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 - 115.119

Effective December 29, 2011

§115.110. Applicability and Definitions. 

(a) Applicability. Except as specified in §115.111 of this title (relating to 

Exemptions), this division applies to any storage tank in which volatile organic 

compounds are placed, stored, or held that is located in:

(1) the Beaumont-Port Arthur area, as defined in §115.10 of this title 

(relating to Definitions);

(2) the Dallas-Fort Worth area, as defined in §115.10 of this title; 

(3) the El Paso area, as defined in §115.10 of this title; 

(4) the Houston-Galveston-Brazoria area, as defined in §115.10 of this title; 

and

(5) Aransas, Bexar, Calhoun, Gregg, Matagorda, Nueces, San Patricio, 

Travis, and Victoria Counties.

(b) Definitions. Unless specifically defined in the Texas Clean Air Act (Texas 

Health and Safety Code, Chapter 382) or in §§3.2, 101.1, or 115.10 of this title (relating to 

Definitions, respectively), the terms in this division have the meanings commonly used 

in the field of air pollution control. In addition, the following meanings apply in this 

division unless the context clearly indicates otherwise.

(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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

(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 must extend 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) Storage capacity--The volume of a storage tank as determined by 

multiplying the internal cross-sectional area of the tank by the average internal height of 

the tank shell.

(11) Storage tank--A stationary vessel, reservoir, or container used to 

store volatile organic compounds. This definition does not include: components that are 

not directly involved in the containment of liquids or vapors; subsurface caverns or 

porous rock reservoirs; or process tanks or vessels.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(12) 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. 

(13) Vapor recovery unit--A device that transfers hydrocarbon vapors 

to a fuel liquid or gas system, a sales liquid or gas system, or a liquid storage tank.

Adopted December 7, 2011 Effective December 29, 2011

§115.111. Exemptions.

(a) The following exemptions apply 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), except as noted in paragraphs (2) and (9) - (11) of this 

subsection. 

(1) Except as provided in §115.118 of this title (relating to Recordkeeping 

Requirements), a storage tank storing volatile organic compounds (VOC) with a true 

vapor pressure less than 1.5 pounds per square inch absolute (psia) is exempt from the 

requirements of this division. 

(2) A storage tank with storage capacity less than 210,000 gallons storing 

crude oil or condensate prior to custody transfer in the Beaumont-Port Arthur, DallasFort Worth, or El Paso areas is exempt from the requirements of this division. This 

exemption no longer applies in the Dallas-Fort Worth area beginning March 1, 2013.

(3) A storage tank with a storage capacity less than 25,000 gallons located 

at a motor vehicle fuel dispensing facility is exempt from the requirements of this 

division. 

(4) A welded storage 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) An external floating roof storage tank storing waxy, high pour point 

crude oils is exempt from any secondary seal requirements of §115.112(a), (d), and (e) of 

this title (relating to Control Requirements). 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(6) A welded storage tank storing VOC with a true vapor pressure less than 

4.0 psia is exempt from any external floating roof secondary seal requirement if any of 

the following types of primary seals were 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) A welded storage tank storing crude oil with a true vapor pressure 

equal to or greater than 4.0 psia and less than 6.0 psia is exempt from any external 

floating roof secondary seal requirement if any of the following types of primary seals 

were 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) A storage tank with storage capacity less than 1,000 gallons is exempt 

from the requirements of this division.

(9) In the Houston-Galveston-Brazoria area, a storage tank or tank battery 

storing condensate, as defined in §101.1 of this title (relating to Definitions), prior to 

custody transfer with a condensate throughput exceeding 1,500 barrels (63,000 gallons) 

per year on a rolling 12-month basis is exempt from the requirement in §115.112(d)(4) or 

(e)(4)(A) of this title, to control flashed gases if the owner or operator demonstrates, 

using the test methods specified in §115.117 of this title (relating to Approved Test 

Methods), that uncontrolled VOC emissions from the individual storage 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. 

(10) In the Dallas-Fort Worth area, a storage tank or tank battery storing 

condensate prior to custody transfer with a condensate throughput exceeding 3,000 

barrels (126,000 gallons) per year on a rolling 12-month basis is exempt from the 

requirement in §115.112(e)(4)(B)(i) of this title, to control flashed gases if the owner or 

operator demonstrates, using the test methods specified in §115.117 of this title, that 

uncontrolled VOC emissions from the individual storage tank, or from the aggregate of 

storage tanks in a tank battery, are less than 50 tons per year on a rolling 12-month 

basis. This exemption no longer applies 15 months after the date the commission 

publishes notice in the Texas Register as specified in §115.119(b)(1)(C) of this title 

(relating to Compliance Schedules) that the Dallas-Fort Worth area has been reclassified 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

as a severe nonattainment area for the 1997 Eight-Hour Ozone National Ambient Air 

Quality Standard.

(11) In the Dallas-Fort Worth area, on or after the date specified in 

§115.119(b)(1)(C) of this title, a storage tank or tank battery storing condensate prior to 

custody transfer with a condensate throughput exceeding 1,500 barrels (63,000 gallons)

per year on a rolling 12-month basis is exempt from the requirement in 

§115.112(e)(4)(B)(ii) of this title, to control flashed gases if the owner or operator 

demonstrates, using the test methods specified in §115.117 of this title, that uncontrolled 

VOC emissions from the individual storage 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) The following exemptions apply in Gregg, Nueces, and Victoria Counties. 

(1) Except as provided in §115.118 of this title, a storage tank storing VOC 

with a true vapor pressure less than 1.5 psia is exempt from the requirements of this 

division. 

(2) A storage tank with storage capacity less than 210,000 gallons storing 

crude oil or condensate prior to custody transfer is exempt from the requirements of this 

division. 

(3) A storage tank with storage capacity less than 25,000 gallons located at 

a motor vehicle fuel dispensing facility is exempt from the requirements of this division. 

(4) A welded storage 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) An external floating roof storage tank storing waxy, high pour point 

crude oils is exempt from any secondary seal requirements of §115.112(b) of this title. 

(6) A welded storage tank storing VOC with a true vapor pressure less than 

4.0 psia is exempt from any external secondary seal requirement if any of the following 

types of primary seals were 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. 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(7) A welded storage tank storing crude oil with a true vapor pressure 

equal to or greater than 4.0 psia and less than 6.0 psia is exempt from any external 

secondary seal requirement if any of the following types of primary seals were 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) A storage tank with storage capacity less than 1,000 gallons is exempt 

from the requirements of this division. 

(c) The following exemptions apply in Aransas, Bexar, Calhoun, Matagorda, San 

Patricio, and Travis Counties. 

(1) A storage tank storing VOC with a true vapor pressure less than 1.5 psia 

is exempt from the requirements of this division. 

(2) Slotted guidepoles installed in a floating roof or cover storage tank are 

exempt from the provisions of §115.112(c) of this title. 

(3) A storage tank with storage capacity between 1,000 gallons and 25,000 

gallons is exempt from the requirements of §115.112(c)(1) of this title if construction 

began before May 12, 1973. 

(4) A storage tank with storage capacity less than or equal to 420,000 

gallons is exempt from the requirements of §115.112(c)(3) of this title. 

(5) A storage tank with storage capacity less than 1,000 gallons is exempt 

from the requirements of this division.

Adopted December 7, 2011 Effective December 29, 2011

§115.112. Control Requirements. 

(a) The following requirements apply in the Beaumont-Port Arthur, Dallas-Fort 

Worth, and El Paso areas, as defined in §115.10 of this title (relating to Definitions). The 

control requirements in this subsection no longer apply in the Dallas-Fort Worth area 

beginning March 1, 2013. 

(1) No person shall place, store, or hold in any storage tank any volatile 

organic compounds (VOC) unless the storage tank is capable of maintaining working 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

compliance with the control requirements 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 a Storage Tank Storing Volatile Organic Compounds 

(VOC) Other than Crude Oil and Condensate 

True Vapor Pressure

(pounds per square 

inch absolute (psia))

Storage Capacity

(gallon (gal))

Control Requirements

≥ 1.5 psia and < 11 psia > 1,000 gal and ≤ 

25,000 gal 

Submerged fill pipe

or 

Vapor control system

≥ 1.5 psia and < 11 psia > 25,000 gal and ≤ 

40,000 gal

Internal floating cover,

or 

External floating roof 

(any type), 

or 

Vapor control system

≥ 1.5 psia and < 11 psia > 40,000 gal Internal floating cover, 

or 

External floating roof 

with primary seal (any 

type) and secondary seal, 

or 

Vapor control system

≥ 11 psia > 1,000 gal and ≤ 

25,000 gal

Submerged fill pipe 

or 

Vapor control system

≥ 11 psia > 25,000 gal Submerged fill pipe 

and 

Vapor control system
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

Table II(a): Required Control for a Storage Tank Storing Crude Oil and Condensate 

True Vapor Pressure

(pounds per square 

inch absolute (psia))

Storage Capacity

(gallon (gal)) Control Requirements

≥ 1.5 psia and < 11 psia > 1,000 gal and ≤ 

40,000 gal

Submerged fill pipe 

or

Vapor control system

≥ 1.5 psia and < 11 psia > 40,000 gal Internal floating cover, 

or 

External floating roof 

with primary seal (any 

type) and secondary seal, 

or

Vapor control system

≥ 11 psia > 1,000 gal and ≤ 

40,000 gal

Submerged fill pipe 

or 

Vapor control system

≥ 11 psia > 40,000 gal Submerged fill pipe 

and

Vapor control system

(2) For an external floating roof or internal floating cover storage tank 

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 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 or cover is being floated off or landed on the roof or 

cover leg supports. 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

or cover is being floated off the roof or cover leg supports or at the manufacturer's 

recommended setting. 

(D) Any roof or cover 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. 

(F) For an external floating roof storage tank , secondary seals must 

be the rim-mounted type (the seal must be continuous from the floating roof to the tank 

wall). The accumulated area of gaps that exceed 1/8 inch in width between the 

secondary seal and storage tank wall may not be greater than 1.0 square inch per foot of 

tank diameter. 

(3) Vapor control systems, as defined in §115.10 of this title, used as a 

control device on any storage tank must maintain a minimum control efficiency of 90%. 

If a flare is used, it must be designed and operated in accordance with 40 Code of 

Federal Regulations §60.18(b) - (f) (as amended through December 22, 2008 (73 FR 

78209)) and be lit at all times when VOC vapors are routed to the flare.

(b) The following requirements apply in Gregg, Nueces, and Victoria Counties. 

(1) No person shall place, store, or hold in any storage tank any VOC, 

unless the storage tank is capable of maintaining working pressure sufficient at all times 

to prevent any vapor or gas loss to the atmosphere or is in compliance with the control 

requirements specified in Table I(a) in subsection (a)(1) of this section for VOC other 

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

oil and condensate. If a flare is used as a vapor recovery system, as defined in §115.10 of 

this title, it must be designed and operated in accordance with 40 Code of Federal 

Regulations §60.18(b) - (f) (as amended through December 22, 2008 (73 FR 78209)) 

and be lit at all times when VOC vapors are routed to the flare.

(2) For an external floating roof or internal floating cover storage tank 

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

(B) Automatic bleeder vents (vacuum breaker vents) must be closed 

at all times except when the roof or cover is being floated off or landed on the roof or 

cover leg supports. 

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

or cover is being floated off the roof or cover leg supports or at the manufacturer's 

recommended setting. 

(D) Any roof or cover 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. 

(F) For an external floating roof storage tank , secondary seals must 

be the rim-mounted type (the seal shall be continuous from the floating roof to the tank 

wall). The accumulated area of gaps that exceed 1/8 inch in width between the 

secondary seal and tank wall may not be greater than 1.0 square inch per foot of tank 

diameter. 

(c) The following requirements apply in Aransas, Bexar, Calhoun, Matagorda, San 

Patricio, and Travis Counties. 

(1) No person may place, store, or hold in any storage tank any VOC, other 

than crude oil or condensate, unless the storage tank is capable of maintaining working 

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

compliance with the control requirements specified in Table I(b) of this paragraph for 

VOC other than crude oil and condensate. 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

Table I(b). Required Control for a Storage Tank Storing Volatile Organic Compounds 

(VOC) Other than Crude Oil and Condensate

True Vapor Pressure

(pounds per square 

inch absolute (psia))

Storage Capacity

(gallon (gal))

Control Requirements

≥ 1.5 psia and < 11 psia > 1,000 gal and ≤ 

25,000 gal

Submerged fill pipe 

or 

Vapor control system

≥ 1.5 psia and < 11 psia > 25,000 gal Internal floating cover or 

external floating roof (any 

type) 

or 

Vapor control system

≥ 11 psia > 1,000 gal and ≤ 

25,000 gal

Submerged fill pipe 

or 

Vapor control system

≥ 11 psia > 25,000 gal Submerged fill pipe 

and 

Vapor control system

(2) For an external floating roof or internal floating cover storage tank 

subject to the provisions of paragraph (1) of this subsection, the following requirements 

apply. 

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

seal or seal fabric. 

(B) All tank gauging and sampling devices must 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 storage tank unless the storage tank 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 control devices, 

properly maintained and operated:
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(A) an internal floating cover or external floating roof, as defined in 

§115.10 of this title. These control devices will not be allowed if the VOC has a true vapor 

pressure of 11.0 psia or greater. All tank-gauging and tank-sampling devices must be 

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

(B) a vapor control system as defined in §115.10 of this title. 

(d) The following requirements apply in the Houston-Galveston-Brazoria area, as 

defined in §115.10 of this title. The requirements in this subsection no longer apply 

beginning March 1, 2013. 

(1) No person shall place, store, or hold in any storage tank any VOC 

unless the storage tank is capable of maintaining working pressure sufficient at all times 

to prevent any vapor or gas loss to the atmosphere or is in compliance with the control 

requirements 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 an external floating roof or internal floating cover storage tank 

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 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 or cover 

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 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 external floating roof drain that empties into the stored 

liquid must be equipped with a slotted membrane fabric cover that covers at least 90% 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 an internal floating cover storage tank 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 an external floating roof storage tank , secondary seals must 

be the rim-mounted 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 in width between the secondary seal and 

storage tank wall may not be greater than 1.0 square inch per foot of storage tank 

diameter. 

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

storage tank must be equipped with one of the following control device configurations:

(i) a pole wiper and pole float that has a seal or wiper 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) a retrofit to a solid guidepole system;

(v) a flexible enclosure system; or 

(vi) a cover on an external floating roof tank. 

(H) The external floating roof or internal floating cover must be 

floating on the liquid surface at all times except as specified in this subparagraph. The 

external floating roof or internal floating cover may be supported by the leg supports or 

other support devices, such as hangers from the fixed roof, during the initial fill or refill 

after the storage tank has been cleaned 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 storage capacity less than 

25,000 gallons or the vapor pressure of the material stored is less than 1.5 psia; 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

time the floating roof or cover is landed until the floating roof or cover is within ten 

percent by volume of being refloated; 

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

emissions from roof or cover landings, have been included in a floating roof or cover 

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 VOC emissions from floating roof or cover 

landings at the regulated entity, as defined in §101.1 of this title, are less than 25 tons per 

year. 

(3) Vapor control systems, as defined in §115.10 of this title, used as a 

control device on any storage tank must maintain a minimum control efficiency of 90%.

(4) For a storage tank storing condensate, as defined in §101.1 of this title, 

prior to custody transfer, flashed gases must be routed to a vapor control system 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) For a storage tank storing crude oil or condensate prior to custody 

transfer or at a pipeline breakout station, flashed gases must be routed to a vapor 

control system if the uncontrolled VOC emissions from an individual storage tank, or 

from the aggregate of storage tanks in a tank battery, 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) The owner or operator may make direct measurements using 

the measuring instruments and methods specified in §115.117 of this title (relating to 

Approved Test Methods). 

(B) The owner or operator may use 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, the owner or operator may use 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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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. 

(D) Other test methods or computer simulations may be allowed if 

approved by the executive director. 

(e) The control requirements in this subsection apply in the Houston-GalvestonBrazoria and Dallas-Fort Worth areas beginning March 1, 2013, except as specified in 

§115.119 of this title (relating to Compliance Schedules). 

(1) No person shall place, store, or hold VOC in any storage tank unless the 

storage tank is capable of maintaining working pressure sufficient at all times to prevent 

any vapor or gas loss to the atmosphere or is in compliance with the control 

requirements specified in Table 1 of this paragraph for VOC other than crude oil and 

condensate or Table 2 of this paragraph for crude oil and condensate. 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

Table 1: Required Control for a Storage Tank Storing Volatile Organic Compounds Other 

Than Crude Oil and Condensate

True Vapor Pressure

(pounds per square 

inch absolute (psia))

Storage Capacity

(gallon (gal))

Control Requirements

≥ 1.5 psia and < 11 

psia

> 1,000 gal and ≤ 

25,000 gal

Submerged fill pipe, 

or 

Vapor control system 

≥ 1.5 psia and < 11 

psia

> 25,000 gal and ≤ 

40,000 gal

Internal floating cover, 

or 

External floating roof (any 

type), 

or 

Vapor control system 

≥ 1.5 psia and < 11 

psia

> 40,000 gal Internal floating cover, 

or 

External floating roof with 

primary seal (any type) and 

secondary seal, 

or 

Vapor control system 

≥ 11 psia > 1,000 gal and ≤ 

25,000 gal

Submerged fill pipe, 

or 

Vapor control system 

≥ 11 psia > 25,000 gal Submerged fill pipe 

and 

Vapor control system 
Texas Commission on Environmental Quality Page 17

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

Table 2: Required Control for a Storage Tank Storing Crude Oil and Condensate 

True Vapor Pressure

(pounds per square 

inch absolute (psia))

Storage Capacity

(gallon (gal))

Control Requirements

≥ 1.5 psia and < 11 

psia

> 1,000 gal and ≤ 

40,000 gal

Submerged fill pipe, 

or

Vapor control system 

≥ 1.5 psia and < 11 

psia

> 40,000 gal Internal floating cover, 

or 

External floating roof with 

primary seal (any type) and 

secondary seal, 

or

Vapor control system 

≥ 11 psia > 1,000 gal and ≤ 

40,000 gal

Submerged fill pipe, 

or 

Vapor control system 

≥ 11 psia > 40,000 gal Submerged fill pipe 

and

Vapor control system 

(2) For an external floating roof or internal floating cover storage tank 

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 must provide a projection below the liquid surface. Automatic bleeder vents 

(vacuum breaker vents) and rim space vents are not subject to this requirement.

(B) All openings in an internal floating cover or external floating 

roof 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 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. Automatic bleeder vents (vacuum breaker vents), rim space vents, leg 

sleeves, and roof or cover drains are not subject to this requirement.
Texas Commission on Environmental Quality Page 18

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(C) 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. 

(D) 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. 

(E) Any external floating 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 an internal floating cover storage tank are not subject to this 

requirement. 

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

seal or seal fabric. 

(G) For an external floating roof storage tank , secondary seals must 

be the rim-mounted 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 in width between the secondary seal and 

storage tank wall may not be greater than 1.0 square inch per foot of storage tank 

diameter. 

(H) Each opening for a slotted guidepole in an external floating roof 

storage tank must be equipped with one of the following control device configurations: 

(i) a pole wiper and pole float that has a seal or wiper 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) a retrofit to a solid guidepole system;

(v) a flexible enclosure system; or

(vi) a cover on an external floating roof tank. 
Texas Commission on Environmental Quality Page 19

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(I) The external floating roof or internal floating cover must be 

floating on the liquid surface at all times except as allowed under the following 

circumstances:

(i) during the initial fill or refill after the storage tank has 

been cleaned;

(ii) when necessary for preventive maintenance, roof or cover 

repair, primary seal inspection, or removal and installation of a secondary seal, if 

product is not transferred into or out of the storage tank, emissions are minimized, and 

the repair is completed within seven calendar days; 

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

incompatible liquid; 

(iv) when the storage tank has a storage capacity less than 

25,000 gallons; 

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

time the storage tank has been emptied to the extent practical or the drain pump loses 

suction until the floating roof or cover is within 10% by volume of being refloated; 

(vi) when all VOC emissions from the storage tank, including 

emissions from floating roof or cover landings, have been included in an emissions limit 

or cap approved under Chapter 116 of this title prior to March 1, 2013; or 

(vii) when all VOC emissions from floating roof or cover 

landings at the regulated entity are less than 25 tons per year. 

(3) A control device used to comply with this subsection must meet one of 

the following conditions at all times when VOC vapors are routed to the device.

(A) A control device, other than a vapor recovery unit or a 

flare, must maintain the following minimum control efficiency: (i) in the HoustonGalveston-Brazoria area, 90%; and

(ii) in the Dallas-Fort Worth area, 95%.

(B) A vapor recovery unit must be designed to process all vapor 

generated by the maximum liquid throughput of the storage tank or the aggregate of 

storage tanks in a tank battery and must transfer recovered vapors to a pipe or container 

that is vapor-tight, as defined in §115.10 of this title.
Texas Commission on Environmental Quality Page 20

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(C) A flare must be designed and operated in accordance with 40 

Code of Federal Regulations §60.18(b) - (f) (as amended through December 22, 2008 

(73 FR 78209)) and be lit at all times when VOC vapors are routed to the flare.

(4) For a storage tank storing condensate prior to custody transfer, flashed 

gases must be routed to a vapor control system if the condensate throughput of an 

individual tank or the aggregate of tanks in a tank battery exceeds: 

(A) in the Houston-Galveston-Brazoria area, 1,500 barrels (63,000 

gallons) per year on a rolling 12-month basis; and

(B) in the Dallas-Fort Worth area:

(i) 3,000 barrels (126,000 gallons) per year on a rolling 12-

month basis; or

(ii) 15 months after the date the commission publishes notice 

in the Texas Register as specified in §115.119(b)(1)(C) of this title that the Dallas-Fort 

Worth area has been reclassified as a severe nonattainment area for t he 1997 EightHour Ozone National Ambient Air Quality Standard, 1,500 barrels (63,000 gallons) per 

year on a rolling 12-month basis.

(5) For a storage tank storing crude oil or condensate prior to custody 

transfer or at a pipeline breakout station, flashed gases must be routed to a vapor 

control system if the uncontrolled VOC emissions from an individual storage tank, or 

from the aggregate of storage tanks in a tank battery, equal or exceed: 

(A) in the Houston-Galveston-Brazoria area, 25 tons per year on a 

rolling 12-month basis; and

(B) in the Dallas-Fort Worth area:

(i) 50 tons per year on a rolling 12-month basis; or

(ii) 15 months after the date the commission publishes notice 

in the Texas Register as specified in §115.119(b)(1)(C) of this title that the Dallas-Fort 

Worth area has been reclassified as a severe nonattainment area for the 1997 Eight-Hour 

Ozone National Ambient Air Quality Standard, 25 tons per year on a rolling 12-month 

basis.

(6) Uncontrolled emissions from a storage tank or tank battery storing 

crude oil or condensate prior to custody transfer or at a pipeline breakout station 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 
Texas Commission on Environmental Quality Page 21

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

subparagraphs (A) or (B) of this paragraph are higher than emissions estimated using 

the default factors or charts in subparagraphs (C) or (D) of this paragraph, the higher 

values must be used. 

(A) The owner or operator may make direct measurements using 

the measuring instruments and methods specified in §115.117 of this title. 

(B) The owner or operator may use other test methods or computer 

simulations approved by the executive director. 

(C) The owner or operator may use 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. 

(D) For crude oil storage only, the owner or operator may use 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.

Adopted December 7, 2011 Effective December 29, 2011

§115.113. 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 December 7, 2011 Effective December 29, 2011

§115.114. Inspection Requirements. 

(a) The following inspection requirements apply 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).

(1) For an internal floating cover storage tank , the internal floating cover 

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. 

(A) If the internal floating cover is not resting on the surface of the 

volatile organic compounds (VOC) inside the storage tank and is not resting on the leg 
Texas Commission on Environmental Quality Page 22

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

supports; or liquid has accumulated on the internal floating cover; 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 Subchapter F, Division 3 of this chapter (relating to Degassing of Storage Tanks, 

Transport Vessels, and Marine Vessels). 

(B) 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.

(2) For an external floating roof storage tank , the secondary seal gap must 

be physically measured at least once every 12 months to insure compliance with 

§115.112(a)(2)(F), (d)(2)(F), and (e)(2)(G) of this title (relating to Control 

Requirements).

(A) If the secondary seal gap exceeds the limitations specified by 

§115.112(a)(2)(F), (d)(2)(F), and (e)(2)(G) 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 Subchapter F, Division 3 of this chapter . 

(B) 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 storage tank is equipped with a mechanical shoe or liquidmounted primary seal, compliance with §115.112(a)(2)(F), (d)(2)(F), and (e)(2)(G) of 

this title can be determined by visual inspection.

(4) For an external floating roof storage tank , the secondary seal must be 

visually inspected at least once every six months to ensure compliance with 

§115.112(a)(2)(E) and (F), (d)(2)(E) and (F), and (e)(2)(F) and (G) of this title.

(A) 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 
Texas Commission on Environmental Quality Page 23

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 Subchapter F, 

Division 3 of this chapter . 

(B) 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) The following inspection requirements apply in Gregg, Nueces, and Victoria 

Counties.

(1) For an internal floating cover storage tank, the following inspection 

requirements apply.

(A) If during an inspection of an internal floating cover storage 

tank, the internal floating cover 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 cover; 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. 

(B) 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. 

(2) For an external floating roof storage tank , the secondary seal gap must 

be physically measured at least once every 12 months to insure compliance with 

§115.112(b)(2)(F) of this title. 

(A) 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.
Texas Commission on Environmental Quality Page 24

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(B) 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 storage tank is equipped with a mechanical shoe or liquidmounted primary seal, compliance with §115.112(b)(2)(F) of this title can be determined 

by visual inspection. 

(4) For an external floating roof storage tank , the secondary seal must be 

visually inspected at least once every 12 months to insure compliance with 

§115.112(b)(2)(E) - (F) of this title. 

(A) 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. 

(B) 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.

(c) The following inspection requirements apply in Aransas, Bexar, Calhoun, 

Matagorda, San Patricio, and Travis Counties.

(1) For an internal floating cover storage tank, the following inspection 

requirements apply.

(A) If during an inspection of an internal floating cover storage 

tank, the internal floating cover 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 cover; 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. 
Texas Commission on Environmental Quality Page 25

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(B) 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. 

(2) For an external floating roof storage tank, the following inspection 

requirements apply.

(A) 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 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. 

(B) 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.

Adopted December 7, 2011 Effective December 29, 2011

§115.115. Monitoring Requirements. 

(a) The following monitoring requirements apply 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). An affected owner or operator shall install 

and maintain monitors to measure operational parameters of any of the following 

control devices installed to meet applicable control requirements. Such monitors must 

be sufficient to demonstrate proper functioning of those devices to design specifications.

(1) For a direct-flame incinerator, the owner or operator shall continuously 

monitor the exhaust gas temperature immediately downstream of the device.

(2) For a condensation system, the owner or operator shall continuously 

monitor the outlet gas temperature to ensure the temperature is below the 
Texas Commission on Environmental Quality Page 26

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

manufacturer's recommended operating temperature for controlling the volatile organic 

compounds (VOC) vapors routed to the device.

(3) For a carbon adsorption system or carbon adsorber, as defined in 

§101.1 of this title (relating to Definitions), the owner or operator shall:

(A) continuously monitor the exhaust gas VOC concentration of a 

carbon adsorption system that regenerates the carbon bed directly to determine 

breakthrough. For the purpose of this paragraph, breakthrough is defined as a measured 

VOC concentration exceeding 100 parts per million by volume above background 

expressed as methane. The owner or operator may conduct this monitoring using 

Method 21, as specified in §115.117 of this title (relating to Approved Test Methods), if 

the monitoring is conducted once every seven calendar days; or

(B) switch the vent gas flow to fresh carbon at a regular 

predetermined time interval that is less than the carbon replacement interval 

determined by the maximum design flow rate and the VOC concentration in the gas 

stream vented to the carbon adsorption system or carbon adsorber. 

(4) For a catalytic incinerator, the owner or operator shall continuously 

monitor the inlet and outlet gas temperature.

(5) For a vapor recovery unit used to comply with §115.112(e)(3) of this 

title (relating to Control Requirements), the owner or operator shall continuously 

monitor at least one of the following operational parameters:

(A) run-time of the compressor or motor in a vapor recovery unit;

(B) total volume of recovered vapors; or

(C) other parameters sufficient to demonstrate proper functioning 

to design specifications.

(6) For a control device not listed in this subsection, the owner or operator 

shall continuously monitor one or more operational parameters sufficient to 

demonstrate proper functioning of the control device to design specifications.

(b) In Victoria County, the owner or operator shall monitor operational 

parameters of any of the emission control devices listed in this subsection installed to 

meet applicable control requirements. 

(1) For a direct-flame incinerator, the owner or operator shall continuously

monitor the exhaust gas temperature immediately downstream of the device . 
Texas Commission on Environmental Quality Page 27

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(2) For a condensation system or catalytic incinerator, the owner or 

operator shall continuously monitor the inlet and outlet gas temperature .

(3) For a carbon adsorption system or carbon adsorber, the owner or 

operator shall continuously monitor the exhaust gas VOC concentration to determine if 

breakthrough has occurred. The owner or operator may conduct this monitoring using 

Method 21, as specified in §115.117 of this title, if the monitoring is conducted once every 

seven calendar days.

Adopted December 7, 2011 Effective December 29, 2011

§115.116. Testing Requirements.

(a) The testing requirements in this subsection apply in the Dallas-Fort Worth,

Houston-Galveston-Brazoria, Beaumont-Port Arthur, and El Paso areas, as defined in 

§115.10 of this title (relating to Definitions) .

(1) For a vapor control system, other than a vapor recovery unit or a flare, 

used to comply with the control requirements in §115.112(a)(3) and (e)(3)(A) of this title 

(relating to Control Requirements), an initial control efficiency test must be conducted 

in accordance with the approved test methods in §115.117 of this title (relating to 

Approved Test Methods). If the vapor control system is modified in any way that could 

reasonably be expected to decrease the control efficiency, the device must be retested 

within 60 days of the modification.

(2) A flare used to comply with the control requirements in §115.112(a)(3) 

and (e)(3)(C) of this title must meet the design verification test requirements in 40 Code 

of Federal Regulations §60.18(f) (as amended through December 22, 2008 (73 FR 

78209)). 

(b) The testing requirements in this subsection apply in Gregg, Nueces, and 

Victoria Counties.

(1) For a vapor control system, other than a vapor recovery unit or a flare, 

compliance with the control requirements in §115.112(b) of this title must be 

demonstrated in accordance with the approved test methods in §115.117 of this title.

(2) A flare must meet the design verification test requirements in 40 Code 

of Federal Regulations §60.18(f) (as amended through December 22, 2008 (73 FR 

78209)).

Adopted December 7, 2011 Effective December 29, 2011

§115.117. Approved Test Methods. 
Texas Commission on Environmental Quality Page 28

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

For the Beaumont-Port Arthur, Dallas-Fort Worth, El Paso, and HoustonGalveston-Brazoria areas, as defined in §115.10 of this title (relating to Definitions) and 

Gregg, Nueces, and Victoria Counties, compliance with the requirements in this division 

must be determined by applying the following test methods, as appropriate: 

(1) Methods 1 - 4 (40 Code of Federal Regulations (CFR) Part 60, 

Appendix A) for determining flow rates, as necessary; 

(2) Method 18 (40 CFR Part 60, Appendix A) for determining gaseous 

organic compound emissions by gas chromatography; 

(3) Method 21 (40 CFR Part 60, Appendix A-7) for determining volatile 

organic compounds concentrations for the purposes of determining the presence of 

leaks and determining breakthrough on a carbon adsorption system or carbon adsorber. 

If the owner or operator chooses to conduct a test to verify a vapor-tight requirement, 

Method 21 is acceptable;

(4) Method 22 (40 CFR Part 60, Appendix A) for determination of visible 

emissions from flares; 

(5) Method 25 (40 CFR Part 60, Appendix A) for determining total 

gaseous nonmethane organic emissions as carbon; 

(6) Methods 25A or 25B (40 CFR Part 60, Appendix A) for determining 

total gaseous organic concentrations using flame ionization or nondispersive infrared 

analysis; 

(7) test method described in 40 CFR §60.113a(a)(1)(ii) (effective April 8, 

1987) for measurement of storage tank seal gap; 

(8) true vapor pressure must be determined using standard reference texts 

or American Society for Testing and Materials Test Method D323, 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. 

For the purposes of temperature correction, the owner or operator shall use the actual 

storage temperature. Actual storage temperature of an unheated storage tank may be 

determined using the maximum local monthly average ambient temperature as reported 

by the National Weather Service. Actual storage temperature of a heated storage tank 

must be determined using either the measured temperature or the temperature set point 

of the storage tank ; 

(9) mass flow meter, positive displacement meter, or similar device for 

measuring the volumetric flow rate of flash, working, breathing, and standing emissions 
Texas Commission on Environmental Quality Page 29

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

from crude oil and condensate over a 24-hour period representative of normal 

operation. For crude oil and natural gas production sites, volumetric flow rate 

measurements must be made while the producing wells are operational; 

(10) test methods referenced in paragraphs (2), (5), and (6) 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 volatile organic compounds in flashed gases from crude 

oil and condensate storage; 

(11) test methods other than those specified in this section may be used if 

validated by 40 CFR Part 63, Appendix A, Test Method 301 and approved by the 

executive director; or

(12) minor modifications to these test methods approved by the executive 

director.

Adopted December 7, 2011 Effective December 29, 2011

§115.118. Recordkeeping Requirements. 

(a) The following recordkeeping requirements apply 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).

(1) The owner or operator of storage tank claiming an exemption in 

§115.111 of this title (relating to Exemptions) shall maintain records sufficient to 

demonstrate continuous compliance with the applicable exemption criteria. Where 

applicable, true vapor pressure, volatile organic compounds (VOC) content type, or a 

combination of the two must be recorded initially and at every change of service or when 

the storage tank is emptied and refilled.

(2) The owner or operator of an external floating roof storage tank that is 

exempt from the requirement for a secondary seal in accordance with §115.111(a)(1), (6), 

and (7) of this title and is used to store VOC with a true vapor pressure greater than 1.0 

pounds per square inch absolute (psia) shall maintain records of the type of VOC stored 

and the average monthly true vapor pressure of the stored liquid.

(3) The owner or operator shall maintain records of the results of

inspections required by §115.114(a) of this title (relating to Inspection Requirements). 

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 where the accumulated area of such gaps is greater than 1.0 square inch 

per foot of tank diameter. These calculated emissions inventory reportable emissions 
Texas Commission on Environmental Quality Page 30

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 equation. 

( ) 90

πD

G

G

G G EI E E 8thL

a

m a

Reportable 1Seal 2Seals ×



 





×













 − = − ×

Where:

EIReportable = The calculated emissions inventory reportable emissions that must be 

reported in the annual emissions inventory submittal required by §101.10 of this title 

(relating to Emissions Inventory Requirements.

E1Seal = The AP-42 estimate of emissions from a floating roof or floating cover tank with 

a primary seal only. The material is assumed to be stored at a temperature equal to the 

maximum of the local monthly average temperatures during the emission inventory 

reporting year as reported by the National Weather Service. Units are pounds per day.

E2Seals = The AP-42 estimate of emissions from a floating roof or floating cover tank with 

primary and secondary seals. The material is assumed to be stored at a temperature 

equal to the maximum of the local monthly average temperatures during the emission 

inventory reporting year as reported by the National Weather Service. Units are pounds 

per day.

Gm = The area of measured seal gaps greater than 1/8 inch wide. Units are square 

inches.

Ga = The area of allowable seal gaps greater than 1/8 inch wide, equal to one square inch 

per foot of tank diameter. Units are square inches.

G8thL = The length of measured seal gaps greater than 1/8 inch wide. Units are linear 

feet.

D = The diameter of the storage tank. Units are feet.

90 = Constant. Units are days.

(4) The owner or operator shall maintain records of any operational 

parameter monitoring required in §115.115(a) of this title (relating to Monitoring 

Requirements) . Such records must be sufficient to demonstrate proper functioning of 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

those devices to design specifications and must include, but are not limited to, the 

following.

(A) For a direct-flame incinerator, the owner or operator shall 

continuously record the exhaust gas temperature immediately downstream of the 

device.

(B) For a condensation system, the owner or operator shall 

continuously record the outlet gas temperature to ensure the temperature is below the 

manufacturer's recommended operating temperature for controlling the VOC vapors 

routed to the device.

(C) For a carbon adsorption system or carbon adsorber, the owner 

or operator shall:

(i) continuously record the exhaust gas VOC concentration of 

any carbon adsorption system monitored according to §115.115(a)(3)(A) of this title ; or

(ii) record the date and time of each switch between carbon 

containers and the method of determining the carbon replacement interval if the carbon 

adsorption system or carbon adsorber is switched according to §115.115(a)(3)(B) of this 

title.

(D) For a catalytic incinerator, the owner or operator shall 

continuously record the inlet and outlet gas temperature.

(E) For a vapor recovery unit, the owner or operator shall maintain 

records of the continuous operational parameter monitoring required in §115.115(a)(5) 

of this title.

(F) For any other control device not listed in this paragraph, the 

owner or operator shall maintain records of the continuous operational parameter 

monitoring required in §115.115(a)(6) of this title sufficient to demonstrate proper 

functioning of the control device to design specifications.

(5) The owner or operator shall maintain the results of any testing 

conducted in accordance with §115.116 of this title (relating to Testing Requirements) or 

§115.117 of this title (relating to Approved Test Methods) at an affected site. Results may 

be maintained at an off-site location if made available for review within 24 hours.

(6) In the Houston-Galveston-Brazoria and Dallas-Fort Worth areas, the 

owner or operator shall maintain the following additional records.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(A) The owner or operator of a fixed roof storage tank that is not 

required in §115.112(d)(1) or (e)(1) of this title (relating to Control Requirements) to be 

equipped with an external floating roof, internal floating cover, or vapor control system 

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 a storage tank with 

storage capacity of 25,000 gallons or less storing VOC other than crude oil or 

condensate, or to a storage tank with storage capacity of 40,000 gallons or less storing 

crude oil or condensate.

(B) 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 a vapor control system shall maintain records of the estimated 

uncontrolled emissions from the storage tank on a rolling 12-month basis. The records 

must be made available for review within 72 hours upon request by authorized 

representatives of the executive director, the United States Environmental Protection 

Agency, or any local air pollution control agency with jurisdiction.

(C) The owner or operator of an external floating roof or internal 

floating cover storage tank meeting the extended compliance date in §115.119(a)(1)(A) or 

(b)(1)(A) of this title (relating to Compliance Schedules) shall maintain records of the 

date of the last time the storage tank was emptied and degassed.

(7) 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, or any local air pollution control agency with 

jurisdiction. In the Dallas-Fort Worth area, any records created on or after March 1, 

2011, must be maintained for at least five years. 

(b) The following recordkeeping requirements apply in Gregg, Nueces, and 

Victoria Counties.

(1) The owner or operator of an external floating roof storage tank that is 

exempt from the requirement for a secondary seal in accordance with §115.111(b)(1), (6), 

and (7) of this title and used to store VOC with a true vapor pressure greater than 1.0 

psia shall maintain records of the type of VOC stored and the average monthly true 

vapor pressure of the stored liquid. 

(2) The owner or operator shall record the results of inspections required 

by §115.114(b) of this title. 

(3) In Victoria County, the owner or operator shall continuously record 

operational parameters of any of the following emission control devices installed to meet 
Texas Commission on Environmental Quality Page 33

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

applicable control requirements in §115.112 of this title. 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 condensation system or 

catalytic incinerator; and

(C) the exhaust gas VOC concentration of any carbon adsorption 

system or carbon adsorber, to determine if breakthrough has occurred. 

(4) The owner or operator shall maintain records of the results of any 

testing conducted in accordance with §115.117 of this title at an affected site. 

(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, or any local air pollution control agency with 

jurisdiction.

Adopted December 7, 2011 Effective December 29, 2011

§115.119. Compliance Schedules. 

(a) In Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, 

and Waller Counties, the compliance date has already passed and the owner or operator 

of each storage tank in which any volatile organic compounds (VOC) is placed, stored, or 

held shall continue to comply with this division except as follows. 

(1) The affected owner or operator shall comply with the requirements of 

§§115.112(d); 115.115(a)(1), (2), (3)(A), and (4); 115.117, and 115.118(a) of this title 

(relating to Control Requirements; Monitoring Requirements; Approved Test Methods; 

and Recordkeeping Requirements, respectively) no later than January 1, 2009. Section 

115.112(d) of this title no longer applies in the Houston-Galveston-Brazoria area 

beginning March 1, 2013. Prior to March 1, 2013, the owner or operator of a storage tank 

subject to §115.112(d) of this title shall continue to comply with §115.112(d) of this title 

until compliance has been demonstrated with the requirements of §115.112(e) of this 

title.

(A) If compliance with these requirements would require emptying 

and degassing of the storage tank, compliance is not required until the next time the 

storage tank is emptied and degassed but no later than January 1, 2017.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(B) The owner or operator of each storage tank with a storage 

capacity less than 210,000 gallons storing crude oil and condensate prior to custody 

transfer shall comply with the requirements of this division no later than January 1, 

2009, regardless if compliance with these requirements would require emptying and 

degassing of the storage tank.

(2) The affected owner or operator shall comply with §§115.112(e), 

115.115(a)(3)(B), (5), and (6), and 115.116 of this title (relating to Testing Requirements) 

as soon as practicable, but no later than March 1, 2013.

(A) If compliance with these requirements would require emptying 

and degassing of the storage tank, compliance is not required until the next time the 

storage tank is emptied and degassed but no later than January 1, 2017.

(B) The owner or operator of each storage tank with a storage 

capacity less than 210,000 gallons storing crude oil and condensate prior to custody 

transfer shall comply with these requirements no later than March 1, 2013, regardless if 

compliance with these requirements would require emptying and degassing of the 

storage tank.

(b) In Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, 

and Tarrant Counties, the owner or operator of each storage tank in which any VOC is 

placed, stored, or held was required to be in compliance with this division on or before 

March 1, 2009, and shall continue to comply with this division, except as follows.

(1) The affected owner or operator shall comply with §§115.112(e), 

115.115(a)(3)(B), (5), and (6), 115.116, and 115.118(a)(6) of this title as soon as 

practicable, but no later than March 1, 2013.

(A) If compliance with §115.112(e) of this title would require 

emptying and degassing of the storage tank, compliance is not required until the next 

time the storage tank is emptied and degassed but no later than December 1, 2021. 

(B) The owner or operator of a storage tank with a storage capacity 

less than 210,000 gallons storing crude oil and condensate prior to custody transfer 

shall comply with these requirements no later than March 1, 2013, regardless if 

compliance with these requirements would require emptying and degassing of the 

storage tank.

(C) As soon as practicable but no later than 15 months after the 

commission publishes notice in the Texas Register that the Dallas-Fort Worth area has 

been reclassified as a severe nonattainment area for the 1997 Eight-Hour Ozone 

National Ambient Air Quality Standard the owner or operator of a storage tank storing 

crude oil or condensate prior to custody transfer or at a pipeline breakout station is 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

required to be in compliance with the control requirements in §115.112(e)(4)(B)(ii) and 

(5)(B)(ii) of this title except as specified in §115.111(a)(11) of this title (relating to 

Exemptions).

(2) The owner or operator is no longer required to comply with §115.112(a) 

of this title beginning March 1, 2013. 

(c) In Hardin, Jefferson, and Orange Counties, the owner or operator of each 

storage tank in which any VOC is placed, stored, or held was required to be in 

compliance with this division by March 7, 1997, and shall continue to comply with this 

division, except that compliance with §115.115(a)(3)(B), (5), and (6), and §115.116 of this 

title is required as soon as practicable, but no later than March 1, 2013. 

(d) In El Paso County, the owner or operator of each storage tank in which any 

VOC is placed, stored, or held was required to be in compliance with this division by 

January 1, 1996, and shall continue to comply with this division, except that compliance 

with §115.115(a)(3)(B), (5), and (6), and §115.116 of this title is required as soon as 

practicable, but no later than March 1, 2013. 

(e) In Aransas, Bexar, Calhoun, Gregg, Matagorda, Nueces, San Patricio, Travis, 

and Victoria Counties, the owner or operator of each storage tank in which any VOC is 

placed, stored, or held was required to be in compliance with this division by July 31, 

1993, and shall continue to comply with this division, except that compliance with 

§115.116(b) of this title is required as soon as practicable, but no later than March 1, 

2013. 

(f) The owner or operator of each storage tank in which any VOC is placed, 

stored, or held that becomes subject to this division on or after the date specified in 

subsections (a) - (e) of this section, shall comply with the requirements in this division 

no later than 60 days after becoming subject.

Adopted December 7, 2011 Effective December 29, 2011
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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, 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

(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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 (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.
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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, 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);

(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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

(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

.

(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
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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

'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 
Texas Commission on Environmental Quality Page 43

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

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

(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.

(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 
Texas Commission on Environmental Quality Page 45

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 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:
Texas Commission on Environmental Quality Page 46

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

(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 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, 
Texas Commission on Environmental Quality Page 48

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 49

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

(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.

(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 
Texas Commission on Environmental Quality Page 51

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

(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, 
Texas Commission on Environmental Quality Page 52

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 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
Texas Commission on Environmental Quality Page 53

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 1995

'115.132. Control Requirements.

(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;
Texas Commission on Environmental Quality Page 54

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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:

(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;
Texas Commission on Environmental Quality Page 55

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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.

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:
Texas Commission on Environmental Quality Page 56

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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;

(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
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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.

(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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

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.

(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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

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

(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.

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

(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.

(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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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 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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

(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
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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.

(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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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;

(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:
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

(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 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 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

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

(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).

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

(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 (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:
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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 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
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

'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 17, 1999
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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:
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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

(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;
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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;

(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 non-methane 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;
Texas Commission on Environmental Quality Page 80

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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 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 
Texas Commission on Environmental Quality Page 81

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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.

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
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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 = (F)(D) 

D

 

where:

F = Average flow rate per emission event

D = Annual duration of emission event
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(4) Batch - A noncontinuous process involving the bulk movement of 

material through sequential manufacturing steps. Mass, temperature, concentration, 

and other properties of a system 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.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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.

(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 = Vpi x (Mi / MWi

 (M

)

i / MWi )

where:

Vpi

M

= Vapor pressure of VOC component i

i

MW

= Mass of VOC component i

i = 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);
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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).

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

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

(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%.

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

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).

(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.
Texas Commission on Environmental Quality Page 89

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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

(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.
Texas Commission on Environmental Quality Page 90

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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:

(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%;
Texas Commission on Environmental Quality Page 91

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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;

(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;
Texas Commission on Environmental Quality Page 92

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(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., steamassisted, 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

(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 
Texas Commission on Environmental Quality Page 93

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

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

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

(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 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.
Texas Commission on Environmental Quality Page 95

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

Adopted September 28, 2005 Effective October 20, 2005