Tillman® Fire Resistant FR7A® & Split Cowhide FR Cotton Split Leg Bib Apron. 9 oz, green flame resistant bib apron. 24” x 48”. Made from flame resistant, 100% cotton Westex® FR7A®. 9 oz flame resistant 100% cotton fabric meets ASTM D6413-10. ASTM D6413-10 is used to determine a pass/fail criteria for ASTM F1506, which requires a maximum char length of 6 inches.