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April 4 , 2012

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

109 T

. W

. Alexander Drive Research Triangle Park, NC 27711

RE: Supplemental Mineral Wool Comments

Dear Ms. Fairchild :

Pursuant to our recent telephone conversation, this letter and attachments supplement t he North

American Insulation Manufacturers Association ’s (“NAIMA”) previous comments (Febru ary 3, 2012) . Set forth herein are additional subcategorization options for carbonyl sulfide (“COS”), hydrochloric acid (“HCl”), and hydrogen fluoride (“HF”) ; a recommendation for adoption of work practices as an alternative to HF and HCl limits; and an a lternative calculation method for

HF and HCl

.

Subcategory Option

NAIMA urges EPA to consider subcategorizing the industry based on “open top” cupolas and “closed top” cupolas. Open top cupolas are different in that the mineral charge is inserted at the top of the cupola rather than the side. “Open top” is a process distinction differing from the other mineral wool cupolas. In addition, the open top cupolas are exposed to the environmental elements; when it rains or snows, the moisture goes throu gh the top. Based on these differences, NAIMA recommends the following subcategories:

“Open Top” Cupolas

• Amerrock

– Nolanville, Texas

• Rock Wool Manufacturing

– Leeds, Alabama

“Closed Top” Cupolas

• IIG

– Phenix City, Alabama

• Isolatek International

– Hunti ngton, Indiana

• Thermafiber

– Wabash, Indiana

• USG

– Red Wing, Minnesota

• USG

– Walworth, WisconsinMs . Susan Fairchild April 4 , 2012 Page 2

S ubcategory Option

NAIMA urges EPA to consider subcategorizing the industry to reflect the diversity of the industry location in different USDA climate zones . The climate zone directly impacts the combustion process. Specifically, combustion performance is likely to be impacted by inlet air

temperature ; humidity; changes in geographic climates; and seasonal weather. 1 Based on these zones, NAIMA recommends t he following subcategories:

USDA Climate Zone 5a (Attachment)

• USG

– Red Wing, Minnesota

USDA Climate Zone 5b (Attachment s )

• USG

– Walworth, Wisconsin

• Thermafiber

– Wabash, Indiana

• Isolatek International

– Huntington, Indiana

USDA Climate Zone 8 a (Attachment s )

• IIG

– Phenix City, Alabama

• Amerrock

– Nolanville, Texas

USDA Climate Zone 7b (Attachment)

• Rock Wool Manufacturing

– Leeds, Alabama

S ubcategory O ption

NAIMA also urges EPA to subcategorize the industry based on unique fuels and raw materia ls. A different grade of coke is used by different facilities. Depending on the source of the slag, each batch of slag will possess unique attributes and constituents. Similarly, the t y pe of rock and the rock’s constituents will vary. In addition, the combination of rock and slag wool varies by facility depending upon available raw materials and the product being made. Under this approach, every facility has a singular and distinct combination of fuel and raw materials. Therefore, each facility c ould be placed in a separate subcategory based on unique fuels and raw

materials.

Work Practices Alternative

NAIMA recommends setting a work practice standard as a nother alternative approach for HF and HCl. Specifically, NAIMA recommends that instead of an e mission limit, since emissions are so low, a work practice standard or simply following the manufacturers recommended operations and maintenance (“O&M”) would adequately keep the HF and HCl limits low. EPA

1 M.C. Janus, G.A. Richards, M.J. Yip, and E.H . Robey, “Effect of Ambient Conditions and Fuel Composition on Combustion Stability,” Conference Proceedings of American Society of Mechanical Engineers/International Gas Turbine Institute Turbo Expo Meeting, 1997.Ms . Susan Fairchild April 4 , 2012 Page 3

does have authority to promulgate work practice s tandards as the court noted in the Brick MACT

case.

Alternative Statistical Method

Lastly, a statistician from one of the mineral wool companies has offered an alternative method

of calculation for HF and HCl . NAIMA forward s this to EPA for their consideration:

The output of this formula, using Z value of 4, is 0.31 for HF and 0.20 for HCl.

EPA is using:

This is the Chebychev rule:

This uses EPA ’s formula, but replaces the student’s t statistic at 99% with the Che bychev

statistic. You can make the UPL rise very quickly by adjusting the Z level.Ms . Susan Fairchild April 4 , 2012 Page 4

If EPA is interested in discussing this statistical formula , NAIMA can put the Agency in contact

with th e mineral wool representative who created it

.

Please do not hesitate to contact me if you have any questions.

Sincerely,

Angus E. Crane

Angus E. Crane Executive Vice President, General Counsel

Attachments

cc: Mr. Jeffrey A. Telander Sector Policies and Programs Division Metals and Minerals Group (D243

- 02)

Offi ce of Air Quality Planning and Standards U.S. Environmental Protection Agency

109 TW Alexander Drive Research Triangle Park, NC 27711

Mr. David Reeves

RTI International

P.O. Box 12194 Research Triangle Park, NC 27709