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Two of the largest steel producers
in Asia have recently selected Protectowire Linear
Heat Detection Systems for protecting cable trays
from overheat and fire throughout their massive
production facilities.
In Korea, Pohang Iron and Steel Corporation (POSCO)
is the worlds largest steel maker with over a 28
million-ton annual production capacity. With two
facilities, in Pohang City in the east and Kwangyang
City in the west, POSCO has committed to putting
peoples concerns and safety over its own private
interests by installing cable tray fire detection
products from the world's largest manufacturer and
supplier of linear heat detection systems.
The initial system installed at Pohang City, a
1,112-hectare (2,747 acre) facility, is divided into
4 separate substations with each substation
monitoring 34 detection zones of Protectowire linear
heat detection cable at 1,525 meters (5,000 feet)
per zone. Each substation contains one Protectowire
FS2000 control panel with digital display for
monitoring the 51,850 meters (170,000 feet) of
sensor. Output from each substation to a Central
Control room is via RS 232 C serial port in the
FS2000 panel. In total, 207,740 meters (680,000
feet) of Protectowire linear heat detection cable is
installed to detect the earliest occurrence of an
overheat or fire in cable trays. Similar systems are
installed in the Kwangyang facility with the initial
installation protecting 62,788 meters (205,997 feet
) of cable trays.
Boasteel in Shanghai, China is another Asian steel
giant with deep concerns about fire and personnel
safety at their manufacturing plants. After an
exhaustive search of the available fire detection
technologies throughout the world, Boasteel
engineers selected the Protectowire Linear Heat
Detection System for cable tray installations in
their hot mill and rolling mill production
facilities.
Click to enlarge.
A typical hot/cold rolling mill has
literally miles and miles of cable trays carrying
power, data and communication cables. Fire in a
cable tray from short- circuited, overloaded or
aging cable would be catastrophic in terms of the
economic loss due to a shutdown.
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The early warning, fast response of
Protectowire's linear heat detector when used in
direct contact with or in close proximity to a
suspected source of overheat makes it the most
suitable means of fire detection available for cable
trays.
Click to enlarge.
The initial system installation at
Boasteel was a cold rolling mill with nearly 300,000
meters (984,250 feet) of cable trays to protect. The
system is configured using six (6) Protectowire
FS2000 control panels with 46 zones of monitoring
for each panel.
Click to enlarge.
Each monitored zone has 1,066 meters
(3,500 feet) of Protectowire linear heat detector
installed in horizontal, vertical and stacked trays.
The 276 detection zones of cable trays required 294
kilometers (183 miles) of linear heat detector to be
installed in this one mill. Boasteel currently has 6
other similar mills with Protectowire systems
installed.
Click to enlarge.
The installation of Protectowire
linear heat detection cable in cable trays requires
a thorough examination and overview of the area
where trays are located. Many trays are stacked
vertically, have risers, drops and reversed
directions and with varying widths. After
determining the length and widths of various trays,
a plan view is developed so the installation is
configured as follows:
Linear heat detection cable shall be installed in
cable trays in a sinusoidal pattern across the tray
in a continuous loop. Maximum cable length shall not
exceed 3,500 feet (1,066 meters) per zone when using
an FS2000 control panel or 5,000 feet (1,525 meters)
when using a 2600 HD control panel. The total amount
of linear heat detection cable per tray is
determined by the width of the tray and a multiplier
calculated specifically for the width of the tray.
Refer to Protectowire
data sheet # 7877
for correct multiplier to use.
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Each zone shall terminate in a
junction box with an appropriate value of
end-of-line resistor. A separate route shall Be
given to each cable run at any one junction box. At
50 ft. intervals along the detector cable from the
start of
the zone, the side of the cable tray shall be
labeled by the field personnel.
Each label shall identify a reference point, the
detector zone, distance from start of the zone, and
appropriate junction box number from which the
measurement began. Labels should be located so as to
easily read in attempting to locate a fault in the
detector cable.
When detection cable goes from one tray to
another, the detector shall not be routed through
holes in the bottom of the tray. Routing may be
up/down the outside of the tray and shall be
supported and kept next to the tray using
appropriate cable tray clips specified by The
Protectowire Company. Care must be taken so that a
minimum bend radius of at not less than 3 inches is
maintained throughout the detector installation.
When the detection cable must be returned or
doubled back through the same tray, it shall be
de-sensitized (spliced to a copper pair cable )and
routed a straight line with a copper paired
conductor. It shall be fastened/tye-wrapped at a
maximum of 1.5m (5 ft.) intervals and at all changes
of elevation or direction of the tray. In any event,
the cable must follow the contour of electric cables
in the tray at the point where the return begins.
The loop resistance of the detection cable measured
from the beginning of the zone at the junction box
will be 20 ohms per 31m (100 feet) of conductor pair
when loop is operative (no faults) , and
considerably less when in alarm
(shorted).
The detection cable shall be loaded onto and fed
from a wire reel as it is field installed. This will
prevent the spring tension of the detector cable
from unraveling the bundle. Detection cable is
supplied in 500 foot (152 meter) coils or 2,500 foot
(762 meter) spools.
Steel producers with Protectowire cable tray
systems installed:
Wuhan Steel Company, China
Baosteel, China
China Steel Corp, China
National Steel Corporation, Phillipines
POSCO, Korea
Bilbao Steel, Spain
CSN, Volta Redonda, Brazil
Bethlehem Steel Corp.
U.S. Steel Corp.
Armco Steel Corp.
Republic Steel Corp.
Inland Steel Co.
Sharon Steel Corp.
Jones & Laughlin Steel Corp.
Lone Star Steel Co.
Granite City Steel Div., National Steel Corp.
Crucible Steel Div., Colt Ind. Canada, Ltd.
Wheeling Pittsburgh Steel Corp.
Georgetown Steel Corp.
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