Page 1 of 9

Subpart N—Glass Production

§98.140 Definition of the source category.

(a) A glass manufacturing facility manufactures flat glass, container glass, pressed and 

blown glass, or wool fiberglass by melting a mixture of raw materials to produce molten glass 

and form the molten glass into sheets, containers, fibers, or other shapes. A glass manufacturing 

facility uses one or more continuous glass melting furnaces to produce glass.

(b) A glass melting furnace that is an experimental furnace or a research and development 

process unit is not subject to this subpart.

§98.141 Reporting threshold.

You must report GHG emissions under this subpart if your facility contains a glass 

production process and the facility meets the requirements of either §98.2(a)(1) or (2).

§98.142 GHGs to report.

You must report:

(a) CO2 process emissions from each continuous glass melting furnace.

(b) CO2 combustion emissions from each continuous glass melting furnace.

(c) CH4 and N2O combustion emissions from each continuous glass melting furnace. You 

must calculate and report these emissions under subpart C of this part (General Stationary Fuel 

Combustion Sources) by following the requirements of subpart C.

(d) CO2, CH4, and N2O emissions from each stationary fuel combustion unit other than 

continuous glass melting furnaces. You must report these emissions under subpart C of this part 

(General Stationary Fuel Combustion Sources) by following the requirements of subpart C.

§98.143 Calculating GHG emissions.
Page 2 of 9

You must calculate and report the annual process CO2 emissions from each continuous 

glass melting furnace using the procedure in paragraphs (a) through (c) of this section.

(a) For each continuous glass melting furnace that meets the conditions specified in 

§98.33(b)(4)(ii) or (iii), you must calculate and report under this subpart the combined process 

and combustion CO2 emissions by operating and maintaining a CEMS to measure CO2 emissions 

according to the Tier 4 Calculation Methodology specified in §98.33(a)(4) and all associated 

requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources).

(b) For each continuous glass melting furnace that is not subject to the requirements in 

paragraph (a) of this section, calculate and report the process and combustion CO2 emissions 

from the glass melting furnace by using either the procedure in paragraph (b)(1) of this section or 

the procedure in paragraph (b)(2) of this section, except as specified in paragraph (c) of this 

section.

(1) Calculate and report under this subpart the combined process and combustion CO2

emissions by operating and maintaining a CEMS to measure CO2 emissions according to the Tier 

4 Calculation Methodology specified in §98.33(a)(4) and all associated requirements for Tier 4 

in subpart C of this part (General Stationary Fuel Combustion Sources).

(2) Calculate and report the process and combustion CO2 emissions separately using the 

procedures specified in paragraphs (b)(2)(i) through (b)(2)(vi) of this section.

(i) For each carbonate-based raw material charged to the furnace, obtain from the supplier 

of the raw material the carbonate-based mineral mass fraction.

(ii) Determine the quantity of each carbonate-based raw material charged to the furnace.

(iii) Apply the appropriate emission factor for each carbonate-based raw material charged 

to the furnace, as shown in Table N-1 to this subpart.
Page 3 of 9

(iv) Use Equation N-1 of this section to calculate process mass emissions of CO2 for each 

furnace:

Where:

ECO2 = Process emissions of CO2 from the furnace (metric tons).

n = Number of carbonate-based raw materials charged to furnace.

MFi = Annual average decimal mass fraction of carbonate-based mineral i in carbonatebased raw material i.

Mi = Annual amount of carbonate-based raw material i charged to furnace (tons).

2000/2205 = Conversion factor to convert tons to metric tons.

EFi = Emission factor for carbonate-based raw material i (metric ton CO2 per metric ton 

carbonate-based raw material as shown in Table N-1 to this subpart).

Fi = Decimal fraction of calcination achieved for carbonate-based raw material i, assumed 

to be equal to 1.0.

(v) You must calculate the total process CO2 emissions from continuous glass melting 

furnaces at the facility using Equation N-2 of this section:

Where:

CO2 = Annual process CO2 emissions from glass manufacturing facility (metric tons).

ECO2i = Annual CO2 emissions from glass melting furnace i (metric tons).

k = Number of continuous glass melting furnaces.
Page 4 of 9

(vi) Calculate and report under subpart C of this part (General Stationary Fuel 

Combustion Sources) the combustion CO2 emissions in the glass furnace according to the 

applicable requirements in subpart C.

(c) As an alternative to data provided by the raw material supplier, a value of 1.0 can be 

used for the mass fraction (MFi) of carbonate-based mineral i in Equation N-1 of this section.

§98.144 Monitoring and QA/QC requirements.

(a) You must measure annual amounts of carbonate-based raw materials charged to each 

continuous glass melting furnace from monthly measurements using plant instruments used for 

accounting purposes, such as calibrated scales or weigh hoppers. Total annual mass charged to 

glass melting furnaces at the facility shall be compared to records of raw material purchases for 

the year.

(b) Unless you use the default value of 1.0, you must measure carbonate-based mineral 

mass fractions at least annually to verify the mass fraction data provided by the supplier of the 

raw material; such measurements shall be based on sampling and chemical analysis using 

consensus standards that specify X-ray fluorescence. For measurements made in years prior to 

the emissions reporting year 2014, you may also use ASTM D3682-01 (Reapproved 2006) 

Standard Test Method for Major and Minor Elements in Combustion Residues from Coal 

Utilization Processes (incorporated by reference, see §98.7) or ASTM D6349-09 Standard Test 

Method for Determination of Major and Minor Elements in Coal, Coke, and Solid Residues from 

Combustion of Coal and Coke by Inductively Coupled Plasma—Atomic Emission Spectrometry

(incorporated by reference, see § 98.7).

(c) Unless you use the default value of 1.0, you must determine the annual average mass 

fraction for the carbonate-based mineral in each carbonate-based raw material by calculating an 
Page 5 of 9

arithmetic average of the monthly data obtained from raw material suppliers or sampling and 

chemical analysis.

(d) Unless you use the default value of 1.0, you must determine on an annual basis the 

calcination fraction for each carbonate consumed based on sampling and chemical analysis using 

an industry consensus standard. If performed, this chemical analysis must be conducted using an 

x-ray fluorescence test or other enhanced testing method published by an industry consensus 

standards organization (e.g., ASTM, ASME, API, etc.).

§98.145 Procedures for estimating missing data.

A complete record of all measured parameters used in the GHG emissions calculations is 

required (e.g., carbonate raw materials consumed, etc.). If the monitoring and quality assurance 

procedures in §98.144 cannot be followed and data is missing, you must use the most appropriate 

of the missing data procedures in paragraphs (a) and (b) of this section. You must document and 

keep records of the procedures used for all such missing value estimates.

(a) For missing data on the monthly amounts of carbonate-based raw materials charged to 

any continuous glass melting furnace use the best available estimate(s) of the parameter(s), based 

on all available process data or data used for accounting purposes, such as purchase records.

(b) For missing data on the mass fractions of carbonate-based minerals in the carbonatebased raw materials assume that the mass fraction of each carbonate based mineral is 1.0.

§ 98.146 Data reporting requirements.

In addition to the information required by § 98.3(c), each annual report must contain the 

information specified in paragraphs (a) and (b) of this section, as applicable.
Page 6 of 9

(a) If a CEMS is used to measure CO2 emissions, then you must report under this subpart 

the relevant information required under § 98.36 for the Tier 4 Calculation Methodology and the 

following information specified in paragraphs (a)(1) and (2) of this section:

(1) Annual quantity of each carbonate-based raw material charged to each continuous 

glass melting furnace and for all furnaces combined (tons).

(2) Annual quantity of glass produced by each glass melting furnace and by all furnaces 

combined (tons).

(b) If a CEMS is not used to determine CO2 emissions from continuous glass melting 

furnaces, and process CO2 emissions are calculated according to the procedures specified in § 

98.143(b), then you must report the following information as specified in paragraphs (b)(1) 

through (b)(9) of this section:

(1) Annual process emissions of CO2 (metric tons) for each continuous glass melting 

furnace and for all furnaces combined.

(2) Annual quantity of each carbonate-based raw material charged (tons) to all furnaces 

combined.

(3) Annual quantity of glass produced (tons) from each continuous glass melting furnace 

and from all furnaces combined.

(4) Reserved.

(5) Results of all tests, if applicable, used to verify the carbonate-based mineral mass 

fraction for each carbonate-based raw material charged to a continuous glass melting furnace, as 

specified in paragraphs (b)(5)(i) through (b)(5)(iii) of this section.

(i) Date of test.

(ii) Method(s) and any variations used in the analyses.
Page 7 of 9

(iii) Mass fraction of each sample analyzed.

(6) Reserved.

(7) Method used to determine decimal fraction of calcination, unless you used the default 

value of 1.0.

(8) Total number of continuous glass melting furnaces.

(9) The number of times in the reporting year that missing data procedures were followed 

to measure monthly quantities of carbonate-based raw materials or mass fraction of the 

carbonate-based minerals for any continuous glass melting furnace (months).

§ 98.147 Records that must be retained.

In addition to the information required by § 98.3(g), you must retain the records listed in 

paragraphs (a) through (d) of this section.

(a) If a CEMS is used to measure emissions, then you must retain the records required 

under § 98.37 for the Tier 4 Calculation Methodology and the following information specified in 

paragraphs (a)(1) and (a)(2) of this section:

(1) Monthly glass production rate for each continuous glass melting furnace (tons).

(2) Monthly amount of each carbonate-based raw material charged to each continuous 

glass melting furnace (tons).

(b) If process CO2 emissions are calculated according to the procedures specified in § 

98.143(b), you must retain the records in paragraphs (b)(1) through (b)(5) of this section.

(1) Monthly glass production rate for each continuous glass melting furnace (metric 

tons).

(2) Monthly amount of each carbonate-based raw material charged to each continuous 

glass melting furnace (metric tons).
Page 8 of 9

(3) Data on carbonate-based mineral mass fractions provided by the raw material supplier 

for all raw materials consumed annually and included in calculating process emissions in 

Equation N-1 of this subpart, if applicable.

(4) Results of all tests, if applicable, used to verify the carbonate-based mineral mass 

fraction for each carbonate-based raw material charged to a continuous glass melting furnace, 

including the data specified in paragraphs (b)(4)(i) through (b)(4)(v) of this section.

(i) Date of test.

(ii) Method(s), and any variations of the methods, used in the analyses.

(iii) Mass fraction of each sample analyzed.

(iv) Relevant calibration data for the instrument(s) used in the analyses.

(v) Name and address of laboratory that conducted the tests.

(5) The decimal fraction of calcination achieved for each carbonate-based raw material, if 

a value other than 1.0 is used to calculate process mass emissions of CO2.

(c) All other documentation used to support the reported GHG emissions.

(d) 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 (d)(1) 

through (3) of this section. Retention of this file satisfies the recordkeeping requirement for the 

data in paragraphs (d)(1) through (3) of this section.

(1) Annual average decimal mass fraction of carbonate-based mineral in each carbonatebased raw material for each continuous glass melting furnace (specify the default value, if used, 

or the value determined according to § 98.144) (percentage, expressed as a decimal) (Equation 

N-1 of § 98.143).
Page 9 of 9

(2) Annual amount of each carbonate-based raw material charged to each continuous 

glass melting furnace (tons) (Equation N-1).

(3) Decimal fraction of calcination achieved for each carbonate-based raw material for 

each continuous glass melting furnace (specify the default value, if used, or the value determined 

according to § 98.144) (percentage, expressed as a decimal) (Equation N-1).

§98.148 Definitions.

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

subpart A of this part.

Table N-1 to Subpart N of Part 98—CO2 Emission Factors for Carbonate-Based Raw 

Materials

Carbonate-based

raw material—mineral CO2 emission factora

Limestone—CaCO3 0.440

Dolomite—CaMg(CO3)2 0.477

Sodium carbonate/soda ash—Na2CO3 0.415

Barium carbonate—BaCO3 0.223

Potassium carbonate—K2CO3 0.318

Lithium carbonate (Li2CO3) 0.596

Strontium carbonate (SrCO3) 0.298

a

Emission factors in units of metric tons of CO2 emitted per metric ton of carbonate-based raw 

material charged to the furnace.