35 Ill. Adm. Code 211.3770
Metallic Shoe-Type Seal
Section 211
Section 211.3770 Metallic
Shoe-Type Seal
"Metallic shoe-type
seal" means a primary or secondary seal constructed of metal sheets
(shoes) which are joined together to form a ring, springs or levers which
attach the shoes to the floating roof and hold the shoes against the tank wall,
and a coated membrane which is suspended from the shoes to the floating roof.