Section 233. Line brattice.
(a) General rule.--Substantially constructed line brattice shall be used from the last open crosscut of an entry or room when necessary or required by the department to provide adequate ventilation for the workmen and to remove gases and explosive fumes. When damaged by falls or otherwise, line brattice shall be repaired promptly.
(b) Spacing.--The space between the line brattice and the rib shall be large enough to permit the flow of a sufficient volume of air to keep the working face clear of flammable and noxious gases.
(c) Construction material.--Brattice cloth used underground shall be constructed of approved flame-resistant material.