§ 57.22221. Overcast and undercast construction (I-A, II-A, III, and V-A mines).
62 words·~1 min read·
/us/cfr/t30/s§ 57.22221·A research copy — for the controlling text, always check the official state or federal source. Not legal advice.
Overcasts and undercasts shall be---
(a)Of substantial construction; (b)(1) Constructed of noncombustible materials; or
(2)Where constructed of combustible materials, the outside surfaces shall be coated with at least one inch of construction plaster containing perlite and gypsum; at least one inch of expanded vermiculite, Portland cement and limestone; or other coatings with equivalent fire resistance;
(c)Kept clear of obstructions.