30 CFR § 75.1107-4 Automatic fire sensors and manual actuators; installation; minimum requirements.
(a)(1) Where fire suppression devices are installed on unattended
underground equipment, one or more point-type sensors or equivalent shall be
installed for each 50 square feet of top surface area, or fraction thereof,
of such equipment, and each sensor shall be designed to activate the first
suppression system and disconnect the electrical power source to the
equipment protected, and, except where sprinklers are used, there shall be
in addition, a manual actuator installed to operate the system. Where
sprinklers are used, provision shall be made for manual application of water
to the protected equipment in lieu of a manual actuator.
(2) Two or more manual actuators, where practicable, shall
be installed, as provided in paragraphs (a)(2)(i) and (ii) of this section,
to activate fire suppression devices on attended equipment purchased on or
after the effective date of this §75.1107-4. At least one manual actuator
shall be used on equipment purchased prior to the effective date of this
(i) Manual actuators installed on attended equipment
regularly operated by a miner, as provided in §75.1107-1(c)(1) shall be
located at different locations on the equipment, and at least one manual
actuator shall be located within easy reach of the operator's normal
(ii) Manual actuators to activate fire suppression
devices on attended equipment not regularly operated by a miner, as provided
in §75.1107-1(c)(2), shall be installed at
different location, and at least one manual actuator shall be installed so as
to be easily reached by the miner at the jobsite or by persons approaching
(b) Sensors shall, where practicable, be installed in accordance with
the recommendations set forth in National Fire Code No. 72A "Local Protective
Signaling Systems" (NFPA No. 72A-1967).
(c) On unattended equipment the fire suppression device shall operate
independently of the power to the main motor (or equivalent) so it will
remain operative if the circuit breakers (or other protective device)
actuates. On attended equipment powered through a trailing cable the fire
suppression device shall operate independently of the electrical power
provided by the cable.
(d) Point-type sensors (such as thermocouple, bimetallic strip, or
rate of temperature rise) located in ventilated passageways shall be
installed downwind from the equipment to be protected.
(e) Sensor systems shall include a device or method for determining
their operative condition.