§57.22222 — Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines) Brattice cloth and ventilation tubing shall be approved by MSHA in accordance with 30 CFR part 7, or shall bear a BC or VT acceptance number issued by the MSHA Approval and Certification Center.
[54 FR 30508, July 20, 1989]