30 CFR § 57.11052 Refuge areas.
Refuge areas shall be--
(a) Of fire-resistant construction, preferably in untimbered areas of
the mine; (b) Large enough to accommodate readily the normal number of persons
in the particular area of the mine; (c) Constructed so they can be made gastight; and (d) Provided with compressed air lines, waterlines, suitable
handtools, and stopping materials.