4) A combustion unit exhaust stream is exempt from this division provided that the 

unit is not being used as a control device for any vent gas stream which is subject to this division and 

which originates from a non-combustion source. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.129. Counties and Compliance Schedules. 

(a) The owner or operator of each vent gas stream in Aransas, Bexar, Brazoria, Calhoun, 

Chambers, Collin, Dallas, Denton, El Paso, Fort Bend, Galveston, Hardin, Harris, Jefferson, Liberty, 

Matagorda, Montgomery, Nueces, Orange, San Patricio, Tarrant, Travis, Victoria, and Waller 

Counties shall continue to comply with this division (relating to Vent Gas Control) as required by 

'115.930 of this title (relating to Compliance Dates). 

(b) The owner or operator of each bakery in Collin, Dallas, Denton, and Tarrant Counties 

subject to '115.122(a)(3)(C) of this title (relating to Control Requirements) shall comply with 

''115.121(a)(3), 115.122(a)(3)(C), and 115.126(6) of this title (relating to Emission Specifications; 

Control Requirements; and Monitoring and Recordkeeping Requirements) as soon as practicable, but no 

later than one year, after the commission publishes notification in the Texas Register of its 

determination that this contingency rule is necessary as a result of failure to attain the national ambient 
Texas Commission on Environmental Quality Page 36 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

air quality standard (NAAQS) for ozone by the attainment deadline or failure to demonstrate reasonable 

further progress as set forth in Federal Clean Air Act (FCAA), '172(c)(9). 

(c) The owner or operator of each bakery in El Paso County subject to '115.122(a)(3)(D) of 

this title shall comply with ''115.121(a)(3), 115.122(a)(3)(D), and 115.126(6) of this title as soon as 

practicable, but no later than one year, after the commission publishes notification in the Texas Register 

of its determination that this contingency rule is necessary as a result of failure to attain the NAAQS for 

ozone by the attainment deadline or failure to demonstrate reasonable further progress as set forth in 

FCAA, '172(c)(9). 

(d) The owner or operator of each vent gas stream in Ellis, Johnson, Kaufman, Parker, and 

Rockwall Counties shall comply with this division as soon as practicable, but no later than March 1, 

2009. 

Adopted November 15, 2006 Effective December 7, 2006 

SUBCHAPTER B: GENERAL VOLATILE ORGANIC COMPOUND SOURCES 

DIVISION 3: WATER SEPARATION 

''115.131 - 115.133, 115.135 - 115.137, 115.139 

Effective December 7, 2006 

'115.131. Emission Specifications. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/ Fort Worth, El Paso, and Houston/ 

Galveston areas as defined in '115.10 of this title (relating to Definitions), any volatile organic 

compound (VOC) water separator equipped with a vapor recovery system in order to comply with 

'115.132(a) of this title (relating to Control Requirements) shall reduce emissions such that the true 

partial pressure of the VOC in vent gases to the atmosphere will not exceed a level of 0.5 psia (3.4 

kPa). 

(b) For all persons in Gregg, Nueces, and Victoria Counties, any VOC water separator 

equipped with a vapor recovery system in order to comply with '115.132(b) of this title shall reduce 

emissions such that the partial pressure of the VOC in vent gases to the atmosphere will not exceed a 

level of 1.5 psia (10.3 kPa). 

(c) For all persons in Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, 

any VOC water separator equipped with a vapor recovery system in order to comply with '115.132(c) 

of this title shall reduce emissions such that the true partial pressure of the VOC in vent gases to the 

atmosphere will not exceed a level of 1.5 psia (10.3 kPa). 

Adopted October 25, 1995 Effective November 20, 1995 

'115.132. Control Requirements. 
Texas Commission on Environmental Quality Page 37 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

no person shall use any single or multiple compartment volatile organic compound (VOC) water 

separator which separates materials containing VOC obtained from any equipment which is processing, 

refining, treating, storing, or handling VOC, unless each compartment is controlled in one of the 

following ways: 

(1) the compartment totally encloses the liquid contents and has all openings (such as 

roof seals and access doors) sealed such that the separator can hold a vacuum or pressure without 

emissions to the atmosphere, except through a pressure relief valve. All gauging and sampling devices 

shall be vapor-tight except during gauging or sampling. The pressure relief valve must be designed to 

open only as necessary to allow proper operation, and must be set at the maximum possible pressure 

necessary for proper operation, but such that the valve will not vent continuously; 

(2) the compartment is equipped with a floating roof or internal floating cover which 

will rest on the surface of the contents and be equipped with a closure seal or seals to close the space 

between the roof edge and tank wall. All gauging and sampling devices shall be vapor-tight except 

during gauging or sampling; 

(3) the compartment is equipped with a vapor recovery system which satisfies the 

provisions of '115.131(a) of this title (relating to Emission Specifications); 

(4) any water separator that becomes subject to the provisions of paragraphs (1), (2), 

or (3) of this subsection by exceeding provisions of '115.137(a) of this title (relating to Exemptions) 

will remain subject to the provisions of this subsection, even if throughput or emissions later fall below 

the exemption limits unless and until emissions are reduced to no more than the controlled emissions 

level existing before implementation of the project by which throughput or emission rate was reduced to 

less than the applicable exemption limits in '115.137(a) of this title; and 

(A) the project by which throughput or emission rate was reduced is authorized 

by any permit or permit amendment or standard permit or permit by rule required by Chapter 116 or 

Chapter 106 of this title (relating to Control of Air Pollution by Permits for New Construction or 

Modification; and Permits by Rule. If a permit by rule is available for the project, compliance with this 

subsection must be maintained for 30 days after the filing of documentation of compliance with that 

permit by rule; or 

(B) if authorization by permit, permit amendment, standard permit, or permit 

by rule is not required for the project, the owner/operator has given the executive director 30 days' 

notice of the project in writing. 

(b) For Gregg, Nueces, and Victoria Counties, no person shall use any single or multiple 

compartment VOC water separator which separates materials containing VOC obtained from any 

equipment which is processing, refining, treating, storing, or handling VOC, unless each compartment 

is controlled in one of the following ways: 
Texas Commission on Environmental Quality Page 38 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) the compartment totally encloses the liquid contents and has all openings (such as 

roof seals and access doors) sealed such that the separator can hold a vacuum or pressure without 

emissions to the atmosphere, except through a pressure relief valve. All gauging and sampling devices 

shall be vapor-tight except during gauging or sampling. The pressure relief valve must be designed to 

open only as necessary to allow proper operation, and must be set at the maximum possible pressure 

necessary for proper operation, but such that the valve will not vent continuously; 

(2) the compartment is equipped with a floating roof or internal floating cover which 

will rest on the surface of the contents and be equipped with a closure seal or seals to close the space 

between the roof or cover edge and tank wall. All gauging and sampling devices shall be vapor-tight, 

except during gauging or sampling; 

(3) the compartment is equipped with a vapor recovery system which satisfies the 

provisions of '115.131(b) of this title. 

(c) For Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, no person 

shall use any single or multiple compartment VOC water separator which separates materials containing 

VOC obtained from any equipment which is processing, refining, treating, storing, or handling VOC, 

unless each compartment is controlled in one of the following ways: 

(1) the compartment totally encloses the liquid contents and has all openings (such as 

roof seals and access doors) sealed such that the separator can hold a vacuum or pressure without 

emissions to the atmosphere, except through a pressure relief valve. All gauging and sampling devices 

shall be vapor-tight except during gauging or sampling. The pressure relief valve must be designed to 

open only as necessary to allow proper operation, and must be set at the maximum possible pressure 

necessary for proper operation, but such that the valve will not vent continuously; 

(2) the compartment is equipped with a floating roof or internal floating cover which 

will rest on the surface of the contents and be equipped with a closure seal or seals to close the space 

between the roof or cover edge and tank wall. All gauging and sampling devices shall be vapor-tight 

except during gauging or sampling; 

(3) the compartment is equipped with a vapor recovery system which satisfies the 

provisions of '115.131(c) of this title. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.133. Alternate Control Requirements. 

Alternate methods of demonstrating and documenting continuous compliance with the applicable 

control requirements or exemption criteria in this division (relating to Water Separation) may be 

approved by the executive director in accordance with '115.910 of this title (relating to Alternate 

Means of Control) if emission reductions are demonstrated to be substantially equivalent. 
Texas Commission on Environmental Quality Page 39 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Adopted April 26, 2002 Effective May 16, 2002 

'115.135. Testing Requirements. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

compliance with '115.131(a), '115.132(a), and '115.137 of this title (relating to Emission 

Specifications; Control Requirements; and Exemptions) shall be determined by applying the following 

test methods, as appropriate: 

(1) Test Methods 1-4 (40 Code of Federal Regulations (CFR) 60, Appendix A) for 

determining flow rate, as necessary; 

(2) Test Method 18 (40 CFR 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(3) Test Method 25 (40 CFR 60, Appendix A) for determining total gaseous 

nonmethane organic emissions as carbon; 

(4) Test Methods 25A or 25B (40 CFR 60, Appendix A) for determining total gaseous 

organic concentrations using flame ionization or nondispersive infrared analysis; 

(5) determination of true vapor pressure at actual storage temperature using American 

Society for Testing Materials (ASTM) Test Methods D323, D2879, D4953, D5190, or D5191; using 

API Publication 2517, Third Edition, 1989 or standard reference texts to convert from Reid vapor 

pressure to true vapor pressure, where applicable; 

(6) minor modifications to these test methods approved by the Executive Director. 

(b) For Gregg, Nueces, and Victoria Counties, compliance with '115.131(b), '115.132(b), 

and '115.137(b) of this title shall be determined by applying the following test methods, as appropriate: 

(1) Test Methods 1-4 (40 CFR 60, Appendix A) for determining flow rate, as 

necessary; 

(2) Test Method 18 (40 CFR 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(3) Test Method 25 (40 CFR 60, Appendix A) for determining total gaseous 

nonmethane organic emissions as carbon; 

(4) Test Methods 25A or 25B (40 CFR 60, Appendix A) for determining total gaseous 

organic concentrations using flame ionization or nondispersive infrared analysis; 
Texas Commission on Environmental Quality Page 40 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(5) determination of true vapor pressure at actual storage temperature using ASTM 

Test Methods D323, D2879, D4953, D5190, or D5191; and using API Publication 2517, Third 

Edition, 1989 or standard reference texts to convert from Reid vapor pressure to true vapor pressure, 

where applicable; or 

(6) minor modifications to these test methods approved by the Executive Director. 

Adopted October 25, 1995 Effective November 20, 1995 

'115.136. Monitoring and Recordkeeping Requirements. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

the following recordkeeping requirements shall apply. 

(1) Any person who operates a single or multiple compartment volatile organic 

compound (VOC) water separator without the controls specified in '115.132(a) of this title (relating to 

Control Requirements) shall maintain complete and up-to-date records sufficient to demonstrate 

continuous compliance with the applicable exemption criteria including, but not limited to, the names 

and true vapor pressures of all such materials stored, processed, or handled at the affected property, 

and any other necessary operational information. 

(2) Affected persons shall install and maintain monitors to continuously measure and 

record operational parameters of any emission control device installed to meet applicable control 

requirements. Such records must be sufficient to demonstrate proper functioning of those devices to 

design specifications, including: 

(A) the exhaust gas temperature immediately downstream of any direct-flame 

incinerator; 

(B) the gas temperature immediately upstream and downstream of any catalytic 

incinerator or chiller; and 

(C) the VOC concentration of any carbon adsorption system exhaust gas to 

determine if breakthrough has occurred. 

(3) Affected persons shall maintain the results of any testing conducted in accordance 

with the provisions specified in '115.135(a) of this title (relating to Testing Requirements). 

(4) All records shall be maintained at the affected facility for at least two years and be 

made available upon request to representatives of the executive director, EPA, or any local air pollution 

control agency having jurisdiction in the area. 

(b) For Gregg, Nueces, and Victoria Counties, the following recordkeeping requirements shall 

apply. 
Texas Commission on Environmental Quality Page 41 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) Any person who operates a single or multiple compartment VOC water separator 

without the controls specified in '115.132(b) of this title shall maintain complete and up-to-date records 

sufficient to demonstrate continuous compliance with the applicable exemption criteria including, but 

not limited to, the names and true vapor pressures of all such materials stored, processed, or handled at 

the affected property, and any other necessary operational information. 

(2) In Victoria County, affected persons shall install and maintain monitors to 

continuously measure and record operational parameters of any emission control device installed to 

meet applicable control requirements. Such records must be sufficient to demonstrate proper 

functioning of those devices to design specifications, including: 

(A) the exhaust gas temperature immediately downstream of any direct-flame 

incinerator; 

(B) the gas temperature immediately upstream and downstream of any catalytic 

incinerator or chiller; and 

(C) the exhaust gas VOC concentration of any carbon adsorption system, as 

defined in '115.10 of this title (relating to Definitions), to determine if breakthrough has occurred. 

(3) Affected persons shall maintain the results of any testing conducted in accordance 

with the provisions specified in '115.135(b) of this title. 

(4) All records shall be maintained at the affected facility for at least two years and be 

made available upon request to representatives of the executive director, EPA, or any local air pollution 

control agency having jurisdiction in the area. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.137. Exemptions. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

the following exemptions shall apply. 

(1) Any volatile organic compound (VOC) water separator used exclusively in 

conjunction with the production of crude oil or condensate is exempt from '115.132(a) of this title 

(relating to Control Requirements) if the emissions from the separator have a combined weight of VOC 

equal to or less than 100 pounds (45.4 kg) in any continuous 24-hour period. When emissions from 

multiple sources (including, but not limited to, VOC water separators, treaters, storage tanks, and 

saltwater disposal tanks) are routed through a common vent, the calculation of VOC emissions for 

purposes of this exemption shall be based upon the total of all emission sources which are routed to the 

common vent. It is unacceptable to disconnect any of the multiple sources routed through a common 

vent for purposes of complying with this exemption. 
Texas Commission on Environmental Quality Page 42 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(2) Any single or multiple compartment VOC water separator which separates 

materials having a true vapor pressure of VOC less than 0.5 pounds per square inch absolute (psia) (3.4 

kPa) obtained from any equipment is exempt from '115.132(a) of this title. 

(3) Any single or multiple compartment VOC water separator which is designed solely 

to capture stormwater, spills, or exterior surface cleanup waters is exempt from this division (relating to 

Water Separation), provided that the separator is fully covered. These separators are not required to be 

equipped with pressure/vacuum vents or vapor control systems. 

(b) For Gregg, Nueces, and Victoria Counties, the following exemptions shall apply. 

(1) VOC water separators used exclusively in conjunction with the production of crude 

oil or condensate are exempt from '115.132(b) of this title. 

(2) Any single or multiple compartment VOC water separator which separates less than 

200 gallons (757 liters) a day of materials containing VOC obtained from any equipment is exempt 

from '115.132(b) of this title. 

(3) Any single or multiple compartment VOC water separator which separates 

materials having a true vapor pressure of VOC less than 1.5 psia (10.3 kPa) obtained from any 

equipment is exempt from '115.132(b) of this title. 

(4) In Gregg County, any single or multiple compartment VOC water separator which 

separates materials obtained from any equipment in a facility other than a petroleum refinery is exempt 

from '115.132(b) of this title. 

(5) Any single or multiple compartment VOC water separator which is designed solely 

to capture stormwater, spills, or exterior surface cleanup waters is exempt from this division, provided 

that the separator is fully covered. These separators are not required to be equipped with 

pressure/vacuum vents or vapor control systems. 

(c) For Aransas, Bexar, Calhoun, Matagorda, San Patricio, and Travis Counties, the following 

exemptions shall apply. 

(1) VOC water separators used exclusively in conjunction with the production of crude 

oil or condensate are exempt from '115.132(c) of this title. 

(2) Any single or multiple compartment VOC water separator which separates less than 

200 gallons (757 liters) a day of materials containing VOC obtained from any equipment is exempt 

from '115.132(c) of this title. 
Texas Commission on Environmental Quality Page 43 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(3) Any single or multiple compartment VOC water separator which separates 

materials having a true vapor pressure of VOC less than 1.5 psia (10.3 kPa) obtained from any 

equipment is exempt from '115.132(c) of this title. 

(4) Any single or multiple compartment VOC water separator which is designed solely 

to capture stormwater, spills, or exterior surface cleanup waters is exempt from this division, provided 

that the separator is fully covered. These separators are not required to be equipped with 

pressure/vacuum vents or vapor control systems. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.139. Counties and Compliance Schedules. 

(a) The owner or operator of each volatile organic compound (VOC) water separator in 

Aransas, Bexar, Brazoria, Calhoun, Chambers, Collin, Dallas, Denton, El Paso, Fort Bend, Galveston, 

Gregg, Hardin, Harris, Jefferson, Liberty, Matagorda, Montgomery, Nueces, Orange, San Patricio, 

Tarrant, Travis, Victoria, and Waller Counties shall continue to comply with this division (relating to 

Water Separation) as required by '115.930 of this title (relating to Compliance Dates). 

(b) The owner or operator of each VOC water separator in Ellis, Johnson, Kaufman, Parker, 

and Rockwall Counties shall comply with this division as soon as practicable, but no later than March 

1, 2009. 

Adopted November 15, 2006 Effective December 7, 2006 
Texas Commission on Environmental Quality Page 44 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER B: GENERAL VOLATILE ORGANIC COMPOUND SOURCES 

DIVISION 4: INDUSTRIAL WASTEWATER 

''115.140, 115.142 - 115.149 

Effective December 7, 2006

'115.140. Industrial Wastewater Definitions. 

The following terms, when used in this division, shall have the following meanings, unless the 

context clearly indicates otherwise. Additional definitions for terms used in this division are found in 

''115.10, 101.1, and 3.2 of this title (relating to Definitions). 

(1) Affected source category - Any of the following source categories: 

(A) organic chemicals, plastics, and synthetic fibers manufacturing industry 

under Standard Industrial Classification (SIC) codes 2821, 2823, 2824, 2865, and 2869; 

(B) pesticides manufacturing industry under SIC code 2879; 

(C) petroleum refining industry under SIC code 2911; 

(D) pharmaceutical manufacturing industry under SIC codes 2833, 2834, and 

2836; 

(E) hazardous waste treatment, storage, and disposal facilities industry under 

SIC codes 4952, 4953, and 4959. 

(2) Affected volatile organic compound (VOC) wastewater stream - A VOC 

wastewater stream from an affected source category with either a VOC concentration greater than or 

equal to 10,000 parts per million by weight (ppmw) or a VOC concentration greater than or equal to 

1,000 ppmw and a flow rate greater than or equal to 10 liters per minute (2.64 gallons per minute), as 

determined in accordance with '115.148 of this title (relating to Determination of Wastewater 

Characteristics). 

(3) Plant - All facilities included within the same commission account number. 

(4) Point of generation - The location where a VOC wastewater stream exits a process 

unit. 

(5) Properly operated biotreatment unit - A suspended growth process that generates 

biomass and recycles biomass to maintain biomass concentrations in the treatment unit. The average 

concentration of suspended biomass maintained in the aeration basin of a properly operated biotreatment 

unit shall equal or exceed 1.0 kilogram per cubic meter (kg/m3

), measured as total suspended solids. 
Texas Commission on Environmental Quality Page 45 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(6) Volatile organic compounds (VOC) wastewater - Water which, as part of a 

facility process, has come into contact with VOC and is intended for treatment, disposal, or discharge 

without further use in the process unit. 

(7) Water seal controls - A seal pot, p-leg trap, or other type of trap filled with water 

(e.g., flooded sewers that maintain water levels adequate to prevent air flow through the system) that 

creates a water barrier between the water level of the seal and the atmosphere. The water level of the 

seal must be maintained in the vertical leg of a drain in order to be considered a water seal. 

(8) Wet weather retention basin - An impoundment or tank that is used to store 

rainfall runoff that would exceed the capacity of the wastewater treatment system until it can be 

returned to the wastewater treatment system or, if the water meets the applicable discharge limits, 

discharged without treatment. These units may also be used to store wastewater during periods when 

the wastewater treatment system is shut down for maintenance or emergencies. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.142. Control Requirements. 

The owner or operator of an affected source category within a plant in the Beaumont/Port 

Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, as defined in '115.10 of this title 

(relating to Definitions), shall comply with the following control requirements. Any component of a 

wastewater storage, handling, transfer, or treatment facility, if the component contains an affected 

volatile organic compounds (VOC) wastewater stream, shall be controlled in accordance with either 

paragraph (1) or (2) of this section, except for properly operated biotreatment units which shall meet the 

requirements of paragraph (3) of this section. In the Dallas/Fort Worth and El Paso areas, and until 

December 31, 2002 in the Houston/Galveston area, the control requirements apply from the point of 

generation of an affected VOC wastewater stream until the affected VOC wastewater stream is either 

returned to a process unit or is treated to remove VOC so that the wastewater stream no longer meets 

the definition of an affected VOC wastewater stream. In the Beaumont/Port Arthur area, and after 

December 31, 2002 in the Houston/Galveston area, the control requirements apply from the point of 

generation of an affected VOC wastewater stream until the affected VOC wastewater stream is either 

returned to a process unit, or is treated to reduce the VOC content of the wastewater stream by 90% by 

weight and also reduce the VOC content of the same VOC wastewater stream to less than 1,000 parts 

per million by weight. For wastewater streams which are combined and then treated to remove VOC, 

the amount of VOC to be removed from the combined wastewater stream shall be at least the total 

amount of VOC that would be removed to treat each individual affected VOC wastewater stream so that 

they no longer meet the definition of affected VOC wastewater stream, except for properly operated 

biotreatment units which shall meet the requirements of paragraph (3) of this section. For this division, 

a component of a wastewater storage, handling, transfer, or treatment facility shall include, but is not 

limited to, wastewater storage tanks, surface impoundments, wastewater drains, junction boxes, lift 

stations, weirs, and oil-water separators. 

(1) The wastewater component shall meet the following requirements. 
Texas Commission on Environmental Quality Page 46 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(A) All components shall be fully covered or be equipped with water seal 

controls. For any component equipped with water seal controls, the only acceptable alternative to water 

as the sealing liquid in a water seal is the use of ethylene glycol, propylene glycol, or other low vapor 

pressure antifreeze, which may be used only during the period of November through February. For 

any process drain not equipped with water seal controls, the process drain shall be equipped with a 

gasketed seal, or a tightly-fitting cap or plug. 

(B) All openings shall be closed and sealed, except when the opening is in 

actual use for its intended purpose or the component is maintained at a pressure less than atmospheric 

pressure. 

(C) All liquid contents shall be totally enclosed. 

(D) For junction boxes and vented covers, the following requirements apply. 

(i) In the Dallas/Fort Worth and El Paso areas, and until December 31, 

2002 in the Houston/Galveston area, if any cover, other than a junction box cover, is equipped with a 

vent, the vent shall be equipped with either a vapor control system which maintains a minimum control 

efficiency of 90% or a closed system which prevents the flow of VOC vapors from the vent during 

normal operation. Any junction box vent shall be equipped with a vent pipe at least 90 centimeters 

(cm) (36 inches (in.)) in length and no more than 10.2 cm (4.0 in.) in diameter. 

(ii) In the Beaumont/Port Arthur area, and after December 31, 2002 in 

the Houston/Galveston area, the following requirements apply. 

(I) If any cover or junction box cover, except for junction 

boxes described in subclause (II) of this clause, is equipped with a vent, the vent shall be equipped with 

either a vapor control system which maintains a minimum control efficiency of 90% or a closed system 

which prevents the flow of VOC vapors from the vent during normal operation. 

(II) Any junction box that is filled and emptied by gravity flow 

(i.e., there is no pump) or is operated with no more than slight fluctuations in the liquid level may be 

vented to the atmosphere, provided it is equipped with: 

(-a-) a vent pipe at least 90 cm (36 in.) in length and 

no more than 10.2 cm (4.0 in.) in diameter; and 

(-b-) water seal controls which are installed and 

maintained at the wastewater entrance(s) to or exit from the junction box restricting ventilation in the 

individual drain system and between components in the individual drain system. 

(E) All gauging and sampling devices shall be vapor-tight except during 

gauging or sampling. 
Texas Commission on Environmental Quality Page 47 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(F) Any loading or unloading to or from a portable container by pumping shall 

be performed with a submerged fill pipe. 

(G) All seals and cover connections shall be maintained in proper condition. 

For purposes of this paragraph, "proper condition" means that covers shall have a tight seal around the 

edge and shall be kept in place except as allowed by this division, that seals shall not be broken or have 

gaps, and that sewer lines shall have no visible gaps or cracks in joints, seals, or other emission 

interfaces. 

(H) If any seal or cover connection is found to not be in proper condition, a 

first attempt at repair shall be made no later than five calendar days after the leak or improper condition 

is found. The repair or correction shall be completed as soon as possible but no later than 15 calendar 

days after detection, unless the repair or correction is technically infeasible without requiring a process 

unit shutdown, in which case the repair or correction shall be made at the next process unit shutdown. 

Test Method 21 must be used to confirm that a leak or improper condition is repaired, and the 

following records shall be maintained: 

(i) the date on which a leak or improper condition is discovered; 

(ii) the date on which a first attempt at repair was made to correct the 

leak or improper condition; 

(iii) the date on which a leak or improper condition is repaired; and 

(iv) the date and instrument reading of the recheck procedure after a 

leak or improper condition is repaired. 

(2) If a wastewater component is equipped with an internal or external floating roof, it 

shall meet the following requirements. 

(A) All openings in an internal or external floating roof except for automatic 

bleeder vents (vacuum breaker vents) and rim space vents shall provide a projection below the liquid 

surface or be equipped with a cover, seal, or lid. Any cover, seal, or lid shall be in a closed (i.e., no 

visible gap) position at all times except when the opening is in actual use for its intended purpose. 

(B) Automatic bleeder vents (vacuum breaker vents) shall be closed at all times 

except when the roof is being floated off or landed on the roof leg supports. 

(C) Rim vents, if provided, shall be set to open only when the roof is being 

floated off the roof leg supports or at the manufacturer's recommended setting. 

(D) Any roof drain that empties into the stored liquid shall be provided with a 

slotted membrane fabric cover that covers at least 90% of the area of the opening. 
Texas Commission on Environmental Quality Page 48 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(E) There shall be no visible holes, tears, or other openings in any seal or seal 

fabric. 

(F) For external floating roof storage tanks, the secondary seals shall be the 

rim-mounted type (i.e., the seal shall be continuous from the floating roof to the tank wall). The 

accumulated area of gaps that exceed 1/8 in. (0.32 cm) in width between the secondary seal and tank 

wall shall be no greater than 1.0 in.2

 per foot (21 cm2/meter) of tank diameter. 

(3) In the Beaumont/Port Arthur area, and after December 31, 2002 in the 

Houston/Galveston area, each properly operated biotreatment unit shall meet the following 

requirements. 

(A) The VOC content of the wastewater shall be reduced by 90% by weight; 

and 

(B) The average concentration of suspended biomass maintained in the aeration 

basin of the biotreatment unit shall equal or exceed 1.0 kilogram per cubic meter (kg/m3), measured as 

total suspended solids. 

(4) Any wastewater component that becomes subject to this division by exceeding the 

provisions of '115.147 of this title (relating to Exemptions) or an affected VOC wastewater stream as 

defined in '115.140 of this title (relating to Industrial Wastewater Definitions) will remain subject to 

the requirements of this division, even if the component later falls below those provisions, unless and 

until emissions are reduced to no more than the controlled emissions level existing prior to the 

implementation of the project by which throughput or emission rate was reduced to less than the 

applicable exemption levels in '115.147 of this title; and 

(A) the project by which throughput or emission rate was reduced is authorized 

by any permit or permit amendment or standard permit or permit by rule required by Chapter 116 or 

Chapter 106 of this title (relating to Control of Air Pollution by Permits for New Construction or 

Modification; and Permits by Rule). If a permit by rule is available for the project, compliance with 

this division must be maintained for 30 days after the filing of documentation of compliance with that 

permit by rule; or 

(B) if authorization by permit, permit amendment, standard permit, or permit 

by rule is not required for the project, the owner or operator has given the executive director 30 days' 

notice of the project in writing. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.143. Alternate Control Requirements. 

(a) Alternate means of control. Alternate methods of demonstrating and documenting 
Texas Commission on Environmental Quality Page 49 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

continuous compliance with the applicable control requirements or exemption criteria in this division 

(relating to Industrial Wastewater) may be approved by the executive director in accordance with 

'115.910 of this title (relating to Availability of Alternate Means of Control) if emission reductions are 

demonstrated to be substantially equivalent. 

(b) 90% overall control option. As an alternative to the control requirements of '115.142 of 

this title (relating to Control Requirements), the owner or operator of a wastewater storage, handling, 

transfer, or treatment facility may elect to ensure that the overall control of volatile organic compounds 

(VOC) emissions at the account from wastewater from affected source categories is at least 90% less 

than the 1990 baseline emissions inventory, provided that the following requirements are met. 

(1) To qualify for the control option available under this subsection after December 31, 

1996, the owner or operator of a wastewater component for which a control plan was not previously 

submitted shall submit a control plan to the executive director, the appropriate regional office, and any 

local air pollution control program with jurisdiction which demonstrates that the overall control of VOC 

emissions at the account from wastewater from affected source categories will be at least 90% less than 

the 1990 baseline emissions inventory. Any control plan submitted after December 31, 1996, must be 

approved by the executive director before the owner or operator may use the control option available 

under this subsection for compliance. At a minimum, the control plan shall include the applicable 

emission point number (EPN); the facility identification number (FIN); the calendar year 1990 emission 

rates of wastewater from affected source categories (consistent with the 1990 emissions inventory); a 

plot plan showing the location, EPN, and FIN associated with a wastewater storage, handling, transfer, 

or treatment facility; the VOC emission rates for the preceding calendar year; and an explanation of the 

recordkeeping procedure and calculations which will be used to demonstrate compliance. The VOC 

emission rates shall be calculated in a manner consistent with the 1990 emissions inventory. 

(2) The owner or operator shall submit an annual report no later than March 31 of each 

year to the executive director, the appropriate regional office, and any local air pollution control 

program with jurisdiction, which demonstrates that the overall control of VOC emissions at the account 

from wastewater from affected source categories during the preceding calendar year is at least 90% less 

than the 1990 baseline emissions inventory. At a minimum, the report shall include the EPN; FIN; the 

throughput of wastewater from affected source categories; a plot plan showing the location, EPN, and 

FIN associated with a wastewater storage, handling, transfer, or treatment facility; and the VOC 

emission rates for the preceding calendar year. The emission rates for the preceding calendar year shall 

be calculated in a manner consistent with the 1990 emissions inventory. 

(3) All representations in control plans and annual reports become enforceable 

conditions. It shall be unlawful for any person to vary from such representations if the variation will 

cause a change in the identity of the specific emission sources being controlled or the method of control 

of emissions unless the owner or operator submits a revised control plan to the executive director, the 

appropriate regional office, and any local air pollution control program with jurisdiction no later than 

30 days after the change. All control plans and reports shall include documentation that the overall 

reduction of VOC emissions at the account from wastewater from affected source categories continues 

to be at least 90% less than the 1990 baseline emissions inventory. The emission rates shall be 

calculated in a manner consistent with the 1990 emissions inventory. 
Texas Commission on Environmental Quality Page 50 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(c) The owner or operator of an affected source category within a plant may elect to comply 

with the provisions of 40 Code of Federal Regulations 63, Subpart G (National Emission Standards for 

Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry for 

Process Vents, Storage Vessels, Transfer Operations, and Wastewater, January 22, 2001) as an 

alternative to complying with this division, provided that: 

(1) the term "VOC" is substituted each place that Subpart G references the term 

"hazardous air pollutant" or "HAP"; 

(2) in Table 9 of Appendix to Subpart G - Table and Figures, the average fraction 

removed (FR) value required for VOC not specifically listed in this table is 0.90; and 

(3) before implementing the option available under this subsection, the owner or 

operator provides written notice to the executive director, the appropriate regional office, and any local 

air pollution control program with jurisdiction of the intention to use this option. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.144. Inspection and Monitoring Requirements. 

The owner or operator of an affected source category within a plant in the Beaumont/Port 

Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas shall comply with the following 

inspection and monitoring requirements. 

(1) All seals and covers used to comply with '115.142(1) of this title (relating to 

Control Requirements) shall be inspected according to the following schedules to ensure compliance 

with '115.142(1)(G) and (H) of this title: 

(A) initially and semiannually thereafter to ensure compliance with 

'115.142(1)(G) of this title; and 

(B) upon completion of repair to ensure compliance with '115.142(1)(G) and 

(H) of this title. 

(2) Floating roofs and internal floating covers used to comply with '115.142(2) of this 

title shall be subject to the following requirements. All secondary seals shall be inspected according to 

the following schedules to ensure compliance with '115.142(2)(E) and (F) of this title. 

(A) If the primary seal is vapor-mounted, the secondary seal gap area shall be 

physically measured annually to ensure compliance with '115.142(2)(F) of this title. 

(B) If the tank is equipped with a mechanical shoe or liquid-mounted primary 

seal, compliance with '115.142(2)(F) of this title may be determined by visual inspection. 
Texas Commission on Environmental Quality Page 51 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(C) All secondary seals shall be visually inspected semiannually to ensure 

compliance with '115.142(2)(E) and (F) of this title. 

(3) Monitors shall be installed and maintained as required by this section to measure 

operational parameters of any emission control device or other device installed to comply with 

'115.142 of this title. Such monitoring and parameters shall be sufficient to demonstrate proper 

functioning of those devices to design specifications, and include the monitoring and parameters listed 

in subparagraphs (A) - (H) of this paragraph, as applicable. In lieu of the monitoring and parameters 

listed in subparagraphs (A) - (H) of this paragraph, other monitoring and parameters may be approved 

or required by the executive director: 

(A) for an enclosed non-catalytic combustion device (including, but not limited 

to, a thermal incinerator, boiler, or process heater), continuously monitor and record the temperature of 

the gas stream either in the combustion chamber or immediately downstream before any substantial heat 

exchange; 

(B) for a catalytic incinerator, continuously monitor and record the temperature 

of the gas stream immediately before and after the catalyst bed; 

(C) for a condenser (chiller), continuously monitor and record the temperature 

of the gas stream at the condenser exit; 

(D) for a carbon adsorber, continuously monitor and record the VOC 

concentration of exhaust gas stream to determine if breakthrough has occurred. If the carbon adsorber 

does not regenerate the carbon bed directly in the control device (e.g., a carbon canister), the exhaust 

gas stream shall be monitored daily or at intervals no greater than 20% of the design replacement 

interval, whichever is greater, or as an alternative to conducting monitoring, the carbon may be 

replaced with fresh carbon at a regular predetermined time interval that is less than the carbon 

replacement interval that is determined by the maximum design flow rate and the VOC concentration in 

the gas stream vented to the carbon adsorber; 
Texas Commission on Environmental Quality Page 52 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(E) for a flare, meet the requirements specified in 40 Code of Federal 

Regulations '60.18(b) and Chapter 111 of this title (relating to Control of Air Pollution from Visible 

Emissions and Particulate Matter); 

(F) for a steam stripper, continuously monitor and record the steam flow rate, 

the wastewater feed mass flow rate, the wastewater feed temperature, and condenser vapor outlet 

temperature; 

(G) for a vapor combustor, continuously monitor and record the exhaust gas 

temperature either in the combustion chamber or immediately downstream before any substantial heat 

exchange. Alternatively, the owner or operator of a vapor combustor may consider the unit to be a 

flare and meet the requirements of subparagraph (E) of this paragraph; and 

(H) for vapor control systems other than those specified in subparagraphs (A) -

(G) of this paragraph, continuously monitor and record the appropriate operating parameters. 

(4) In the Beaumont/Port Arthur and Houston/Galveston areas, units used to comply 

with '115.142(3) of this title shall: 

(A) initially demonstrate a 90% reduction in VOCs by using the methods in 

'115.145 of this title (relating to Approved Test Methods); and 

(B) measure on a weekly basis the total suspended solids in the aeration basin 

of the biotreatment unit. 

(5) All water seal controls shall be inspected weekly to ensure that the water seal 

controls are effective in preventing ventilation, except that daily inspections are required for those seals 

that have failed three or more inspections in any 12-month period. Upon request by the executive 

director, EPA, or any local program with jurisdiction, the owner or operator shall demonstrate (e.g., by 

visual inspection or smoke test) that the water seal controls are properly designed and restrict 

ventilation. 

(6) All process drains not equipped with water seal controls shall be inspected monthly 

to ensure that all gaskets, caps, and/or plugs are in place and that there are no gaps, cracks, or other 

holes in the gaskets, caps, and/or plugs. In addition, all caps and plugs shall be inspected monthly to 

ensure that they are tightly-fitting. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.145. Approved Test Methods. 

Compliance with the emission specifications, vapor control system efficiency, and certain 

control requirements, inspection requirements, and exemption criteria of ''115.142 - 115.144 and 

115.147 of this title (relating to Control Requirements; Alternate Control Requirements; Inspection and 
Texas Commission on Environmental Quality Page 53 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Monitoring Requirements; and Exemptions) shall be determined by applying one or more of the 

following test methods and procedures, as appropriate. 

(1) Gas flow rate. Test Methods 1-4 (40 Code of Federal Regulations (CFR) Part 60, 

Appendix A) are used for determining gas flow rates, as necessary. 

(2) Concentration of Volatile Organic Compounds (VOC). 

(A) Test Method 18 (40 CFR Part 60, Appendix A) is used for determining 

gaseous organic compound emissions by gas chromatography. 

(B) Test Method 25 (40 CFR 60, Appendix A) is used for determining total 

gaseous nonmethane organic emissions as carbon. 

(C) Test Methods 25A or 25B (40 CFR 60, Appendix A) are used for 

determining total gaseous organic concentrations using flame ionization or nondispersive infrared 

analysis. 

(3) Performance requirements for flares and vapor combustors. 

(A) For flares, the performance test requirements of 40 CFR 60.18(b) shall 

apply. 

(B) For vapor combustors, the owner or operator may consider the unit to be a 

flare and meet the performance test requirements of 40 CFR 60.18(b) rather than the procedures of 

paragraphs (1) and (2) of this section. 

(C) Compliance with the requirements of 40 CFR 60.18(b) will be considered 

to represent 98% control of the VOC in the flare inlet. 

(4) Vapor pressure. Use standard reference texts or American Society for Testing and 

Materials (ASTM) Test Methods D323-89, D2879, D4953, D5190, or D5191 for the measurement of 

vapor pressure, adjusted for actual storage temperature in accordance with American Petroleum 

Institute Publication 2517, Third Edition, 1989. 

(5) Leak determination by instrument method. Use Test Method 21 (40 CFR 60, 

Appendix A) for determining VOC leaks and for monitoring a carbon canister in accordance with 

'115.144(3)(D) of this title. 

(6) Determination of VOC concentration of wastewater samples. Use Test Method 

5030 (purge and trap) followed by Test Method 8015 with a DB-5 boiling point (or equivalent column), 

and flame ionization detector, with the detector calibrated with benzene (SW-846 and 40 CFR Part 

261); Test Methods 3810, 5030 (followed by 8020), 8240, 8260, and 9060 (SW-846 and 40 CFR Part 

261); Test Methods 602 and 624 (40 CFR Part 136); Test Method 5310(B) (Standard Methods 17th 
Texas Commission on Environmental Quality Page 54 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Edition); or Test Method 25D (40 CFR Part 60, Appendix A). 

(7) Determination of total suspended solids. Use Method 160.2 (Methods for 

Chemical Analysis of Water and Wastes, EPA-600/4-79-020) or Method 2540D (Standard Methods for 

the Examination of Water and Wastewater, 18th Edition, American Public Health Association). 

(8) Determination of biotreatment unit efficiency. Use the methods found in 40 CFR 

63 Appendix C or 40 CFR 63.145. A stream-specific list of VOCs shall be used and is determined as 

follows: 

(A) compounds with concentrations below one part per million by weight 

(ppmw) or below the lower detection limit may be excluded; 

(B) for the owner or operator that can identify at least 90% by weight of the 

VOCs in the wastewater stream, the individual VOCs that are 5.0% by weight or greater are required 

to be included on the list. If less than half of the total VOCs in the wastewater are represented by the 

compounds that are 5.0% by weight or greater, the owner or operator shall include those individual 

VOCs with the greatest mass on the stream-specific list of VOCs until 75 compounds or every 

compound, whichever is fewer, is included on the list, except as provided by subparagraph (A) of this 

paragraph. The owner or operator shall document that the site-specific list of VOCs is representative of 

the process wastewater stream; and 

(C) for the owner or operator that can identify at least 50% by weight of the 

VOCs in the wastewater stream, the individual VOCs with the greatest mass on the stream-specific list 

of VOCs up to 75 compounds or every compound, whichever is fewer, shall be included on the list, 

except as provided by subparagraph (A) of this paragraph. The owner or operator shall document that 

the site-specific list of VOCs is representative of the process wastewater stream. 

(9) Minor modifications. Minor modifications to these test methods may be used, if 

approved by the executive director. 

(10) Alternate test methods. Test methods other than those specified in paragraphs (1) 

- (8) of this section may be used if validated by 40 CFR 63, Appendix A, Test Method 301 (effective 

December 29, 1992). For the purposes of this paragraph, substitute "executive director" each place that 

Test Method 301 references "administrator." 

Adopted April 26, 2002 Effective May 16, 2002 

'115.146. Recordkeeping Requirements. 

The owner or operator of an affected source category within a plant in the Beaumont/Port 

Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas shall comply with the following 

recordkeeping requirements. 
Texas Commission on Environmental Quality Page 55 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) Complete and up-to-date records shall be maintained as needed to demonstrate 

compliance with '115.142 and '115.143 of this title (relating to Control Requirements; and Alternate 

Control Requirements) which are sufficient to demonstrate the characteristics of wastewater streams and 

the qualification for any exemptions claimed under '115.147 of this title (relating to Exemptions). 

(2) Records shall be maintained of the results of any inspection or monitoring 

conducted in accordance with '115.144 of this title (relating to Inspection and Monitoring 

Requirements). Records shall be sufficient to demonstrate proper functioning of applicable control 

equipment to design specifications to ensure compliance with '115.142 and '115.143 of this title. 

(3) Records shall be maintained of the results of any testing conducted in accordance 

with '115.145 of this title (relating to Approved Test Methods). 

(4) All records shall be maintained at the plant for at least two years and be made 

available upon request to representatives of the executive director, EPA, or any local air pollution 

control agency having jurisdiction in the area. 

Adopted October 27, 1999 Effective November 18, 1999 

'115.147. Exemptions. 

The following exemptions apply in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston areas. 

(1) Any plant with an annual volatile organic compounds (VOC) loading in 

wastewater, as determined in accordance with '115.148 of this title (relating to Determination of 

Wastewater Characteristics), less than or equal to ten megagrams (Mg) (11.03 tons) is exempt from the 

control requirements of '115.142 of this title (relating to Control Requirements). 

(2) At any plant with an annual VOC loading in wastewater, as determined in 

accordance with '115.148 of this title greater than ten Mg (11.03 tons), any person who is the owner or 

operator of the plant may exempt from the control requirements of '115.142 of this title one or more 

affected VOC wastewater streams for which the sum of the annual VOC loading in wastewater for all of 

the exempted streams is less than or equal to ten Mg (11.03 tons). 

(3) Unless specifically required by this division (relating to Industrial Wastewater), any 

piece of equipment of a wastewater storage, handling, transfer, or treatment facility to which the 

control requirements of '115.142 of this title apply is exempt from the requirements of any other 

division of this chapter. This paragraph does not apply to pieces of equipment or components which 

are subject to the requirements of Subchapter D, Division 3, and/or Subchapter H of this chapter 

(relating to Fugitive Emission Control in Petroleum Refining, Natural Gas/Gasoline Processing, and 

Petrochemical Processes in Ozone Nonattainment Areas; and Highly-Reactive Volatile Organic 

Compounds). 
Texas Commission on Environmental Quality Page 56 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(4) If compliance with the control requirements of '115.142 of this title would create a 

safety hazard in a component of a wastewater storage, handling, transfer, or treatment facility, the 

owner or operator may request the executive director to exempt that component from the control 

requirements of '115.142 of this title. The executive director shall approve the request if justified by 

the likelihood and magnitude of the potential injury and if the executive director determines that 

reducing or eliminating the hazard is technologically or economically unreasonable based on the 

emissions reductions that would be achieved. 

(5) Wet weather retention basins are exempt from the requirements of this division. 

(6) Petroleum refineries in the Beaumont/Port Arthur area are exempt from the 

requirements of this division. 

(7) The following exemptions apply to petroleum refineries in the Houston/Galveston 

area. 

(A) Petroleum refineries are exempt from the requirement in '115.142 of this 

title that after December 31, 2002, the control requirements apply from the point of generation of an 

affected VOC wastewater stream until the affected VOC wastewater stream is either returned to a 

process unit, or is treated to reduce the VOC content of the wastewater stream by 90% by weight and 

also reduce the VOC content of the same VOC wastewater stream to less than 1,000 parts per million 

by weight, provided that petroleum refineries continue to apply the requirement in '115.142 of this title 

that the control requirements apply from the point of generation of an affected VOC wastewater stream 

until the affected VOC wastewater stream is either returned to a process unit, or is treated to remove 

VOC so that the wastewater stream no longer meets the definition of an affected VOC wastewater 

stream. 

(B) Junction boxes are exempt from the requirements of '115.142(1)(D)(ii) of 

this title, provided that after December 31, 2002 they continue to comply with the requirements of 

'115.142(1)(D)(i) of this title. 

(C) Properly operated biotreatment units are exempt from the requirements of 

''115.142(3), 115.144(4), and 115.145(7) and (8) of this title (relating to Control Requirements; 

Inspection and Monitoring Requirements; and Approved Test Methods). 

Adopted December 13, 2002 Effective January 17, 2003 

'115.148. Determination of Wastewater Characteristics. 

The determination of the characteristics of a wastewater stream for purposes of this division 

(relating to Industrial Wastewater) shall be made as follows. 

(1) The characteristics shall be determined at a location between the point of generation 

and before the wastewater stream is exposed to the atmosphere, treated for volatile organic compounds 
Texas Commission on Environmental Quality Page 57 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(VOC) removal, or mixed with another wastewater stream. For wastewater streams which, prior to 

November 15, 1993, were either actually being mixed or construction had commenced which would 

result in the wastewater streams being mixed, this mixing shall not establish a limit on where the 

characteristics may be determined. 

(2) The flow rate of a wastewater stream shall be determined on the basis of an annual 

average by one of the following methods: 

(A) the highest annual quantity of wastewater managed, based on historical 

records for the most recent five years of operation, or for the entire time the wastewater stream has 

existed if less than five years but at least one year; 

(B) the maximum design capacity of the wastewater component; 

(C) the maximum design capacity to generate wastewater of the process unit 

generating the wastewater stream; 

(D) measurements that are representative of the actual, normal wastewater 

generation rates. 

(3) The VOC concentration of a wastewater stream shall be determined on the basis of 

a flow-weighted annual average by one of the following methods, or by a combination of the methods. 

If the executive director determines that the VOC concentration cannot be adequately determined by 

knowledge of the wastewater, or by bench-scale or pilot-scale test data, the VOC concentration shall be 

determined in accordance with subparagraph (C) of this paragraph, or by a combination of the methods 

in subparagraphs (A), (B), and (C) of this paragraph. VOC with a Henry's Law Constant less than 

7.5x10-5 atm-m3

/mole at 25 degrees Celsius shall not be included in the determination of VOC 

concentration. 

(A) Knowledge of the wastewater. Sufficient information to document the 

VOC concentration. Examples of information include material balances, records of chemical 

purchases, or previous test results. 

(B) Bench-scale or pilot-scale test data. Sufficient information to demonstrate 

that the bench-scale or pilot-scale test concentration data are representative of the actual VOC 

concentration. 

(C) Measurements. Collect a minimum of three representative samples from 

the wastewater stream and determine the VOC concentration for each sample in accordance with 

'115.145 of this title (relating to Approved Test Methods). The VOC concentration of the wastewater 

stream shall be the flow-weighted average of the individual samples. 

(4) The annual VOC loading in wastewater for a wastewater stream shall be the annual 

average flow rate determined in paragraph (2) of this section multiplied by the annual average VOC 
Texas Commission on Environmental Quality Page 58 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

concentration determined in paragraph (3) of this section. 

(5) The annual VOC loading in wastewater for a plant shall be the sum of the annual 

VOC loading in wastewater for each affected VOC wastewater stream. 

Adopted October 27, 1999 Effective November 18, 1999 

'115.149. Counties and Compliance Schedules. 

(a) The owner or operator of each affected source category within a plant in Brazoria, 

Chambers, Collin, Dallas, Denton, El Paso, Fort Bend, Galveston, Hardin, Harris, Jefferson, Liberty, 

Montgomery, Orange, Tarrant, and Waller Counties shall continue to comply with this division 

(relating to Industrial Wastewater) as required by '115.930 of this title (relating to Compliance Dates). 

(b) The owner or operator of each affected source category within a plant in Ellis, Johnson, 

Kaufman, Parker, and Rockwall Counties shall comply with this division as soon as practicable, but no 

later than March 1, 2009. 

Adopted November 15, 2006 Effective December 7, 2006 
Texas Commission on Environmental Quality Page 59 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER B: GENERAL VOLATILE ORGANIC COMPOUND SOURCES 

DIVISION 5: MUNICIPAL SOLID WASTE LANDFILLS 

''115.152, 115.153, 115.155 - 115.157, 115.159 

Effective May 16, 2002

'115.152. Control Requirements. 

(a) For the Houston/Galveston, El Paso, and Dallas/Fort Worth ozone nonattainment areas as 

defined in '115.10 of this title (relating to Definitions), no person shall operate or allow the operation 

of a municipal solid waste landfill (MSWLF) unless each owner or operator of a MSWLF calculates the 

nonmethane organic compounds (NMOC) emission rate for the landfill using the procedures provided in 

'60.753 of the proposed federal rules published in the May 30, 1991, issue of the Federal Register (58 

FR 104). The volatile organic compound emission rate shall be calculated and recalculated annually 

using the following default values: Generation Rate Constant, K = 0.05 1/year; Generation Potential, 

Lo = 170 m3

/Mg; Non-methane Gas Concentration, CNMOC = 4000 ppmv. If at any time the calculated 

NMOC emission rate exceeds 150 Megagrams (Mg) per year, the owner or operator shall: 

(1) install a gas collection and control system (GCCS) subject to the requirements of 

'60.752(b)(2)(ii) of the proposed federal rules published in the May 30, 1991, issue of the Federal 

Register (58 FR 104). Alternative design methodologies to the GCCS are subject to the approval of the 

executive director; 

(2) control NMOC gas emissions in one of the following ways: 

(A) the total collected gas is routed to an open flare designed and operated in 

accordance with 40 CFR '60.18; 

(B) the total collected gas is routed to a control device which reduces the total 

collected gas emissions by 98% or to less than 20 parts per million by volume; or 

(C) the total collected gas is routed to a gas treatment system which processes 

the collected gas for subsequent use or sale. The sum of all emissions from any atmospheric vent from 

the gas treatment system shall be subject to the requirements of subparagraph (A) of this paragraph. 

(3) operate the GCCS in compliance with '60.754 of the proposed federal rules 

published in the May 30, 1991, issue of the Federal Register (58 FR 104). 

(b) The GCCS may be capped or removed if all of the following conditions are met: 

(1) the landfill shall no longer accept waste and shall be permanently closed; 

(2) the GCCS shall have been in continuous operation for at least 15 years; and 
Texas Commission on Environmental Quality Page 60 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(3) the calculated NMOC emission rate shall be less than 150 Mg per year on three 

successive test dates. The test dates shall be no closer than three months apart, and no longer than six 

months apart. 

Adopted May 4, 1994 Effective May 27, 1994 

'115.153. Alternate Control Requirements. 

For all persons in the Houston/Galveston, El Paso, and Dallas/Fort Worth ozone nonattainment 

areas, alternate methods of demonstrating and documenting continuous compliance with the applicable 

control requirements or exemption criteria in this division (relating to Municipal Solid Waste Landfills) 

may be approved by the executive director in accordance with '115.910 of this title (relating to 

Availability of Alternate Means of Control) if emission reductions are demonstrated to be substantially 

equivalent. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.155. Approved Test Methods. 

Compliance with '115.152 of this title (relating to Control Requirements) shall be determined 

by applying the following test methods, as appropriate: 

(1) Test Methods 1-4 (40 CFR 60, Appendix A) for determining flow rate, oxygen 

concentration, or moisture, as necessary; 

(2) Test Method 2E as proposed under 40 CFR 60, Appendix A, published in the May 

30, 1991, issue of the Federal Register (58 FR 104) for designing the area of influence of the gas 

collection and control system (GCCS); 

(3) Test Method 3C as proposed under 40 CFR 60, Appendix A, published in the May 

30, 1991, issue of the Federal Register (58 FR 104) for measuring the concentration of nitrogen in the 

landfill gas; 

(4) Test Method 18 (40 CFR 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(5) Test Method 21 (40 CFR 60, Appendix A) for determining volatile organic 

compound leaks; 

(6) Test Method 25 (40 CFR 60, Appendix A) for determining total gaseous 

nonmethane (CH4) organic emissions as carbon; 

(7) Test Methods 25A or 25B (40 CFR 60, Appendix A) for determining total gaseous 

organic concentrations using flame ionization or nondispersive infrared analysis; 
Texas Commission on Environmental Quality Page 61 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(8) Test Method 25C as proposed under 40 CFR 60, Appendix A, published in the 

May 30, 1991, issue of the Federal Register (58 FR 104) for determining non-CH4 organic compounds 

in landfill gases; 

(9) determination of true vapor pressure using American Society for Testing and 

Materials Test Methods D323-89, D2879, D4953, D5190, or D5191 for the measurement of Reid 

vapor pressure, adjusted for actual storage temperature in accordance with American Petroleum 

Institute Publication 2517, Third Edition, 1989; 

(10) one of the above test methods with minor modifications as approved by the 

Executive Director. 

Adopted May 4, 1994 Effective May 27, 1994 

'115.156. Monitoring and Recordkeeping Requirements. 

For the Houston/Galveston, El Paso, and Dallas/Fort Worth ozone nonattainment areas, the 

following recordkeeping requirements shall apply. 

(1) For municipal solid waste landfills (MSWLF), which are not subject to the 

requirements of '115.152 of this title (relating to Control Requirements), the owner or operator of each 

landfill shall maintain complete and up-to-date records sufficient to demonstrate continuous compliance 

with the applicable exemption criteria including, but not limited to, an annual calculation of the nonmethane organic compounds (NMOC) emissions rate and any other necessary operational information. 

(2) For MSWLF, which are subject to the requirements of '115.152 of this title, the 

owner or operator of each landfill shall install and maintain monitors to continuously measure and 

record operational parameters of any emission control device installed to meet applicable control 

requirements. Such records must be sufficient to demonstrate proper functioning of those devices to 

design specifications, including but not limited to: 

(A) the exhaust gas temperature immediately downstream for any direct-flame 

incinerator or enclosed flare; 

(B) the gas temperature immediately upstream and downstream for any 

catalytic incinerator or chiller; 

(C) the NMOC concentration for any carbon adsorption system exhaust gas to 

determine if breakthrough has occurred; 

(D) the gas flowrate to the combustion device; 

(E) monthly readings of the gauge pressure at each well in the gas collection 
Texas Commission on Environmental Quality Page 62 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

header; 

(F) the percent methane concentration at each well in the gas collection header; 

and 

(G) the dates and reasons for any maintenance and repair of the required gas 

collection and control system and control devices and the estimated quantity and duration of NMOC 

emissions during such activities. 

(3) Each owner or operator of a MSWLF shall annually submit an emissions inventory 

report as required by '101.10 of this title (relating to Emissions Inventory Requirements). This report 

shall include: 

(A) calculation of the NMOC emission rate; 

(B) a map or plot of the landfill, providing the size and location, and 

identifying all areas where waste may be landfilled according to the provisions of the permit; 

(C) the maximum design capacity; 

(D) notification of any increase in the size of the landfill. The increase may 

result from: 

(i) an increase in the permitted area or depth of the landfill; 

(ii) a change in the operating procedures; or 

(iii) any other means which will increase the maximum design capacity 

of the landfill; and 

(E) notification of closure. 

(i) For purposes of this subchapter, closure means that waste is no 

longer being placed in the landfill, and no additional wastes will be placed in the landfill without filing 

a notification of modification, as prescribed by the commission. 

(ii) Landfills that are closed permanently between reporting periods 

shall report as directed by '101.10 of this title and continue reporting until the calculated NMOC 

comission rate falls below 150 Mg per year on three successive test dates. The test dates shall be no 

closer than three months apart, and no longer that six months apart. 

Adopted April 30, 1997 Effective May 22, 1997 

'115.157. Exemptions. 
Texas Commission on Environmental Quality Page 63 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

For the Houston/Galveston, El Paso, and Dallas/Fort Worth ozone nonattainment areas, the 

following facilities are exempt: 

(1) any municipal solid waste landfill (MSWLF) with a capacity of less than 100,000 

Mg (111,000 tons); 

(2) any MSWLF which closed or stopped receiving waste prior to November 8, 1987, 

and does not have the capacity to receive more waste. 

Adopted May 4, 1994 Effective May 27, 1994 

'115.159. Counties and Compliance Schedule. 

(a) All affected municipal solid waste landfills (MSWLFs) in Collin, Dallas, Denton, and 

Tarrant Counties shall demonstrate compliance with this division (relating to Municipal Solid Waste 

Landfills) as soon as practicable, but no later than May 31, 1996. 

(b) All affected MSWLFs in El Paso County shall demonstrate compliance with this division as 

soon as practicable, but no later than November 15, 1996. 

(c) All affected MSWLFs in Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, 

Montgomery, and Waller Counties shall demonstrate compliance with this division as soon as 

practicable, but no later than one year, after the commission publishes notification in the Texas Register 

of its determination that this contingency rule is necessary as a result of failure to attain the National 

Ambient Air Quality Standard (NAAQS) for ozone by the attainment deadline or failure to demonstrate 

reasonable further progress as set forth in the 1990 Amendments to the Federal Clean Air Act (FCAA), 

'172(c)(9). 

Adopted April 26, 2002 Effective May 16, 2002 
Texas Commission on Environmental Quality Page 64 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER B: GENERAL VOLATILE ORGANIC COMPOUND SOURCES 

DIVISION 6: BATCH PROCESSES 

''115.160 - 115.167, 115.169 

Effective October 20, 2005 

'115.160. Batch Process Definitions. 

The following words and terms, when used in this division (relating to Batch Processes), shall 

have the following meanings, unless the context clearly indicates otherwise. Additional definitions for 

terms used in this division are found in ''3.2, 101.1, and 115.10 of this title (relating to Definitions). 

(1) Aggregated - The summation of all process vents containing volatile organic 

compounds (VOC) within a process. 

(2) Annual mass emissions total - The sum of all VOC emissions (pounds per year), 

evaluated before control but after the last recovery device, from a process vent. Annual mass emissions 

shall be calculated from an individual process vent or groups of process vents by using emission 

estimation equations contained in Chapter 3 of EPA's Control of Volatile Organic Compound Emissions 

from Batch Processes-Alternative Control Techniques Information Document (EPA-453/R-94-020, 

February 1994) and then multiplying by the historical duration and frequency of the emission or groups 

of emissions over the course of a year. For process vents that are included in a new source review air 

permit, standard permit, or permit by rule registered by Form PI-8, the annual mass emissions total 

shall be based on the maximum allowable emission rate (MAER) levels in the permit or Form PI-8 

(adjusted to represent the level before control, but after the last recovery device), whether they 

correspond to the maximum design production potential or to the actual annual production estimate. 

(3) Average flow rate - The flow rate in standard cubic feet per minute (scfm) 

averaged over the amount of time that VOCs are emitted during an emission event. For the evaluation 

of average flow rate from an aggregate of sources, the average flow rate is the weighted average of the 

average flow rates of the emission events and their annual venting time, or: 

Average flow rate = 3(F)(D) 

3D 

where: 

F = Average flow rate per emission event 

D = Annual duration of emission event 

(4) Batch - A noncontinuous process involving the bulk movement of material through 

sequential manufacturing steps. Mass, temperature, concentration, and other properties of a system 
Texas Commission on Environmental Quality Page 65 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

vary with time. Batch processes are not characterized by steady-state conditions. Reactants are not 

added and products are not removed simultaneously. 

(5) Batch cycle - A manufacturing event of an intermediate or product from start to 

finish in a batch process. 

(6) Batch process (for the purpose of determining reasonably available control 

technology (RACT) applicability) - The batch equipment assembled and connected by pipes, or 

otherwise operated in a sequence of steps, to manufacture a product in a batch fashion. 

(7) Batch process train - An equipment train that is used to produce a product or 

intermediates in batch fashion. A typical equipment train consists of equipment used for the synthesis, 

mixing, and purification of a material. 

(8) Emissions before control - The emissions total before the application of a control 

device but after the last recovery device, or the emissions total if no control device is used. The 

emissions total may not be reduced to account for discharge of VOC into wastewater if the wastewater 

is further handled or processed with the potential for VOC emissions to the atmosphere. 

(9) Primary fuel - The fuel that provides the principal heat input to a device. To be 

considered a primary fuel, the fuel must be able to sustain operation without the addition of other fuels. 

(10) Process vent - A vent gas stream that is discharged from a batch process. Process 

vents include gas streams that are discharged directly to the atmosphere or are discharged to the 

atmosphere after diversion through a recovery device. Process vents exclude relief valve discharges, 

leaks from equipment, vents from storage tanks, vents from transfer/loading operations, and vents from 

wastewater. Process gaseous streams that are used as primary fuels are also excluded. The lines that 

transfer such fuels to a plant fuel gas system are not considered to be vents. 

(11) RACT - Reasonably available control technology. 

(12) Recovery device - An individual unit of equipment capable of and used for 

recovering chemicals for use, reuse, or sale. Recovery devices include, but are not limited to, 

absorbers, carbon adsorbers, and condensers. 

(13) Unit operations - Those discrete processing steps that occur within distinct 

equipment that are used to prepare reactants, facilitate reactions, separate and purify products, and 

recycle materials. 

(14) Volatility - As follows. 

(A) Low volatility VOCs are those which have a vapor pressure less than or 

equal to 75 millimeters of mercury (mm Hg) at 20 degrees Celsius. 
Texas Commission on Environmental Quality Page 66 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(B) Moderate volatility VOCs are those which have a vapor pressure greater 

than 75 and less than or equal to 150 mm Hg at 20 degrees Celsius. 

(C) High volatility VOCs are those which have a vapor pressure greater than 

150 mm Hg at 20 degrees Celsius. 

(D) To evaluate VOC volatility for single unit operations that service numerous 

VOCs or for processes handling multiple VOCs, the weighted average volatility can be calculated from 

the total amount of each VOC emitted in a year and the individual component vapor pressure, as 

follows. 

Weighted average volatility = 3Vpi x (Mi / MWi)

3 (Mi / MWi ) 

where: 

Vpi = Vapor pressure of VOC component i 

Mi = Mass of VOC component i 

MWi = Molecular weight of VOC component i 

Adopted December 13, 2002 Effective January 17, 2003 

'115.161. Applicability. 

(a) The provisions of ''115.162 - 115.167 of this title (relating to Control Requirements; 

Alternate Control Requirements; Determination of Emissions and Flow Rates; Approved Test Methods 

and Testing Requirements; Monitoring and Recordkeeping Requirements; and Exemptions) apply to 

vent gas streams at batch process operations in the Beaumont/Port Arthur and Houston/Galveston areas, 

as defined in '115.10 of this title (relating to Definitions), under the following Standard Industrial 

Classification (SIC) codes: 

(1) 2821 (plastic resins and materials); 

(2) 2833 (medicinals and botanicals); 

(3) 2834 (pharmaceutical preparations); 

(4) 2861 (gum and wood chemicals); 

(5) 2865 (cyclic crudes and intermediates); 

(6) 2869 (industrial organic chemicals, not elsewhere classified); and 

(7) 2879 (agricultural chemicals, not elsewhere classified). 
Texas Commission on Environmental Quality Page 67 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(b) Any batch process operation that is exempt under '115.167(1) or (2)(A) of this title is 

subject to the requirements of Division 2 of this subchapter (relating to Vent Gas Control). 

(c) Any batch process in the Houston/Galveston area in which a highly-reactive volatile organic 

compound, as defined in '115.10 of this title, is a raw material, intermediate, final product, or in a 

waste stream is subject to the requirements of Subchapter H of this chapter (relating to Highly-Reactive 

Volatile Organic Compounds) in addition to the applicable requirements of either this division (relating 

to Batch Processes) or Division 2 of this subchapter, whichever of these two divisions applies. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.162. Control Requirements. 

The owner or operator of each batch process operation in the Beaumont/Port Arthur and 

Houston/Galveston areas shall comply with the following control requirements. 

(1) Reasonable available control technology (RACT) equations. The volatile organic 

compounds (VOC) mass emission rate from individual process vents or for process vent streams in 

aggregate within a batch process shall be reduced by 90% if the actual average flow rate value (in 

standard cubic feet per minute (scfm)) is below the flow rate (FR) value calculated using the applicable 

RACT equation for the volatility range (low, moderate, or high) of the material being emitted when the 

annual mass emission total (AE, in pounds per year) are input. The RACT equations, specific to 

volatility, are as follows: 

(A) Low volatility: FR = 0.07(AE) - 1821; 

(B) Moderate volatility: FR = 0.031(AE) - 494; 

(C) High volatility: FR = 0.013(AE) - 301. 

(2) Successive ranking scheme. For aggregate streams within a process, the control 

requirements must be evaluated with the following successive ranking scheme until control of a segment 

of unit operations is required or until all unit operations have been eliminated from the process pool. 

(A) If, for the process vent streams in aggregate, the value of FR calculated 

using the applicable RACT equation in paragraph (1) of this section is negative (i.e., less than zero), 

then the process is exempt from the 90% control requirements, and the successive ranking scheme of 

subparagraph (F) of this paragraph does not apply. This would occur if the mass annual emission rates 

are below the lower limits specified in '115.167(2)(A) of this title (relating to Exemptions). 

(B) If, for the process vent streams in aggregate, the actual average flow rate 

value (in scfm) is below the value of FR calculated using the applicable RACT equation in paragraph 

(1) of this section, then the overall emissions from the batch process must be reduced by 90%, and the 
Texas Commission on Environmental Quality Page 68 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

successive ranking scheme of subparagraph (F) of this paragraph does not apply. The owner or 

operator has the option of selecting which unit operations are to be controlled and to what levels, 

provided that the overall control meets the specified level of 90%. Single units that qualify for 

exemption under '115.167(2)(B) of this title do not have to be controlled even if all units should qualify 

for this exemption. 

(C) If, for the process vent streams in aggregate, the actual average flow rate 

value (in scfm) is greater than the value of FR calculated using the applicable RACT equation in 

paragraph (1) of this section (and the calculated value of FR is a positive number), then the control 

requirements must be evaluated with the successive ranking scheme of subparagraph (F) of this 

paragraph until control of a segment of unit operations is required or until all unit operations have been 

eliminated from the process pool. Single units that qualify for exemption under '115.167(2)(B) of this 

title do not have to be included in the rankings and do not have to be controlled. 

(D) Sources that are required to be controlled to the level specified by RACT 

(i.e., 90%) will have an average flow rate that is below the flow rate specified by the applicable RACT 

equation in paragraph (1) of this section (when the source's annual emission total is input). The 

applicability criterion is implemented on a two-tier basis. First, single pieces of batch equipment 

corresponding to distinct unit operations shall be evaluated over the course of an entire year, regardless 

of what materials are handled or what products are manufactured in them. Second, equipment shall be 

evaluated as an aggregate if it can be linked together based on the definition of a process. 

(E) To determine applicability of a RACT option in the aggregation scenario, 

all the VOC emissions from a single process shall be summed to obtain the annual mass emission total, 

and the weighted average flow rate from each process vent in the aggregation shall be used as the 

average flow rate. 

(F) All unit operations in the batch process, as defined for the purpose of 

determining RACT applicability, shall be ranked in ascending order according to their ratio of annual 

emissions (pounds per year) divided by average flow rate (in scfm). Sources with the smallest ratios 

shall be listed first. This list of sources constitutes the "pool" of sources within a batch process. The 

annual emission total and average flow rate of the pool of sources shall then be compared against the 

RACT equations in paragraph (1) of this section to determine whether control of the pool is required. 

(i) If control is not required after the initial ranking, unit operations 

having the lowest annual emissions/average flow rate ratio shall then be eliminated one by one, and the 

characteristics of annual emission and average flow rate for the remaining pool of equipment must be 

evaluated with each successive elimination of a source from the pool. 

(ii) Control of the unit operations remaining in the pool to the specified 

level (i.e., 90%) shall be required once the aggregated characteristics of annual emissions and average 

flow rate have met the specified cutoffs. The owner or operator has the option of selecting which unit 

operations are to be controlled and to what levels, provided that the overall control meets the specified 

level of 90%. 
Texas Commission on Environmental Quality Page 69 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(3) Once-in, always-in. Any batch process operation that becomes subject to the 

provisions of this division by exceeding provisions of '115.167 of this title will remain subject to the 

provision of this division, even if throughput or emissions later fall below exemption limits, unless and 

until emissions are reduced to no more than the controlled emissions level existing before 

implementation of the project by which throughput or emission rate was reduced to less than the 

applicable exemption limits in '115.167 of this title; and 

(A) the project by which throughput or emission rate was reduced is authorized 

by any permit or permit amendment or standard permit or permit by rule required by Chapter 116 or 

Chapter 106 of this title (relating to Control of Air Pollution by Permits for New Construction or 

Modification; and Permits by Rule). If a permit by rule is available for the project, compliance with 

this division must be maintained for 30 days after the filing of documentation of compliance with that 

permit by rule; or 

(B) if authorization by permit, permit amendment, standard permit, or permit 

by rule is not required for the project, the owner/operator has given the executive director 30 days=

notice of the project in writing. 

Adopted December 6, 2000 Effective January 18, 2001 

'115.163. Alternate Control Requirements. 

Alternate methods of demonstrating and documenting continuous compliance with the applicable 

control requirements or exemption criteria in this division (relating to Batch Processes) may be 

approved by the executive director in accordance with '115.910 of this title (relating to Availability of 

Alternate Means of Control) if emission reductions are demonstrated to be substantially equivalent. 

Adopted October 27, 1999 Effective November 18, 1999 

'115.164. Determination of Emissions and Flow Rates. 

The owner or operator of each batch process operation in the Beaumont/Port Arthur and 

Houston/Galveston areas shall determine the mass emissions and flow rates as follows. 

(1) Determination of Uncontrolled Annual Emission Total. The owner or operator 

shall determine the annual mass emissions total by using engineering estimates of the uncontrolled 

emissions from a process vent or group of process vents within a batch process train and multiplying by 

the potential or permitted number of batch cycles per year. Engineering estimates must follow the 

guidance contained in EPA's Control of Volatile Organic Compound Emissions from Batch Processes -

Alternative Control Techniques Information Document (EPA-453/R-94-020, February 1994). 

Alternatively, if an emissions measurement is used to measure vent emissions, the measurement must 

conform with the requirements of measuring incoming mass flow rate of volatile organic compounds as 

specified in '115.165 of this title (relating to Approved Test Methods and Testing Requirements). 
Texas Commission on Environmental Quality Page 70 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(2) Determination of Average Flow Rate. To obtain a value for average flow rate, the 

owner or operator may choose to measure the flow rates or to estimate the flow rates using the 

estimation methods contained in EPA's Control of Volatile Organic Compound Emissions from Batch 

Processes - Alternative Control Techniques Information Document (EPA-453/R-94-020, February 

1994). For existing manifolds, the average flow rate may be the flow rate that was assumed in the 

design. 

Adopted December 6, 2000 Effective January 18, 2001 

'115.165. Approved Test Methods and Testing Requirements. 

The owner or operator of each batch process operation in the Beaumont/Port Arthur and 

Houston/Galveston areas shall comply with the following. 

(1) Performance testing conditions. For the purpose of determining compliance with 

the control requirements of this division (relating to Batch Processes), the process unit shall be run at a 

scenario that represents maximum batch rates (e.g., three batches per day, 1,000 lbs per batch, etc.) 

during any performance test. 

(2) Test methods. The owner or operator of each batch process operation shall use the 

following methods to determine compliance with the percent reduction efficiency requirement of 

'115.162 of this title (relating to Control Requirements). 

(A) Flow rate. 

(i) Test Methods 1 or 1A (40 Code of Federal Regulations (CFR) 60, 

Appendix A) as appropriate, shall be used for selection of the sampling sites if the flow rate measuring 

device is a rotameter. No traverse is necessary when the flow measuring device is an ultrasonic probe. 

 The control device inlet sampling sites for determination of vent stream volatile organic compounds 

(VOC) composition reduction efficiency shall be before the control device and after the control device. 

(ii) Test Methods 2, 2A, 2C, or 2D (40 CFR 60, Appendix A) as 

appropriate, shall be used for determination of gas stream volumetric flow rate. Flow rate 

measurements shall be made continuously. 

(B) Concentration of VOC. Test Method 18 (40 CFR 60, Appendix A) (gas 

chromatography) or Test Method 25A (40 CFR 60, Appendix A) (flame ionization) shall be used to 

determine the concentration of VOC in the control device inlet and outlet. 

(i) The sampling time for each run shall be the entire length of the 

batch cycle, during which readings shall be taken: 

(I) continuously if Method 25A is used; or 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(II) as often as is possible using Method 18, with a maximum 

of one-minute intervals between measurements throughout the batch cycle. 

(ii) The emission rate of the process vent or inlet to the control device 

shall be determined by combining continuous concentration and flow rate measurements at simultaneous 

points throughout the batch cycle. 

(iii) The mass flow rate of the control device outlet shall be determined 

by combining continuous concentration and flow rate measurements at simultaneous points throughout 

the batch cycle. 

(iv) The efficiency of the control device shall be determined by 

integrating the mass flow rates obtained in clauses (ii) and (iii) of this subparagraph over the time of the 

batch cycle, and dividing the difference in inlet and outlet mass flow totals by the inlet mass flow total. 

(C) Performance requirements for flares and vapor combustors. 

(i) For flares, the performance test requirements of 40 CFR 60.18(b) 

shall apply. 

(ii) For vapor combustors, the owner or operator may consider the unit 

to be a flare and meet the performance test requirements of 40 CFR 60.18(b). 

(iii) Compliance with the requirements of 40 CFR 60.18(b) will be 

considered to represent 98% control of the VOC in the flare inlet. 

(D) Minor modifications. Minor modifications to these test methods may be 

used, if approved by the executive director. 

(E) Alternate test methods. Test methods other than those specified in 

subparagraphs (B) and (C) of this paragraph may be used if validated by 40 CFR 63, Appendix A, Test 

Method 301 (effective December 29, 1992). For the purposes of this paragraph, substitute Aexecutive 

director@ each place that Test Method 301 references Aadministrator.@

Adopted December 6, 2000 Effective January 18, 2001 

'115.166. Monitoring and Recordkeeping Requirements. 

The owner or operator of each batch process operation in the Beaumont/Port Arthur and 

Houston/Galveston areas shall maintain the following information for at least five years at the plant, as 

defined by its air quality account number, except that the five-year record retention requirement does 

not apply to records generated before December 31, 2000. The owner or operator shall make the 

information available upon request to representatives of the executive director, EPA, or any local air 

pollution control agency having jurisdiction in the area: 
Texas Commission on Environmental Quality Page 72 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) Vapor control systems. For vapor control systems used to control emissions from 

batch process operations, records of appropriate parameters to demonstrate compliance, including: 

(A) continuous monitoring and recording of: 

(i) for a direct-flame incinerator, the exhaust gas temperature in the 

firebox or in the ductwork immediately downstream of the firebox before any substantial heat exchange. 

The temperature monitoring device shall have an accuracy of "0.5 degrees Celsius, or alternatively, 

"1.0%; 

(ii) for a catalytic incinerator, the exhaust gas temperature immediately 

before and after the catalyst bed. The temperature monitoring device shall have an accuracy of "0.5 

degrees Celsius, or alternatively, "1.0%; 

(iii) for an absorber, either: 

(I) the scrubbing liquid temperature. The temperature 

monitoring device shall have an accuracy of "1.0% of the temperature being monitored in degrees 

Celsius, or alternatively, "0.02 specific gravity unit; or 

(II) the concentration level of volatile organic compounds 

(VOC) exiting the recovery device based on a detection principle such as infrared, photoionization, or 

thermal conductivity; 

(iv) for a condenser or refrigeration system, either: 

(I) the condenser exit temperature. The temperature 

monitoring device shall have an accuracy of "1.0% of the temperature being monitored in degrees 

Celsius, or alternatively, "0.5 degrees Celsius; or 

(II) the concentration level of VOC exiting the recovery device 

based on a detection principle such as infrared, photoionization, or thermal conductivity; 

(v) for a carbon adsorption system, as defined in '101.1 of this title 

(relating to Definitions), either: 

(I) steam flow (using an integrating steam flow monitoring 

device) and the carbon bed temperature. The steam flow monitor shall have an accuracy of "10%. 

The temperature monitor shall have an accuracy of "1.0% of the temperature being monitored in 

degrees Celsius, or "0.5 degrees Celsius, whichever is greater; or 

(II) the concentration level of VOC exiting the recovery device 

based on a detection principle such as infrared, photoionization, or thermal conductivity; 
Texas Commission on Environmental Quality Page 73 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(vi) for a pressure swing adsorption unit that is the final recovery 

device, the temperature of the bed near the inlet and near the outlet. The temperature monitoring 

device shall have an accuracy of "1.0% of the temperature being monitored in degrees Celsius, or "0.5 

degrees Celsius; and 

(vii) for a vapor combustor, the exhaust gas temperature in the firebox 

or in the ductwork immediately downstream of the firebox before any substantial heat exchange. The 

temperature monitoring device shall have an accuracy of "0.5 degrees Celsius, or alternatively, "1.0%. 

 Alternatively, the owner or operator of a vapor combustor may consider the unit to be a flare and meet 

the requirements of subparagraph (B) of this paragraph; 

(B) for flares, the requirements specified in 40 Code of Federal Regulations 

'60.18(b) and Chapter 111 of this title (relating to Control of Air Pollution from Visible Emissions and 

Particulate Matter); and 

(C) for vapor control systems other than those specified in subparagraphs (A) 

and (B) of this paragraph, records of appropriate operating parameters. 

(2) Process vents. A record of the following emission stream parameters for each 

process vent contained in the batch process: 

(A) the annual mass emission total and documentation verifying these values. 

If emission estimate equations are used, the documentation shall be the calculations coupled with the 

expected or permitted (if available) number of emission events per year; and 

(B) the average flow rate in standard cubic feet per minute and documentation 

verifying these values. 

(3) Performance test monitoring parameters. Records of the following parameters 

required to be measured during a performance test required under '115.165 of this title (relating to 

Approved Test Methods and Testing Requirements) and required to be monitored under paragraph (1) 

of this section: 

(A) where an owner or operator seeks to demonstrate compliance with 

'115.162 of this title (relating to Control Requirements) through use of either a direct-flame or catalytic 

incinerator, the average firebox temperature of the incinerator (or the average temperature upstream and 

downstream of the catalyst bed for a catalytic incinerator), measured continuously and averaged over 

the same time period as the performance test; 

(B) where an owner or operator seeks to demonstrate compliance with 

'115.162 of this title through use of a smokeless flare, the flare design (i.e., steam-assisted, 

air-assisted, or nonassisted), all visible emissions readings, heat content determinations, flow rate 

measurements, and exit velocity determinations made during the performance test; continuous flare pilot 

flame monitoring; and all periods of operations during which the pilot flame is absent; and 
Texas Commission on Environmental Quality Page 74 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(C) where an owner or operator seeks to demonstrate compliance with 

'115.162 of this title: 

(i) with an absorber as the final control device, the exit specific gravity 

(or alternative parameter which is a measure of the degree of absorbing liquid saturation, if approved by 

the executive director) and average exit temperature of the absorbing liquid measured continuously and 

averaged over the same time period as the performance test (both measured while the vent stream is 

routed normally); 

(ii) with a condenser as the control device, the average exit (product 

side) temperature measured continuously and averaged over the same time period as the performance 

test while the vent stream is routed normally; 

(iii) with a carbon adsorption system as the control device, the total 

steam mass flow measured continuously and averaged over the same time period as the performance test 

(full carbon bed cycle), temperature of the carbon bed after regeneration (and within 15 minutes of 

completion of any cooling cycle(s)), and duration of the carbon bed steaming cycle (all measured while 

the vent stream is routed normally); 

(iv) the concentration level or reading indicated by an organic 

monitoring device at the outlet of the absorber, condenser, or carbon adsorption system, measured 

continuously and averaged over the same time period as the performance test while the vent stream is 

routed normally; and 

(v) with a pressure swing adsorption unit as the final recovery device, 

the temperature of the bed near the inlet and near the outlet. The temperature monitoring device shall 

have an accuracy of "1.0% of the temperature being monitored in degrees Celsius, or "0.5 degrees 

Celsius. 

Adopted December 13, 2002 Effective January 17, 2003 

'115.167. Exemptions. 

The following exemptions apply. 

(1) Batch process operations at an account that has total volatile organic compound 

(VOC) emissions (determined before control but after the last recovery device) of less than the 

following rates from all stationary emission sources included in the account are exempt from the 

requirements of this division (relating to Batch Processes), except for '115.161(b) and (c) of this title 

(relating to Applicability): 

(A) 50 tons per year (tpy) in the Beaumont-Port Arthur area; and 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(B) 25 tpy in the Houston-Galveston-Brazoria area. 

(2) The following are exempt from the requirements of this division, except for 

''115.161(b) and (c), 115.164, and 115.166(2) and (3) of this title (relating to Applicability; 

Determination of Emissions and Flow Rates; and Monitoring and Recordkeeping Requirements). 

(A) Combined vents from a batch process train that have the following annual 

mass emissions total. 

Volatility Range 

Lower Limit of Annual 

Mass Emissions Total in 

pounds per year (lb/yr) 

Low 26,014 

Moderate 15,935 

High 23,154 

(B) Single unit operations that have an annual mass emissions total of 500 

pounds per year or less. 

Adopted September 28, 2005 Effective October 20, 2005 

'115.169. Counties and Compliance Schedules. 

(a) The owner or operator of each batch process operation in Hardin, Jefferson, and Orange 

Counties at an account that has total volatile organic compound (VOC) emissions (determined before 

control but after the last recovery device) of 100 tons per year or more shall continue to comply with 

this division (relating to Batch Processes) as required by '115.930 of this title (relating to Compliance 

Dates). 

(b) The owner or operator of each batch process operation in Brazoria, Chambers, Fort Bend, 

Galveston, Harris, Liberty, Montgomery, and Waller Counties shall demonstrate compliance with this 

division as soon as practicable, but no later than December 31, 2002. All batch process operations 

subject to this division in Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, 

and Waller Counties must continue to comply with the requirements of Division 2 of this subchapter 

(relating to Vent Gas Control) until these batch process operations are in compliance with the 

requirements of this division. 

(c) The owner or operator of each batch process operation in Hardin, Jefferson, and Orange 

Counties at an account that has total VOC emissions (determined before control but after the last 
Texas Commission on Environmental Quality Page 76 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

recovery device) of 50 tons per year or more but less than 100 tons per year shall demonstrate 

compliance with this division as soon as practicable, but no later than December 31, 2006. All batch 

process operations subject to this division in Hardin, Jefferson, and Orange Counties must continue to 

comply with the requirements of Division 2 of this subchapter until these batch process operations are 

in compliance with the requirements of this division. 

Adopted September 28, 2005 Effective October 20, 2005 
Texas Commission on Environmental Quality Page 1 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER F: MISCELLANEOUS INDUSTRIAL SOURCES 

DIVISION 1: CUTBACK ASPHALT 

''115.510, 115.512, 115.513, 115.515 - 115.517, 115.519 

Effective December 7, 2006

'115.510. Cutback Asphalt Definitions. 

The following terms, when used in this division (relating to Cutback Asphalt), shall have the 

following meanings, unless the context clearly indicates otherwise. Additional definitions for terms 

used in this division are found in '115.10 of this title (relating to Definitions), '101.1 of this title 

(relating to Definitions), and '3.2 of this title (relating to Definitions). 

(1) Asphalt emulsion - An emulsion consisting of a continuous and discontinuous 

phase, composed principally of a semisolid or liquid asphaltic base, water, and an emulsifying agent. 

(2) Conventional cutback asphalt - Any cutback asphalt which does not meet the 

definition of an exempt cutback asphalt. 

(3) Cutback asphalt - Any asphaltic cement which has been liquified by blending with 

petroleum solvents (diluents). 

(4) Exempt cutback asphalt - Any cutback asphalt which, when tested in accordance 

with American Society of Testing Materials Test Method D 402, ADistillation of Cutback Asphalt 

Products,@ as published in the 1997 edition of the Annual Book of ASTM Standards, shows the distillate 

fraction recovered up to 260 degrees Celsius (500 degrees Fahrenheit) to be less than 5.0% by volume 

of the total distillate recovered up to a temperature of 316 degrees Celsius (680 degrees Fahrenheit). 

Adopted July 28, 1999 Effective August 18, 1999 

'115.512. Control Requirements. 

The following control requirements shall apply in Nueces, Bastrop, Caldwell, Hays, Travis, 

and Williamson Counties and the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston areas as defined in '115.10 of this title (relating to Definitions). 

(1) The use of conventional cutback asphalt containing volatile organic compounds 

(VOC) solvents for the paving of roadways, driveways, or parking lots is restricted to no more than 

7.0% of the total annual volume averaged over a two-year period of asphalt used by or specified for use 

by any state, municipal, or county agency who uses or specifies the type of asphalt application. 
Texas Commission on Environmental Quality Page 2 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(2) In the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston 

areas and in Bastrop, Caldwell, Hays, Travis, and Williamson Counties, no person shall allow the use, 

application, sale, or offering for sale of conventional cutback asphalt containing VOC solvents for 

paving roadways, driveways, or parking lots during the period from April 16 to September 15 of any 

year. 

(3) When asphalt emulsion is used or produced, the maximum VOC content shall not 

exceed 12% by weight or the following limitations, whichever is more stringent: 

(A) 0.5% by weight for seal coats; 

(B) 3.0% by weight for chip seals when dusty or dirty aggregate is used; 

(C) 8.0% by weight for mixing with open graded aggregate with less than 

1.0% by weight of dust or clay-like materials adhering to the coarse aggregate fraction (1/4 inch in 

diameter or greater); and 

(D) 12% by weight for mixing with dense graded aggregate when used to 

produce a mix designed to have 10% or less voids when fully compacted. 

Adopted November 17, 2004 Effective December 9, 2004 

'115.513. Alternate Control Requirements. 

Alternate methods of demonstrating and documenting continuous compliance with the applicable 

control requirements or exemption criteria in this division may be approved by the executive director in 

accordance with '115.910 of this title (relating to Availability of Alternate Means of Control) if 

emission reductions are demonstrated to be substantially equivalent. 

Adopted July 28, 1999 Effective August 18, 1999 

'115.515. Testing Requirements. 

Compliance with '115.510 and '115.512 of this title (relating to Cutback Asphalt Definitions; 

and Control Requirements) shall be determined by applying the following test methods, as appropriate: 

(1) American Society of Testing and Materials (ASTM) Test Method D 244, AStandard 

Test Methods for Emulsified Asphalts, Sections 11 to 15, Residue and Oil Distillate by Distillation,@ as 

published in the 1997 edition of the Annual Book of ASTM Standards, for determining volatile organic 

compound (VOC) content of asphalt emulsions; 
Texas Commission on Environmental Quality Page 3 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(2) ASTM Test Method D 402, AStandard Test Method for Distillation of Cut-Back 

Asphaltic Products,@ as published in the 1997 edition of the Annual Book of ASTM Standards, for 

determining the VOC content of cutback asphalt; or 

(3) minor modifications to these test methods approved by the executive director. 

Adopted July 28, 1999 Effective August 18, 1999 

'115.516. Recordkeeping Requirements. 

In Nueces, Bastrop, Caldwell, Hays, Travis, and Williamson Counties and the Beaumont/Port 

Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, any state, municipal, or county 

agency who uses or specifies the use of cutback asphalt or asphalt emulsion shall maintain records 

sufficient to document compliance with applicable restrictions and shall make such records available 

upon request to representatives of the executive director, EPA, or the local air pollution control agency 

having jurisdiction in the area. 

Adopted November 17, 2004 Effective December 9, 2004 

'115.517. Exemptions. 

For persons in Nueces, Bastrop, Caldwell, Hays, Travis, and Williamson Counties and the 

Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston Areas, the following are 

exempt from the provisions of '115.512(2) of this title (relating to Control Requirements): 

(1) asphalt concrete made with cutback asphalt, used for patching, which is stored in a 

long-life stockpile (longer than one-month storage); and 

(2) cutback asphalt used solely as a penetrating prime coat. 

Adopted November 17, 2004 Effective December 9, 2004 

'115.519. Counties and Compliance Schedules. 

(a) All affected persons in Brazoria, Chambers, Collin, Dallas, Denton, El Paso, Fort Bend, 

Galveston, Hardin, Harris, Jefferson, Liberty, Montgomery, Nueces, Orange, Tarrant, and Waller 

Counties shall continue to comply with applicable sections of this division (relating to Cutback Asphalt) 

as required by '115.930 of this title (relating to Compliance Dates). 

(b) All affected persons in Bastrop, Caldwell, Hays, Travis, and Williamson Counties shall 

comply with applicable sections of this division as soon as practicable, but no later than December 31, 

2005. 
Texas Commission on Environmental Quality Page 4 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(c) All affected persons in Ellis, Johnson, Kaufman, Parker, and Rockwall Counties shall 

comply with applicable sections of this division as soon as practicable, but no later than March 1, 2009. 

Adopted November 15, 2006 Effective December 7, 2006 
Texas Commission on Environmental Quality Page 5 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER F: MISCELLANEOUS INDUSTRIAL SOURCES 

DIVISION 2: PHARMACEUTICAL MANUFACTURING FACILITIES 

''115.531 - 115.537, 115.539 

Effective December 7, 2006 

'115.531. Emission Specifications. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas 

as defined in '115.10 of this title (relating to Definitions), the owner or operator of a synthesized 

pharmaceutical manufacturing facility shall satisfy the following emission specifications: 

(1) Reactors, Distillation Units, Crystallizers, Centrifuges, and Vacuum Dryers. The 

emission of volatile organic compounds (VOC) from these sources shall be controlled by means of 

surface condensers from which the condenser outlet gas temperature must not exceed the following: 

When VOC Vapor Pressure Outlet gas 

At 68EF (20EC) Exceeds Maximum Temperature

 5.8 psia (40 kPa) -13EF (-25EC) 

2.9 psia (20 kPa) 5EF (-15EC) 

1.5 psia (10 kPa) 32EF ( 0EC) 

1.0 psia ( 7 kPa) 50EF ( 10EC) 

0.5 psia (3.5 kPa) 77EF ( 25EC) 

(2) Air Dryers and Exhaust Systems. VOC emissions from all air dryers and 

production equipment exhaust systems shall be reduced to not more than 33 lbs/day (15 kg/day) or 

controlled in accordance with '115.532(a)(4) of this title (relating to Control Requirements). 

(3) Loading Facilities. VOC emissions from truck or railcar deliveries to storage tanks 

at loading facilities shall be controlled in accordance with '115.532(a)(4) of this title. 

(b) For Gregg, Nueces, and Victoria Counties, the owner or operator of a synthesized 

pharmaceutical manufacturing facility shall satisfy the following emission specifications: 

(1) Reactors, Distillation Units, Crystallizers, Centrifuges, and Vacuum Dryers. The 

emission of VOC from these sources shall be controlled by means of surface condensers from which the 

condenser outlet gas temperature must not exceed the following: 

When VOC Vapor Pressure Outlet gas 

At 68EF (20EC) Exceeds Maximum Temperature

 5.8 psia (40 kPa) -13EF (-25EC) 

2.9 psia (20 kPa) 5EF (-15EC) 

1.5 psia (10 kPa) 32EF ( 0EC) 
Texas Commission on Environmental Quality Page 6 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

1.0 psia ( 7 kPa) 50EF ( 10EC) 

0.5 psia (3.5 kPa) 77EF ( 25EC) 

(2) Air Dryers and Exhaust Systems. VOC emissions from all air dryers and 

production equipment exhaust systems shall be reduced to not more than 33 lbs/day (15 kg/day) or 

controlled in accordance with '115.532(b)(4) of this title. 

(3) Loading Facilities. VOC emissions from truck or railcar deliveries to storage tanks 

at loading facilities shall be controlled in accordance with '115.532(b)(4) of this title. 

Adopted May 8, 1992 Effective August 1, 1992 

'115.532. Control Requirements. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

the owner or operator of a synthesized pharmaceutical manufacturing facility shall provide the following 

specified controls. 

(1) Tanks. 

(A) All in-process tanks that contain volatile organic compounds (VOC) at any 

time shall be kept covered, except when production, sampling, maintenance, or inspection procedures 

require operator access. 

(B) All storage tanks that store VOC shall have pressure vacuum conservation 

vents installed which are set at plus or minus 0.8 inches of water (plus or minus 0.2 kPa), unless a 

more effective control system is used. 

(2) Centrifuges and filters. Centrifuges, rotary vacuum filters, and other filters having 

an exposed liquid surface which process liquids containing VOC shall be enclosed. 

(3) Leaks. 

(A) All liquid leaks containing VOC from a process unit or storage tank shall 

be repaired the first time the equipment is off-line long enough to complete the repair. 

(B) All liquid or gaseous leaks of VOC observed during loading operations 

shall be repaired immediately. Loading operations shall be discontinued until the leak is repaired. 

(4) Air dryers, production equipment exhaust systems, and loading facilities. Sources 

affected by '115.531(a) of this title (relating to Emission Specifications) shall be controlled by a system 

with a reduction efficiency of at least 90% of the uncontrolled emissions. 
Texas Commission on Environmental Quality Page 7 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(5) Pharmaceutical manufacturing facility. Any pharmaceutical manufacturing facility 

that becomes subject to the provisions of paragraphs (1) - (4) of this subsection by exceeding provisions 

of '115.537(a) of this title (relating to Exemptions) will remain subject to the provisions of this 

subsection, even if throughput or emissions later fall below exemption limits, unless and until emissions 

are reduced to no more than the controlled emissions level existing before implementation of the project 

by which throughput or emission rate was reduced to less than the applicable exemption limits in 

'115.537(a) of this title; and: 

(A) the project by which throughput or emission rate was reduced is authorized 

by any permit or permit amendment or standard permit or permit by rule required by Chapter 116 or 

Chapter 106 of this title (relating to Control of Air Pollution by Permit for New Construction or 

Modification; and Permits by Rule). If a permit by rule is available for the project, compliance with 

this subsection must be maintained for 30 days after the filing of documentation of compliance with that 

permit by rule; or 

(B) if authorization by permit, permit amendment, standard permit, or permit 

by rule is not required for the project, the owner/operator has given the executive director 30 days' 

notice of the project in writing. 

(b) For Gregg, Nueces, and Victoria Counties, the owner or operator of a synthesized 

pharmaceutical manufacturing facility shall provide the following specified controls. 

(1) Tanks. 

(A) All in-process tanks that contain VOC at any time shall be kept covered, 

except when production, sampling, maintenance, or inspection procedures require operator access. 

(B) All storage tanks that store VOC shall have pressure vacuum conservation 

vents installed which are set at plus or minus 0.8 inches of water (plus or minus 0.2 kPa), unless a 

more effective control system is used. 

(2) Centrifuges and filters. Centrifuges, rotary vacuum filters, and other filters having 

an exposed liquid surface which process liquids containing VOC shall be enclosed. 

(3) Leaks. 

(A) All liquid leaks containing VOC from a process unit or storage tank shall 

be repaired the first time the equipment is off-line long enough to complete the repair. 

(B) All liquid or gaseous leaks of VOC observed during loading operations 

shall be repaired immediately. Loading operations shall be discontinued until the leak is repaired. 
Texas Commission on Environmental Quality Page 8 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(4) Air dryers, production equipment exhaust systems, and loading facilities. Sources 

affected by '115.531(b) of this title shall be controlled by a system with a reduction efficiency of at 

least 90% of the uncontrolled emissions. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.533. Alternate Control Requirements. 

Alternate methods of demonstrating and documenting continuous compliance with the applicable 

control requirements or exemption criteria in this division (relating to Pharmaceutical Manufacturing 

Facilities) may be approved by the executive director in accordance with '115.910 of this title (relating 

to Availability of Alternate Means of Control) if emission reductions are demonstrated to be 

substantially equivalent. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.534. Inspection Requirements. 

(a) For all affected persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston areas, the following inspection requirements shall apply. 

(1) Inspection for visible liquid leaks, visible fumes, or significant odors resulting from 

the transfer of VOC from trucks or railcars to storage tanks at loading facilities shall be conducted by 

the owner or operator of any pharmaceutical manufacturing facility. 

(2) VOC loading or unloading through the affected transfer lines shall be discontinued 

immediately when a leak is observed and shall not be resumed until the observed leak is repaired. 

(b) For all affected persons in Gregg, Nueces, and Victoria Counties, the following inspection 

requirements shall apply: 

(1) Inspection for visible liquid leaks, visible fumes, or significant odors resulting from 

the transfer of VOC from trucks or railcars to storage tanks at loading facilities shall be conducted by 

the owner or operator of any pharmaceutical manufacturing facility. 

(2) VOC loading or unloading through the affected transfer lines shall be discontinued 

immediately when a leak is observed and shall not be resumed until the observed leak is repaired. 

Adopted May 8, 1992 Effective August 1, 1992 

'115.535. Testing Requirements. 
Texas Commission on Environmental Quality Page 9 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

compliance with this division (relating to Pharmaceutical Manufacturing Facilities) shall be determined 

by applying the following test methods, as appropriate: 

(1) Test Methods 1-4 (40 Code of Federal Regulations (CFR) 60, Appendix A) for 

determining flow rate, as necessary; 

(2) Test Method 18 (40 CFR 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(3) Test Method 25 (40 CFR 60, Appendix A) for determining total gaseous 

nonmethane organic emissions as carbon; 

(4) Test Methods 25A or 25B (40 CFR 60, Appendix A) for determining total gaseous 

organic concentrations using flame ionization or nondispersive infrared analysis; 

(5) determination of true vapor pressure using American Society of Testing and 

Materials (ASTM) Test Method D323-82 for the measurement of Reid vapor pressure, adjusted for 

actual storage temperature in accordance with API Publication 2517, Third Edition, 1989; or 

(6) minor modifications to these test methods approved by the executive director. 

(b) For Gregg, Nueces, and Victoria Counties, compliance with this division shall be 

determined by applying the following test methods, as appropriate: 

(1) Test Methods 1-4 (40 CFR 60, Appendix A) for determining flow rate, as 

necessary; 

(2) Test Method 18 (40 CFR 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(3) Test Method 25 (40 CFR 60, Appendix A) for determining total gaseous 

nonmethane organic emissions as carbon; 

(4) Test Methods 25A or 25B (40 CFR 60, Appendix A) for determining total gaseous 

organic concentrations using flame ionization or nondispersive infrared analysis; 

(5) determination of true vapor pressure using ASTM Test Method D323-82 for the 

measurement of Reid vapor pressure, adjusted for actual storage temperature in accordance with API 

Publication 2517, Third Edition, 1989; or 

(6) minor modifications to these test methods approved by the executive director. 
Texas Commission on Environmental Quality Page 10 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Adopted April 26, 2002 Effective May 16, 2002 

'115.536. Monitoring and Recordkeeping Requirements. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

the following recordkeeping requirements shall apply. 

(1) The owner or operator of any pharmaceutical manufacturing facility which utilizes 

a surface condenser to control emissions of volatile organic compound (VOC) from process units 

affected by '115.531(a)(1) of this title (relating to Emission Specifications) shall install and maintain 

monitors to continuously measure and record the outlet gas temperature to ensure proper functioning in 

accordance with design specifications. 

(2) The owner or operator of any pharmaceutical manufacturing facility which utilizes 

a vapor recovery system to satisfy the requirements of '115.531(a) of this title or '115.532(a) of this 

title (relating to Control Requirements) shall: 

(A) install and maintain monitors to continuously measure and record 

operational parameters of all required control devices as necessary to ensure the proper functioning of 

those devices in accordance with design specifications, including: 

(i) the exhaust gas temperature of direct-flame incinerators and/or the 

gas temperature immediately upstream and downstream of any catalyst bed, 

(ii) the exhaust gas VOC concentration of any carbon adsorption 

system, as defined in '115.10 of this title (relating to Definitions), to determine if breakthrough has 

occurred, 

(iii) the total amount of VOC recovered by carbon adsorption or other 

solvent recovery systems during a calendar month, or 

(iv) the daily emission rate of VOC from the control device; 

(B) maintain a record of the dates and reasons for any maintenance and repair 

of the required control devices and the estimated quantity and duration of VOC emissions during such 

activities. 

(3) The owner or operator of any pharmaceutical manufacturing facility which is 

exempted from the requirements in accordance with the provisions of '115.537(a) of this title (relating 

to Exemptions) shall maintain a record of the following information, as appropriate: 

(A) the vapor pressure of materials transferred at loading facilities, stored in 

tanks, or processed in centrifuges and filters; and 
Texas Commission on Environmental Quality Page 11 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(B) the daily emissions rate of VOC. 

(4) The owner or operator of any affected pharmaceutical manufacturing facility shall 

maintain records of any testing conducted at an affected facility in accordance with the provisions 

specified in '115.535(a) of this title (relating to Testing Requirements), and 

(5) The owner or operator of any affected pharmaceutical manufacturing facility shall 

maintain all records at the affected facility for at least two years and make such records available upon 

request to representatives of the executive director, United States Environmental Protection Agency 

(EPA), or local air pollution control agency. 

(b) For Gregg, Nueces, and Victoria Counties, the following recordkeeping requirements shall 

apply. 

(1) The owner or operator of any pharmaceutical manufacturing facility which utilizes 

a surface condenser to control emissions of VOC from process units affected by '115.531(b)(1) of this 

title shall install and maintain monitors to continuously measure and record the outlet gas temperature to 

ensure proper functioning in accordance with design specifications. 

(2) The owner or operator of any pharmaceutical manufacturing facility which utilizes 

a vapor recovery system to satisfy the requirements of '115.531(b) of this title or '115.532(b) of this 

title shall: 

(A) install and maintain monitors to continuously measure and record 

operational parameters of all required control devices as necessary to ensure the proper functioning of 

those devices in accordance with design specifications, including: 

(i) the exhaust gas temperature of direct-flame incinerators and/or the 

gas temperature immediately upstream and downstream of any catalyst bed, 

(ii) in Victoria County, the exhaust gas VOC concentration of any 

carbon adsorption system, as defined in '115.10 of this title, to deter-mine if breakthrough has 

occurred, 

(iii) the total amount of VOC recovered by carbon adsorption or other 

solvent recovery systems during a calendar month, or 

(iv) the daily emission rate of VOC from the control device; 

(B) maintain a record of the dates and reasons for any maintenance and repair 

of the required control devices and the estimated quantity and duration of VOC emissions during such 

activities. 
Texas Commission on Environmental Quality Page 12 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(3) The owner or operator of any pharmaceutical manufacturing facility which is 

exempted from the requirements in accordance with the provisions of '115.537(b) of this title shall 

maintain a record of the following information, as appropriate: 

(A) the vapor pressure of materials transferred at loading facilities, stored in 

tanks, or processed in centrifuges and filters; and 

(B) the daily emissions rate of VOC. 

(4) The owner or operator of any affected pharmaceutical manufacturing facility shall 

maintain records of any testing conducted at an affected facility in accordance with the provisions 

specified in '115.535(b) of this title, and 

(5) The owner or operator of any affected pharmaceutical manufacturing facility shall 

maintain all records at the affected facility for at least two years and make such records available upon 

request to representatives of the executive director, EPA, or local air pollution control agency. 

Adopted April 30, 1997 Effective May 22, 1997 

'115.537. Exemptions. 

(a) For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston areas, 

the following exemptions shall apply: 

(1) Storage tanks at loading facilities with capacities less than or equal to 2,000 gallons 

(7,571 liters) are exempt from the requirements of '115.531(a)(3) of this title (relating to Emission 

Specifications). 

(2) Storage tanks at loading facilities that store volatile organic compounds (VOC) with 

vapor pressures less than or equal to 4.1 psia (28 kPa) at 68EF (20EC) are exempt from the 

requirements of '115.531(a)(3) of this title. 

(3) Storage tanks containing VOC with vapor pressures less than or equal to 1.5 psia 

(10.3 kPa) at 68EF (20EC) are exempt from the requirements of '115.532(a)(1)(B) of this title (relating 

to Control Requirements). 

(4) Centrifuges and filters which process liquids containing VOC with vapor pressures 

less than 0.5 psia (3.4 kPa) at 68EF (20EC) are exempt from the requirements of '115.532(a)(2) of this 

title. 
Texas Commission on Environmental Quality Page 13 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(5) Any individual unit which, when uncontrolled, will emit a combined weight of 

VOC less than 15 lbs. (6.8 kg) in any continuous 24-hour period is exempt from the provisions of 

'115.531(a) and '115.532(a) of this title. 

(b) For Gregg, Nueces, and Victoria Counties, the following exemptions shall apply: 

(1) Storage tanks at loading facilities with capacities less than or equal to 2,000 gallons 

(7,571 liters) are exempt from the requirements of '115.531(b)(3) of this title. 

(2) Storage tanks at loading facilities that store VOC with vapor pressures less than or 

equal to 4.1 psia (28 kPa) at 68EF (20EC) are exempt from the requirements of '115.531(b)(3) of this 

title. 

(3) Storage tanks containing VOC with vapor pressures less than or equal to 1.5 psia 

(10.3 kPa) at 68EF (20EC) are exempt from the requirements of '115.532(b)(1)(B) of this title. 

(4) Centrifuges and filters which process liquids containing VOC with vapor pressures 

less than 0.5 psia (3.4 kPa) at 68EF (20EC) are exempt from the requirements of '115.532(b)(2) of this 

title. 

(5) Any facility which, when uncontrolled, will emit a combined weight of VOC less 

than 550 lbs. (249.5 kg) in any continuous 24-hour period is exempt from the provisions of '115.531(b) 

of this title and '115.532(b) of this title. 

Adopted April 30, 1997 Effective May 22, 1997 

'115.539. Counties and Compliance Schedules. 

(a) All affected persons in Brazoria, Chambers, Collin, Dallas, Denton, El Paso, Fort Bend, 

Galveston, Gregg, Hardin, Harris, Jefferson, Liberty, Montgomery, Nueces, Orange, Tarrant, 

Victoria, and Waller Counties shall continue to comply with this division (relating to Pharmaceutical 

Manufacturing Facilities) as required by '115.930 of this title (relating to Compliance Dates). 

(b) All affected persons in Ellis, Johnson, Kaufman, Parker, and Rockwall Counties shall 

comply with this division as soon as practicable, but no later than March 1, 2009. 

Adopted November 15, 2006 Effective December 7, 2006 
Texas Commission on Environmental Quality Page 14 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER F: MISCELLANEOUS INDUSTRIAL SOURCES 

DIVISION 3: DEGASSING OR CLEANING OF STATIONARY, MARINE, 

AND TRANSPORT VESSELS 

''115.541 - 115.547, 115.549 

Effective June 14, 2007 

§115.541. Emission Specifications. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas as defined in §115.10 of this title (relating to Definitions), the 

following emission specifications apply to degassing during or in preparation of cleaning. 

(1) For all stationary volatile organic compound (VOC) storage tanks with a nominal 

storage capacity of one million gallons or more and after January 1, 2009, storage tanks in the 

Houston/Galveston/Brazoria area with a nominal storage capacity of 250,000 gallons or greater or with 

a nominal storage capacity of 75,000 gallons or greater storing materials with a true vapor pressure 

greater than 2.6 pounds per square inch absolute (psia). 

(A) No person shall permit VOC emissions with a vapor space partial pressure 

greater than or equal to 0.5 psia (3.4 kilo Pascals (kPa)) under actual storage conditions unless the 

vapors are processed by a vapor control system. 

(B) The vapor control system must maintain a control efficiency of at least 

90%. 

(C) When conducting degassing or cleaning operations, no avoidable liquid or 

gaseous leaks, as detected by sight or sound, may originate from the degassing or cleaning operations. 

(D) The intentional bypassing of a vapor control device used during degassing 

or cleaning is prohibited. Any visible VOC leak originating from the vapor control device or other 

associated product recovery device must be repaired as soon as practical. 

(2) For all transport vessels, as defined in §115.10 of this title, with a nominal storage 

capacity of 8,000 gallons or more. 

(A) No person shall permit VOC emissions with a vapor space partial pressure 

greater than or equal to 0.5 psia (3.4 kPa) under actual storage conditions unless the vapors are 

processed by a vapor control system. 

(B) The vapor control system must maintain a control efficiency of at least 

90%. 
Texas Commission on Environmental Quality Page 15 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(C) When conducting degassing or cleaning operations, no avoidable liquid or 

gaseous leaks, as detected by sight or sound, may originate from the degassing or cleaning operations. 

(D) The intentional bypassing of a vapor control device used during degassing 

or cleaning is prohibited. Any visible VOC leak originating from the vapor control device or other 

associated product recovery device must be repaired as soon as practical. 

(E) All transport vessels, as defined in §115.10 of this title, must be kept vaportight at all times until the VOC vapors remaining in the vessel are discharged to a vapor control system. 

(b) For all persons in the Beaumont/Port Arthur and Houston/Galveston/Brazoria areas, the 

following emission specifications apply to degassing during or in preparation of cleaning for all marine 

vessels, as defined in §101.1 of this title (relating to Definitions), that have a nominal storage capacity 

of 10,000 barrels (420,000 gallons) or more and contain VOC. 

(1) No person shall degas or clean a tank that carried a VOC with a vapor partial 

pressure greater than or equal to 0.5 psia (3.4 kPa) unless the vapors are processed by a vapor control 

system. 

(2) The vapor control system must maintain a control efficiency of at least 90%. 

(3) When conducting degassing or cleaning operations, no avoidable liquid or gaseous 

leaks, as detected by sight or sound, may originate from the degassing or cleaning operations. 

(4) The intentional bypassing of a vapor control device used during degassing or 

cleaning is prohibited. Any visible VOC leak originating from the vapor control device or other 

associated product recovery device must be repaired as soon as possible. 

(5) All marine vessels, as defined in §101.1 of this title, containing VOC must have all 

cargo tank closures properly secured, or maintain a negative pressure within the tank when a closure is 

opened, and must have all pressure/vacuum relief valves operating within certified limits as specified by 

classification society or flag state until the vapors are discharged to a vapor control system if the vessel 

is degassed or cleaned. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.542. Control Requirements. 

(a) For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas as defined in §115.10 of this title (relating to Definitions), the 

following control requirements apply to stationary storage tanks and transport vessels. 

(1) No person shall permit the degassing or cleaning of volatile organic compounds 
Texas Commission on Environmental Quality Page 16 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(VOC) from a stationary storage tank or transport vessel unless the vapors are processed by a vapor 

control system. 

(2) When degassing or cleaning is effected through the hatches of a transport vessel 

with a loading arm equipped with a vapor collection adapter, then pneumatic, hydraulic, or other 

mechanical means must be provided to force a vapor-tight seal between the adapter and the hatch. A 

means must be provided to minimize liquid drainage from the degassing or cleaning device when it is 

removed from the hatch of any transport vessel or to accomplish drainage before such removal. 

(3) When degassing or cleaning is effected through the hatches or manways of 

stationary VOC storage tanks, all lines must be equipped with fittings that make vapor-tight connections 

and that are closed when disconnected; or equipped to permit residual VOC in the line to discharge into 

a recovery or disposal system after degassing or cleaning is complete. 

(4) Degassing and cleaning equipment must be designed and operated to prevent 

avoidable VOC leaks. 

(5) In the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and until January 1, 

2009, in the Houston/Galveston/Brazoria areas, vapors must be routed to the control device until a 

turnover of at least four vapor space volumes has occurred, or four turnovers of the vapor space under 

a floating roof, or the partial vapor pressure is less than 0.5 pounds per square inch absolute (psia) 

(19,000 parts per million by weight (ppmw), or 34,000 parts per million by volume (ppmv) expressed 

as methane). After one of these conditions has been satisfied, the storage tank or transport vessel may 

be vented to the atmosphere for the remainder of the degassing or cleaning process. 

(6) After January 1, 2009, in the Houston/Galveston/Brazoria area, vapors must be 

routed to the control device until the VOC measured concentration before the inlet to the control device 

is less than 34,000 ppmv as methane or less than 50% of the lower explosive limit (LEL). After this 

condition has been satisfied, the storage tank or transport vessel may be vented to the atmosphere for 

the remainder of the degassing or cleaning process provided that the VOC concentration remains below 

34,000 ppmv as methane or less than 50% of the LEL. The VOC concentration must be measured once 

every 12 hours if the storage tank or transport vessel is vented continuously to the atmosphere, and 

upon restart of the degassing and cleaning operation if venting to the atmosphere has been suspended 

for more than four hours. If any measurements of the VOC concentration equal or exceed 34,000 ppmv 

as methane or are equal to or greater than 50% of the LEL, the storage tank or transport vessel must be 

routed to the control device until the concentration is below 34,000 ppmv as methane or less than 50% 

of the LEL. While venting to the atmosphere, measurements must continue until five consecutive 

readings of VOC concentrations collected at 12 hour intervals are measured to be less than 34,000 

ppmv or less than 50% of the LEL. 

(b) For all persons in the Beaumont/Port Arthur and Houston/Galveston/Brazoria areas, the 

following control requirements apply to marine vessels. 
Texas Commission on Environmental Quality Page 17 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(1) No person shall permit the degassing or cleaning of a marine vessel containing 

VOC unless the vapors are processed by a vapor control system. 

(2) When degassing or cleaning is effected through the hatches of a marine vessel 

containing VOC with a loading arm equipped with a vapor collection adapter, then pneumatic, 

hydraulic, or other mechanical means must be provided to force a vapor-tight seal between the adapter 

and the hatch, or a negative pressure inside the cargo tank must be maintained. A means must be 

provided to minimize liquid drainage from the degassing or cleaning device and line when they are 

removed from the hatch of any marine vessel containing VOC or to accomplish drainage before such 

removal. 

(3) Degassing and cleaning equipment must be designed and operated to prevent 

avoidable VOC leaks. 

(4) In the Beaumont/Port Arthur area and until January 1, 2009, in the 

Houston/Galveston/Brazoria area, vapors must be routed to the control device until the marine vessel is 

stripped VOC liquid-free and a turnover of at least four vapor space volumes has occurred, the partial 

vapor pressure is less than 0.5 psia (19,000 ppmw, or 34,000 ppmv expressed as methane), or the 

concentration of VOC is less than 20% of the LEL. After one of these conditions has been satisfied, the 

marine vessel may be vented to the atmosphere for the remainder of the degassing or cleaning process. 

(5) After January 1, 2009, in the Houston/Galveston/Brazoria area, vapors must be 

routed to the control device until the VOC measured concentration before the inlet to the control device 

is less than 34,000 ppmv as methane or less than 50% of the LEL. After this condition has been 

satisfied, the marine vessel may be vented to the atmosphere for the remainder of the degassing or 

cleaning process provided that the VOC concentration remains below 34,000 ppmv as methane or less 

than 50% of the LEL. The VOC concentration must be measured once every 12 hours if the marine 

vessel is vented continuously to the atmosphere, and upon restart of the degassing and cleaning 

operation if venting to the atmosphere has been suspended for more than four hours. If any 

measurements of the VOC concentration equal or exceed 34,000 ppmv as methane or are equal to or 

greater than 50% of the LEL, the marine vessel must be routed to the control device until the 

concentration is below 34,000 ppmv as methane or less than 50% of the LEL. While venting to the 

atmosphere, measurements must continue until five consecutive readings of VOC concentrations 

collected at 12-hour intervals are measured to be less than 34,000 ppmv or less than 50% of the LEL. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.543. Alternate Control Requirements. 

For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas as defined in §115.10 of this title (relating to Definitions), alternate 

methods of demonstrating and documenting continuous compliance with the applicable control 

requirements or exemption criteria in this division (relating to Degassing or Cleaning of Stationary, 

Marine, and Transport Vessels) may be approved by the executive director in accordance with 
Texas Commission on Environmental Quality Page 18 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

§115.910 of this title (relating to Availability of Alternate Means of Control) if emission reductions are 

demonstrated to be substantially equivalent. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.544. Inspection Requirements. 

For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas as defined in §115.10 of this title (relating to Definitions), the 

following inspection requirements apply. 

(1) Inspection for visible liquid leaks, visible fumes, or significant odors resulting from 

volatile organic compound (VOC) transfer operations must be conducted during each degassing or 

cleaning operation by the owner or operator of the VOC degassing and cleaning facility. 

(2) VOC degassing or cleaning through the affected transfer lines must be discontinued 

when a leak is observed and the leak cannot be repaired within a reasonable length of time. The 

intentional bypassing of a vapor control device during cleaning or degassing is prohibited. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.545. Approved Test Methods. 

For the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and Houston/Galveston/Brazoria 

areas as defined in §115.10 of this title (relating to Definitions), compliance with §115.541 and 

§115.542 of this title (relating to Emission Specifications and Control Requirements) must be 

determined by applying the following test methods, as appropriate: 

(1) Test Methods 1-4 (40 Code of Federal Regulations (CFR) Part 60, Appendix A) for 

determining flow rates; 

(2) Test Method 18 (40 CFR Part 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(3) Test Method 25 (40 CFR Part 60, Appendix A) for determining total gaseous 

nonmethane organic emissions as carbon; 

(4) Test Methods 25A or 25B (40 CFR Part 60, Appendix A) for determining total 

gaseous organic concentrations using flame ionization or nondispersive infrared analysis; 

(5) additional test procedures described in 40 CFR §60.503(b), (c), and (d) (effective 

February 14, 1989) for determining compliance for bulk gasoline terminals; 
Texas Commission on Environmental Quality Page 19 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(6) Test Method 21 (40 CFR Part 60, Appendix A) for determining volatile organic 

compound (VOC) leaks; 

(7) determination of true vapor pressure using American Society for Testing and 

Materials (ASTM) Test Method D323-89, D2879, D4953, D5190, or D5191 for the measurement of 

Reid vapor pressure, adjusted for actual storage temperature in accordance with API Publication 2517, 

Third Edition, 1989; 

(8) Test Method 27 (40 CFR Part 60, Appendix A) for determining tank-truck leaks; 

(9) 40 CFR §63.565(c) (effective September 19, 1995) or 40 CFR §61.304(f) (effective 

October 17, 2000) for determination of marine vessel vapor tightness; 

(10) minor modifications to these test methods approved by the executive director; or 

(11) VOC concentration measurements required by §115.542(a)(6) and (b)(5) of this 

title (relating to Control Requirements) must be performed using one of the methods or measurement 

instruments listed in subparagraphs (A) – (F) of this paragraph. 

(A) Test Method 21 (40 CFR Part 60, Appendix A). The instrument response 

factor criteria in §8.1 of the United States Environmental Protection Agency Method 21 may be 

determined using the average composition of the liquid in the tank rather than for each individual liquid. 

(B) Test Method 18 (40 CFR Part 60, Appendix A) except that only one bag 

sample needs to be collected for each concentration measurement. 

(C) Bag samples, provided the means of collecting the sample and the type of 

bag used are appropriate and representative of the type of space being sampled and the analytical 

method used to evaluate bag contents are appropriate for the concentration levels and compound types. 

(D) Test Method 25A (40 CFR Part 60, Appendix A). 

(E) Portable hydrocarbon gas analyzer using an appropriate detector that is 

effective in the concentration range being measured and calibrated with compounds of interest in each 

case. Analyzers must be calibrated and maintained according to manufacturer’s specifications. 

(F) Lower explosive limit detector. The detector must be calibrated and 

maintained according to manufacturer’s specifications. 

Adopted May 23, 2007 Effective June 14, 2007 

§115.546. Monitoring and Recordkeeping Requirements. 

For facilities in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 
Texas Commission on Environmental Quality Page 20 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Houston/Galveston/Brazoria areas as defined in §115.10 of this title (relating to Definitions) affected by 

§115.541 and §115.542 of this title (relating to Emission Specifications and Control Requirements), the 

owner or operator of any volatile organic compound (VOC) degassing or cleaning facility shall maintain 

the following information at the facility for at least two years and shall make such information available 

upon request to representatives of the executive director, the United States Environmental Protection 

Agency, or any local air pollution control agency having jurisdiction in the area: 

(1) for storage tank, transport vessel, or marine vessel degassing or cleaning 

operations: 

(A) a record of the type and number of all transport vessels, stationary VOC 

storage tanks, and marine vessels that are degassed or cleaned at the affected facility; 

(B) the chemical name and estimated liquid quantity of VOC contained in each 

vessel prior to degassing or cleaning; 

(C) the chemical name and estimated liquid quantity of VOC removed from 

each storage tank, transport vessel, or marine vessel; and 

(D) after January 1, 2009, in the Houston/Galveston/Brazoria area, a record of 

the measurements of VOC concentration or percent of lower explosive limit from the storage tank, 

transport vessel, or marine vessel being degassed while the tank or vessel is vented to the atmosphere; 

(2) for vapor control systems: 

(A) continuous monitoring and recording of the exhaust gas temperature 

immediately downstream of a direct-flame incinerator; 

(B) continuous monitoring and recording of the inlet and outlet gas temperature 

of a catalytic incinerator; and 

(C) continuous monitoring and recording of the exhaust gas VOC concentration 

for carbon adsorption systems that contain facilities to regenerate the carbon bed directly, as defined in 

§115.10 of this title (relating to Definitions); or periodic monitoring of the exhaust gas VOC as 

specified by 40 Code of Federal Regulations §61.354(d) (effective October 17, 2000), of any carbon 

adsorption system that does not regenerate the carbon bed directly, to determine breakthrough; 

(3) the results of any leak inspection and repair conducted in accordance with the 

provisions specified in §115.544 of this title (relating to Inspection Requirements); and 

(4) the results of any testing conducted in accordance with the provisions specified in 

§115.545 of this title (relating to Approved Test Methods). 
Texas Commission on Environmental Quality Page 21 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Adopted May 23, 2007 Effective June 14, 2007 

§115.547. Exemptions. 

For all persons in the Beaumont/Port Arthur, Dallas/Fort Worth, El Paso, and 

Houston/Galveston/Brazoria areas as defined in §115.10 of this title (relating to Definitions), the 

following exemptions apply. 

(1) Degassing or cleaning any storage tank, transport vessel, or marine vessel with a 

vapor space partial pressure less than 0.5 pounds per square inch absolute (psia) (3.4 kilo Pascals) of 

volatile organic compound (VOC) under actual storage conditions is exempt from the requirements of 

this division (relating to Degassing or Cleaning of Stationary, Marine, and Transport Vessels). 

(2) Degassing or cleaning any transport vessel with a nominal storage capacity of less 

than 8,000 gallons, or any stationary VOC storage tank with a nominal storage capacity of less than 1 

million gallons, or any marine vessel with a nominal storage capacity of less than 10,000 barrels 

(420,000 gallons), is exempt from the requirements of this division. After January 1, 2009, stationary 

VOC storage tanks in the Houston/Galveston/Brazoria area with a nominal storage capacity and vapor 

pressure of stored liquid as listed in subparagraphs (A) and (B) of this paragraph are no longer exempt 

from the requirements of this division. 

(A) Storage tanks with nominal storage capacity greater than or equal to 

250,000 gallons but less than 1 million gallons. 

(B) Storage tanks with nominal storage capacity greater than or equal to 75,000 

gallons but less than 250,000 gallons storing materials with true vapor pressure greater than 2.6 psia. 

(3) Any stationary VOC storage tank during preventative maintenance, roof repair, 

primary seal inspection, or removal and installation of a secondary seal, if product is not moved in or 

out of the storage tank, emissions are minimized, and the repair is completed within seven calendar 

days, is exempt from the requirements of this division. 

(4) Any marine vessel that has sustained damage that prevents a cargo tank's opening 

from being properly secured, causes the onboard vapor recovery system to be inoperative, or prevents 

the pressure/vacuum relief valves from operating within certified limits as specified by classification 

society or flag state is exempt from §115.541(b) and §115.542(b) of this title (relating to Emission 

Specifications and Control Requirements); however, all reasonable measures must be taken to minimize 

VOC emissions. 

(5) Any oceangoing, self-propelled marine vessel is exempt from the degassing or 

cleaning requirements of this division. 
Texas Commission on Environmental Quality Page 22 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

Adopted May 23, 2007 Effective June 14, 2007 

§115.549. Counties and Compliance Schedules. 

(a) All affected persons in the Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris, 

Jefferson, Liberty, Montgomery, Orange, and Waller Counties shall continue to comply with this 

division (relating to Degassing or Cleaning of Stationary, Marine, and Transport Vessels) as required 

by §115.930 of this title (relating to Compliance Dates). 

(b) All affected persons in Collin, Dallas, Denton, and Tarrant Counties shall be in compliance 

with this division as soon as practicable, but no later than one year, after the commission publishes 

notification in the Texas Register of its determination that this contingency rule is necessary as a result 

of failure to attain the national ambient air quality standard (NAAQS) for ozone by the attainment 

deadline or failure to demonstrate reasonable further progress as set forth in the 1990 Amendments to 

the Federal Clean Air Act (FCAA), §172(c)(9). 

(c) All affected persons in El Paso County shall be in compliance with this division as soon as 

practicable, but no later than one year, after the commission publishes notification in the Texas Register 

of its determination that this contingency rule is necessary as a result of failure to attain the NAAQS for 

ozone by the attainment deadline or failure to demonstrate reasonable further progress as set forth in the 

1990 Amendments to the FCAA, §172(c)(9). 

(d) All affected persons in Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, 

Montgomery, and Waller Counties shall comply with the requirements in §115.542(a)(6) and (b)(5), 

and §115.546(1)(D) of this title (relating to Control Requirements and Monitoring and Recordkeeping 

Requirements) as soon as practicable but no later January 1, 2009. 

Adopted May 23, 2007 Effective June 14, 2007 
Texas Commission on Environmental Quality Page 23 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

SUBCHAPTER F: MISCELLANEOUS INDUSTRIAL SOURCES 

DIVISION 4: PETROLEUM DRY CLEANING SYSTEMS 

''115.552, 115.553, 115.555 - 115.557, 115.559 

Effective May 16, 2002 

'115.552. Control Requirements. 

(a) For the Dallas/Fort Worth, El Paso, and Houston/Galveston areas as defined in '115.10 of 

this title (relating to Definitions), the owner or operator of any dry cleaning facility which uses 

petroleum-based solvents shall not operate the facility unless the following requirements are satisfied. 

(1) Dryers. The owner or operator of a dry cleaning facility shall either: 

(A) install, maintain, and operate a solvent-recovery dryer that recovers at 

least 85% by weight of the used petroleum solvent; 

(B) install, maintain, and operate a petroleum dry-to-dry dryer that recovers at 

least 85% by weight of the used petroleum solvent; or 

(C) route the exhaust air stream from the standard dryer to any other properly 

functioning control device which reduces the total emissions of volatile organic compounds (VOC) to 

the atmosphere by at least 85% by weight. 

(2) Filtration systems. The owner or operator of a petroleum solvent filtration system 

shall either: 

(A) install, maintain, and operate a cartridge filtration system according to the 

manufacturer's recommendations. The owner or operator shall drain all filter cartridges in their closed 

housings for at least eight hours before their removal; or 

(B) maintain and operate a regenerative filter or any other filtration medium 

according to the manufacturers' recommendations. The owner or operator shall drain the filter medium 

in its closed housing for at least eight hours before its removal. Upon removal, the owner or operator 

shall directly place the filter medium in disposable vapor tight containers or bags and shall keep these 

containers or bags vapor tight at all times until they are properly landfilled. 

(3) Fugitive emissions. The owner or operator shall ensure that: 

(A) there are no visual, audible, or smellable leaks from any portion of the dry 

cleaning equipment. Visual inspection of all equipment and system components shall be conducted at 

least weekly; 
Texas Commission on Environmental Quality Page 24 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(B) all washer and dryer traps, access doors, and other parts of the equipment 

where solvent may be exposed to the atmosphere are kept closed at all times except when required for 

proper operation or maintenance; 

(C) all solvent-contaminated waste materials are stored in closed containers 

prior to proper disposal; 

(D) repair of any visual, audible, or olfactory leak in any portion of the 

equipment shall be completed within three working days from the time the leak is detected. If 

necessary repair parts are not on hand, the owner or operator shall order the necessary parts within 

three working days and shall repair the leak no later than three working days after the parts arrive. 

(b) Any petroleum solvent dry cleaning facility that becomes or is currently subject to the 

control requirements of subsection (a) of this section by exceeding the exemption limit of '115.157 of 

this title (relating to Exemptions) shall remain subject to the provisions of this section, even if its 

consumption of petroleum solvent later falls below the exemption level, unless and until its uncontrolled 

solvent consumption is reduced to no more than its solvent consumption level before lifting controls; 

and: 

(1) the project by which solvent consumption was reduced is authorized by any permit 

or permit amendment or standard permit or permit by rule required by Chapter 116 or Chapter 106 of 

this title (relating to Control of Air Pollution by Permits for New Construction or Modification; and 

Permits by Rule). If a permit by rule is available for the project, compliance with this subsection shall 

be maintained for 30 days after the filing of documentation of compliance with that permit by rule; or 

(2) if authorization by permit, permit amendment, standard permit, or permit by rule is 

not required for the project, the owner/operator has given the executive director 30 days' notice of the 

project in writing. 

Adopted April 26, 2002 Effective May 16, 2002 

'115.553. Alternate Control Requirements. 

For all affected persons in the Dallas/Fort Worth, El Paso, and Houston/Galveston areas as 

defined in '115.10 of this title (relating to Definitions), alternate methods of demonstrating and 

documenting continuous compliance with the applicable control requirements or exemption criteria in 

this undesignated head (relating to Petroleum Dry Cleaning Systems) may be approved by the executive 

director in accordance with '115.910 of this title (relating to Availability of Alternate Means of 

Control) if emission reductions are demonstrated to be substantially equivalent. 

Adopted April 30, 1997 Effective May 22, 1997 
Texas Commission on Environmental Quality Page 25 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

'115.555. Testing Methods and Procedures. 

(a) To demonstrate initial compliance with the provisions of '115.552(a)(1)(A) of this title 

(relating to Control Requirements), the owner or operator of an affected facility shall perform an initial 

test to verify that the flow rate of recovered solvent from the recovery dryer is no greater than 1.7 fluid 

ounces per minute (50 milliliters per minute) at the termination of the recovery cycle. The test shall be 

conducted for the duration of one week during which no less than 50% of the dryer loads shall be 

monitored for their final recovered solvent flow rate. The location point for measuring the flow rate of 

recovered solvent shall be the outlet of the solvent-water separator. Near the end of the recovery cycle 

the entire flow of recovered solvent shall be diverted to a graduated cylinder. As the recovered solvent 

collects in the graduated cylinder the elapsed time is monitored and recorded in periods of greater than 

or equal to one minute. At the same time, the volume of solvent in the graduated cylinder is monitored 

and recorded to determine the volume of recovered solvent that is collected during each time period. 

The recovered solvent flow rate is calculated by dividing the volume of solvent collected per period by 

the length of time elapsed during the period and converting the results with appropriate factors into 

units of ounces or milliliters per minute. The recovery cycle and the monitoring procedure should 

continue until the flow rate of solvent is less than or equal to 1.7 fluid ounces per minute (50 milliliters 

per minute). 

(b) To demonstrate initial compliance with the provisions of '115.552(a)(1)(C) of this title, the 

owner or operator of an affected facility shall apply the following test methods, as appropriate: 

(1) Test Methods 1-4 (40 Code of Federal Regulations (CFR) 60, Appendix A) for 

determining flow rate, as necessary; 

(2) Test Method 18 (40 CFR 60, Appendix A) for determining gaseous organic 

compound emissions by gas chromatography; 

(3) Test Method 25 (40 CFR 60, Appendix A) for determining total gaseous nonmethane organic emissions as carbon; 

(4) Test Methods 25A (40 CFR 60, Appendix A) for determining total gaseous organic 

concentrations using flame ionization or nondispersive infrared analysis; or 

(5) one of the above test methods with minor modifications as approved by the 

Executive Director. 

Adopted May 4, 1994 Effective May 27, 1994 

'115.556. Recordkeeping Requirements. 
Texas Commission on Environmental Quality Page 26 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(a) For the Dallas/Fort Worth, El Paso, and Houston/Galveston areas as defined in '115.10 of 

this title (relating to Definitions), the owner or operator of any dry cleaning facility which uses 

petroleum-based solvent shall maintain records of monthly solvent consumption for at least two rolling 

years in a readily accessible location at the plant site. Solvent consumption of the previous consecutive 

12 months shall be calculated monthly and used for determining if the exemption threshold in '115.557 

of this title (relating to Exemptions) has been exceeded. 

(b) For the Dallas/Fort Worth, El Paso, and Houston/Galveston areas as defined in '115.10 of 

this title, the owner or operator of a dry cleaning facility subject to the requirements of '115.552 of this 

title (relating to Control Requirements) shall maintain: 

(1) records of the performance test required under the provisions of '115.555(a) of this 

title (relating to Test Methods and Procedures) if the facility elects to comply with the control 

requirements of '115.552(a)(1)(A) of this title; 

(2) documentation which demonstrates compliance with the provisions of '115.555(b) 

of this title if the facility elects to comply with the control requirements of '115.552(a)(1)(C) of this 

title. 

Adopted May 4, 1994 Effective May 27, 1994 

'115.557. Exemptions. 

For the Dallas/Fort Worth, El Paso, and Houston/Galveston areas as defined in '115.10 of this 

title (relating to Definitions), any petroleum solvent dry cleaning facility that consumes less than 2,000 

gallons of petroleum solvent per year is exempted from the requirements of '115.552(a)(1) of this title 

(relating to Control Requirements.) 

Adopted May 4, 1994 Effective May 27, 1994 

'115.559. Counties and Compliance Schedules. 

(a) All affected petroleum solvent dry cleaning facilities in Collin, Dallas, Denton, and Tarrant 

Counties shall be in compliance with this division (relating to Petroleum Dry Cleaning Systems) as soon 

as practicable, but no later than one year, after the commission publishes notification in the Texas 

Register of its determination that this contingency rule is necessary as a result of failure to attain the 

national ambient air quality standard (NAAQS) for ozone by the attainment deadline or failure to 

demonstrate reasonable further progress as set forth in the 1990 Amendments to the Federal Clean Air 

Act, '172(c)(9). 
Texas Commission on Environmental Quality Page 27 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds 

(b) All affected petroleum solvent dry cleaning facilities in El Paso County shall be in 

compliance with ''115.552, 115.553, and 115.555-115.557 of this title as soon as practicable, but no 

later than one year, after the commission publishes notification in the Texas Register of its 

determination that this contingency rule is necessary as a result of failure to attain the NAAQS for 

ozone by the attainment deadline or failure to demonstrate reasonable further progress as set forth in the 

1990 Amendments to the Federal Clean Air Act, '172(c)(9). 

(c) All affected petroleum solvent dry cleaning facilities in Brazoria, Chambers, Fort Bend, 

Galveston, Hardin, Harris, Jefferson, Liberty, Montgomery, Orange, and Waller Counties shall be in 

compliance with ''115.552, 115.553, and 115.555-115.557 of this title as soon as practicable, but no 

later than one year, after the commission publishes notification in the Texas Register of its 

determination that this contingency rule is necessary as a result of failure to attain the NAAQS for 

ozone by the attainment deadline or failure to demonstrate reasonable further progress as set forth in the 

1990 Amendments to the Federal Clean Air Act, '172(c)(9). 

(d) Any petroleum solvent dry cleaning facility that becomes subject to the control 

requirements of '115.552(a)(1) of this title by exceeding the exemption threshold as identified in 

'115.557 of this title shall be in compliance as soon as practicable, but no later than two years from the 

time the exemption level was exceeded. 

Adopted April 26, 2002 Effective May 16, 2002