(Adopted: 08/27/07; Amended: 01/28/08; Amended: 08/25/08) 

MDAQMD Rule 1165 1165-1

Glass Melting Furnaces 

Rule 1165 

Glass Melting Furnaces 

(A) General 

(1) Purpose 

(a) The purpose of this rule is to limit the emissions of oxides of nitrogen 

(NOX), carbon monoxide (CO), volatile organic compounds (VOCs), and 

oxides of sulfur (SOX) from glass melting furnaces. 

(2) Applicability 

(a) This rule shall apply to any glass melting furnace. 

(3) Exemptions 

The provisions of this rule shall not apply to: 

(a) Except for section (D)(2)(a), the provisions of this rule shall not apply to 

electric glass melting furnaces where all the heat is supplied by an electric 

current from electrodes submerged in the molten glass, except that other 

fuels for startup may supply heat when the furnace contains no molten 

glass. 

(b) Except for section (D)(2)(a), the provisions of this rule shall not apply to 

any glass melting furnace that is designed to produce less than 4.55 Mg 

(5 tons) of glass per day. 

(c) The provisions of this rule shall not apply to hand glass melting furnaces. 

(d) The emission limits in Section (C)(1) Table 1 shall not apply during 

periods of startup, shutdown, or idling, provided the owner/operator 

complies with the applicable requirements of Section (C)(3), (C)(4), 

(C)(5), and (E)(3). 

(B) Definitions 

For the purpose of this rule the following definitions shall apply: 

(1) Air-Fuel Firing – Operation of a glass melting furnace where greater than 50 

percent of the oxidant for the fuel comes from ambient air. 100 percent air-fuel 

fired means operation of a glass melting furnace where the oxidant is exclusively 

ambient air. 
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(2) Block 24-hour Average – The arithmetic average of the hourly NOX emission 

rates of a furnace as measured over 24 one-hour periods, daily, from 12:00 a.m. to 

11:59 p.m., excluding periods of system calibration. 

(3) California Air Resources Board (CARB) – The California Air Resources Board, 

the powers and duties of which are described in Part 2 of Division 26 of the 

California Health & Safety Code (commencing with section 39500). 

(4) Container Glass – Any glass manufactured by pressing, blowing in molds, 

drawing, rolling, or casting which is used as a container as listed in Standard 

Industrial Classification 3221 (SIC 3221). 

(5) Fiberglass – Material consisting of fine filaments of glass that are combined in 

yarn and woven or spun into fabrics, or that are used as reinforcement in other 

materials or in masses as thermal or acoustical insulating products for the 

construction industry. 

(6) Flat Glass – Any continuous flat glass sheets produced by the float, sheet, rolled, 

or plate glass process, which is used in windows, windshields, tabletops, or similar 

products listed in SIC 3211. 

(7) Furnace Rebuild – A cold repair that is commenced after the end of a furnace 

campaign period or expected life cycle of a furnace. 

(8) Glass Melting Furnace – A unit comprising a refractory vessel in which raw 

materials are charged, melted at high temperature, refined, and conditioned to 

produce molten glass. The unit includes foundations, superstructures and 

retaining walls, raw material charger systems, heat exchangers, melter cooling 

system, exhaust system, refractory brick work, fuel supply and electrical boosting 

equipment, integral control systems and instrumentation, and appendages for 

conditioning and distributing molten glass to forming apparatuses. The forming 

apparatuses, including the float bath used in flat glass manufacturing and flow 

channels in fiberglass manufacturing, are not considered part of the glass melting 

furnace. 

(9) Hand Glass Melting Furnace – A glass melting furnace where the molten glass is 

removed from the furnace by a glassworker using a blowpipe or a pontil. 

(10) Idling – The operation of a furnace at less than 25 percent of the permitted glass 

production capacity or fuel use capacity as stated on the District permit. 

(11) Liquefied Petroleum Gas (LPG) –A general term for any of the following gasses: 

commercial propane, commercial butane, propane-butane (PB) mixtures, and 

special duty propane. 

(12) Oxygen-Assisted Combustion – Operation of a glass melting furnace where the 

oxidant is greater than the oxygen content in the ambient air or greater than 20.9 

percent oxygen. 
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Glass Melting Furnaces 

(13) Oxy-Fuel Fired – Operation of a glass melting furnace where greater than 50 

percent of the oxidant for the fuel is provided from enriched oxygen streams. 

(14) Permitted Glass Production Capacity – The maximum pull rate as stated in the 

District permit. 

(15) Primary Furnace Combustion System – The burners in a furnace that are used 

during the production of glass. 

(16) PUC-Quality Natural Gas – A gaseous fuel that meets the requirements specified 

in California Public Utilities Commission (PUC) General Order 58-A. PUCquality natural gas also means that the sulfur content is no more than one-fourth 

grain of hydrogen sulfide per 100 standard cubic feet and no more than five grains 

total sulfur per 100 standard cubic feet. 

(17) Pull Rate – The amount of glass coming out of a glass melting furnace, expressed 

in short tons per day. 

(18) Rolling 30-day Average – The arithmetic average of the daily emission rates of a 

furnace over a contiguous 30-day period, excluding periods of system calibration. 

(19) Shutdown – The period of time during which a glass melting furnace is taken from 

operational to non-operational status by allowing it to cool down from its 

operating temperature to a cold or ambient temperature as the fuel supply is turned 

off. 

(20) Startup – The period of time, after initial construction or a furnace rebuild, during 

which a glass melting furnace is heated to operating temperature by the primary 

furnace combustion system, and systems and instrumentation are brought to 

stabilization. 

(21) United States Environmental Protection Agency (USEPA) – The United States 

Environmental Protection Agency, the Administrator of the USEPA and his or her 

authorized representative. 

(22) Volatile Organic Compound (VOC) – Any volatile compound of carbon, 

excluding methane, carbon monoxide, carbon dioxide, carbonic acid, metallic 

carbides or carbonates, ammonium carbonate, and those compounds listed in 40 

CFR 51.100(s)(1). 

(C) Requirements 

(1) Except as specified in section (A)(3)(d), the owner/operator of any glass melting 

furnace shall not operate a furnace in such a manner that results in NOX, CO, or 

VOC emissions exceeding the limits in Table 1. 
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Glass Melting Furnaces 

Table 1 

NOX, CO, and VOC Emission Limits

Type of Furnace Combustion 

Type NOX CO VOC 

100% AirFuel Fired 4.0 lb/ton of glass pulled on 

a block 24-hour average 300 ppmv 20 ppmv 

Container Glass or 

Fiberglass Oxygen 

Assisted 

Combustion 

4.0 lb/ton of glass pulled on 

a block 24-hour average 

1.0 lb/ton of 

glass pulled 

0.25 lb/ton of 

glass pulled 

100% AirFuel Fired 

9.2 lb/ton of glass pulled on 

a block 24 hour average 

and

7.0 lb/ton of glass pulled on 

a rolling 30-day average 

300 ppmv 20 ppmv 

Flat Glass 

Oxygen 

Assisted 

Combustion 

9.2 lb/ton of glass pulled on 

a block 24 hour average 

and

7.0 lb/ton of glass pulled on 

a rolling 30-day average 

0.9 lb/ton of 

glass pulled 

0.1 lb/ton of 

glass pulled 

(2) All glass melting furnaces subject to Table 1 emission limits shall limit SOX by: 

(a) Firing PUC-quality natural gas, propane, or LPG. 

(b) Liquid fuel may be used as a backup fuel or standby fuel provided the 

liquid fuel contains no more than 15 ppm sulfur and the furnace exhaust is 

controlled by a SOX emission control system with a control efficiency of 

50 percent or greater. 

(3) Startup Requirements 

(a) The owner/operator shall submit a request for a startup exemption to the 

APCO, CARB, and the USEPA in conjunction with or in advance of an 

application for Authority to Construct (ATC) associated with a furnace 

rebuild. 

(b) The owner/operator shall submit to the APCO, CARB, and the USEPA 

any information deemed necessary by the APCO, CARB, or the USEPA 

to determine the appropriate length of startup exemption. This 

information shall include, but is not limited to: 
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Glass Melting Furnaces 

(i) A detailed list of activities to be performed during startup, and a 

reasonable explanation for the length of time needed to complete 

each activity; and 

(ii) A description of the material process flow rates, system operating 

parameters, etc., that the owner/operator plans to evaluate during 

the process of optimization; and 

(iii) Clearly identified control technologies or strategies to be 

employed; and 

(iv) Explicit description of what physical conditions prevail during 

startup periods that prevent the controls from being effective; and 

(v) Reasonably precise estimate as to when physical conditions will 

have reached a state that allows for the effective control of 

emissions. 

(c) Startup exemptions shall begin upon activation of the primary combustion 

system. 

(d) The actual length of the startup exemption shall be determined by the 

APCO, CARB and USEPA at the time of the Authority to Construct 

(ATC) issuance, but in any case, it shall not exceed the amount of time 

specified in Table 2. The approval for the startup exemption shall be in 

writing from each agency. 

Table 2 

Maximum Startup Time

Column I Column II 

Type of Furnace Maximum Startup 

NOX control system 

that meets section 

(C)(3)(d)(i) provisions 

Maximum Startup 

NOX control system 

that does not meet 

section (C)(3)(d)(i) 

provisions 

Container glass 100 days 70 days 

Fiber glass 105 days 40 days 

Flat glass 208 days 104 days 

(i) Maximum startup time for Table 2, Column I, must have a NOX

control system that meets one or more of the following conditions: 

a. Is innovative, 

b. Is not in common use, 

c. Is not readily available from a commercial supplier, 

d. Is funded as original research by a public agency. 
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Glass Melting Furnaces 

(ii) Maximum startup time for those furnaces with NOX controls that 

do not meet any of the conditions in section (C)(3)(d)(i) shall 

comply with startup times in Table 2, Column II. 

(e) During the startup period, the stoichiometric ratio of the primary furnace 

combustion system shall not exceed five percent excess oxygen, as 

calculated from the actual fuel and oxidant flow measurements for 

combustion in the glass melting furnace. 

(f) The emission control system shall be in operation as soon as 

technologically feasible during startup to minimize emissions. 

(g) Notifications shall be performed and records shall be kept in accordance 

with section (D)(2). 

(4) Shutdown Requirements 

(a) The duration of shutdown, as measured from the time the furnace 

operations drop below the idle threshold as specified in section (B)(10) to 

when all emissions from the furnace cease, shall not exceed 20 days. 

(i) The emission control system shall be in operation whenever 

technologically feasible during shutdown to minimize emissions. 

(ii) Notifications shall be performed and records kept in accordance 

with section (D)(2). 

(5) Idling Requirements 

(a) The emission control system shall be in operation whenever 

technologically feasible during idling to minimize emissions. 

(b) The NOX, CO, and VOC emission during idling shall not exceed the 

amount calculated by multiplying the applicable emission limit of NOX, 

VOC, or CO in pounds per ton of glass produced by the furnace permitted 

production capacity in tons of glass produced per day. 

(c) Notifications shall be performed and records kept in accordance with 

section (D)(2). 

(6) Compliance Determination 

(a) The emissions measured for compliance with NOX, CO, and VOC limits 

shall be averaged over a three hour period in accordance with the 

applicable test methods in section (E)(1), or, if a Continuous Emission 

Monitoring System (CEMS) or an alternate emission monitoring method 

is used, the applicable requirements of sections (E)(2)(a) or (E)(2)(b), 

respectively. 
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Glass Melting Furnaces 

(b) Any source testing result, CEMS, or alternate emission monitoring 

method averaged value exceeding the applicable emission limits in section 

(C)(1) shall constitute a violation of the rule. Any rolling 30-day 

averaged value from CEMS or alternate emission monitoring method that 

exceeds the applicable emission limit in (C)(1) shall constitute a violation 

of the rule for each day of the averaged period. 

(7) The owner/operator of any glass melting furnace shall implement a NOX CEMS or 

a NOX alternative emissions monitoring method on each furnace, that is approved 

in writing by the APCO, CARB, and USEPA, and that meets the requirements of 

section (E)(2). 

(D) Monitoring and Records 

(1) Administrative Requirements 

(a) Permitted Glass Production Capacity and Fuel Use Capacity 

Each permit to operate for a glass melting furnace shall specify a 

maximum daily glass production limit (units of tons of glass pulled per 

day) and maximum furnace heat input limit (MMBtu/hr) consistent with 

compliance with this rule.

(2) Operations Records 

(a) The owner/operator of any glass melting furnace subject to section (C) or 

claiming exemption under section (A)(3) of this rule shall maintain an 

operating log for each furnace that includes, on a daily basis: 

(i) Total hours of operation; 

(ii) Type of fuel used in each furnace; 

(iii) Quantity of fuel used by each furnace, and the quantity of glass 

pulled by each furnace; 

(iv) NOX emission rate in lb/ton of glass pulled. 

(3) The Owner/Operator shall maintain records of source tests and operating 

parameters established during initial source test, maintenance, repair, and 

malfunction. 

(4) The Owner/Operator shall maintain all records required by this rule for five-years, 

and shall produce those records for inspection by the APCO or his designee upon 

request. 

(5) Compliance Source Testing 

(a) Each glass melting furnace shall be source tested at least once every 

calendar year, but not more than once every 18 months and not sooner 

than every six months to demonstrate compliance with the applicable 

requirements of section (C). 
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(b) Source test conditions shall be representative of normal operations, but 

not less than 60 percent of either the maximum glass production capacity 

or the furnace’s maximum fuel use capacity for each furnace, whichever 

limit is stated in the PTO. 

(c) For source testing performed in accordance with section (D)(5)(a), the 

arithmetic average of three 30-consecutive-minute test runs shall apply. If 

two of the three runs individually demonstrate emissions above the 

applicable limit, the test cannot be used to demonstrate compliance for the 

furnace, even if the averaged emissions of all three test runs is less than 

the applicable limit. 

(E) Compliance Procedures and Test methods

(1) Test Methods 

(a) Oxides of Nitrogen – EPA Method 7E, EPA Method 19, or CARB 

Method 100. 

(b) Carbon monoxide (ppmv) – EPA Method 10, or CARB Method 100 

(c) Volatile Organic Compound (ppmv) – EPA Method 25A expressed in 

terms of carbon. EPA Test Method 18 or CARB Method 422 shall be 

used to determine emissions of exempt compounds. 

(d) Stack gas oxygen, carbon dioxide, excess air, and dry molecular weight – 

EPA Method 3 or 3A, or CARB Method 100. 

(e) Stack gas velocity and volumetric flow rate – EPA Method 2. 

(f) The SOX emission control system efficiency shall be determined using the 

following: 

(i) EPA Method 2 for measuring flow rates; and 

(ii) EPA Method 6C or EPA Method 8 for measuring total SOX

(expressed as SO2) concentrations at the inlet and outlet of the 

control device. 

(g) Alternative Test Methods 

(i) Other test methods demonstrated to provide results that are 

acceptable for purposes of determining compliance with any 

provisions of this rule may also be used after review and approval 

in writing by the District, CARB and USEPA. 

(2) Emissions Monitoring Systems 

(a) An approved CEMS shall comply with the most recently adopted version 

of all of the following requirements: 
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Glass Melting Furnaces 

(i) 40 CFR Part 51; 

(ii) 40 CFR Part 60.7; 

(iii) 40 CFR Part 60.13; 

(iv) 40 CFR Part 60 Appendix B (Performance specifications); 

(v) 40 CFR Part 60 Appendix F (Quality Assurance Procedures; and 

(b) Any approved alternate emission monitoring method pursuant to the 

provisions of (E)(2)(a) above shall be capable of determining the furnace 

emissions on an hourly basis and shall comply with the following 

requirements: 

(i) 40 CFR 64 (Compliance Assurance Monitoring); and 

(ii) 40 CFR 60.13 (Monitoring Requirements). 

(3) Notifications and Records for Startup, Shutdown, and Idling 

(a) The owner/operator of any glass melting furnace claiming an exemption 

under section (A)(3)(c) shall notify the APCO by telephone at least 24 

hours before initiating idling, shutdown, or startup. This notification shall 

include: 

(i) Date and time of the start of the exempt operation; and 

(ii) Reason for performing the operation; and 

(iii) An estimated completion date. 

(b) The owner/operator shall notify the APCO by telephone within 24 hours 

after completion of the idling, shutdown, or startup. 

(c) The owner/operator claiming exemption under section (A)(3)(d) shall 

maintain all operating records and support documentation necessary to 

support claim of exemption, and shall meet the following requirements: 

(i) The records and support documentation shall be retained on-site 

for five years; and 

(ii) The records and support documentation shall be made available to 

the APCO, CARB, or USEPA during normal business hours; and 

(iii) The records and support documentation shall be submitted to the 

APCO, CARB, or USEPA upon request. 

(4) Records for Exempt Furnaces 

(a) An owner/operator claiming exemption under section (A)(3)(a) or section 

(A)(3)(b) shall maintain records and documentation necessary to support 

claim of exemption. 

(b) Records and support documentation specified in section (E)(4)(a) shall 

meet the following requirements: 

(i) The records and support documentation shall be retained on-site 

for five years; and 
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(ii) The records and support documentation shall be made available to 

the APCO, CARB, or USEPA during normal business hours; and 

(iii) The records and support documentation shall be submitted to the 

APCO, CARB, or USEPA upon request. 

(5) Calculation Methods 

(a) The pollutant emission rate in ppmv shall be converted to lb/hr by using 

the appropriate conversion equations in ARB Method 100, EPA Method 

19, or an equivalent conversion method approved, in writing, by the 

APCO, CARB, and the USEPA. The mass emission rate in lb/hr shall be 

converted to lb/ton of glass pulled according to the following equation: 

pull rate in tons/hr

lb/hr of pollutant lbs of pollutant ton of glass pulled =

(b) 100 percent air-fuel fired furnaces that have concentration limits in ppmv 

values shall be subject to the CO and VOC emission limits specified in 

section (C)(1). These limits are referenced at dry stack gas conditions and 

8.0 percent by volume of stack oxygen. The CO and VOC emission 

concentrations shall be corrected to 8.0 percent oxygen by using the 

equation below, or an equivalent correction method that is approved, in 

writing, by the APCO, CARB, and the USEPA. 

( ) ( ) x ( ) ppmv CO

20.9% %O

12.9%

ppmv CO measured

measured

corrected − 2

=

( ) ( ) x ( ) ppmv VOC

20.9% %O

12.9%

ppmv VOC measured

measured

corrected − 2

=

(c) The owner/operator of a oxy-fuel fired furnace, oxygen-assisted 

combustion furnace, or a furnace utilizing any fuel oxidants other than 

100 percent ambient air, shall submit to the APCO, CARB, and USEPA 

for approval any methodologies and data that will be used to calculate 

emission rates for NOX, CO, and VOC if the methods are different than 

specified in section (E)(5)(a) or (E)(5)(b). Unless the owner/operator 

received prior written approval from the APCO, CARB, and USEPA of 

all the calculation methods to be used that are different than specified in 

(E)(5)(a) or (E)(5)(b), compliance with the emission limits cannot be fully 

demonstrated, and it shall be deemed to be a violation of this rule. 

(F) Violations 

(1) Failure to comply with any provision of this rule shall constitute a violation of the 

rule. 

(2) A violation of the limits contained in this rule as determined by any one of these 

test methods shall constitute a violation of this rule. 
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Glass Melting Furnaces 

(3) When one or more test method or set of test methods are specified for any testing, 

a violation of any requirement of this rule established by any one of the specified 

test methods or set of test methods shall constitute a violation of the rule. 

[SIP: Submitted as amended 08/25/08 on mm/dd/yy] 
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