TM 5-810-15
(9) Safety escapes. Conveyors will include
percentage of fines during the handling, conveying
means of egress that comply with all applicable
and stockpiling process, thus causing particles to
codes. In no case will the distance from any
become airborne, creating a more dusty
location on the conveyor to a safety escape to
environment. Coal dust can impair the operation of
grade level exceed 200 feet.
coal conveying equipment and create an unhealthy
(10) Carbon dioxide, or steam protection
working environment which increases the risk of
should be considered for bunkers, bins and silos. A
fires and explosions. Methane detectors and a vent
method of transporting coal from a silo to a remote
system should be installed in coal storage
yard area in the event of a fire will be considered in
enclosures to reduce danger of explosion.
the design.
(2) Conveyor fires are usually started by fric-
(11) There are numerous types of fire detec-
tion between seized idlers and the conveyor belt,
tion sensors and detectors such as heat, continuous
seized bearings or improperly aligned or maintained
thermal sensor, fixed temperature spot sensor,
equipment. If a fire on a conveyor should occur,
fusible thermal wire, pneumatic rate of rise, series
the conveyor, the upstream and downstream
thermal detector, smoke detectors, ionization de-
conveyors, auxiliary feed equipment such as crush-
tectors, flame, ultraviolet, infrared and numerous
ers and dust collectors must all be stopped immedi-
others. There is no single, all purpose sensor or
ately.
detector for a fire protection system and a well
b. Design. The following items will be given
designed system usually requires a wide range of
consideration when designing a conveyor fire pro-
sensors for maximum system protection. Matching
tection system:
the specific type and configuration of the detector
(1) An automatic wet or dry pipe sprinkler
or sensor to a particular hazard is very difficult and
system should be installed along conveyors, to
a professional fire protection systems engineer who
protect the carrying and return belts, conveyor
has experience with the design and operation of
drives, underground tunnels and control areas.
coal handling fire protection systems should be
(2) Automatic deluge systems require large
consulted.
flow rates to protect the conveyor and the
conveyor galleries. The water supply system will be
5-25.
Control system.
investigated to see if it can support the required
a. General. Control of the individual conveying
flow rates when a fire protection system is
system operations should be conducted from a
determined to be necessary.
single control room. The following items should be
(3) Adequate means of removing fire protec-
considered:
tion water from below grade tunnels must be
(1) The control system will be capable of
provided to ensure that personnel can be evacuated
providing a local manual, remote manual or fully
before a hazardous water build up occurs.
automatic control of the conveying system.
(4) A dry pipe or preaction type system,
(2) Conveyor controls will be interlocked to
which employ a fusible link or glass bulb sprinkler
prevent coal spills in the event of a system
heads, are usually used in areas that are subject to
malfunction and to shut the conveying systems
freezing conditions. This type of system is the more
down in a set sequence. The controls will provide
popular type of fire protection system.
a foolproof sequential method of starting and stop-
(5) A wet pipe system, which is basically the
ping upstream and downstream equipment in the
same as dry pipe, except that water is in the system
conveying system.
piping at all times, is usually suitable for areas not
(3) A locked remote control panel will be
subject to freezing.
located next to each piece of equipment they
(6) A fire detection and evacuation alarm
control, so that the equipment can be locally
system will be provided throughout all facilities
operated by maintenance personnel. Local panels
with pull stations at all exterior exits and sufficient
will be interlocked with main control panel so that
evacuation alarms to overcome the normally higher
both panels cannot be operated at the same time.
level of noise found in power plants. The fire
(4) Each system will be adequately
detection and evacuation alarms will give indication
monitored with alarm and control devices so that
in main and auxiliary control roams and into the
the operating status of the system can be
plant main fire alarm system.
determined from indicating lights on the control
(7) Adequate fire hydrant protection will be
room graphic or mimic display panel.
provided for all coal piles and consideration will be
(5) Indicating lights will be provided on a
given to the long term methods of coal pile storage
separate annunciator panel for belt misalignment,
to minimize spontaneous combustion.
plugged chute, drive motor overload, emergency
(8) Draft barriers or fire walls will be pro-
stop, zero speed, or any other safety device. The
vided at each end of conveyor galleries.
5-16
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