30 CFR Part 57Public Domain
§ 57.8535 — Seals
Subpart G — Ventilation
Seals shall be provided with a means for checking the quality of air behind the seal and a means to prevent a water head from developing unless the seal is designed to impound water.
Public Domain: 30 CFR Part 57 (MSHA Safety and Health Standards — Underground Metal and Nonmetal Mines) is a U.S. government publication and is not subject to copyright. Text extracted from the official source ↗. Figures are served from the eCFR; if one does not load, use the link in its place.