[Code of Federal Regulations]
[Title 40, Volume 15]
[Revised as of July 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR65.2]

[Page 18-28]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 65_CONSOLIDATED FEDERAL AIR RULE--Table of Contents
 
                      Subpart A_General Provisions
 
Sec. 65.2  Definitions.

    All terms used in this part shall have the meaning given them in the 
Act and in this section. If a term is defined both in this section and 
in other parts that reference the use of this part, the term shall have 
the meaning given in this section for purposes of this part. If a term 
is not defined in the Act or in this section, the term shall have the 
meaning given in the referencing subpart for purposes of this part. The 
terms follow:
    Act means the Clean Air Act (42 U.S.C. 7401 et seq.).
    Administrator means the Administrator of the United States 
Environmental Protection Agency (EPA) or his or her authorized 
representative (for

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example, a State that has been delegated the authority to implement the 
provisions of this part).
    Approved permit program means a State permit program approved by the 
Administrator as meeting the requirements of part 70 of this chapter or 
a Federal permit program established in this chapter pursuant to title V 
of the Act (42 U.S.C. 7661).
    Automated continuous parameter monitoring system means a continuous 
parameter monitoring system that automatically both records the measured 
data and calculates hourly averages.
    Automated monitoring and recording system means any means of 
measuring values of monitored parameters and creating a hard copy or 
computer record of the measured values that does not require manual 
reading of monitoring instruments and manual transcription of data 
values. Automated monitoring and recording systems include, but are not 
limited to, computerized systems, strip charts, and circular charts.
    Batch process means a process in which the equipment is fed 
intermittently or discontinuously. Processing then occurs in this 
equipment after which the equipment is generally emptied. Examples of 
industries that use batch processes include pharmaceutical production 
and pesticide production.
    Batch product-process equipment train means the collection of 
equipment (for example, connectors, reactors, valves, pumps) configured 
to produce a specific product or intermediate by a batch process.
    Boiler means any enclosed combustion device that extracts useful 
energy in the form of steam and is not an incinerator or a process 
heater. Boiler also means any industrial furnace as defined in 40 CFR 
260.10.
    Bottoms receiver means a tank that collects distillation bottoms 
before the stream is sent for storage or for further downstream 
processing.
    By compound means by individual stream components, not carbon 
equivalents.
    Car-seal means a seal that is placed on a device that is used to 
change the position of a valve (for example, from opened to closed) in 
such a way that the position of the valve cannot be changed without 
breaking the seal.
    Closed vent system means a system that is not open to the atmosphere 
and is composed of piping, ductwork, connections, and, if necessary, 
flow inducing devices that transport gas or vapor from an emission point 
to a control device. A closed vent system does not include the vapor 
collection system that is part of any tank truck or railcar or the 
loading arm or hose that is used for vapor return. For transfer racks, 
the closed vent system begins at, and includes, the first block valve on 
the downstream side of the loading arm or hose used to convey displaced 
vapors.
    Closed vent system shutdown means a work practice or operational 
procedure that stops production from a process unit or part of a process 
unit during which it is technically feasible to clear process material 
from a closed vent system or part of a closed vent system consistent 
with safety constraints and during which repairs can be effected. An 
unscheduled work practice or operational procedure that stops production 
from a process unit or part of a process unit for less than 24 hours is 
not a closed vent system shutdown. An unscheduled work practice or 
operational procedure that would stop production from a process unit or 
part of a process unit for a shorter period of time than would be 
required to clear the closed vent system or part of the closed vent 
system of materials and start up the unit, and would result in greater 
emissions than delay of repair of leaking components until the next 
scheduled closed vent system shutdown, is not a closed vent system 
shutdown. The use of spare equipment and technically feasible bypassing 
of equipment without stopping production are not closed vent system 
shutdowns.
    Closed-loop system means an enclosed system that returns process 
fluid to a process.
    Closed-purge system means a system or combination of systems and 
portable containers to capture purged liquids. Containers must be 
covered or closed when not being filled or emptied.
    Combustion device means an individual unit of equipment, such as a 
flare, incinerator, process heater, or

[[Page 20]]

boiler, used for the combustion of organic emissions.
    Compliance date means the date by which a regulated source is 
required to be in compliance with a relevant standard, limitation, 
prohibition, or any federally enforceable requirement established by the 
Administrator (or a State with an approved permit program) pursuant to 
the Act.
    Connector means flanged, screwed, or other joined fittings used to 
connect two pipelines or a pipeline and a piece of equipment. A common 
connector is a flange. Joined fittings welded completely around the 
circumference of the interface are not considered connectors for the 
purpose of this regulation. For the purpose of reporting and 
recordkeeping, connector means joined fittings that are not 
inaccessible, ceramic, or ceramic-lined (for example, porcelain, glass, 
or glass-lined) as described in Sec. 65.108(e)(2).
    Continuous parameter monitoring system or CPMS means the total 
equipment that may be required to meet the data acquisition and 
availability requirements of this part used to sample, condition (if 
applicable), analyze, and provide a record of process or control system 
parameters.
    Continuous record means documentation, either in hard copy or 
computer-readable form, of data values measured at least once every 15 
minutes and recorded at the frequency specified in Sec. 65.161(a).
    Continuous seal means a seal that is designed to form a continuous 
closure that completely covers the space between the wall of the storage 
vessel and the edge of the floating roof. A continuous seal may be a 
vapor-mounted, liquid-mounted, or metallic shoe seal. A continuous seal 
may be constructed of fastened segments so as to form a continuous seal.
    Control device means any combustion device, recovery device, or any 
combination of these devices used to comply with this part. Such 
equipment or devices include, but are not limited to, absorbers, carbon 
adsorbers, condensers, incinerators, flares, boilers, and process 
heaters. For process vents (as defined in this section), recovery 
devices are not considered control devices except for the recovery 
devices specified in Sec. 65.63(a)(2)(ii). A fuel gas system is not a 
control device. For a steam stripper, a primary condenser is not 
considered a control device.
    Control system means the combination of the closed vent system and 
the control devices used to collect and control vapors or gases from a 
regulated source.
    Day means a calendar day.
    Distance piece means an open or enclosed casing through which the 
piston rod travels, separating the compressor cylinder from the 
crankcase.
    Double block and bleed system means two block valves connected in 
series with a bleed valve or line that can vent the line between the two 
block valves.
    Ductwork means a conveyance system such as those commonly used for 
heating and ventilation systems. It is often made of sheet metal and 
often has sections connected by screws or crimping. Hard-piping is not 
ductwork.
    Emission point means an individual process vent, storage vessel, 
transfer rack, wastewater stream, or equipment leak.
    Empty or emptying means the removal of the stored liquid from a 
storage vessel. Storage vessels where stored liquid is left on the 
walls, as bottom clingage, or in pools due to bottom irregularities are 
considered empty. Lowering of the stored liquid level, so that the 
floating roof is resting on its legs, as necessitated by normal vessel 
operation (for example, when changing stored material or when 
transferring material out of the vessel for shipment) is not considered 
emptying.
    Equipment means each of the following that is subject to control 
under the referencing subpart: pump, compressor, agitator, pressure 
relief device, sampling connection system, open-ended valve or line, 
valve, connector, and instrumentation system; and any control devices or 
systems used to comply with subpart F of this part.
    Equivalent method means any method of sampling and analyzing for an 
air pollutant that has been demonstrated to the Administrator's 
satisfaction to have a consistent and quantitatively known relationship 
to the reference method under specified conditions.
    External floating roof or EFR means a pontoon-type (noncontact) or 
double-

[[Page 21]]

deck-type (contact) roof that is designed to rest on the stored liquid 
surface in a storage vessel with no fixed roof.
    Failure, EFR (referred to as EFR failure) is defined as any time the 
external floating roof's primary seal has holes, tears, or other 
openings in the shoe, seal fabric, or seal envelope; or the secondary 
seal has holes, tears, or other openings in the seal or the seal fabric; 
or the gaskets no longer close off the stored liquid surface from the 
atmosphere; or a slotted membrane has more than 10 percent open area.
    Failure, internal floating roof type A (referred to as IFR type A 
failure) means any time, as determined during visual inspection through 
roof hatches, in which the internal floating roof is not resting on the 
surface of the stored liquid inside the storage vessel and is not 
resting on the leg supports; or there is stored liquid on the floating 
roof; or there are holes, tears, or other openings in the seal or seal 
fabric; or there are visible gaps between the seal and the wall of the 
storage vessel.
    Failure, internal floating roof type B (referred to as IFR type B 
failure) means any time, as determined during internal inspections, the 
internal floating roof's primary seal has holes, tears, or other 
openings in the seal or the seal fabric; or the secondary seal (if one 
has been installed) has holes, tears, or other openings in the seal or 
the seal fabric; or the gaskets no longer close off the stored liquid 
surface from the atmosphere; or a slotted membrane has more than 10 
percent open area.
    Fill or filling means the introduction of liquids into a storage 
vessel, but not necessarily to complete capacity.
    First attempt at repair, for the purposes of subparts F and G of 
this part, means to take action for the purpose of stopping or reducing 
leakage of organic material to the atmosphere, followed by monitoring as 
specified in Sec. 65.104(b) and Sec. 65.143(c), as appropriate, to 
verify whether the leak is repaired, unless the owner or operator 
determines by other means that the leak is not repaired.
    Fixed roof means a roof that is mounted (for example, permanently 
affixed) on a storage vessel in a stationary manner and that does not 
move with fluctuations in stored liquid level.
    Flame zone means the portion of the combustion chamber in a boiler 
or process heater occupied by the flame envelope.
    Floating roof means a roof consisting of an external floating roof 
or an internal floating roof that is designed to rest upon and is 
supported by the stored liquid and is equipped with a continuous seal.
    Flow indicator means a device that indicates whether gas flow is 
present in a line, or whether the valve position would allow gas flow to 
be present in a line.
    Fuel gas means gases that are combusted to derive useful work or 
heat.
    Fuel gas system means the offsite and onsite piping and flow and 
pressure control system that gathers gaseous stream(s) generated by 
onsite operations, may blend them with other sources of gas, and 
transports the gaseous stream for use as fuel gas in combustion devices 
or in-process combustion equipment, such as furnaces and gas turbines, 
either singly or in combination.
    Group 1 process vent means a process vent for which the flow rate is 
greater than or equal to 0.011 standard cubic meter per minute (0.39 
cubic feet per minute); the total concentration is greater than or equal 
to the appropriate value in table 1 of subpart D of this part, and the 
total resource effectiveness index value, calculated according to Sec. 
65.64(h) is less than or equal to 1.0.
    Group 2A process vent means a process vent that is not Group 1 or 
Group 2B for which monitoring and recordkeeping are required to 
demonstrate a total resource effectiveness index value greater than 1.0.
    Group 2B process vent means a process vent that is not Group 1 or 
Group 2A for which monitoring and recordkeeping are not required to 
demonstrate a total resource effectiveness index value greater than 4.0, 
or which is exempt from control requirements due to the vent stream's 
flow rate, regulated material concentration, or total resource 
effectiveness index value.
    Halogenated vent stream or halogenated stream means, for purposes of

[[Page 22]]

this part, a vent stream determined to be halogenated by the procedures 
specified in Sec. 65.85(c) for transfer racks and in Sec. 65.64(g) for 
process vents, as applicable.
    Halogens and hydrogen halides means hydrogen chloride (HCl), 
chlorine (Cl2), hydrogen bromide (HBr), bromine 
(Br2), and hydrogen fluoride (HF).
    Hard-piping means pipe or tubing that is manufactured and installed 
using good engineering judgment and standards, such as ASME B31.3, 
Process Piping (available from the American Society of Mechanical 
Engineers, PO Box 2900, Fairfield, NJ 07007-2900).
    High-throughput transfer racks means those transfer racks that 
transfer greater than or equal to a total of 11.8 million liters per 
year (3.12 million gallons per year) of liquid containing regulated 
material.
    In food/medical service means that a piece of equipment in regulated 
material service contacts a process stream used to manufacture a Food 
and Drug Administration-regulated product where leakage of a barrier 
fluid into the process stream would cause any of the following:
    (1) A dilution of product quality so that the product would not meet 
written specifications;
    (2) An exothermic reaction that is a safety hazard;
    (3) The intended reaction to be slowed down or stopped; or
    (4) An undesired side reaction to occur.
    In gas/vapor service means that a piece of equipment in regulated 
material service contains a gas or vapor when in operation.
    In heavy liquid service means that a piece of equipment in regulated 
material service is not in gas/vapor service or in light liquid service.
    In light liquid service means that a piece of equipment in regulated 
material service contains a liquid that meets the following conditions:
    (1) The vapor pressure of one or more of the organic compounds is 
greater than 0.3 kilopascals at 20 [deg]C (0.04 pounds per square inch 
at 68 [deg]F);
    (2) The total concentration of the pure organic compound 
constituents having a vapor pressure greater than 0.3 kilopascals at 20 
[deg]C (0.04 pounds per square inch at 68 [deg]F) is equal to or greater 
than 20 percent by weight of the total process stream; and
    (3) The fluid is a liquid at operating conditions.(Note: Vapor 
pressures may be determined by standard reference texts or American 
Society for Testing and Materials (ASTM) D-2879, available from American 
Society for Testing and Materials, 1916 Race Street, Philadelphia, 
Pennsylvania 19103; or University Microfilms International, 300 North 
Zeeb Road, Ann Arbor, Michigan 48106.)
    In liquid service means that a piece of equipment in regulated 
material service is not in gas/vapor service.
    In regulated material service means, for the purposes of the 
equipment leak provisions of subpart F of this part, equipment which 
meets the definition of ``in volatile organic compound service,'' ``in 
volatile hazardous air pollutant service,'' ``in benzene service,'' ``in 
vinyl chloride service,'' or ``in organic hazardous air pollutant 
service'' as defined in the referencing subpart.
    In vacuum service means that equipment is operating at an internal 
pressure that is at least 5 kilopascals (0.7 pounds per square inch) 
below ambient pressure.
    In-situ sampling systems means nonextractive samplers or in-line 
samplers.
    Incinerator means an enclosed combustion device that is used for 
destroying organic compounds. Auxiliary fuel may be used to heat waste 
gas to combustion temperatures. Any energy recovery section present is 
not physically formed into one manufactured or assembled unit with the 
combustion section; rather, the energy recovery section is a separate 
section following the combustion section and the two are joined by ducts 
or connections carrying flue gas. This energy recovery section 
limitation does not apply to an energy recovery section used solely to 
preheat the incoming vent stream or combustion air.
    Initial startup means, for new or reconstructed sources, the first 
time the source begins production. For additions or changes not defined 
as a new source by an applicable referencing subpart, initial startup 
means the first time additional or changed equipment is put into 
operation. Initial startup does not

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include operation solely for testing equipment. Initial startup does not 
include subsequent startup (as defined in this section) of process units 
following malfunctions or process unit shutdowns. Except for equipment 
leaks, initial startup also does not include subsequent startups (as 
defined in this section) of process units following changes in product 
for flexible operation units or following recharging of equipment in 
batch operation.
    Instrumentation system means a group of equipment components used to 
condition and convey a sample of the process fluid to analyzers and 
instruments for the purpose of determining process operating conditions 
(for example, composition, pressure, flow). Valves and connectors are 
the predominant type of equipment used in instrumentation systems; 
however, other types of equipment may also be included in these systems. 
Only valves nominally 0.5 inches and smaller in diameter and connectors 
nominally 0.75 inches and smaller in diameter are considered 
instrumentation systems for the purposes of subpart F of this part.
    Intermediate change to monitoring means a modification to federally 
required monitoring involving ``proven technology'' (generally accepted 
by the scientific community as equivalent or better) that is applied on 
a site-specific basis and that may have the potential to decrease the 
stringency of the associated emission limitation or standard. Though 
site-specific, an intermediate change may set a national precedent for a 
source category and may ultimately result in a revision to the federally 
required monitoring. Examples of intermediate changes to monitoring 
include, but are not limited to:
    (1) Use of a continuous monitoring system (CEMS) in lieu of a 
parameter monitoring approach;
    (2) Decreased frequency for non-continuous parameter monitoring or 
physical inspections;
    (3) Changes to quality control requirements for parameter 
monitoring; and
    (4) Use of an electronic data reduction system in lieu of manual 
data reduction.
    Intermediate change to test method means a within-method 
modification to a federally enforceable test method involving ``proven 
technology'' (generally accepted by the scientific community as 
equivalent or better) that is applied on a site-specific basis and that 
may have the potential to decrease the stringency of the associated 
emission limitation or standard. Though site-specific, an intermediate 
change may set a national precedent for a source category and may 
ultimately result in a revision to the federally enforceable test 
method. In order to be approved, an intermediate change must be 
validated according to EPA Method 301 (40 CFR part 63, appendix A) to 
demonstrate that it provides equal or improved accuracy or precision. 
Examples of intermediate changes to a test method include, but are not 
limited to:
    (1) Modifications to a test method's sampling procedure including 
substitution of sampling equipment that has been demonstrated for a 
particular sample matrix; and use of a different impinger absorbing 
solution;
    (2) Changes in sample recovery procedures and analytical techniques, 
such as changes to sample holding times and use of a different 
analytical finish with proven capability for the analyte of interest; 
and
    (3) ``Combining'' a federally required method with another proven 
method for application to processes emitting multiple pollutants.
    Internal floating roof or IFR means a pontoon-type (noncontact) or 
double-deck-type (contact) roof that is designed to rest or float on the 
stored liquid surface inside a storage vessel that has a fixed roof.
    Liquid-mounted seal means a foam-or liquid-filled continuous seal 
mounted in contact with the stored liquid.
    Liquids dripping means any visible leakage from a seal including 
dripping, spraying, misting, clouding, and ice formation. Indications of 
liquids dripping include puddling or new stains that are indicative of 
an existing evaporated drip.
    Loading cycle means the time period from the beginning of filling a 
tank truck or railcar until flow to the control device ceases as 
determined by the flow indicator.
    Low-throughput transfer racks means those transfer racks that 
transfer less

[[Page 24]]

than a total of 11.8 million liters per year (3.12 million gallons per 
year) of liquid containing regulated material.
    Major change to monitoring means a modification to federally 
required monitoring that uses ``unproven technology or procedures'' (not 
generally accepted by the scientific community) or is an entirely new 
method (sometimes necessary when the required monitoring is unsuitable). 
A major change to monitoring may be site-specific or may apply to one or 
more source categories and will almost always set a national precedent. 
Examples of major changes to monitoring include, but are not limited to:
    (1) Use of a new monitoring approach developed to apply to a control 
technology not contemplated in the applicable regulation in this part;
    (2) Use of a predictive emission monitoring system (PEMS) in place 
of a required continuous emission monitoring system (CEMS);
    (3) Use of alternative calibration procedures that do not involve 
calibration gases or test cells;
    (4) Use of an analytical technology that differs from that specified 
by a performance specification;
    (5) Decreased monitoring frequency for a continuous emission 
monitoring system, continuous opacity monitoring system, predictive 
emission monitoring system, or continuous parameter monitoring system;
    (6) Decreased monitoring frequency for a leak detection and repair 
program; and
    (7) Use of alternative averaging times for reporting purposes.
    Major change to test method means a modification to a federally 
enforceable test method that uses ``unproven technology or procedures'' 
(not generally accepted by the scientific community) or is an entirely 
new method (sometimes necessary when the required test method is 
unsuitable). A major change to a test method may be site-specific or may 
apply to one or more source categories and will almost always set a 
national precedent. In order to be approved, a major change must be 
validated according to EPA Method 301 (40 CFR part 63, appendix A). 
Examples of major changes to a test method include, but are not limited 
to:
    (1) Use of an unproven analytical finish;
    (2) Use of a method developed to fill a test method gap;
    (3) Use of a new test method developed to apply to a control 
technology not contemplated in the applicable regulation in this part; 
and
    (4) Combining two or more sampling/analytical methods (at least one 
unproven) into one for application to processes emitting multiple 
pollutants.
    Malfunction means any sudden, infrequent, and not reasonably 
preventable failure of air pollution control equipment, monitoring 
equipment, process equipment, or a process to operate in a normal or 
usual manner. Failures that are caused in part by poor maintenance or 
careless operation are not malfunctions. Malfunctions that do not affect 
a regulated source or compliance with this part are not malfunctions for 
purposes of this part.
    Metallic shoe seal or mechanical shoe seal means metal sheets that 
are held vertically against the wall of the storage vessel by springs, 
weighted levers, or other mechanisms and connected to the floating roof 
by braces or other means. A flexible coated fabric (envelope) spans the 
annular space between the metal sheet and the floating roof.
    Minor change to monitoring means:
    (1) A modification to federally required monitoring that:
    (i) Does not decrease the stringency of the compliance and 
enforcement measures of the relevant standard;
    (ii) Has no national significance (e.g., does not affect 
implementation of the applicable regulation in this part for other 
affected sources, does not set a national precedent, and individually 
does not result in a revision to the monitoring requirements); and
    (iii) Is site-specific, made to reflect or accommodate the 
operational characteristics, physical constraints, or safety concerns of 
an affected source.
    (2) Examples of minor changes to monitoring include, but are not 
limited to:
    (i) Modifications to a sampling procedure, such as use of an 
improved sample conditioning system to reduce maintenance requirements;
    (ii) Increased monitoring frequency; and

[[Page 25]]

    (iii) Modification of the environmental shelter to moderate 
temperature fluctuation and thus protect the analytical instrumentation.
    Minor change to test method means:
    (1) A modification to a federally enforceable test method that:
    (i) Does not decrease the stringency of the emission limitation or 
standard;
    (ii) Has no national significance (e.g., does not affect 
implementation of the applicable regulation in this part for other 
affected sources, does not set a national precedent, and individually 
does not result in a revision to the test method); and
    (iii) Is site-specific, made to reflect or accommodate the 
operational characteristics, physical constraints, or safety concerns of 
an affected source.
    (2) Examples of minor changes to a test method include, but are not 
limited to:
    (i) Field adjustments in a test method's sampling procedure, such as 
a modified sampling traverse or location to avoid interference from an 
obstruction in the stack, increasing the sampling time or volume, use of 
additional impingers for a high moisture situation, accepting 
particulate emission results for a test run that was conducted with a 
lower than specified temperature, substitution of a material in the 
sampling train that has been demonstrated to be more inert for the 
sample matrix; and
    (ii) Changes in recovery and analytical techniques such as a change 
in quality control/quality assurance requirements needed to adjust for 
analysis of a certain sample matrix.
    Nonautomated monitoring and recording system means manual reading of 
values measured by monitoring instruments and manual transcription of 
those values to create a record. Nonautomated systems do not include 
strip charts nor circular charts.
    Nonrepairable means that it is technically infeasible to repair a 
piece of equipment from which a leak has been detected without a process 
unit shutdown.
    One-hour period means the 60-minute period commencing on the hour.
    Onsite or on-site means, with respect to records required to be 
maintained by this part, that the records are stored at a location 
within a plant site that encompasses the regulated source. Onsite 
includes, but is not limited to, storage at the regulated source to 
which the records pertain, or storage in central files elsewhere at the 
plant site.
    Open-ended valve or line means any valve except relief valves having 
one side of the valve seat in contact with process fluid and one side 
open to the atmosphere, either directly or through open piping.
    Organic monitoring device means a device used to indicate the 
concentration level of organic compounds based on a detection principle 
such as infrared, photo ionization, or thermal conductivity.
    Owner or operator means any person who owns, leases, operates, 
controls, or supervises a regulated source or a stationary source of 
which a regulated source is a part.
    Part 70 permit means any permit issued, renewed, or revised pursuant 
to part 70 of this chapter.
    Performance test means the collection of data resulting from the 
execution of a test method (usually three emission test runs) used to 
demonstrate compliance with a relevant emission standard as specified in 
the performance test section of the relevant standard.
    Permit program means a comprehensive State operating permit system 
established pursuant to title V of the Act (42 U.S.C. 7661) and 
regulations codified in part 70 of this chapter and applicable State 
regulations, or a comprehensive Federal operating permit system 
established pursuant to title V of the Act and regulations codified in 
part 71 of this chapter.
    Permitting authority means one of the following:
    (1) The State air pollution control agency, local agency, other 
State agency, or other agency authorized by the Administrator to carry 
out a permit program under part 70 of this chapter; or
    (2) The Administrator, in the case of EPA-implemented permit 
programs under title V of the Act (42 U.S.C. 7661) and part 71 of this 
chapter.
    Plant site means all contiguous or adjoining property that is under 
common control, including properties that are

[[Page 26]]

separated only by a road or other public right-of-way. Common control 
includes properties that are owned, leased, or operated by the same 
entity, parent entity, subsidiary, or any combination thereof.
    Polymerizing monomer means, for the purposes of this part, a 
compound which may form polymer buildup in pump mechanical seals 
resulting in rapid mechanical seal failure.
    Pressure release means the emission of materials resulting from the 
system pressure being greater than the set pressure of the relief 
device. This release can be one release or a series of releases over a 
short time period.
    Pressure relief device or valve means a device used to prevent 
operating pressures from exceeding the maximum allowable working 
pressure of the process equipment. A common pressure relief device is a 
spring-loaded pressure relief valve. Devices that are actuated either by 
a pressure of less than or equal to 2.5 pounds per square inch gauge or 
by a vacuum are not pressure relief devices.
    Primary fuel means the fuel that provides the principal heat input 
to the device. To be considered primary, the fuel must be able to 
sustain operation without the addition of other fuels.
    Process heater means an enclosed combustion device that transfers 
heat liberated by burning fuel directly to process streams or to heat 
transfer liquids other than water. A process heater may, as a secondary 
function, heat water in unfired heat recovery sections.
    Process unit means the equipment specified in the definitions of 
process unit or chemical manufacturing process unit in the applicable 
referencing subpart. If the referencing subpart does not define process 
unit, then, for the purposes of this part, process unit means the 
equipment assembled and connected by pipes or ducts to process raw 
materials and to manufacture an intended product.
    Process unit shutdown means a work practice or operational procedure 
that stops production from a process unit or part of a process unit 
during which it is technically feasible to clear process material from a 
process unit or part of a process unit consistent with safety 
constraints and during which repairs can be effected. An unscheduled 
work practice or operational procedure that stops production from a 
process unit or part of a process unit for less than 24 hours is not a 
process unit shutdown. An unscheduled work practice or operational 
procedure that would stop production from a process unit or part of a 
process unit for a shorter period of time than would be required to 
clear the process unit or part of the process unit of materials and 
start up the unit, and would result in greater emissions than delay of 
repair of leaking components until the next scheduled process unit 
shutdown is not a process unit shutdown. The use of spare equipment and 
technically feasible bypassing of equipment without stopping production 
are not process unit shutdowns.
    Process vent means a process vent or vent stream as they are defined 
in the referencing subpart.
    Recovery device means an individual unit of equipment capable of and 
normally used for the purpose of recovering chemicals for fuel value 
(i.e., net positive heating value), use, reuse, or for sale for fuel 
value, use, or reuse. Equipment capable of and used for the purpose of 
recovering chemicals, but not normally for use, reuse or sale, are not 
recovery devices but are control devices. Examples of equipment that may 
be recovery devices include absorbers, carbon adsorbers, condensers, 
oil-water separators or organic-water separators, or organic removal 
devices such as decanters, strippers, or thin-film evaporation units.
    Reference method means any method of sampling and analyzing for an 
air pollutant as specified in an applicable subpart, the appendices to 
40 CFR part 60 or 63, or in appendix B of 40 CFR part 61.
    Referencing subpart means 40 CFR part 60, subparts Ka, Kb, VV, DDD, 
III, NNN, and RRR; 40 CFR part 61, subparts V, Y, and BB; and 40 CFR 
part 63, subparts G and H.
    Regulated material means, for the purposes of this part, the 
material regulated by the specific referencing subpart, including 
volatile organic liquids (VOL), volatile organic compounds (VOC), 
organic hazardous air pollutants (HAP's), benzene, vinyl chloride,

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or other chemicals or groups of chemicals.
    Regulated source means, for the purposes of this part, the 
stationary source, the group of stationary sources, or the portion of a 
stationary source that is regulated by a relevant standard or other 
requirement established pursuant to this part, or 40 CFR part 60, 61, or 
63.
    Relief device or valve means a device or valve used only to release 
an unplanned, nonroutine discharge. A relief device or valve discharge 
can result from an operator error, a malfunction such as a power failure 
or equipment failure, or other unexpected cause that requires immediate 
venting of gas from process equipment in order to avoid safety hazards 
or equipment damage.
    Repaired means, for the purposes of subparts F and G of this part, 
that equipment meets the following conditions:
    (1) Is adjusted, or otherwise altered, to eliminate a leak as 
defined in the applicable section of this part; and
    (2) Unless otherwise specified in applicable provisions of this 
part, is monitored as specified in Sec. 65.104(b) and Sec. 65.143(c) 
to verify that emissions from the equipment are below the applicable 
leak definition.
    Routed to a process or route to a process means the emissions are 
conveyed to any enclosed portion of a process unit where the emissions 
are predominantly recycled and/or consumed in the same manner as a 
material that fulfills the same function in the process and/or 
transformed by chemical reaction into materials that are not regulated 
materials and/or incorporated into a product; and/or recovered.
    Run means one of a series of emission or other measurements needed 
to determine emissions for a representative operating period or cycle as 
specified in this part. Unless otherwise specified, a run may be either 
intermittent or continuous within the limits of good engineering 
practice.
    Sampling connection system means an assembly of equipment within a 
process unit used during periods of representative operation to take 
samples of the process fluid. Equipment used to take nonroutine grab 
samples is not considered a sampling connection system.
    Secondary fuel means a fuel fired through a burner other than the 
primary fuel burner that provides supplementary heat in addition to the 
heat provided by the primary fuel.
    Sensor means a device that measures a physical quantity or the 
change in a physical quantity, such as temperature, pressure, flow rate, 
pH, or liquid level.
    Set pressure means, for the purposes of subparts F and G of this 
part, the pressure at which a properly operating pressure relief device 
begins to open to relieve atypical process system operating pressure.
    Shutdown means the cessation of operation of a regulated source (for 
example, chemical manufacturing process unit or a reactor, air oxidation 
reactor, distillation unit) and equipment required or used to comply 
with this part, or the emptying and degassing of a storage vessel. 
Shutdown is defined here for purposes including, but not limited to, 
periodic maintenance, replacement of equipment, or repair. Shutdown does 
not include the routine rinsing or washing of equipment in batch 
operation between batches.
    Simultaneous loading means, for a shared control device, loading of 
regulated materials from more than one transfer arm at the same time so 
that the beginning and ending times of loading cycles coincide or 
overlap and there is no interruption in vapor flow to the shared control 
device.
    Single-seal system means, for the purposes of subpart C of this 
part, a floating roof having one continuous seal. This seal may be a 
vapor-mounted, liquid-mounted, or metallic shoe seal.
    Specific gravity monitoring device means a unit of equipment used to 
monitor specific gravity and having a minimum accuracy of 0.02 specific gravity units.
    Startup means the setting into operation of a regulated source (for 
example, chemical manufacturing process unit or a reactor, air oxidation 
reactor, distillation unit, a storage vessel after emptying and 
degassing) and/or equipment required or used to comply with this part. 
Startup includes initial startup, operation solely for testing

[[Page 28]]

equipment, the recharging of equipment in batch operation, and 
transitional conditions due to changes in product for flexible operation 
units.
    State means all non-Federal authorities, including local agencies, 
interstate associations, and statewide programs, that have delegated 
authority to implement the provisions of this part; the referencing 
subparts; and/or the permit program established under part 70 of this 
chapter. The term State shall have its conventional meaning where clear 
from the context.
    Steam jet ejector means a steam nozzle that discharges a high-
velocity jet across a suction chamber that is connected to the equipment 
to be evacuated.
    Stuffing box pressure means the fluid (liquid or gas) pressure 
inside the casing or housing of a piece of equipment, on the process 
side of the inboard seal.
    Surge control vessel means feed drums, recycle drums, and 
intermediate vessels. Surge control vessels are used within a process 
unit (as defined in the specific subpart that references this part) when 
in-process storage, mixing, or management of flow rates or volumes is 
needed to assist in production of a product.
    Temperature monitoring device means a unit of equipment used to 
monitor temperature and having a minimum accuracy of 1 percent of the temperature being monitored expressed 
in degrees Celsius or 1.2 degrees Celsius ( 
[deg]C), whichever is greater.
    Title V permit means any permit issued, renewed, or revised pursuant 
to Federal or State regulations established under 40 CFR part 70 or 71 
to implement title V of the Act (42 U.S.C. 7661).
    Total organic compounds or TOC means those compounds measured 
according to the procedures specified in Sec. 65.64(c) and Sec. 
65.158(b)(3)(ii)(A), as applicable. Those compounds that the 
Administrator has determined do not contribute appreciably to the 
formation of ozone and that are specifically excluded from the 
definition of volatile organic compound at 40 CFR 51.100(s), as amended, 
are to be excluded for the purposes of measuring the hourly emission 
rate as required in Sec. 65.64(f) for process vents subject to subpart 
III, NNN, or RRR of part 60 of this chapter.
    Total resource effectiveness index value or TRE index value means a 
calculated value used to determine whether control is required for a 
process vent. It is based on process vent flow rate, emission rate of 
regulated material, net heating value, and corrosion properties 
(halogenated compound content), as quantified by the equations given 
under Sec. 65.64(h).
    Vapor balancing system means a piping system that is designed to 
collect regulated material vapors displaced from tank trucks or railcars 
during loading and to route the collected regulated material vapors to 
the storage vessel from which the liquid being loaded originated, or to 
another storage vessel connected by a common header; or to compress and 
route to a process or a fuel gas system the collected regulated material 
vapors.
    Vapor-mounted seal means a continuous seal that is mounted so that 
there is a vapor space between the stored liquid and the bottom of the 
seal.
    Visible emission means the observation of an emission of opacity or 
optical density above the threshold of vision.