Texas Commission on Environmental Quality Page 1 

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

SUBCHAPTER F: MISCELLANEOUS INDUSTRIAL SOURCES

DIVISION 3: DEGASSING OF STORAGE TANKS, TRANSPORT VESSELS, 

AND MARINE VESSELS

§§115.540 - 115.542, 115.543, 115.544, 115.545, 115.546, 115.547, 115.549

Effective February 17, 2011 

§115.540. Applicability and Definitions.

(a) Applicability. Except as specified in §115.547 of this title (relating to 

Exemptions), this division applies to degassing during, or in preparation of, cleaning any 

storage tank, transport vessel, or marine vessel containing volatile organic compounds 

with a true vapor pressure greater than or equal to 0.5 pounds per square inch absolute 

under actual storage conditions. In this division, the operator of any storage tank, 

transport vessel, or marine vessel refers to the regulated entity performing or 

outsourcing the degassing operation.

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

(relating to Definitions), this division applies to any storage tank, transport vessel, or 

marine vessel.

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

division applies to any storage tank or transport vessel in Collin, Dallas, Denton, and 

Tarrant Counties. This division does not apply to any tank or vessel in Ellis, Johnson, 

Kaufman, Parker, or Rockwall Counties.

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

applies to any storage tank or transport vessel.

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

title, this division applies to any storage tank, transport vessel, or marine vessel.

(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), 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) Cleaning--The process of washing or rinsing a storage tank, transport 

vessel, or marine vessel, or removing sludge or rinsing liquid from a storage tank, 

transport vessel, or marine vessel.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(2) Degassing--The process of removing volatile organic compounds 

vapor from a storage tank, transport vessel, or marine vessel during, or in preparation 

of, cleaning.

(3) Drain-dry floating roof tank--A floating roof tank designed to 

completely drain its entire contents to a sump in a manner that leaves no free-standing 

liquid in the tank or the sump.

(4) Recirculation system--A vapor-tight system that is composed of 

piping, ductwork, connections, flow inducing devices, and a control device. The 

recirculation system conducts volatile organic compounds vapor from a storage tank, 

transport vessel, or marine vessel to a control device and conducts the exhaust from the 

outlet of the control device back into the same tank or vessel. The recirculation system 

does not include the storage tank, transport vessel, or marine vessel that is being 

degassed .

(5) 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 or the volume of a transport vessel or marine vessel as determined by the 

manufacturer's original design capacity.

(6) 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.

(7) Vapor-tight--A condition that exists when no component of a system 

has a leak greater than 500 parts per million expressed as methane measured using 

Method 21 (40 Code of Federal Regulations Part 60, Appendix A-7).

Adopted January 26, 2011 Effective February 17, 2011

§115.541. Emission Specifications.

(a) All volatile organic compounds (VOC) vapors from a storage tank, transport 

vessel, or marine vessel subject to this division must be routed to a control device in 

accordance with the requirements in §115.542 of this title (relating to Control 

Requirements) during degassing operations unless the VOC concentration, measured in 

accordance with the procedure described in §115.544(b)(3) of this title (relating to 

Inspection, Monitoring, and Testing Requirements), is less than 34,000 parts per 

million by volume (ppmv) expressed as methane or 50% of the lower explosive limit.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(b) The intentional bypassing of a control device used to comply with this division 

is prohibited. Any visible VOC leak originating from the control device, or other 

associated product recovery device, must be repaired as soon as practical. 

(c) No avoidable liquid or gaseous leaks, as detected by sight or sound, may 

originate from the degassing operation.

(d) In addition to the requirements in subsections (a) - (c) of this section, a 

transport vessel must be kept vapor-tight at all times until the VOC vapors are routed to 

a control device.

(e) In addition to the requirements in subsections (a) - (c) of this section, a 

marine vessel must: 

(1) have all cargo tank closures properly secured or maintain a negative 

pressure within the vessel when a closure is opened; and

(2) have all pressure or vacuum relief valves operating within certified 

limits, as specified by classification society or flag state, until the VOC vapors are routed 

to a control device.

(f) In addition to the requirements in subsections (a) - (c) of this section, all VOC 

vapors from a floating roof storage tank that is not a drain-dry floating roof storage tank 

must be routed to a control device as soon as practical but no later than: 

(1) 24 hours after the tank has been emptied to the extent practical or the 

drain pump loses suction for a floating roof storage tank containing VOC liquids with a 

true vapor pressure greater than or equal to 1.5 pounds per square inch absolute (psia) 

under actual storage conditions;

(2) 72 hours after the tank has been emptied to the extent practical or the 

drain pump loses suction for a floating roof storage tank containing VOC liquids with a 

true vapor pressure less than 1.5 psia under actual storage conditions; or.

(3) the time limit specified in a permit issued under Chapter 116 of this 

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

Modification) up to a maximum of 72 hours after the tank has been emptied to the 

extent practical or the drain pump loses suction.

Adopted January 26, 2011 Effective February 17, 2011

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

(a) A control device used to comply with §115.541 of this title (relating to 

Emission Specifications) must meet one of the following conditions at all times when 

volatile organic compounds (VOC) vapors are routed to the device.

(1) The control device must maintain a control efficiency of at least 90% 

and must be operated in a manner consistent with how the device was operated during 

the control efficiency demonstration required in §115.544(c) of this title (relating to 

Inspection, Monitoring, and Testing Requirements).

(2) The control device must be a flare that is 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 is lit at all times when VOC vapors are routed to 

the flare.

(3) The control device must be a recirculation system that does not cause 

the pressure inside the tank or vessel to increase by more than one inch water pressure 

above atmospheric pressure at any time during the degassing operation.

(4) The VOC concentration at the outlet of the control device must be less 

than 500 parts per million by volume (ppmv) at 0% oxygen, dry basis, expressed as 

methane.

(b) All VOC vapors must be routed to a control device until the VOC 

concentration is less than 34,000 ppmv expressed as methane or less than 50% of the 

lower explosive limit . After one of the conditions has been satisfied, the tank or vessel 

may be vented to the atmosphere without control for the remainder of the degassing 

operation, except as specified in §115.544(b)(4) of this title.

(c) Degassing equipment must be designed and operated to prevent avoidable 

liquid or gaseous VOC leaks.

(d) When degassing is effected through the hatches or manways of a storage tank, 

all lines must be equipped with fittings that make vapor-tight connections .

(e) When degassing is effected through the hatches of a transport vessel with a 

loading arm equipped with a vapor collection adapter, then pneumatic, hydraulic, or 

other mechanical means must be provided to force a vapor-tight seal between the 

adapter and the hatch. A means must be provided to minimize liquid drainage from the 

degassing equipment when it is removed from the hatch or to accomplish drainage 

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

(f) When degassing is effected through the hatches of a marine vessel with a 

loading arm equipped with a vapor collection adapter, then pneumatic, hydraulic, or 

other mechanical means must be provided to force a vapor-tight seal between the 

adapter and the hatch, or a negative pressure inside the cargo tank must be maintained. 

A means must be provided to minimize liquid drainage from the degassing equipment 

when it is removed from the hatch or to accomplish drainage before such removal.

Adopted January 26, 2011 Effective February 17, 2011

§115.543. Alternate Control Requirements.

For the owner or operator of a storage tank, transport vessel, or marine vessel 

subject to this division, 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 January 26, 2011 Effective February 17, 2011

§115.544. Inspection, Monitoring, and Testing Requirements.

(a) Inspection requirements. The following inspection requirements apply during 

the degassing of any storage tank, transport vessel, or marine vessel subject to this 

division.

(1) Inspection for visible liquid leaks, visible fumes, or significant odors 

resulting from volatile organic compounds (VOC) transfer operations must be 

conducted during each degassing operation. 

(2) Degassing through the affected transfer lines must be discontinued 

when a leak is observed and the leak cannot be repaired within a reasonable length of 

time.

(b) Monitoring requirements. The following monitoring requirements apply 

during the degassing of any storage tank, transport vessel, or marine vessel subject to 

this division. Monitoring at least once every 15 minutes is sufficient to demonstrate 

compliance with the continuous monitoring requirements in this subsection.

(1) Any monitoring device used to comply with this subsection must be 

installed, calibrated, maintained, and operated according to the manufacturer's 

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

(2) The owner or operator shall monitor any operational parameters 

necessary to demonstrate the proper functioning of a control device used to comply with 

this division at all times when VOC vapors are routed to the device.

(A) For a carbon adsorption system, the owner or operator shall 

continuously monitor the exhaust gas VOC concentration of any carbon adsorption 

system that regenerates the carbon bed directly to determine breakthrough. 

Alternatively, the owner or operator shall periodically monitor the exhaust gas VOC 

determine breakthrough and switch the exhaust gas flow to fresh carbon for any carbon 

adsorption system that does not regenerate the carbon bed directly, as specified by 40 

Code of Federal Regulations (CFR) §61.354(d) (as amended through October 17, 2000 

(65 FR 62160)), except that any monitoring must be conducted at intervals no greater 

than 20% of the design carbon replacement interval. For the purpose of this division, 

breakthrough is defined as a measured VOC concentration exceeding 100 parts per 

million by volume (ppmv) above background expressed as methane.

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

continuously monitor the inlet and outlet gas temperature.

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

continuously monitor 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.

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

continuously monitor the exhaust gas temperature immediately downstream of the 

device.

(E) For a flare, the owner or operator shall use one of the following 

methods to demonstrate compliance with the requirements in 40 CFR §60.18 (as 

amended through December 22, 2008 (73 FR 78209)). 

(i) The owner or operator shall continuously monitor the net 

heating value of the gas stream routed to the flare. 

(ii) The owner or operator shall continuously monitor the 

total volume of supplemental fuel added to the gas stream routed to the flare and 

continuously maintain sufficient supplemental fuel to meet the minimum net heating 

value requirements in 40 CFR §60.18 assuming that the net heating value contribution 

from the degassed VOC vapor is equivalent to a level corresponding to 50% of the lower 

explosive limit (LEL). The owner or operator may estimate the volumetric flow rate from 

the tank or vessel for the purpose of this calculation if the flow rate of the degassed VOC 

vapor is not directly monitored. 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(iii) The owner or operator shall use calculations to 

demonstrate that for the material stored in the tank or vessel the net heating value of the 

gas stream routed to the flare cannot drop below the minimum net heating value 

requirements in 40 CFR §60.18 until the concentration of VOC in the vapors being 

routed to the flare is less than the concentration limits in §115.542(b) of this title 

(relating to Control Requirements).

(iv) If the flare is a non-assisted flare that qualifies for the 

provisions in 40 CFR §60.18(c)(3)(i), the owner or operator may elect to continuously 

monitor the hydrogen content of the gas stream routed to the flare and continuously 

meet the minimum 8.0% by volume hydrogen content requirement in lieu of the 

requirements in clauses (i) - (iii) of this subparagraph.

(F) For any control device used to comply with the optional exhaust 

gas concentration limit in §115.542(a)(4) of this title, the owner or operator shall 

monitor the exhaust gas VOC concentration within one hour after beginning the 

degassing operation. The VOC concentration measurement must be a one-hour test run 

using one of the following methods: 

(i) the integrated bag sampling procedure in Method 18 (40 

CFR Part 60, Appendix A), §§8.2.1.1 - 8.2.1.4, and a total hydrocarbon analyzer that 

meets instrument and calibration specifications in Method 21; or

(ii) Method 25A (40 CFR Part 60, Appendix A) to monitor 

the exhaust gas VOC concentration.

(G) For a thermal oxidizer or vapor combustor, the owner or 

operator shall continuously monitor the combustion chamber temperature. If necessary 

to demonstrate compliance with subsection (c)(3) of this section, the owner or operator 

shall also continuously monitor the gas flow rate into the thermal oxidizer or vapor 

combustor to determine the combustion chamber residence time.

(H) For a recirculation system, the owner or operator shall:

(i) continuously monitor the pressure inside the tank or 

vessel or continuously monitor the gas flow rate at the inlet and outlet of the control 

device; and

(ii) monitor all components of the recirculation system, 

including all valves and connectors, for VOC leaks using the procedure in Method 21 (40 

CFR Part 60, Appendix A-7) and begin this monitoring within one hour after beginning 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

any degassing operation. A leak is defined as a screening concentration greater than 500 

ppmv above background as methane for all components.

(I) For an internal combustion engine, the owner or operator shall 

continuously monitor the engine exhaust gas oxygen content throughout the degassing 

operation.

(J) For a control device not listed in this paragraph, the owner or 

operator shall continuously monitor one or more operational parameters sufficient to 

demonstrate proper functioning of the control device to design specifications.

(3) The owner or operator shall monitor the VOC concentration to 

demonstrate compliance with the VOC concentration or percent LEL thresholds in 

§115.542(b) of this title and determine if the storage tank, transport vessel, or marine 

vessel can be vented to the atmosphere without control for the remainder of the 

degassing operation, except as specified in paragraph (4) of this subsection. The VOC 

concentration must be monitored: 

(A) once per minute for at least five minutes and all measurements 

must be less than the VOC concentration limits in §115.542(b) of this title; or

(B) over a five-minute period using the integrated bag sampling 

procedure in Method 18 (40 CFR Part 60, Appendix A) §§8.2.1.1 - 8.2.1.4 and the 

integrated measurement must be less than the VOC concentration limits in §115.542(b) 

of this title.

(4) After demonstrating compliance with the applicable VOC 

concentration or percent LEL thresholds in §115.542(b) of this title in accordance with 

paragraph (3) of this subsection, the owner or operator of any storage tank, transport 

vessel, or marine vessel shall comply with one of the following conditions.

(A) The VOC concentration inside the tank or vessel must be 

monitored once every 12 hours while venting to the atmosphere without control until 

five consecutive measurements collected at 12 hour intervals are measured to be less 

than 34,000 ppmv expressed as methane or less than 50% of the LEL . The VOC 

concentration measurement required by paragraph (3) of this subsection may be 

considered the first of these five consecutive measurements.

(i) If venting to the atmosphere without control has been 

suspended for more than four hours, the VOC concentration inside the tank or vessel 

must be measured upon restart of the degassing operation.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(ii) If any of the VOC concentration measurements equal or 

exceed 34,000 ppmv expressed as methane or 50% of the LEL , the tank or vessel must 

be routed to the control device until the VOC concentration is below 34,000 ppmv 

expressed as methane or less than 50% of the LEL as determined by subsection (b)(3) of 

this section.

(iii) If the measured VOC concentration is less than 6,800 

ppmv expressed as methane or 10% of the LEL then no further VOC concentration 

measurements are required.

(B) The storage tank, transport vessel, or marine vessel can be 

vented to the atmosphere without control for the remainder of the degassing operation 

and no further VOC measurements are required if the VOC concentration inside the 

tank or vessel is less than 6,800 ppmv expressed as methane or 10% of the LEL before 

the owner or operator stops routing the VOC vapors to a control device in accordance 

with §115.541 of this title (relating to Emission Specifications) and §115.542 of this title.

(5) Minor modifications to the monitoring methods specified in this 

section may be approved by the executive director. Monitoring methods other than 

those specified in this section may be used if approved by the executive director and 

validated by 40 CFR Part 63, Appendix A, Method 301.

(6) The sampling location for monitoring the VOC concentration as 

required by subsection (b)(3) of this section should be immediately before the control 

device or in the transfer line connecting from the tank or vessel to the control device. 

The owner or operator may elect to monitor the VOC concentration at a location inside 

the vapor space of the tank or vessel provided the location is representative of the VOC 

concentration entering the control device.

(c) Testing requirements. The following testing requirements apply to the owner 

or operator of any storage tank, transport vessel, or marine vessel subject to the 

requirements in this division if a control device is used to comply with the emission 

specifications in §115.541 of this title.

(1) For a control device used to comply with the requirements in

§115.542(a)(1) of this title, an initial control efficiency demonstration must be conducted 

in accordance with the approved test methods in §115.545 of this title (relating to 

Approved Test Methods) and the device must be retested after any modification that 

could reasonably be expected to decrease the efficiency of a control device within 60 

days after the modification or before being used to comply with the requirements in 

§115.542(a)(1) of this title, whichever is longer.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(2) For a portable control device used to comply with the requirements in 

§115.542(a)(1) of this title, a periodic control efficiency demonstration must be 

conducted at least once every 60 months in accordance with the approved test methods 

in §115.545 of this title.

(3) For a portable thermal oxidizer or vapor combustor used to comply 

with the requirements in §115.542(a)(1) of this title, the periodic control efficiency 

demonstration in paragraph (2) of this subsection will not be required if the combustion 

chamber temperature is at least 1,400 degrees Fahrenheit and the flow rate of the VOC 

vapors routed to the device is limited to assure at least a 0.5 second combustion 

chamber residence time at all times when the device is in use.

Adopted January 26, 2011 Effective February 17, 2011 

§115.545. Approved Test Methods.

Compliance with the requirements in this division must be determined by 

applying one or more of the following test methods or procedures, as appropriate.

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

Appendix A) must be used for determining flow rates.

(2) Methods 3, 3A, or 3B (40 CFR Part 60, Appendix A) must be used to 

determine exhaust gas oxygen (O2) concentration for making any O2 corrections 

necessary for §115.542(a)(4) of this title (relating to Control Requirements).

(3) Method 18 (40 CFR Part 60, Appendix A) must be used for 

determining gaseous organic compound emissions by gas chromatography.

(A) If Method 18 is used to demonstrate compliance with the 

volatile organic compounds (VOC) concentration monitoring requirements in 

§115.542(b) of this title and §115.544(b)(4) of this title (relating to Inspection, 

Monitoring, and Testing Requirements), only one bag sample needs to be collected for 

each concentration measurement.

(B) If Method 18 is used to demonstrate compliance with the VOC 

concentration monitoring requirements in §115.544(b)(2)(F) of this title for an internal 

combustion engine or any control device used to comply with the option in 

§115.542(a)(4) of this title to limit exhaust concentration, the VOC concentration must 

be determined by using the integrated bag sampling procedure in Method 18, §§8.2.1.1 - 

8.2.1.4.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(4) Method 19 (40 CFR Part 60, Appendix A) may be used for determining 

exhaust gas flow rates on combustion control devices in lieu of using Methods 1 - 4.

(5) Method 21 (40 CFR Part 60, Appendix A-7) must be used for 

determining VOC leaks. An instrument meeting the specifications and calibration 

requirements in Method 21 may be used for demonstrating compliance with the VOC 

concentration monitoring requirements in §115.542(b) and §115.544(b)(3) and (4) of 

this title with the provision that the instrument response factor criteria in §8.1 of 

Method 21 may be determined using the average composition of the liquid in the tank 

rather than for each individual liquid.

(6) Method 25 (40 CFR Part 60, Appendix A) must be used for 

determining total gaseous nonmethane organic emissions as carbon.

(7) Methods 25A or 25B (40 CFR Part 60, Appendix A) must be used for 

determining total gaseous organic concentrations using flame ionization or 

nondispersive infrared analysis.

(8) Method 27 (40 CFR Part 60, Appendix A) must be used for 

determining tank-truck leaks.

(9) A portable O2 analyzer that is calibrated, maintained, and operated 

according to the manufacturer's instructions may be used to determine exhaust gas O2

concentration for making any O2 corrections necessary for §115.542(a)(4) of this title in 

lieu of using Methods 3, 3A, or 3B.

(10) Additional test procedures described in 40 CFR §60.503(b) - (d) 

(effective February 14, 1989) must be used for determining compliance for bulk gasoline 

terminals.

(11) 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, 

Third Edition, 1989. For the purposes of temperature correction, the owner or operator 

shall use the actual storage temperature. Actual storage temperature of an unheated 

tank or vessel may be determined using the maximum local monthly average ambient 

temperature as reported by the National Weather Service. Actual storage temperature of 

a heated tank or vessel must be determined using either the measured temperature or 

the temperature set point of the tank or vessel.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(12) The test procedures in 40 CFR §63.565(c) or §61.304(f) must be used 

for determination of marine vessel vapor tightness.

(13) Lower explosive limit (LEL) detectors may be used for the percent 

LEL concentration measurement required by §115.542(b) and §115.544(b)(3) and (4) of 

this title, if the detector is calibrated and maintained according to manufacturer's 

specifications.

(14) Minor modifications to the test methods in this section may be used if 

approved by the executive director.

(15) 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.

Adopted January 26, 2011 Effective February 17, 2011

§115.546. Recordkeeping and Notification Requirements.

(a) Recordkeeping requirements. The owner or operator of any volatile organic 

compounds (VOC) storage tank, transport vessel, or marine vessel subject to the 

requirements in this division shall maintain the following records on site for at least two 

years. Any records created on or after March 1, 2009, must be maintained on site for at 

least five years. The owner or operator shall make these records available upon request 

to authorized representatives of the executive director, the United States Environmental 

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

(1) For storage tank, transport vessel, or marine vessel degassing 

operations subject to the requirements in this division, the owner or operator shall 

maintain records of:

(A) the type and number of storage tanks, transport vessels, and 

marine vessels that are degassed;

(B) the chemical name and estimated liquid quantity of VOC 

contained in each storage tank, transport vessel, or marine vessel prior to degassing ;

(C) the chemical name and estimated liquid quantity of VOC 

removed from each storage tank, transport vessel, or marine vessel;

(D) the VOC concentration or percent of lower explosive limit 

measurements required in §115.544(b)(3) of this title (relating to Inspection, 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

Monitoring, and Testing Requirements) to determine when the storage tank, transport 

vessel, or marine vessel can be vented to the atmosphere without control; and

(E) the VOC concentration or percent of lower explosive limit 

measurements required by §115.544(b)(4) of this title.

(2) For a control device used to comply with the requirements in this 

division, the owner or operator shall maintain records of any operational parameter 

monitoring required in §115.544(b)(2) of this title. These records must include, but are 

not limited to, the following.

(A) For a carbon adsorption system, the owner or operator shall 

maintain records of the VOC concentration measurements required by 

§115.544(b)(2)(A) of this title.

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

records of the continuous temperature monitoring required in §115.544(b)(2)(B) of this 

title.

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

maintain records of the continuous temperature monitoring required in 

§115.544(b)(2)(C) of this title.

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

maintain records of the continuous temperature monitoring required in 

§115.544(b)(2)(D) of this title.

(E) For a flare, the owner or operator shall maintain records of the 

continuous monitoring or calculations required in §115.544(b)(2)(E) of this title.

(F) For any control device used to comply with the optional exhaust 

concentration limit in §115.542(a)(4) (relating to Control Requirements) of this title, the 

owner or operator shall maintain records of the VOC concentration measurement 

required in §115.544(b)(2)(F) of this title and records of the monitoring method used.

(G) For a thermal oxidizer or vapor combustor, the owner or 

operator shall maintain records of the continuous temperature monitoring required in 

§115.544(b)(2)(G) of this title. If necessary to demonstrate compliance with 

§115.544(c)(3) of this title, the owner or operator shall maintain records of the 

continuous monitoring of the gas flow rate into the thermal oxidizer or vapor combustor 

to determine the combustion chamber residence time.
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(H) For a recirculation system, the owner or operator shall maintain 

records of the continuous pressure or flow rate monitoring required in 

§115.544(b)(2)(H)(i) of this title and records of the VOC leak monitoring required in 

§115.544(b)(2)(H)(ii) of this title, including the VOC measurements and the time the 

monitoring began.

(I) For an internal combustion engine, the owner or operator shall 

maintain records of the continuous engine exhaust gas oxygen content monitoring 

required in §115.544(b)(2)(I) of this title.

(J) For a control device not listed in this paragraph, the owner or 

operator shall maintain records of the continuous operational parameter monitoring 

required in §115.544(b)(2)(J) of this title sufficient to demonstrate proper functioning of 

the control device to design specifications.

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

inspection and repair conducted in accordance with the requirements in §115.544(a) of 

this title.

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

demonstration required in §115.544(c) of this title and the results of any testing 

conducted in accordance with the provisions specified in §115.545 of this title (relating to

Approved Test Methods). The records must contain all applicable requirements from the 

commission's Sampling Procedures Manual, Chapter 14.0, Contents of Sampling 

Reports (January 2003, revision one).

(5) The owner or operator shall maintain records of the manufacturer's 

instructions for installation, calibration, maintenance, and operation for any monitoring 

device used to comply with the requirements in this division.

(b) Notification requirements. In the Houston-Galveston-Brazoria area, upon 

request by authorized representatives of the executive director, the owner or operator of 

any storage tank, transport vessel, or marine vessel subject to this division shall notify 

the appropriate regional office of upcoming degassing operations.

Adopted January 26, 2011 Effective February 17, 2011

§115.547. Exemptions.

The following exemptions apply to the owner or operator of any storage tank, 

transport vessel, or marine vessel subject to this division. 
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Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

(1) Any storage tank with a storage capacity of less than one million gallons 

is exempt from this division. After January 1, 2009, in the Houston-Galveston-Brazoria 

area, the storage tanks listed in subparagraphs (A) and (B) of this paragraph are no 

longer exempt from this division.

(A) Storage tanks with a storage capacity greater than or equal to 

250,000 gallons but less than one million gallons.

(B) Storage tanks with a storage capacity greater than or equal to 

75,000 gallons but less than 250,000 gallons storing materials with true vapor pressure 

greater than 2.6 pounds per square inch absolute.

(2) In the Beaumont-Port Arthur, Dallas-Fort Worth, El Paso, and 

Houston-Galveston-Brazoria areas, any transport vessel with a storage capacity of less 

than 8,000 gallons is exempt from this division.

(3) In the Beaumont-Port Arthur and Houston-Galveston-Brazoria areas, 

any marine vessel with a storage capacity of less than 420,000 gallons is exempt from 

this division.

(4) Any storage tank is exempt from this division during preventative 

maintenance, roof repair, primary seal inspection, or removal and installation of a 

secondary seal, if product is not moved in or out of the storage tank, emissions are 

minimized, and the repair is completed within seven calendar days.

(5) Any marine vessel that has sustained damage that prevents a cargo 

tank's opening from being properly secured, causes the onboard vapor recovery system 

to be inoperative, or prevents the pressure or vacuum relief valves from operating within 

certified limits as specified by classification society or flag state is exempt from the 

requirements in §115.541 and §115.542 of this title (relating to Emission Specifications 

and Control Requirements); however, all reasonable measures must be taken to

minimize emissions of volatile organic compounds. This exemption will only apply for 

30 calendar days after the damage to the cargo tank is sustained. 

(6) Any oceangoing, self-propelled marine vessel is exempt from this 

division.

Adopted January 26, 2011 Effective February 17, 2011

§115.549. Compliance Schedules. 

(a) All affected owners or operators in Brazoria, Chambers, Fort Bend, Galveston, 

Hardin, Harris, Jefferson, Liberty, Montgomery, Orange, and Waller Counties were 
Texas Commission on Environmental Quality Page 16

Chapter 115 - Control of Air Pollution from Volatile Organic Compounds

required to be in compliance with this division by November 15, 1996, and shall 

continue to comply with this division. 

(b) All affected owners or operators in Collin, Dallas, Denton, and Tarrant 

Counties shall be in compliance with this division as soon as practicable, but no later 

than May 21, 2011. If the installation of additional monitoring equipment is necessary to

comply with the requirements in §115.544(b)(2)(E) of this title (relating to Inspection, 

Monitoring, and Testing Requirements), the owner or operator shall comply with the 

requirements no later than March 1, 2012. Until the monitoring equipment necessary to 

demonstrate compliance with the requirements in §115.544(b)(2)(E) of this title is 

installed, the owner or operator shall demonstrate compliance by using engineering 

calculations or other available monitoring or testing data.

(c) All affected owners or operators in El Paso County shall be in compliance with 

this division as soon as practicable, but no later than one year, after the commission 

publishes notification in the Texas Register of its determination that this contingency 

rule is necessary as a result of failure to attain the National Ambient Air Quality 

Standard for ozone by the attainment deadline or failure to demonstrate reasonable 

further progress as set forth in the 1990 Amendments to the Federal Clean Air Act, 

§172(c)(9).

(d) All affected owners or operators in Brazoria, Chambers, Fort Bend, Galveston, 

Harris, Liberty, Montgomery, and Waller Counties shall comply with the requirements 

in §§115.542(b), 115.544(b)(4), and 115.546(a)(1)(E) of this title (relating to Control 

Requirements; Inspection, Monitoring, and Testing Requirements; and Recordkeeping 

and Notification Requirements) as soon as practicable but no later January 1, 2009. If 

the installation of additional monitoring equipment is necessary to comply with the 

requirements in §115.544(b)(2)(E) of this title, the owner or operator shall comply with 

the requirements no later than March 1, 2012. Until the monitoring equipment 

necessary to demonstrate compliance with the requirements in §115.544(b)(2)(E) of this 

title is installed, the owner or operator shall demonstrate compliance by using 

engineering calculations or other available monitoring or testing data.

Adopted January 26, 2011 Effective February 17, 2011