|
Constellation Energy is the oldest gas utility and one
of the earliest electric utilities in the country.
The company today serves more than a million
electric customers and half a million natural gas
customers in a 2,300 square mile area of central
Maryland.
At Brandon Shores, the newest of their ten power
plants, some 20,000 feet of coal conveyors are
protected against fire by a detection system that
guards every inch of every belt.
Click to enlarge.
"We were looking for something extra
reliable," says Bill Deterer, Constellation's
Senior Insurance & Loss Consultant. "Conventional smoke and fire
detectors are okay for spot detection but simply
don't provide the inch-by-inch coverage we wanted."
Deterer found what he was looking for in protection
systems manufactured by The Protectowire Co., Inc.
in Plymouth, Massachusetts. Ideally suited for
conveyor belt installations where the moving belts
can lead to the rapid spread of fire, Protectowire
systems consist of heat-detecting cable that detects
fire or overheat conditions at any point along its
length and signals the location of the condition to
a fire control station.
|
At the Brandon Shores plant, should
fire strike, the system senses the rise in
temperature, shuts down the conveyor belt, and
activates a deluge sprinkler system to quench the
flames. A signal is also simultaneously transmitted
to the central fire control station in the main
plant to alert firefighting personnel.
"We have a plant here that occupies up to 365 acres,
with approximately 160 different fire detection and
suppression systems. The control panel in the main
fire control station not only receives signals from
the system protecting our coal conveyor but also
from our other detection systems of various types
throughout the plant complex. A large Annunciator
panel equipped with zone lights and marker plates
indicates where the fire is actually located."
The heart of the system, the heat-detection cables
themselves, consist of two current -carrying wires
separated by heat-sensitive insulation. At Brandon
Shores, the cables are installed in the area between
the idlers and the rollers and supported by
messenger wire.
Click to enlarge.
The total system includes control
panels, power supplies, deluge valve controls, alarm
initiating devices, alarm indicating devices,
conduit, wire, fittings and all accessories required
to provide a complete operating system.
|
In addition, automatic smoke
detectors of the ionization type are installed for
area protection. Designed to initiate the fire alarm
detection loop upon detecting products of
combustion, they are compatible with the Linear Heat
Detectors and other normally open detection loop
devices.
Standby batteries supply system power in the event
of power failure and are designed to operate the
entire system, including supervision, for a minimum
period of 24 hours. All function automatically
switch back to the regular power supply when AC
power returns.
Fire in a typical coal conveyor is usually caused by
friction due to belt slippage, bearing problems,
static electricity, welding, or spontaneous
combustion. Due to the relatively severe environment
in coal conveyors, fire detection systems used in
such applications must be engineered for this type
of service. The Protectowire Linear Heat Detectors
at Brandon Shores meet these requirements. They are
specifically engineered to withstand abrasive coal
dust, moisture, and highly corrosive atmospheres.
The detection system proved itself two years ago
when welding operation on a conveyor triggered a
blaze in a coal conveyor transfer tower that, had it
spread, could have caused well over a million
dollars in damage. Extinguishing action was
immediate and monetary losses were held to less than
$10,000.
Today, in addition to coal conveyors, Constellation
Energy also
protects transformers and cooling towers with
Protectowire Systems, and further installations are
completed or under way at the companies C.P. Crane
power station also located in Baltimore. |
