Page 1 of 20

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

The HCFC–22 production and HFC–23 destruction source 

category consists of HCFC–22 production processes and HFC–23 

destruction processes.

§ 98.150 Definition of the source category.

(a) An HCFC–22 production process produces HCFC–22 

(chlorodifluoromethane, or CHClF2) from chloroform (CHCl3

(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.

) and 

hydrogen fluoride (HF).

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).

§ 98.151 Reporting threshold.

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

Stationary Fuel Combustion Sources) the emissions of CO

§ 98.152 GHGs to report.

2, CH4,

and N2

(b) You must report HFC–23 emissions from HCFC–22 

production processes and HFC–23 destruction processes.

O from each stationary combustion unit following the 

requirements of subpart C.
Page 2 of 20

(a) The mass of HFC–23 generated from each HCFC–22 

production process shall be estimated by using one of two 

methods, as applicable:

§ 98.153 Calculating GHG emissions.

(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

c

= Mass of HFC–23 generated annually (metric 

tons).

23

F

= Fraction HFC–23 by weight in HFC–23/other 

product stream.

p

p = Period over which mass flows and 

concentrations are measured.

= Mass flow of HFC–23/other product stream 

during the period p (kg).

n = Number of concentration and flow measurement 

periods for the year.

10−3 = Conversion factor from kilograms to metric 

tons.
Page 3 of 20

(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 HFC–23 

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.

Where:

G23

c

= Mass of HFC–23 generated annually (metric 

tons).

23

c

= Fraction HFC–23 by weight in HCFC–22/HFC–23 

stream.

22

P

= Fraction HCFC–22 by weight in HCFC–22/HFC–23 

stream.

22

p = Period over which masses and concentrations 

are measured.

= Mass of HCFC–22 produced over the period p 

(kg), calculated using Equation O–3 of this 

section.

n = Number of concentration and mass measurement 

periods for the year.
Page 4 of 20

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:

Where:

P22 =

O

Mass of HCFC–22 produced over the period p 

(kg).

22 =

U

mass of HCFC–22 that is measured coming out of 

the Production process over the period p (kg).

22 =

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).

Mass of used HCFC–22 that is added to the 

production process upstream of the output 

measurement over the period p (kg).

(c) For HCFC–22 production facilities that do not use a 

thermal oxidizerdestruction device or that have a thermal 

oxidizerdestruction 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 =

G

Mass of HFC–23 emitted annually (metric tons).

23 =

S

Mass of HFC–23 generated annually (metric 

tons).

23 =

OD

Mass of HFC–23 sent off site for sale annually 

(metric tons).

23 = Mass of HFC–23 sent off site for destruction 

(metric tons).
Page 5 of 20

D23 =

I

Mass of HFC–23 destroyed on site (metric 

tons).

23 =

(d) For HCFC–22 production facilities that use a thermal 

oxidizerdestruction device connected to the HCFC–22 production 

equipment, HFC–23 emissions shall be estimated using Equation O–

5 of this section:

Increase in HFC–23 inventory = HFC–23 in 

storage at end of year—HFC–23 in storage at 

beginning of year (metric tons).

Where:

E23

E

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

L

E

= Mass of HFC–23 emitted annually from equipment 

leaks, calculated using Equation O–6 of this 

section (metric tons).

PV

E

= Mass of HFC–23 emitted annually from process 

vents, calculated using Equation O–7 of this 

section (metric tons).

D

(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:

= Mass of HFC–23 emitted annually from thermal 

oxidizerdestruction device (metric tons), 

calculated using Equation O–8 of this section.

Where:

EL

c

= Mass of HFC–23 emitted annually from equipment 

leaks (metric tons).

23 = Fraction HFC–23 by weight in the stream(s) in 

the equipment.
Page 6 of 20

FGt

N

= 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).

Gt

F

= 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).

Lt

N

= 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).

Lt

p = One hour.

= 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).

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:

Where:

EPV

ER

= Mass of HFC–23 emitted annually from process 

vents (metric tons).

T = The HFC–23 emission rate from the process 

vents during the period of the most recent 

test (kg/hr).
Page 7 of 20

PRp

PR

= The HCFC–22 production rate during the period 

p (kg/hr).

T

l

= The HCFC–22 production rate during the most 

recent test period (kg/hr).

p

10−3 = Factor converting kg to metric tons.

= The length of the period p (hours).

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

F

= Mass of HFC–23 emitted annually from the 

destruction device (metric tons).

D

D

= Mass of HFC–23 fed into the destruction device 

annually (metric tons).

23

(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:

= Mass of HFC–23 destroyed annually (metric 

tons).

Where:

D23

F

= Mass of HFC–23 destroyed annually (metric 

tons).

D

DE = Destruction Efficiency of the destruction 

device (fraction).

= Mass of HFC–23 fed into the destruction device 

annually (metric tons).
Page 8 of 20

These requirements apply to measurements that are reported 

under this subpart or that are used to estimate reported 

quantities pursuant to §98.153.

§ 98.154 Monitoring and QA/QC requirements.

(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.

(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.

, gas chromatography) with an 

accuracy and precision of 5 percent or better at the 

concentrations of the process samples.

(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 
Page 9 of 20

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 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 
Page 10 of 20

least weekly using equipment and methods (e.g.

(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.

, 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.

(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.

(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 (hi) of this section.
Page 11 of 20

(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 HFC–23 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 HFC–23 shall be determined. The sensitivity of 

the concentration measurement shall be sufficient to detect an 
Page 12 of 20

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 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.
Page 13 of 20

(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.

(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 

, 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 destroyed.
Page 14 of 20

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 NISTtraceable standards and suitable methods published by a 

consensus standards organization (e.g.

(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.

, 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.

(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 

(

§ 98.155 Procedures for estimating missing data.

e.g., if a meter malfunctions during unit operation or if a 

required process sample is not taken), a substitute data value 
Page 15 of 20

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 
Page 16 of 20

the production rate and the mass flow rate into the destruction 

device.

(a) In addition to the information required by §98.3(c), 

the HCFC–22 production facility shall report the following 

information at the facility level:

§ 98.156 Data reporting requirements.

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

(2) Loss Factor used to account for the loss of HCFC– 22 

upstream of the measurement.

(3) Annual mass of reactants fed into the process in metric 

tons of reactant.

(4) The mass (in metric tons) of materials other than HCFC–

22 and HFC–23 (i.e.

(5) The method for tracking startups, shutdowns, and 

malfunctions and HFC–23 generation/emissions during these 

events.

, unreacted reactants, HCl and other byproducts) that occur in more than trace concentrations and that 

are permanently removed from the process.

(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) Annual mass of the HFC–23 generated in metric tons.

(8) Annual mass of any HFC–23 sent off site for sale in 

metric tons.
Page 17 of 20

(9) Annual mass of any HFC–23 sent off site for destruction 

in metric tons.

(10) Mass of HFC–23 in storage at the beginning and end of 

the year, in metric tons.

(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) Annual mass of HFC–23 fed into the destruction device.

(2) Annual mass of HFC–23 destroyed.

(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 the detection limit of the 

measuring device, report the detection limit and that the 

concentration is below the detection limit.
Page 18 of 20

(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 revised destruction efficiency 

calculated under §98.154(l) and the values used to calculate it, 

specifying whether §98.154(l)(1) or §98.154(l)(2) has been used 

for the calculation. Specifically, the facility shall report the 

following:

(1) Flow rate of HFC–23 being fed into the destruction 

device in kg/hr.

(2) Concentration (mass fraction) of HFC–23 at the outlet 

of the destruction device.

(3) Flow rate at the outlet of the destruction device in 

kg/hr.

(4) Emission rate (in kg/hr) calculated from paragraphs 

(d)(2) and (d)(3) of this section.

(5) Destruction efficiency (DE) calculated from paragraphs 

(d)(1) and (d)(4) of this section.

(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) Destruction efficiency (DE).

(2) The methods used to determine destruction efficiency.
Page 19 of 20

(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.

(a) In addition to the data required by §98.3(g), HCFC–22 

production facilities shall retain the following records:

§ 98.157 Records that must be retained.

(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 

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).
Page 20 of 20

(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).

All terms used in this subpart have the same meaning given 

in the Clean Air Act and subpart A of this part.

§ 98.158 Definitions.

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