"Specialized function coating" means, for purposes of 35 Ill. Adm. Code 219.204(r), a coating that fulfills extremely specific engineering requirements in aerospace applications that are limited in use and are characterized by low volume usage. This category excludes coatings covered in other specialty coating categories in 35 Ill. Adm. Code 219.204(r)(2).
Ill. Admin. Code tit. 35, § 211.6137