UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: May 5, 2011

SUBJECT: Technical Support Document – Commonwealth of Pennsylvania – Control of 

Nitrogen Oxides from Glass Melting Furnaces

/s/

FROM: Rose Quinto, Environmental Engineer

Office of Air Program Planning

TO: File

/s/

THRU: Cristina Fernandez, Associate Director

Office of Air Program Planning

A. BACKGROUND

On July 23, 2010, the Pennsylvania Department of Environmental Protection (PADEP) 

submitted a State Implementation Plan (SIP) revision pertaining to the control of nitrogen oxides 

(NOx) emissions from glass melting furnaces. The manufacturing process requires raw 

materials, such as sand, limestone, soda ash, scrap, and recycled glass, to be fed into a furnace 

where a temperature is maintained in the 2700° to 3100° Fahrenheit range. The raw materials 

then chemically react creating a molten material – glass. The reaction of nitrogen and oxygen in 

the furnace creates NOx emissions, of which NOx is a precursor of ozone. This SIP revision is 

based on the Ozone Transport Commission (OTC) control measure to reduce NOx emissions 

from glass melting furnaces. The OTC members include Pennsylvania, Connecticut, Delaware, 

Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, 

Vermont, Virginia, and the District of Columbia. The OTC was created under section 184 of the 

Clean Air Act (CAA) to establish regulatory programs to reduce ozone precursor emissions, 

which includes the reduction of NOx emissions from glass melting furnaces. 

B. STATE SUBMITTAL

The SIP revision adds definitions and terms to Title 25 of the Pennsylvania Code (25 Pa. Code) 

Chapter 121.1, relating to definitions, used in the substantive provisions of this SIP revision. The 

SIP revision adds a new regulation pertaining to the NOx emission standards in 25 Pa. Code

Chapter 129, Standards of Sources, Sections 129.301 through 129.310, Control of NOx 

Emissions from Glass Melting Furnaces. The SIP revision applies to an owner or operator of a 

glass melting furnace that emits or has the potential to emit NOx at a rate greater than 50 tons per 
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year in the Commonwealth of Pennsylvania, including the local air pollution control agencies in 

Philadelphia and Allegheny Counties. The purpose of the SIP revision is to annually limit the 

emissions of NOx from glass melting furnaces.

The following definitions and terms were added in 25 Pa. Code Section 121.1:

Blown glass – Glassware shaped by blowing air into a molten glass gather.

Cold shutdown – A cold repair or replacement of damaged or worn refractory parts of a glass 

melting furnace while the furnace does not contain molten glass.

Container glass – Glass manufactured by pressing, blowing in molds, drawing, rolling or casting 

which is used as a container.

Fiberglass – Material consisting of fine filaments of glass that are combined into yarn and woven 

or spun into fabrics, or that are used as reinforcement in other materials or in masses as thermal 

or as acoustical insulating product.

Flat glass – Glass produces by the float, sheet, rolled or plate glass process which is used in 

windows, windshields, tabletops or similar products.

Glass melting furnace – A unit comprising a refractory-lined vessel in which raw materials are 

charged and melted at high temperature to produce molten glass.

Idling – The operation of a glass furnace at less than 25% of the permitted production capacity or 

fuel use capacity as stated in the plan approval or operating permit. 

 

Permitted production capacity – The maximum pull rate as stated in the plan approval, operating 

permit or Title V permit. 

Pressed glass – Glassware formed by placing a blob of molten glass in a metal mold, then 

pressing it with a metal plunger or follower to form the inside shape. The resultant piece, termed 

“mold-pressed,” has an interior form independent of the exterior, in contrast to mold-blown 

glass, whose interior corresponds to the outer form.

Primary furnace combustion system – The burners in a glass melting furnace that are used during 

production of glass.

Pull rate – The amount of glass withdrawn from a glass melting furnace, expressed in short tons 

per day.

Shutdown – The period of time during which glass melting furnace is taken from an operational 

to a non-operational status by allowing it to cool down from its operating temperature to a cold or 
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ambient temperature as the fuel supply is turned off.

Start-up – The period of time, after initial construction, shutdown or cold shutdown, during a 

glass melting furnace is heated to stable operating temperature by the primary furnace 

combustion system, and systems and instrumentation are brought to stabilization. 

Summary of the SIP Revision

The SIP revision adds a new regulation in 25 Pa. Code Chapter 129, Control of NOx Emissions 

from Glass Melting Furnaces, Sections 129.301 – 129.310.

Section 129.301, relating to the purpose of the new regulation, annually limits the emissions of 

NOx from glass melting furnaces.

Section 129.302, relating to the applicability, specifies that the regulation applies to an owner or 

operator of a glass melting furnace that emits or has the potential to emit NOx at a rate greater 

than 50 tons per year.

Section 129.303 provides that the emission requirements do not apply during periods of start-up, 

shutdown, or idling if the owner or operator complies with the start-up, shutdown, and idling 

requirements. (See start-up, shutdown, and idling requirements in the PADEP SIP revision 

submittal – sections 129.305, 129.306, and 129.307, and page 5 of the attachment of EPA’s 

Start-up, Shutdown and Malfunction (SSM) Policy – Memorandum of Steven A. Herman and 

Robert Perciasepe, Policy of Excess Emissions During Malfunctions, Start-up and Shutdown, 

September 20, 1999). Owners and operators claiming the exemption shall notify PADEP or the 

local air pollution control agency within 24 hours after initiation of the operation for which the 

exemption is claimed. Additionally, the owner or operator of a glass melting furnace that is 

granted an exemption shall maintain operating records or documentation, or both necessary to 

support the claim for the exemption.

Section 129.304 provides that the owner of a glass melting furnace shall determine allowable 

NOx emissions by multiplying the tons of glass pulled by each of the furnace by: 4.0 pounds of 

NOx per ton of glass pulled for container glass furnaces; 7.0 pounds of NOx per ton of glass 

pulled for pressed or blown glass furnaces; 4.0 pounds of NOx per ton of glass pulled for 

fiberglass furnaces; 7.0 pounds of NOx per ton of glass pulled for flat glass furnaces; and 6.0 

pounds of NOx per ton of glass pulled for all other glass melting furnaces.

Furthermore, the owner or operator of a glass melting furnace shall comply with the allowable 

NOx emissions by January 1, 2012, unless a petition for an alternative emission limitation or 

compliance schedule is submitted, in writing, to PADEP or the local air pollution control agency

by January 1, 2012 and also approved in writing by PADEP or the local air pollution control 

agency.
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The SIP revision also provides a petition process for an alternative NOx emission limitation to 

the owner or operator of a glass melting furnace that demonstrates to PADEP’s satisfaction that it 

is economically or technologically infeasible to meet the established emission limitations in this 

SIP revision. An alternative NOx emission limitation approved by PADEP must be included in 

either a plan approval or an operating permit issued by PADEP or a permit issued by the local air 

pollution control agency. In addition, the SIP revision includes a petition process for an 

alternative compliance schedule if an owner or operator of a glass melting furnace demonstrates 

that compliance cannot be achieved by the January 1, 2012 compliance date.

Section 129.305, relating to start-up requirements, requires the owner or operator of a glass 

melting furnace to submit specific information requested by PADEP or the local air pollution 

control agencies information to assure proper operation of the furnace. The owner or operator of 

a glass melting furnace may submit a request for a start-up exemption in conjunction with the 

approval application, if required. The length of the start-up exemption should not exceed a finite 

number of days depending on the type of the furnace. PADEP or the local air pollution control 

agency shall approve start-up exemptions to the extent that the request identifies the control 

technologies or strategies to be used. Additionally, the owner or operator shall place the 

emission control system in operation as soon as technologically feasible during start-up to 

minimize emissions.

Section 129.306, relating to shutdown requirements, provides that the duration of glass melting 

furnace shutdown, as measured from the time the furnace operations drops below 25% of the 

permitted production capacity or fuel use capacity, to when all emissions from the furnace cease, 

should not exceed 20 days. The owner or operator of a glass melting furnace shall operate the 

emission control system whenever technically feasible, as approved by PADEP or the local air 

pollution control agency, during shutdown to minimize emissions.

Section129.307, relating to idling requirements, provides that the owner or operator of a glass 

melting furnace shall operate the emission control system whenever technically feasible, as 

approved by PADEP or the local air pollution control agency, during idling to minimize 

emissions. The NOx emissions during idling may not exceed the amount calculated using the 

following equation:

Pounds per day emission limit of NOx = (applicable NOx emission limit specified in the 

emission requirements, expressed in pounds per ton of glass produced) x (furnace permitted 

production capacity in tons of glass produced per day).

Section 129.308, relating to compliance determination, requires that the owner or operator of a 

glass melting furnace shall install, operate and maintain continuous emissions monitoring system 

(CEMS) for NOx and other monitoring systems to convert data to required reporting units in 

compliance with 25 Pa. Code Chapter 139, Subchapter C (relating to requirements for source 

monitoring for stationary sources) and calculate actual emissions using the CEMS data reported 
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to PADEP or the local air pollution control agency, no later than14 days prior to the compliance 

date. However, the owner or operator of a glass melting furnace may elect to install and operate 

an alternate NOx emissions monitoring system or method approved, in writing, by PADEP or the 

local air pollution control agency. Data invalidated under Chapter 139, Subchapter C will be

substituted with other values if approved by PADEP or the local air pollution control agency.

Section 129.309, relating to compliance demonstration, provides that the owner or operator of a 

glass melting furnace shall calculate and report to PADEP or the local air pollution control 

agencies on a quarterly basis, no later than 30 days after the end of the quarter, the CEMS data 

and glass production data used to show compliance with the allowable NOx emission limitations.

The glass production data must consist of the quantity of glass in tons pulled per day for each 

furnace. Compliance can be demonstrated on a furnace-by-furnace basis; facility-wide emission 

averaging basis; or a system-wide emissions averaging basis among glass melting furnaces under 

common control of the same owner or operator in the Commonwealth. The owner or operator of 

a glass melting furnace for which PADEP or the local air pollution control agency has granted 

approval to voluntarily opt into a market-based program may not demonstrate compliance on an 

emissions averaging basis. Moreover, an emission reduction obtained by emissions averaging to 

demonstrate compliance with the emission requirements in this SIP revision will not be 

considered surplus for emission reduction credit purposes.

Section 129.310, relating to recordkeeping, provides that the owner or operator of a glass melting 

furnace shall maintain records to demonstrate compliance. The records must include an 

operating log maintained for each glass melting furnace that includes, on a daily basis the 

following: the total hours of operation; the type and quantity of fuel used; and the quantity of 

glass pulled. In addition, the owner or operator of a glass melting furnace shall maintain records 

of the following: source tests and operating parameters established during the initial source test; 

and maintenance, repairs, malfunctions, idling, start-up and shutdown. The records will be 

maintained onsite for 5 years and shall be made available or submitted to PADEP or the local air 

pollution control agency upon request.

C. EPA EVALUATION

This regulation will reduce emissions of NOx from glass melting furnaces to reduce levels of 

ground-level ozone and fine particulate matter (PM2.5). Ground-level ozone is not directly

emitted by pollution sources, but is created as a result of a chemical reaction of NOx and volatile 

organic compounds (VOC) in the presence of light and heat. The reduction of NOx emissions 

will also help protect the public health and environment from high levels of PM2.5, of which NOx 

is a precursor component. The reduction of NOx emissions also reduces visibility impairment 

and acid deposition.
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D. CONCLUSIONS AND RECOMMENDED AGENCY ACTION

The regulation on the control of NOx emissions from glass melting furnaces adopted by the 

Commonwealth of Pennsylvania will result in the reduction of NOx emissions from glass 

melting furnaces and will help the Commonwealth in attaining compliance with the 8-hour ozone 

and PM2.5 national ambient air quality standards (NAAQS). EPA approval of the SIP revision is 

recommended.