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Subpart O—HCFC-22 Production and HFC-23 Destruction

§98.150 Definition of the source category.

The HCFC-22 production and HFC-23 destruction source category consists of HCFC-22 

production processes and HFC-23 destruction processes.

(a) An HCFC-22 production process produces HCFC-22 (chlorodifluoromethane, or 

CHClF2) from chloroform (CHCl3) and hydrogen fluoride (HF).

(b) An HFC-23 destruction process is any process in which HFC-23 undergoes 

destruction. An HFC-23 destruction process may or may not be co-located with an HCFC-22 

production process at the same facility.

§98.151 Reporting threshold.

You must report GHG emissions under this subpart if your facility contains an HCFC-22 

production or HFC-23 destruction process and the facility meets the requirements of either 

§98.2(a)(1) or (a)(2).

§98.152 GHGs to report.

(a) You must report under subpart C of this part (General Stationary Fuel Combustion 

Sources) the emissions of CO2, CH4, and N2O from each stationary combustion unit following 

the requirements of subpart C.

(b) You must report HFC-23 emissions from HCFC-22 production processes and HFC-23 

destruction processes.

§98.153 Calculating GHG emissions.

(a) The mass of HFC-23 generated from each HCFC-22 production process shall be 

estimated by using one of two methods, as applicable:
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(1) Where the mass flow of the combined stream of HFC-23 and another reaction product 

(e.g., HCl) is measured, multiply the weekly (or more frequent) HFC-23 concentration 

measurement (which may be the average of more frequent concentration measurements) by the 

weekly (or more frequent) mass flow of the combined stream of HFC-23 and the other product. 

To estimate annual HFC-23 production, sum the weekly (or more frequent) estimates of the 

quantities of HFC-23 produced over the year. This calculation is summarized in Equation O-1 of 

this section:

Where:

G23 = Mass of HFC-23 generated annually (metric tons).

c23 = Fraction HFC-23 by weight in HFC-23/other product stream.

Fp = Mass flow of HFC-23/other product stream during the period p (kg).

p = Period over which mass flows and concentrations are measured.

n = Number of concentration and flow measurement periods for the year.

10−3 = Conversion factor from kilograms to metric tons.

(2) Where the mass of only a reaction product other than HFC-23 (either HCFC-22 or 

HCl) is measured, multiply the ratio of the weekly (or more frequent) measurement of the HFC23 concentration and the weekly (or more frequent) measurement of the other product 

concentration by the weekly (or more frequent) mass produced of the other product. To estimate 

annual HFC-23 production, sum the weekly (or more frequent) estimates of the quantities of 

HFC-23 produced over the year. This calculation is summarized in Equation O-2 of this section, 

assuming that the other product is HCFC-22. If the other product is HCl, HCl may be substituted 

for HCFC-22 in Equations O-2 and O-3 of this section.
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Where:

G23 = Mass of HFC-23 generated annually (metric tons).

c23 = Fraction HFC-23 by weight in HCFC-22/HFC-23 stream.

c22 = Fraction HCFC-22 by weight in HCFC-22/HFC-23 stream.

P22 = Mass of HCFC-22 produced over the period p (kg), calculated using Equation O-3 

of this section.

p = Period over which masses and concentrations are measured.

n = Number of concentration and mass measurement periods for the year.

10−3 = Conversion factor from kilograms to metric tons.

(b) The mass of HCFC-22 produced over the period p shall be estimated by using 

Equation O-3 of this section:

View or download PDF

Where:

P22 = Mass of HCFC-22 produced over the period p (kg).

O22 = mass of HCFC-22 that is measured coming out of the Production process over the 

period p (kg).

U22 = Mass of used HCFC-22 that is added to the production process upstream of the 

output measurement over the period p (kg).

LF = Factor to account for the loss of HCFC-22 upstream of the measurement. The value 

for LF shall be determined pursuant to §98.154(e).
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(c) For HCFC-22 production facilities that do not use a destruction device or that have a 

destruction device that is not directly connected to the HCFC-22 production equipment, HFC-23 

emissions shall be estimated using Equation O-4 of this section:

Where:

E23 = Mass of HFC-23 emitted annually (metric tons).

G23 = Mass of HFC-23 generated annually (metric tons).

S23 = Mass of HFC-23 sent off site for sale annually (metric tons).

OD23 = Mass of HFC-23 sent off site for destruction (metric tons).

D23 = Mass of HFC-23 destroyed on site (metric tons).

I23 = Increase in HFC-23 inventory = HFC-23 in storage at end of year—HFC-23 in 

storage at beginning of year (metric tons).

(d) For HCFC-22 production facilities that use a destruction device connected to the 

HCFC-22 production equipment, HFC-23 emissions shall be estimated using Equation O-5 of 

this section:

Where:

E23 = Mass of HFC-23 emitted annually (metric tons).

EL = Mass of HFC-23 emitted annually from equipment leaks, calculated using Equation 

O-6 of this section (metric tons).

EPV = Mass of HFC-23 emitted annually from process vents, calculated using Equation 

O-7 of this section (metric tons).
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ED = Mass of HFC-23 emitted annually from destruction device (metric tons), calculated 

using Equation O-8 of this section.

(1) The mass of HFC-23 emitted annually from equipment leaks (for use in Equation O-5 

of this section) shall be estimated by using Equation O-6 of this section:

Where:

EL = Mass of HFC-23 emitted annually from equipment leaks (metric tons).

c23 = Fraction HFC-23 by weight in the stream(s) in the equipment.

FGt = The applicable leak rate specified in Table O-1 of this subpart for each source of 

equipment type and service t with a screening value greater than or equal to 10,000 ppmv 

(kg/hr/source).

NGt = The number of sources of equipment type and service t with screening values 

greater than or equal to 10,000 ppmv as determined according to §98.154(i).

FLt = The applicable leak rate specified in Table O-1 of this subpart for each source of 

equipment type and service t with a screening value of less than 10,000 ppmv (kg/hr/source).

NLt = The number of sources of equipment type and service t with screening values less 

than 10,000 ppmv as determined according to §98.154(j).

p = One hour.

n = Number of hours during the year during which equipment contained HFC-23.

t = Equipment type and service as specified in Table O-1 of this subpart .

10−3 = Factor converting kg to metric tons.

(2) The mass of HFC-23 emitted annually from process vents (for use in Equation O-5 of 

this section) shall be estimated by using Equation O-7 of this section:
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Where:

EPV = Mass of HFC-23 emitted annually from process vents (metric tons).

ERT = The HFC-23 emission rate from the process vents during the period of the most 

recent test (kg/hr).

PRp = The HCFC-22 production rate during the period p (kg/hr).

PRT = The HCFC-22 production rate during the most recent test period (kg/hr).

lp = The length of the period p (hours).

10−3 = Factor converting kg to metric tons.

n = The number of periods in a year.

(3) The total mass of HFC-23 emitted from destruction devices shall be estimated by

using Equation O-8 of this section:

Where:

ED = Mass of HFC-23 emitted annually from the destruction device (metric tons).

FD = Mass of HFC-23 fed into the destruction device annually (metric tons).

D23 = Mass of HFC-23 destroyed annually (metric tons).

(4) For facilities that destroy HFC-23, the total mass of HFC-23 destroyed shall be 

estimated by using Equation O-9 of this section:

Where:

D23 = Mass of HFC-23 destroyed annually (metric tons).

FD = Mass of HFC-23 fed into the destruction device annually (metric tons).
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DE = Destruction Efficiency of the destruction device (fraction).

§98.154 Monitoring and QA/QC requirements.

These requirements apply to measurements that are reported under this subpart or that are 

used to estimate reported quantities pursuant to §98.153.

(a) The concentrations (fractions by weight) of HFC-23 and HCFC-22 in the product 

stream shall be measured at least weekly using equipment and methods (e.g., gas 

chromatography) with an accuracy and precision of 5 percent or better at the concentrations of 

the process samples.

(b) The mass flow of the product stream containing the HFC-23 shall be measured at 

least weekly using weigh scales, flowmeters, or a combination of volumetric and density 

measurements with an accuracy and precision of 1.0 percent of full scale or better.

(c) The mass of HCFC-22 or HCl coming out of the production process shall be 

measured at least weekly using weigh scales, flowmeters, or a combination of volumetric and 

density measurements with an accuracy and precision of 1.0 percent of full scale or better.

(d) The mass of any used HCFC-22 added back into the production process upstream of 

the output measurement in paragraph (c) of this section shall be measured (when being added) 

using flowmeters, weigh scales, or a combination of volumetric and density measurements with 

an accuracy and precision of 1.0 percent of full scale or better. If the mass in paragraph (c) of 

this section is measured by weighing containers that include returned heels as well as newly 

produced fluorinated GHGs, the returned heels shall be considered used fluorinated HCFC-22 

for purposes of this paragraph (d) of this section and §98.153(b).

(e) The loss factor LF in Equation O-3 of this subpart for the mass of HCFC-22 produced 

shall have the value 1.015 or another value that can be demonstrated, to the satisfaction of the 
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Administrator, to account for losses of HCFC-22 between the reactor and the point of 

measurement at the facility where production is being estimated.

(f) The mass of HFC-23 sent off site for sale shall be measured at least weekly (when 

being packaged) using flowmeters, weigh scales, or a combination of volumetric and density 

measurements with an accuracy and precision of 1.0 percent of full scale or better.

(g) The mass of HFC-23 sent off site for destruction shall be measured at least weekly 

(when being packaged) using flowmeters, weigh scales, or a combination of volumetric and 

density measurements with an accuracy and precision of 1.0 percent of full scale or better. If the 

measured mass includes more than trace concentrations of materials other than HFC-23, the 

concentration of the fluorinated GHG shall be measured at least weekly using equipment and 

methods (e.g., gas chromatography) with an accuracy and precision of 5 percent or better at the 

concentrations of the process samples. This concentration (mass fraction) shall be multiplied by

the mass measurement to obtain the mass of the HFC-23 sent to another facility for destruction.

(h) The masses of HFC-23 in storage at the beginning and end of the year shall be 

measured using flowmeters, weigh scales, or a combination of volumetric and density

measurements with an accuracy and precision of 1.0 percent of full scale or better.

(i) The number of sources of equipment type t with screening values greater than or equal 

to 10,000 ppmv shall be determined using EPA Method 21 at 40 CFR part 60, appendix A-7, and 

defining a leak as follows:

(1) A leak source that could emit HFC-23, and

(2) A leak source at whose surface a concentration of fluorocarbons equal to or greater 

than 10,000 ppm is measured.
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(j) The number of sources of equipment type t with screening values less than 10,000 

ppmv shall be the difference between the number of leak sources of equipment type t that could 

emit HFC-23 and the number of sources of equipment type t with screening values greater than 

or equal to 10,000 ppmv as determined under paragraph (i) of this section.

(k) The mass of HFC-23 emitted from process vents shall be estimated at least monthly

by incorporating the results of the most recent emissions test into Equation O-7 of this subpart. 

HCFC-22 production facilities that use a destruction device connected to the HCFC-22 

production equipment shall conduct emissions tests at process vents at least once every five years 

or after significant changes to the process. Emissions tests shall be conducted in accordance with 

EPA Method 18 at 40 CFR part 60, appendix A-6, under conditions that are typical for the 

production process at the facility. The sensitivity of the tests shall be sufficient to detect an 

emission rate that would result in annual emissions of 200 kg of HFC-23 if sustained over one 

year.

(l) For purposes of Equation O-9 of this subpart, the destruction efficiency must be 

equated to the destruction efficiency determined during a new or previous performance test of 

the destruction device. HFC-23 destruction facilities shall conduct annual measurements of HFC23 concentrations at the outlet of the destruction device in accordance with EPA Method 18 at 40 

CFR part 60, appendix A-6. Three samples shall be taken under conditions that are typical for the 

production process and destruction device at the facility, and the average concentration of HFC23 shall be determined. The sensitivity of the concentration measurement shall be sufficient to 

detect an outlet concentration equal to or less than the outlet concentration determined in the 

destruction efficiency performance test. If the concentration measurement indicates that the 

HFC-23 concentration is less than or equal to that measured during the performance test that is 
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the basis for the destruction efficiency, continue to use the previously determined destruction 

efficiency. If the concentration measurement indicates that the HFC-23 concentration is greater 

than that measured during the performance test that is the basis for the destruction efficiency, 

facilities shall either:

(1) Substitute the higher HFC-23 concentration for that measured during the destruction 

efficiency performance test and calculate a new destruction efficiency, or

(2) Estimate the mass emissions of HFC-23 from the destruction device based on the 

measured HFC-23 concentration and volumetric flow rate determined by measurement of 

volumetric flow rate using EPA Method 2, 2A, 2C,2D, or 2F at 40 CFR part 60, appendix A-1, 

or Method 26 at 40 CFR part 60, appendix A-2. Determine the mass rate of HFC-23 into the 

destruction device by measuring the HFC-23 concentration and volumetric flow rate at the inlet 

or by a metering device for HFC-23 sent to the device. Determine a new destruction efficiency

based on the mass flow rate of HFC-23 into and out of the destruction device.

(m) HCFC-22 production facilities shall account for HFC-23 generation and emissions 

that occur as a result of startups, shutdowns, and malfunctions, either recording HFC-23 

generation and emissions during these events, or documenting that these events do not result in 

significant HFC-23 generation and/or emissions.

(n) The mass of HFC-23 fed into the destruction device shall be measured at least weekly 

using flow meters, weigh scales, or a combination of volumetric and density measurements with 

an accuracy and precision of 1.0 percent of full scale or better. If the measured mass includes 

more than trace concentrations of materials other than HFC-23, the concentrations of the HFC-23 

shall be measured at least weekly using equipment and methods (e.g., gas chromatography) with 

an accuracy and precision of 5 percent or better at the concentrations of the process samples. 
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This concentration (mass fraction) shall be multiplied by the mass measurement to obtain the 

mass of the HFC-23 destroyed.

(o) In their estimates of the mass of HFC-23 destroyed, HFC-23 destruction facilities 

shall account for any temporary reductions in the destruction efficiency that result from any

startups, shutdowns, or malfunctions of the destruction device, including departures from the 

operating conditions defined in State or local permitting requirements and/or destruction device 

manufacturer specifications.

(p) Calibrate all flow meters, weigh scales, and combinations of volumetric and density

measures using NIST-traceable standards and suitable methods published by a consensus 

standards organization (e.g., ASTM, ASME, ISO, or others). Recalibrate all flow meters, weigh 

scales, and combinations of volumetric and density measures at the minimum frequency

specified by the manufacturer.

(q) All gas chromatographs used to determine the concentration of HFC-23 in process 

streams shall be calibrated at least monthly through analysis of certified standards (or of 

calibration gases prepared from a high-concentration certified standard using a gas dilution 

system that meets the requirements specified in Method 205 at 40 CFR part 51, appendix M) 

with known HFC-23 concentrations that are in the same range (fractions by mass) as the process 

samples.

§98.155 Procedures for estimating missing data.

(a) A complete record of all measured parameters used in the GHG emissions 

calculations is required. Therefore, whenever a quality-assured value of a required parameter is 

unavailable (e.g., if a meter malfunctions during unit operation or if a required process sample is 
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not taken), a substitute data value for the missing parameter shall be used in the calculations, 

according to the following requirements:

(1) For each missing value of the HFC-23 or HCFC-22 concentration, the substitute data 

value shall be the arithmetic average of the quality-assured values of that parameter immediately 

preceding and immediately following the missing data incident. If, for a particular parameter, no 

quality-assured data are available prior to the missing data incident, the substitute data value 

shall be the first quality-assured value obtained after the missing data period.

(2) For each missing value of the product stream mass flow or product mass, the 

substitute value of that parameter shall be a secondary product measurement where such a 

measurement is available. If that measurement is taken significantly downstream of the usual 

mass flow or mass measurement (e.g., at the shipping dock rather than near the reactor), the 

measurement shall be multiplied by 1.015 to compensate for losses. Where a secondary mass 

measurement is not available, the substitute value of the parameter shall be an estimate based on 

a related parameter. For example, if a flowmeter measuring the mass fed into a destruction 

device is rendered inoperable, then the mass fed into the destruction device may be estimated 

using the production rate and the previously observed relationship between the production rate 

and the mass flow rate into the destruction device.

§ 98.156 Data reporting requirements.

(a) In addition to the information required by § 98.3(c), the HCFC-22 production facility

shall report the following information for each HCFC-22 production process:

(1) Annual mass of HCFC-22 produced in metric tons.

(2) Reserved.

(3) Annual mass of reactants fed into the process in metric tons of reactant.
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(4) The mass (in metric tons) of materials other than HCFC-22 and HFC-23 (i.e.,

unreacted reactants, HCl and other by-products) that occur in more than trace concentrations and 

that are permanently removed from the process.

(5) The method for tracking startups, shutdowns, and malfunctions and HFC-23 

generation/emissions during these events.

(6) The names and addresses of facilities to which any HFC-23 was sent for destruction, 

and the quantities of HFC-23 (metric tons) sent to each.

(7) Reserved.

(8) Reserved.

(9) Reserved.

(10) Reserved.

(11) Annual mass of HFC-23 emitted in metric tons.

(12) Annual mass of HFC-23 emitted from equipment leaks in metric tons.

(13) Annual mass of HFC-23 emitted from process vents in metric tons.

(b) In addition to the information required by § 98.3(c), facilities that destroy HFC-23 

shall report the following for each HFC-23 destruction process:

(1) Reserved.

(2) Reserved.

(3) Annual mass of HFC-23 emitted from the destruction device.

(c) Each HFC-23 destruction facility shall report the concentration (mass fraction) of 

HFC-23 measured at the outlet of the destruction device during the facility's annual HFC-23 

concentration measurements at the outlet of the device. If the concentration of HFC-23 is below 
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the detection limit of the measuring device, report the detection limit and that the concentration 

is below the detection limit.

(d) If the HFC-23 concentration measured pursuant to § 98.154(l) is greater than that 

measured during the performance test that is the basis for the destruction efficiency (DE), the 

facility shall report the method used to calculate the revised destruction efficiency, specifying 

whether § 98.154(l)(1) or (l)(2) has been used for the calculation.

(e) By March 31, 2011 or within 60 days of commencing HFC-23 destruction, HFC-23 

destruction facilities shall submit a one-time report including the following information for each 

destruction process:

(1) Reserved.

(2) The methods used to determine destruction efficiency.

(3) The methods used to record the mass of HFC-23 destroyed.

(4) The name of other relevant federal or state regulations that may apply to the 

destruction process.

(5) If any changes are made that affect HFC-23 destruction efficiency or the methods 

used to record volume destroyed, then these changes must be reflected in a revision to this report. 

The revised report must be submitted to EPA within 60 days of the change.

§ 98.157 Records that must be retained.

(a) In addition to the data required by § 98.3(g), HCFC-22 production facilities shall 

retain the following records:

(1) The data used to estimate HFC-23 emissions.

(2) Records documenting the initial and periodic calibration of the gas chromatographs, 

weigh scales, volumetric and density measurements, and flowmeters used to measure the 
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quantities reported under this rule, including the industry standards or manufacturer directions 

used for calibration pursuant to § 98.154(p) and (q).

(b) In addition to the data required by § 98.3(g), the HFC-23 destruction facilities shall 

retain the following records:

(1) Records documenting their one-time and annual reports in § 98.156(b) through (e).

(2) Records documenting the initial and periodic calibration of the gas chromatographs, 

weigh scales, volumetric and density measurements, and flowmeters used to measure the 

quantities reported under this subpart, including the industry standard practice or manufacturer 

directions used for calibration pursuant to § 98.154(p) and (q).

(c) Verification software records. You must keep a record of the file generated by the 

verification software specified in § 98.5(b) for the applicable data specified in paragraphs (c)(1) 

through (16) of this section. Retention of this file satisfies the recordkeeping requirement for the 

data in paragraphs (c)(1) through (16) of this section.

(1) Factor to account for the loss of HCFC-22 upstream of the measurement over the 

period, determined pursuant to § 98.154(e) (Equation O-3 of § 98.153).

(2) Mass of HCFC-22 that is measured coming out of the production process over the 

period. A period can be one year (kg) (Equation O-3).

(3) Mass of used HCFC-22 that is added to the production process upstream of the output 

measurement over the period. A period can be one year (kg) (Equation O-3).

(4) Mass of HFC-23 generated annually per HCFC-22 production process (metric tons) 

(Equation O-4 of § 98.153).

(5) Mass of HFC-23 sent off site for sale annually per HCFC-22 production process 

(metric tons) (Equation O-4).
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(6) Mass of HFC-23 sent off site for destruction annually per HCFC-22 production 

process (metric tons) (Equation O-4).

(7) Mass of HFC-23 destroyed on site per HCFC-22 production process (metric tons) 

(Equation O-4).

(8) HFC-23 in storage at end of year per HCFC-22 production process (metric tons) 

(Equation O-4).

(9) HFC-23 in storage at beginning of year per HCFC-22 production process (metric 

tons) (Equation O-4).

(10) Mass of HFC-23 fed into each destruction device annually per HCFC-22 production 

process (metric tons) (Equation O-9 of § 98.153 and the calculation method in either § 

98.154(l)(1) or (2)).

(11) Identify if each destruction efficiency for each HCFC-22 production process is 

entered directly, or is calculated using § 98.154(l)(1), or is calculated using § 98.154(l)(2) 

(Equation O-9 and the calculation method in either § 98.154(l)(1) or (2)).

(12) Destruction efficiency of each destruction device for each HCFC-22 production 

process (decimal fraction) (Equation O-9 and the calculation method in either § 98.154(l)(1) or 

(2)).

(13) Volumetric flow rate at the inlet of each destruction device for each HCFC-22 

production process from previous test (kg/hr) (Equation O-9 and the calculation method in either 

§ 98.154(l)(1) or (2)).

(14) Volumetric flow rate at the inlet of destruction device during test for each HCFC-22 

production process (kg/hr) (Equation O-9 and the calculation method in either § 98.154(l)(1) or 

(2)).
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(15) Concentration of HFC-23 at the inlet of destruction device for each HCFC-22 

production process from previous test (weight fraction) (Equation O-9 and the calculation 

method in either § 98.154(l)(1) or (2)).

(16) Concentration of HFC-23 at the inlet of destruction device for each HCFC-22 

production process during test (weight fraction) (Equation O-9 and the calculation method in 

either § 98.154(l)(1) or (2)).

§98.158 Definitions.

All terms used in this subpart have the same meaning given in the Clean Air Act and 

subpart A of this part.

Table O-1 to Subpart O of Part 98—Emission Factors for Equipment Leaks

Equipment type Service

Emission factor

(kg/hr/source)

≥10,000 ppmv <10,000 ppmv

Valves Gas 0.0782 0.000131

Valves Light liquid 0.0892 0.000165

Pump seals Light liquid 0.243 0.00187

Compressor seals Gas 1.608 0.0894

Pressure relief valves Gas 1.691 0.0447

Connectors All 0.113 0.0000810

Open-ended lines All 0.01195 0.00150