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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 
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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.

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
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(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.

(iv) Use Equation N–1 of this section to calculate process 

mass emissions of CO2 for each furnace:

Where:
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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 carbonate-based 

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).

ECO2 i = Annual CO2 emissions from glass melting furnace i 

(metric tons).

k = Number of continuous glass melting furnaces.

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

(General Stationary Fuel Combustion Sources) the combustion CO2
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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) 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
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Combustion of Coal and Coke by Inductively Coupled Plasma—Atomic 

Emission Spectrometry (incorporated by reference, see §98.7).

(c) You must determine the annual average mass fraction for 

the carbonate-based mineral in each carbonate-based raw material 

by calculating an arithmetic average of the monthly data 

obtained from raw material suppliers or sampling and chemical 

analysis.

(d) 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. 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 carbonatebased raw materials charged to any continuous glass melting 
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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 carbonatebased minerals in the carbonate-based 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.

(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), 
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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 each continuous glass melting furnace and for 

all furnaces combined.

(3) Annual quantity of glass produced (tons) from each 

continuous glass melting furnace and from all furnaces combined.

(4) Carbonate-based mineral decimal mass fraction for each 

carbonate-based raw material charged to a continuous glass 

melting furnace.

(5) Results of all tests 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.

(iii) Mass fraction of each sample analyzed.

(6) 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.

(7) Method used to determine decimal fraction of

calcination.
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(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 carbonatebased 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), (b), and (c) 

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).
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(2) Monthly amount of each carbonate-based raw material 

charged to each continuous glass melting furnace (metric tons).

(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.

(4) Results of all tests 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.
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§ 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

aEmission factors in units of metric tons of CO2 emitted per metric ton of 

carbonate-based raw material charged to the furnace.