(Adopted July 7, 1989)(Amended December 7, 1990)(Amended May 13, 1994) 

(Amended December 6, 2002)(Amended June 1, 2007)(Amended February 6, 2009) 

RULE 1173 CONTROL OF VOLATILE ORGANIC COMPOUND LEAKS 

AND RELEASES FROM COMPONENTS AT PETROLEUM 

FACILITIES AND CHEMICAL PLANTS 

(a) Purpose 

This rule is intended to control volatile organic compound (VOC) leaks from 

components and releases from atmospheric process pressure relief devices 

(PRDs). 

(b) Applicability 

This rule applies to components at refineries, chemical plants, lubricating oil and 

grease re-refiners, marine terminals, oil and gas production fields, natural gas 

processing plants and pipeline transfer stations. 

(c) Definitions: 

For the purpose of this rule the following definitions shall apply: 

(1) BACKGROUND is the ambient concentration of total organic compounds 

(TOC) in the air at least one (1) meter upwind of the component to be 

inspected, determined according to the test method in paragraph (j)(1). 

(2) CHEMICAL PLANT is any facility engaged in producing chemicals, 

and/or manufacturing products by chemical processes. Any facility or 

operation that has 282 as the first three digits in its Standard Industrial 

Classification Code as defined in the Standard Industrial Classification 

Manual is included in this definition. 

(3) COMMERCIAL NATURAL GAS is a mixture of hydrocarbons, with at 

least 80 percent methane by volume and less than 10 percent by weight 

VOC, determined according to test methods specified in paragraph (j)(2). 

(4) COMPONENT is any valve, fitting, pump, compressor, pressure relief 

device, diaphragm, hatch, sight-glass, and meter in VOC service. They 

are further classified as: 

(A) MAJOR COMPONENT is any 4-inch or larger valve, any 5-hp or 

larger pump, any compressor, and any 4-inch or larger pressure 

relief device. 

1173 - 1 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 2 

(B) MINOR COMPONENT is any component which is not a major 

component. 

(5) COMPRESSOR is a device used to compress gases and/or vapors by the 

addition of energy, and includes all associated components used for 

connecting and sealing purposes. 

(6) FACILITY is a refinery, chemical plant, lubricating oil and grease rerefiner, marine terminal, oil and gas production field, natural gas 

processing plant, or pipeline transfer station. 

(7) FIELD GAS means feed stock gas entering the natural gas processing 

plant. 

(8) FITTING is a device used to attach or connect pipes or piping details, 

including but not limited to flanges and threaded connections. 

(9) HATCH is any covered opening system that provides access to a tank, 

container or vessel. 

(10) HEAVY LIQUID is any liquid with 10 percent or less VOC by volume 

evaporated at 150o

C (302oF), determined according to test methods 

specified in paragraph (j)(2) or (j)(3). 

(11) INACCESSIBLE COMPONENT is any component located over five 

meters above ground when access is required from the ground; or any 

component located over two meters away from a platform when access is 

required from the platform; or any component which would require the 

elevation of a monitoring personnel higher than two meters above 

permanent support surfaces. 

(12) INSPECTION is a survey of components, using an appropriate analyzer, 

according to the test method in paragraph (j)(1), for the purpose of 

determining compliance with this rule, and may be either of the following: 

(A) OPERATOR INSPECTION is a survey of components by the 

operator or their contractor. 

(B) DISTRICT INSPECTION is a survey of components by District 

personnel or their representatives. 

(13) LEAK is the dripping of either heavy or light liquid; or the detection of a 

concentration of TOC above background, determined according to the test 

method in paragraph (j)(1). 

(14) LIGHT LIQUID is any liquid with more than 10 percent VOC by volume 

evaporated at 150o

C (302oF), determined according to the test method 

specified in subparagraph (j)(2). 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 3 

(15) LUBRICATING OIL AND GREASE RE-REFINER is a facility engaged 

in the blending, compounding, and re-refining of lubricating oils and greases from 

purchased mineral, animal, and vegetable materials, as defined in Standard 

Industrial Classification Code 2992. Petroleum refineries engaged in the 

production of lubricating oils and greases are classified in Standard Industrial 

Classification Code 2911 and therefore are not included in this definition. 

(16) MARINE TERMINAL is a facility, equipment or structure constructed to handle 

the loading or unloading of organic liquid into or out of marine tank vessels, 

defined as in Standard Industrial Classification Codes 4226 and 5171. 

(17) NATURAL GAS PROCESSING PLANT is a facility engaged in the separation 

of 

natural gas liquids from field gas and/or fractionation of the liquids into natural 

gas products, such as ethane, propane, butane, and natural gasoline. Excluded 

from the definition are compressor stations, dehydration units, sweetening units, 

field treatment, underground storage facilities, liquefied natural gas units, and 

field gas gathering systems unless these facilities are located at a natural gas 

processing plant. 

(18) OIL AND GAS PRODUCTION FIELD is a facility on which crude petroleum 

and natural gas production and handling are conducted, as defined in the Standard 

Industrial Classification Manual as Industry No. 1311, Crude Petroleum and 

Natural Gas. 

(19) PIPELINE TRANSFER STATION is a facility which handles the transfer and 

storage of petroleum products or crude petroleum in pipelines. 

(20) PLATFORM is any raised, permanent, horizontal surface for the purpose of 

gaining access to components. 

(21) PRESSURE RELIEF DEVICE (PRD) is a pressure relief valve or a rupture disc. 

(22) PRESSURE RELIEF VALVE (PRV) is a device which is automatically actuated 

by upstream static pressure to the atmosphere (atmospheric PRV) or to a control 

device, and used for safety or emergency purposes. 

(23) PROCESS PRD is a PRD located on process equipment other than storage tanks 

or pipelines used to transport material. 

(24) PUMP is a device used to transport fluids by the addition of energy, and includes 

all associated components used for connecting or sealing purposes. 

(25) REFINERY is a facility that processes petroleum, as defined in the Standard 

Industrial Classification Manual as Industry No. 2911, Petroleum Refining. 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 4 

(26) RELEASE is any VOC emission to the atmosphere from an atmospheric 

PRD caused by an increase in upstream pressure. A leak caused by 

improper reseating of the PRD is not a release. 

(27) REPAIR is corrective action for the purpose of eliminating or reducing 

leaks that may involve the temporary removal or taking out of service of a 

component or PRV. 

(28) RUPTURE DISC is a diaphragm held between flanges for the purpose of 

isolating VOC from the atmosphere or from a downstream pressure relief 

valve. 

(29) TAMPER-PROOF means that all the data collected shall be encrypted 

such that it cannot be modified. 

(30) TELLTALE INDICATOR is a device installed in conjunction with a 

PRD, indicating whether a release has occurred. 

(31) TOTAL ORGANIC COMPOUNDS (TOC) is the concentration of 

gaseous organic compounds determined according to the test method in 

paragraph (j)(1). 

(32) TURNAROUND is a scheduled shutdown of a process unit for 

maintenance and repair work. 

(33) VALVE is a device that regulates or isolates the fluid flow in a pipe, tube, 

or conduit by means of an external actuator. 

(34) VOLATILE ORGANIC COMPOUND (VOC) is as defined in Rule 102. 

(d) Leak Standards 

(1) The operator of a facility subject to this rule shall be in violation of this 

rule if District inspection detects any: 

(A) Light liquid leak of more than three drops per minute; 

(B) Leak greater than 50,000 ppm from a component in light 

liquid/gas/vapor service; 

(C) Leak greater than 500 ppm from a component in heavy liquid 

service; or 

(D) Leak within any continuous 24-hour period and numbering in 

excess of the Leak Thresholds for that component listed below in 

Table 1, if it is: 

(i) A leak from a component in light liquid /gas/vapor service, 

greater than 10,000 ppm; or 

(ii) A leak from an atmospheric PRD, greater than 200 ppm; or 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 5 

(iii) A leak from a pump in heavy liquid service, greater than 

100 ppm. 

TABLE 1. LEAK THRESHOLDS 

Component Type 

Max. No. of Leaks 

for 200 or less 

components inspected 

Max No. of Leaks 

for > 200 components 

inspected 

Valves 1 0.5% of number inspected 

Pumps 2 1% of number inspected 

Compressors 1 1 

Atmospheric PRDs 1 1 

Threaded Pipe 

Connectors 

1 0.5% of number inspected 

Other Components 1 1 

The maximum number of leaks in Table 1 shall be rounded 

upwards to the nearest integer, where required. 

(E) Open-ended lines and valves located at the end of lines that are not 

sealed with a blind flange, plug, cap, or a second closed valve at all 

times, except during operations requiring process fluid flow 

through the open-ended line. 

(2) For the purpose of determining an oil and gas production facility’s 

compliance with the leak standards specified in subparagraphs (d)(1)(B), 

(d)(1)(C), and (d)(1)(D), the operator of the facility may request a written 

approval from the Executive Officer to adjust a leak measurement to 

exclude methane and ethane, provided: 

(A) The operator submits a plan identifying the components to be 

included under paragraph (d)(2); 

(B) The operator demonstrates the methane and ethane content of the 

line product is 50 percent or more by volume, as determined by a 

District approved laboratory, according to the test method in 

paragraph (j)(2); 

(C) The demonstration is based on a sampling and analysis of a 

representative sample obtained on a semiannual basis in 

accordance with the schedule and sample size approved by the 

Executive Officer; and 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 6 

(D) A copy of the analysis results with laboratory analysis is provided 

upon request by the Executive Officer. 

(E) The operator of a Title V facility shall submit an application for 

permit modification to incorporate the approval under paragraph 

(d)(2) in the Title V permit. 

(e) Identification Requirements 

The operator shall: 

(1) Physically identify clearly and visibly all major components in light 

liquid/gas/vapor service and pumps in heavy liquid service for inspection, 

repair, replacement, and recordkeeping purposes. 

(2) Clearly identify all major components in heavy liquid service other than 

pumps subject to paragraph (e)(1), and minor components, in Piping and 

Instrumentation (P&I) flow diagrams, and/or group them together 

functionally for inspection, repair, replacement, and recordkeeping 

purposes. 

(3) Submit the information required to identify components in heavy liquid 

service, as required by paragraphs (e)(1) and (e)(2), for approval by the 

Executive Officer on or before September 1, 2003. 

(4) Any change(s) in major component identification shall require prior 

written approval from the Executive Officer. 

(f) Operator Inspection Requirements 

(1) The operator shall: 

(A) Audio-visually inspect all accessible pumps, compressors, and 

atmospheric PRDs once during every eight-hour operating period, 

except for unmanned oil and gas production fields and unmanned 

pipeline transfer stations. 

(B) Inspect all accessible components in light liquid/gas/vapor service 

and pumps in heavy liquid service quarterly, with pumps in heavy 

liquid service beginning July 1, 2003. 

(C) Inspect all inaccessible components in light liquid/gas/vapor 

service annually. 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 7 

(D) At any refinery with more than 25,000 components: 

(i) At the time of operator inspection, simultaneously record in

an electronic format all component inspections beginning 

January 1, 2004, and 

(ii) Operate and maintain the electronic recording instrument 

according to manufacturer’s specifications. 

(E) Inspect an atmospheric PRD within one calendar day and reinspect 

it within 14 calendar days after every release. 

(F) Inspect all repaired or replaced components within 30 days of the 

repair or replacement. 

(2) The operator may apply for written approval from the Executive Officer to 

change the inspection frequency for each type of accessible component 

other than PRD in light liquid/gas/vapor service at a facility, except pumps 

and compressors, as required in subparagraph (f)(1)(B) from quarterly to 

annually, provided that all components at that facility have been 

successfully operated and maintained for five consecutive quarters with no 

liquid leaks of more than three drops per minute, and with leaks greater 

than 10,000 ppm not exceeding the Leak Thresholds, by component type, 

listed in Table 1. 

(3) The operator may apply for written approval from the Executive Officer to 

change the inspection frequency for all accessible atmospheric PRDs in 

light liquid/gas/vapor at a facility, as required in subparagraph (f)(1)(B), 

from quarterly to annually, provided that all atmospheric PRDs at that 

facility have been successfully operated and maintained for five 

consecutive quarters with no liquid leaks of more than three drops per 

minute and with leaks greater than 200 ppm not exceeding the Leak 

Thresholds listed in Table 1. 

(4) The operator may apply for written approval from the Executive Officer to 

change the inspection frequency for pumps in heavy liquid service at a

facility, as required in subparagraph (f)(1)(B), from quarterly to annually, 

provided that all pumps in heavy liquid service at that facility have been 

successfully operated and maintained for five consecutive quarters, with 

leaks greater than 100 ppm not exceeding the Leak Thresholds listed in 

Table 1 for pumps. 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 8 

(5) The operator shall submit documentation prior to the change in inspection 

frequency, as per paragraphs (f)(2), (f)(3) and (f)(4), for written approval 

from the Executive Officer. 

(6) The operator shall revert to a quarterly inspection frequency for a 

component type, should the annual operator inspection or District 

inspection show any leaks in excess of the thresholds applicable to the 

component type listed below: 

(A) Light liquid leak of more than three drops per minute, or 

(B) Leaks exceeding the maximum number of leaks, by component 

type, listed in Table 1 for: 

(i) Components in light liquid/gas/vapor service, greater than 

10,000 ppm, 

(ii) Pumps in heavy liquid service, greater than 100 ppm, 

(iii) Atmospheric PRDs, greater than 200 ppm. 

(g) Maintenance Requirements 

The operator shall: 

(1) Repair, replace or remove a leaking component as soon as practicable but 

no later than the time period specified in Table 2, Repair Periods. For 

each calendar quarter, the operator may extend the repair period, as 

specified in Table 2, for a total number of leaking components, not to 

exceed 0.05 percent of the number of components inspected during the 

previous quarter, by type, rounded upward to the nearest integer where 

required. 

TABLE 2. REPAIR PERIODS 

Type of Leak Time Period Extended 

Repair Period 

Light liquid/gas/vapor component leaks greater 

than 500 ppm but no more than 10,000 ppm 7 Calendar Days 7 Calendar Days 

Heavy liquid component leaks greater than 100 

ppm but no more than 500 ppm 7 Calendar Days 7 Calendar Days 

Heavy liquid leak greater than 3 drops per 

minute and greater than 100 ppm but no more 

than 500 ppm 

7 Calendar Days 

Any leak greater than 10,000 ppm but no more 

than 25,000 ppm 2 Calendar Days 3 Calendar Days 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 9 

Type of Leak Time Period Extended 

Repair Period 

Atmospheric PRD leaks greater than 200 ppm 

but no more than 25,000 ppm 2 Calendar Days 3 Calendar Days

Any leak greater than 25,000 ppm 1 Calendar Day 

Heavy liquid component leaks greater than 500 

ppm 1 Calendar Day 

Light liquid leaks greater than 3 drops per 

minute 1 Calendar Day 

(2) Replace a component or parts thereof with Best Available Control or 

Retrofit Technology (BACT or BARCT), or vent it to an air pollution 

control device approved by the Executive Officer, after it has been 

subjected to five repair actions within a continuous twelve month period 

for: 

(A) A light liquid leak of greater than three drops per minute, 

(B) A leak greater than 10,000 ppm or 

(C) A leak greater than 200 ppm for an atmospheric PRD. 

(3) The reporting provisions of Rule 430 shall not be applicable to 

components being repaired or replaced under the provisions of this rule, 

except compressors. 

(h) Atmospheric Process PRD Requirements 

(1) The operator of a refinery shall continuously monitor atmospheric PRDs 

located on process equipment by installing tamper-proof electronic valve 

monitoring devices capable of recording the duration of each release and 

quantifying the amount of the compounds released according to the 

following schedule: 

(A) For a refinery with less than 50 atmospheric process PRDs: 

(i) Install monitoring devices on 50 percent of all atmospheric 

process PRDs by January 1, 2009; and 

(ii) Install monitoring devices on the remaining atmospheric 

process PRDs by July 1, 2009. 

(B) For a refinery with more than 50 atmospheric process PRDs: 

(i) Install monitoring devices on 20 percent of all atmospheric 

process PRDs by January 1, 2009, 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 10 

(ii) Install monitoring devices on 40 percent of all atmospheric 

process PRDs by July 1, 2009; and 

(iii) Install monitoring devices on the remaining atmospheric 

process PRDs by July 1, 2010. 

(C) In conjunction with the requirements of subparagraphs (h)(1)(A) 

and (h)(1)(B), the operator of a refinery shall continue to monitor 

all atmospheric process PRDs by use of electronic process control 

instrumentation that allows for real time continuous parameter 

monitoring or telltale indicators until such time that the operator of 

a refinery has demonstrated compliance with subparagraphs 

(h)(1)(A) and (h)(1)(B). 

(D) Notwithstanding the requirements of subparagraphs (h)(1)(A) and 

(h)(1)(B), the operator of a refinery may delay the installation of 

the tamper-proof electronic valve monitoring devices to no later 

than the next scheduled turnaround following June 1, 2007 for that 

process unit PRD(s), provided that the operator demonstrates to the 

satisfaction of the Executive Officer that the installation at an 

earlier date is not feasible or constitutes a safety hazard. 

(E) Notwithstanding the requirements of subparagraphs (h)(1)(A) and 

(h)(1)(B), for any atmospheric process PRD, the operator of a 

refinery may use tamper-proof electronic valve monitoring devices 

in combination with continuous parameter monitoring or tamperproof electronic valve monitoring devices and telltale indicators 

that in combination can record the duration of each release and 

quantify the amount of the compounds released, provided that the 

operator demonstrates on or before the compliance dates in 

subparagraphs (h)(1)(A) and (h)(1)(B) to the satisfaction of the 

Executive Officer that the combination of tamper-proof electronic 

valve monitoring devices, continuous parameter monitoring or 

telltale indicators represents the actual process conditions at the 

location of the process PRD release to the atmosphere. 

(F) The requirements of subparagraphs (h)(1)(A) and (h)(1)(B) do not 

apply to atmospheric process PRDs that will be connected in such 

a manner as to direct all gases and vapors that can be released by 

an atmospheric process PRD to a VOC vapor recovery or control 

system no later than the next scheduled turnaround after 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 11 

December 31, 2008, for that process equipment or unit associated 

with those atmospheric process PRD(s). The operator of a refinery 

must submit a revised compliance plan no later than December 31, 

2008, that identifies the applicable atmospheric process PRD(s) 

and the schedule for connecting the atmospheric process PRD(s) to 

a VOC recovery or control system. Until such time that the 

atmospheric process PRD(s) are connected to a VOC vapor 

recovery or control system, the operator shall monitor all 

atmospheric process PRDs by use of electronic process control 

instrumentation that allows for real time continuous parameter 

monitoring or telltale indicators. 

(G) The requirements of subparagraphs (h)(1)(A) through (h)(1)(F) do 

not apply to atmospheric process PRDs in liquid service that 

release to drains and are regulated under Rule 1176, provided that 

the operator demonstrates to the satisfaction of the Executive 

Officer that all released material meets the definition of heavy 

liquid. 

(2) The operator of a chemical plant shall monitor atmospheric process PRDs 

located on process equipment by one of the following options: 

(A) Install tamper-proof electronic valve monitoring devices capable of 

recording the duration of each release and quantifying the amount 

of compounds released on twenty percent of the atmospheric 

process PRD inventory. The operator shall install the electronic 

valve monitoring devices during the first turnaround after 

December 31, 2003; or 

(B) Use of electronic process control instrumentation that allows for 

real time continuous parameter monitoring, starting July 1, 2004, 

and telltale indicators for the atmospheric process PRDs where 

parameter monitoring is not feasible. The telltale indicators shall 

be installed no later than December 31, 2004. 

(3) The operator of a lubricating oil and grease re-refiner or a marine terminal 

shall monitor atmospheric process PRDs by use of electronic process 

control instrumentation that allows for real time continuous parameter 

monitoring, starting January 1, 2009, and telltale indicators for the 

atmospheric process PRDs where parameter monitoring is not feasible. 

The telltale indicators shall be installed no later than December 31, 2007. 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 12 

(4) By December 31, 2007, the operator shall submit to the District a 

compliance plan or a revised compliance plan, containing the inventory of 

atmospheric process PRDs by size, set pressure and location, and indicate 

the option(s) chosen to comply with paragraphs (h)(1), (h)(2) and (h)(3). 

If applicable, the operator shall indicate the process parameter selected for 

continuous monitoring and the justification for such selection. 

(5) Following any release from an atmospheric process PRD in excess of 500 

pounds of VOC in a continuous 24-hour period, the operator shall conduct 

a failure analysis and implement corrective actions within 30 days to 

prevent the reoccurrence of similar releases. 

(6) At a refinery with a crude oil throughput greater than 20,000 barrels per 

day, the operator shall, as practicable but no later than the first turnaround 

following the requirement to connect becomes effective, connect all 

atmospheric process PRDs serving that equipment to a vapor recovery or 

control system following: 

(A) a second release in excess of 500 pounds of VOC in a continuous 

24-hour period, within any five year period from any atmospheric 

process PRD serving the same piece or pieces of equipment or 

(B) any release in excess of 2,000 pounds of VOC in a continuous 24-

hour period, from any atmospheric process PRD serving the same 

piece or pieces of equipment. 

(7) In lieu of complying with paragraph (h)(6), an operator may elect to pay a 

mitigation fee of $350,000 to the District for any release exceeding the 

thresholds in paragraph (h)(6) and any subsequent release. Within 90 days 

of the release, the operator shall notify the Executive Officer, in writing, 

of the election to pay a mitigation fee and submit payment as requested by 

the Executive Officer. 

(i) Recordkeeping and Reporting Requirements 

(1) The operator shall record all leaks, repairs and reinspections, as required 

in subdivision (f), and submit those records as quarterly or annual 

inspection reports to the Executive Officer no later than 30 days after the 

end of each calendar quarter or no later than 60 days after the end of the 

calendar year, respectively. Upon request by the Executive Officer, the 

operator shall include in the report the reason for extending the repair 

period for any component, as allowed in paragraph (g)(1). The operator 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 13 

shall submit the records in an electronic format approved by the Executive 

Officer and they shall be certified in writing by the facility official 

responsible for the inspection and repair program. 

(2) The operator shall include in all records of operator inspection and repair, 

at a minimum, the component identification and type, service, location, 

leak rate and date and time of inspection. The operator shall maintain 

these records at the facility for a period of at least two (2) years or five (5) 

years for a Title V facility and made available to the Executive Officer on 

request. 

(3) The operator of a refinery, chemical plant, lubricating oil and grease rerefiner, or marine terminal shall: 

(A) Notify the Executive Officer, by telephone or any other District 

approved method, of any atmospheric process PRD release in 

excess of the reportable quantity limits as stipulated in 40 CFR, 

Part 117, Part 302 and Part 355, including any release in excess of 

100 pounds of VOC, within one hour of such occurrence or within 

one hour of the time said person knew or reasonably should have 

known of its occurrence; 

(B) Submit a written report to the Executive Officer within 30 days 

following notification of an atmospheric process PRD release, 

providing the following information: 

(i) PRD type, size and location. 

(ii) Date, time and duration of the PRD release event. 

(iii) Types of VOC released and individual amounts, in pounds, 

including supporting calculations. 

(iv) Cause of the atmospheric process PRD release event. 

(v) Corrective actions taken to prevent a subsequent PRD 

release. 

(C) Submit quarterly reports for all monitored atmospheric process 

PRDs to comply with paragraphs (h)(1), (h)(2) and (h)(3) in an 

electronic format approved by the Executive Officer, indicating the 

parameter(s) monitored as a function of time, no later than 30 days 

after the end of each calendar quarter.

(D) Keep records of the process parameter(s) monitored for a period of 

five years, where elected to comply with paragraphs (h)(1), (h)(2) 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 14 

and (h)(3) and make them available to the Executive Officer upon 

request. 

(j) Test Methods 

(1) Measurements of leak concentrations shall be conducted according to the 

United States Environmental Protection Agency (U.S. EPA) Reference 

Method 21 using an appropriate analyzer calibrated with methane. The 

analyzer shall be calibrated before inspection each day. 

(2) The VOC content shall be determined according to ASTM Method D 

1945 for gases, SCAQMD Method 304-91 for liquids. The percent VOC 

of a liquid evaporated at 150oC (302oF) shall be determined according to 

ASTM Method D 86.

(3) The flash point of heavy liquids shall be determined according to ASTM 

Method D 93. 

(4) Equivalent Test Methods 

A person may use other method to determine compliance with this rule 

provided it is demonstrated to be equivalent and approved in writing by 

the Executive Officers of the District, the California Air Resources Board 

(CARB), and the Regional Administrator of the U.S. EPA, Region IX, or 

their designees. 

(k) Other Rules and Regulation Applicability 

In case of conflict between the provisions of this rule and any other rule, the 

provisions of the rule which more specifically applies to the subject shall prevail. 

(l) Exemptions 

(1) The provisions of this rule shall not apply to the following cases, where 

the person seeking the exemption shall supply the proof of the applicable 

criteria to the satisfaction of the Executive Officer: 

(A) Components which present a safety hazard for inspection as 

documented and established in a safety manual or policy, 

previously, or with the prior written approval of the Executive 

Officer except that the operator shall monitor these components for 

leaks when it is safe to do so. Upon detection of a leak, the 

operator shall repair or replace the component(s) as soon as the 

repairs or replacement can be carried out safely. 
Rule 1173 (Cont.) (Amended February 6, 2009) 

1173 - 15 

(B) Components being repaired or replaced within the specified repair 

or replacement period, as given in Table 2. 

(C) Components exclusively handling commercial natural gas. 

(D) Components exclusively handling fluids with a VOC content of ten 

percent by weight or less, determined according to test methods 

specified in paragraph (j)(2). 

(E) Components incorporated in lines, while operating under negative 

pressures. 

(F) Components totally contained or enclosed such that there are no 

VOC emissions into the atmosphere. 

(G) Components buried below ground. 

(H) Pressure vacuum valves on storage tanks. 

(I) Storage tank hatches subject to Rule 1178. 

(2) The provisions of subdivision (h) and paragraphs (i)(2) and (i)(3) shall not 

apply to PRVs installed for protection from overpressure due to variation 

in ambient temperature provided that they are vented to drains or back into 

the pipeline. A person seeking an exemption under this paragraph shall 

supply proof of the applicable criteria to the satisfaction, upon request, of 

the Executive Officer. 

(3) The provisions of Rules 466, 466.1, and 467 shall not apply to facilities 

subject to this rule. 

(4) The provisions of paragraph (e)(1) and subdivision (f) shall not apply to 

components handling liquids with a flash point greater than 121o

C (250oF), 

as determined according to the test method specified in paragraph (j)(3). 

(5) Atmospheric PRD releases demonstrated to the satisfaction of the 

Executive Officer that result from natural disasters, acts of war or 

terrorism, or external power curtailment beyond the refinery’s control, 

excluding power curtailment due to an interruptible service agreement, 

shall not be subject to the provisions of paragraphs (h) (6) and (h)(7). 

(6) Except for the requirements of subdivision (e), the requirements of this 

rule shall not become effective as to lubricating oil and grease re-refiners 

and to marine terminals until December 31, 2007. Lubricating oil and 

grease re-refiners and marine terminals shall comply with the 

requirements of subdivision (e) no later than September 30, 2007.