30 CFR § 57.22207 Booster fans (I-A, II-A, III, and V-A mines).
(a) Booster fans shall be approved by MSHA under the applicable
requirements of 30 CFR part 18, and be
(1) Provided with an automatic signal device located so
that it can be seen or heard by a person designated by the mine operator to
give an alarm when the fan stops or when methane reaches the following
(a)(1)(i) 1.0 percent at the fan in Subcategory I-A, Category
III, and Subcategory V-A mines; and
(a)(1)(ii) 0.5 percent at the fan in Subcategory II-A
(2) Equipped with a device that automatically
deenergizes power in affected workings should the fan stop; and
(3) Equipped with starting and stopping controls located
at the fan and at another accessible remote location.
(b) Booster fan installations, except for booster fans installed in
ducts, shall be--
(1) Provided with doors which open automatically when all
fans in the installation stop; and
(2) Provided with an air lock when passage through the fan
bulkhead is necessary.