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**VIA E -** **MAIL AND OVERNIGHT MAIL**  August 6 , 2014
Ms. Susan Fairchild Sector Policies and Programs Division Metals and Minerals Group (D243

- 02) Office of Air Quality

Planning and Standards U.S. Environmental Protection Agency 4930 Old Page Road Durham, NC 27703 RE: NAIMA’s Responses To EPA’s Questions

– Work Practices For Startup and Shutdown of Fiber Glass Furnaces Dear Ms. Fairchild: INTRODUCTION The North American Insulation Manufacturers Association (“NAIMA”) appreciates the opportunity

to provide work practices employed by f iber glass insulation manufacturers during startup and shutdown. As NAIMA stated in its written comments, emissions data are not available for startup and shutdown, and the work practices set forth herein provide a sound approach for reducing emissions during startup and shutdown for fiber gl ass furnaces. NAIMA and its members would be willing to elaborate or expand on the information set fort h herein. The work practices described herein reflect input from all of NAIMA’s fiber glass companies. The work practices and related information are organized herein by providing aggregated responses to four questions that were posed to member companies by NAIMA, as suggested by conversations with the Environmental Protection Agency (“EPA”). These work practices set forth herein may

not be used at all facilities. The work practices vary by company depending on the particular design of each facility ’s f urnace and emissions control equipment. Not all work practices are or could be employ ed at every

facility
. Because of the subtle proprietary differences in the same ty pes of furnaces operated by different manufacturers, NAIMA’s response to Question 1 sum marizes the operational practices of all of its members to achieve reduced emissions during startup and shutdown of their fiber glass insulation furnaces. NAIMA believes that additional specificity c an be obtained , where necessary, while protecting the proprietary differences in these furnaces
.Ms . Susan Fairchild

August 6 , 2014 Page 2 QUESTION 1 Question: “What work practices or housekeeping measures are used by f iber glass companies to keep particulate matter (“PM”) (including chrome) emissions low during startup and shutdown for the following furnace types? ”

 Oxy-Fuel : The only time s that an oxy- fuel furnace is started up are after : 1) its initial construction ; 2) it has been shut down and rebuilt at the end of its safe operating life ; or 3) it has been idled due to weakness in the market
. All oxy- fuel furnaces use only natural gas for startup and shutdown. P lease note that a ty pical life span of an oxy- fuel furnace is 6 to 10 ye ars. For startup, the following work practices are observed: 1. The furnace is slowly heated with external natural gas fired sources (heat

-up burners); the use of natural gas and slow heating process help to lower emissions. 2. During this initial heating, good combustion practices are followed to minimize emissions associated with the products of combustion. 3. After the furnace reaches a specific temperature , the dedicated furnace energy sources are initiated. 4. At the appropriate point during the startup process, glass cullet is introduced into the preheated furnace
. 5. The furnace emission control equipment is brought online at the appropriate time during the startup process , prior to introducing batch, to control emissions
. 6. As the control equipment is brought online, its operation is monitored to assure that it is operating within predetermined ranges that assure its proper operation. 7. When the furnace achieves the required steady state level of operation and control equipment is determined to be operating properly, the furnace exhaust gases are routed through the control device and batch raw materials are fed into the f urnace to achieve a normal glass level and operating parameters. For oxy- fuel furnace shutdowns, the following work practices are observed: 1. The introduction of glass raw material (batch) into the furnace is halted
. 2. The input energy

i s reduced to a level to keep the glass molten ; the lowered energy input reduces emissions. 3. Good combustion practices are maintained to minimize emissions associated with the products of combustion. 4. Emission control devices are taken offline when operating conditions permit or are required to preserve the control device. 5. The melter is drained. 6. Energy

to the furnace is discontinued and the furnace is allowed to cool.Ms . Susan Fairchild

August 6 , 2014 Page 3

 Air

- Gas : The only

time s that an air

- gas furnace is started up are : 1) after its initial construction or after it has been shut down ; 2) it has been rebuilt at the end of its safe operating life ; or 3) it has been idled due to weakness in the market . All air

- gas furnaces use only natural gas for startup and shutdown. Please note that the normal life span of an air

- gas furnace is 6 to 9 years. For startup, the following work practices are observed: 1. The furnace is slowly heated with natural gas fired sources. The use of natural gas and graduated increases in heat help to lower emissions. 2. During the initial heating process, good combustion practices are followed to minimize emissions associated with the products of combustion. 3. After the furnace reaches a specific temperature, glass cullet is introduced into the furnace. 4. The furnace emission control equipment is brought online at the appropriate time during the startup process , prior to introducing batch, to control emissions. 5. The control equipment is monitored to assure that it is operating within predetermined ranges that assure its proper operation. 6. When the furnace achieves the required steady state level of operation and control equipment is determined to be operating properly, batch raw materials are fed into the furnace to achieve a normal glass level and operation parameters. For shutdown, the following work practices are observed: 1. Introduction of glass raw material (batch) to the furnace is halted. 2. The input energy into the furnace is reduced to the level required to maintain the glass in a molten state to allow removal of as much of the glass as possible from the furnace. 3. Good combustion practices are maintained to minimize emissions associated with the products of combustion
. 4. Emission control devices are taken offline when operating conditions permit or are required to preserve the control device. Depending on the design, this may o ccur before or after the draining is complete. 5. The furnace is drained and all furnace power is shut off after the glass is finished draining. 6. Energy

to the furnace is discontinued and the furnace is allowed to cool.

 Cold

- Top Electric : Because cold

-top electrics are all electric, there is no combustion. F or cold

-top electrics, furnace rebuilds are ty pically every 4 to 7 ye ars. C old

-top electric furnaces have inherently low PM and chromium emissions. Typ ically, the only time s that a cold

-top furnace is started up are after : 1) its initial construction ; 2) it has been shut down and rebuilt at the end of its safe operating life ; or 3) it has been idled due to weakness in the market
. All cold

-top furnaces are electrically heated exc ept during a portion of the startup process prior to batch introduction
.Ms . Susan Fairchild

August 6 , 2014 Page 4 For startup, the following work practices are observed: 1. Temporary

gas burners are used to slowly heat up the furnace to a specific temperature and operating state. 2. Good combustion practices are followed to minimize emissions associated with the products of combustion. 3. Plant cullet (glass previously produced at the plant) is fed into the furnace to be re melted; use of this ty

pe of cullet lowers melting temperature requirements and helps to reduce emissions. 4. Electric heating replaces the temporary gas startup heaters as the sole source of energy for the furnace. 5. When required operating conditions are achieved, batch is fed into the furnace and a crust or cover is established over the molten glass. 6. Emission control equipment is turned on at the appropriate time depending on the ty pe of control equipment being used and is monitored to assure that it is operating within predetermined ranges that assure its proper operation. Ty pically, a batch cover must be established to get the inlet to the control device below the maximum safe operating temperature of the control device. For furnace shutdowns, the following work practices are observed: 1. Glass raw material (batch) introduction to the furnace is halted
. 2. The input energy

is reduced to a level to keep the glass molten
. 3. Emission control devices are taken offline when operating conditions permit or are required to preserve the control device. Depending on the design, this may b e before or after draining is complete. 4. The furnace is drained
. 5. The furnace electrode power is shut off. 6. Temporary

gas burners are engaged to facilitate the removal of the remaining molten glass from the furnace. 7. Good c ombustion practices are followed to minimize emissions associated with the products of combustion. 8. Energy

to the furnace is discontinued and the furnace is allowed to cool.

 Steel

- Shell Melters : The only time s that a steel

- shell melter is started up are after : 1) its initial construction ; 2) after it has been shut down and rebuilt at the end of its safe operating life ; or 3) it has been idled due to weakness in the market
. All steel

- shell melters are electrically

heated except possibly during part of the startup process. All steel

- shell melters operate on electricity, so emissions are inherently lower; this is a clean fuel as a heat source. P lease note that the order of steps described for steel

- shell melters may vary for each manufacturer. For startup, the following work practices are observed:Ms . Susan Fairchild

August 6 , 2014 Page 5
1. In some facilities, temporary gas burners are used to slowly heat up the furnace to a specific temperature and operating state. In other facilities, the startup begins with electrical power. 2. Good combustion practices are followed to minimize emissions associated with the products of combustion. 3. Plant cullet (glass previously produced at the plant) is fed into the furnace to be re melted ; use of this ty

pe of cullet lowers melting temperature requirements and help s to reduce emissions. 4. Electric heating replaces the temporary gas startup heaters as the sole source of energy for the furnace. 5. Emission control equipment is turned on at the appropriate time depending on the ty pe of control equipment being used and is monitored to assure that it is operating within predetermined ranges that assure its proper operation. Ty pically, a batch cover must be established to get the inlet to the control device below the maximum safe operating temperature of the control device. 6. When required operating conditions are achieved, batch is fed into the furnace and a crust or cover is established over the molten glass. For furnace shutdowns, the following work practices are observed: 1. The introduction of glass raw material (batch) into the furnace is halted. 2. The input energy into the furnace is reduced to the level required to maintain the glass in a molten state to allow removal of as much of the glass as possible from the furnace. 3. Emission control devices are taken offline when operating conditions permit or are required to preserve the control device , which may b e before or after the energy is discontinued and the unit is drained, depending on design. 4. Energy

to the furnace is discontinued and the furnace is allowed to cool. QUESTION 2 Question: “Based on this statement from NAIMA’s comments

– ‘emissions of some

pollutants likely

are higher during the startup period than at normal steady

- state operations, and emission of other pollutants likely are lower
. . .’ (see NAIMA’s February 3 , 2012 comments to EPA on p. 57)

– EPA believes that there may b e variations in emissions from fiber gl ass plants during startup and shutdown. If variations occur, are the variations attributable to furnace ty pe? What other factors might explain variations?” NAIMA agrees that emissions of some pollutants likely are higher during the startup period than at normal steady

state operations, and emissions of other pollutants likely are lower. NAIMA also agrees that emissions from fiber glass plants during startup and shutdown vary f rom plant to plant just as they

do during normal steady state operation and that although some of those variations are attributable to the different furnaces used in the various plants that there are otherMs . Susan Fairchild

August 6 , 2014 Page 6
reasons for those differences in emissions. See NAIMA’s c omments on behalf of the Wool Fiber Glass Manufacturers regarding EPA’s Proposed Rule National Emissions Standards for Hazardous Air Pollutants: Mineral Wool Production and Wool Fiberglass Manufacturing, dated February 3, 2012, p ages 57
- 58. Other factors that likely contribute to those differences in emissions are:

 Differences in the proprietary design and construction of the furnace.  Differences and variations in the batch materials and the sources of those batch materials.  Dif ferences in the emission control equipment used at the plants and variations in operating parameters
.  Differences in how the furnaces are operated. QUESTION 3 Question: “How are emissions monitored during startup and shutdown? What issues might

be detected during monitoring? D oes the monitoring inform you about specific actions that need to be taken to modify the emissions?” For all furnace ty

pes, there is no direct, formal monitoring of actual emissions from the furnace during all phases of startup and shutdown
. Emissions testing using prescribed testing protocols cannot be conducted during startup and shutdown because of the unique operating conditions present during those times. Inf act, EPA standard reference methods only allow for performance te sting to be conducted during steady state operations, which do not exist during startup and shutdown. During periods of startup and shutdown, when control equipment is operational, the control equipment is monitored to determine that it is operating normally. At times when control equipment is not operating or cannot be relied upon because of the nuances of the startup and shutdown process, the manufacturers have come to rely upon operating procedures and work practices that have been developed over the years that appear to produce fewer emissions than others that have been tried. The items identified in response to Question 1 are representative of those work practices and procedures that experience has identified as things that reduce emissions during startup and shutdown. Specific examples of monitoring include:

 Fuel/oxygen ratios are monitored to ensure good combustion practices are followed.  Normal operating parameters of both the furnace and control device are monitored.  Baghouse inlet temperature would be monitored to determine the point at which to start the fan, as would differential pressure across the baghouse.  Generally, the same procedure in reverse would be followed on shutdown.  Monitoring conducted pursuant to specific permit requirements.Ms . Susan Fairchild

August 6 , 2014 Page 7 QUESTION 4 Question: “What measures (work practices or housekeeping measures) are undertaken by

companies to make certain that emissions levels are maintained throughout the startup and shutdown period?” Inaddition to the answers set forth above for e ach furnace ty pe in Question 1, these additional work practices are also relevant:

 Follow startup and shutdown checklists specific to the particular furnace
.  C leaning and maintaining of all emissions control equipment according to manufacturers’ recommendations
.  Routine observation of working equipment to assure proper function of emissions control equipment.  Raw material quality is monitored via certificates of analysis when received from outside vendors by company employees. If you have any questions, p lease do not hesitate to contact me. Sincerely,
Angus E. Crane Executive Vice President, General Counsel
cc: Mr. Keith W. Barnett Group Leader, Office of Air Quality and Planning Standards Sector Policies and Programs Division, Mineral and Manufacturing Group U.S. Environmental Protection Agency 4930 Old Page Road Durham, NC 27703