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Unvented |
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The temperature rise in a building without fire ventilation
is over three times the temperature rise in a building with
fire venting, and where fire venting is absent, the temperature
exceeds that at which structural steelwork will distort and
buckle.
When floor areas are large there is a rapid lateral fire spread
in an unvented building. The hot gases from a fire which involves
only part of the floor area of a building rise to the ceiling
and form a layer; this layer of hot gases will build down
to the floor level and obstruct the seat of the fire.
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Vented |
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No Smoke Logging:
By releasing the heat, smoke and the general products of combustion,
fire venting enables firemen to approach the source of the fire
and tackle it without breathing apparatus
No Explosion:
Fire venting quickly removes the partially burnt gases which
otherwise accumulate in the roofspace and present a danger of
explosion.
Reduces Lateral Spread of Fire:
By preventing heat from mushrooming over the fire area and heating
other materials to the point of ignition, fire venting has a
marked effect on reducing the lateral spread of the fire.
Reduced Roof Temperature:
Fire venting reduces the temperature in the roofspace well below
the softening temperature of structural steelwork.
Reduced Water Damage:
By applying water directly onto the fire, instead of generally
toward smoke logged areas fire venting reduces water damage. |
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| Ventilator Sizing |
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The proper size and quantity of fire ventilators
required is generally based on the occupancy class of the building
relating to the combustible nature of its contents. Listed below
are general classes of occupancy and recommended vent areas.
These are intended as a general guide only and deigners should
consult NFPA 204M or Western Canwell if specific questions arise.
- Low Heat Release Occupancy - Vent
area to floor area 1:150 - Includes building or portions
of buildings containing scattered small quantities of combustible
materials. Typical examples are metal stamping plants, machine
shops with dry machining and like operations, foundries,
breweries, dairy products processing plants, bakeries, meat
packing plants.
- Moderate Heat Release - Vent area
to floor area 1:100 - Includes buildings or portions
of buildings containing moderate quantities of combustible
materials which are fairly uniform. Typical examples are
automobile assembly plants, leather goods, printing and
publishing plants, machine shops using combustible oil coolants.
- High Heat Release Occupancy -
Vent area to floor 1:50 - Includes building or portions
of building containing either hazardous operations or concentrated
quantities of combustible materials of both. Typical examples
are painting departments, oil quenching departments, chemical
plants, paper mills, rubber products manufacturing plants,
chemical plants.
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| Standard Sizes |
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| Model No. |
Inside Dim. W x L |
Vent Area Sq. Ft. |
Net Wt. Lbs. |
| 250-44 |
48" x 48" |
16 |
345 |
| 250-45 |
48" x 60" |
20 |
380 |
| 250-46 |
48" x 72" |
24 |
415 |
| 250-47 |
48" x 84" |
28 |
450 |
| 250-48 |
48" x 96" |
32 |
485 |
| 250-55 |
60" x 60" |
25 |
425 |
| 250-56 |
60" x 72" |
30 |
465 |
| 250-57 |
60" x 84" |
35 |
520 |
| 250-58 |
60" x 96" |
40 |
540 |
| 250-66 |
72" x 72" |
36 |
525 |
| 250-67 |
72" x 84" |
42 |
545 |
| 250-68 |
72" x 96" |
48 |
565 |
| 250-69 |
72" x 108" |
54 |
590 |
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Impact Resistance
- extruded polycarbonate sheet is so tough it withstands the
impact of a 10 pound ball dropped 7 feet onto a 6mm thick sheet
without breakage. Extruded polycarbonate has 4 times the impact
resistance of modified acrylic, and maintains its properties
from minus 40 degrees F to 250 degrees F.
Energy Efficient - Extruded polycarbonate
channels trap air between walls, giving up to 40% greater energy
efficiency over traditional materials.
Skylights, Heat, and Smoke Venting
- Western series 250 Firex* with extruded polycarbonate doors
offers U.L. and FM approved Heat and Smoke ventilators with
the added advantage of skylights. The extruded polycarbonate
panels are translucent, high impact resistant, and energy efficient.
Extruded polycarbonate is one of the most cost effective glazing
materials on the market. Its light weight, rigidity, toughness
and long service life make it far superior to monolithic glazing
with acrylic, glass, or other mediums. Series 250 Fires* with
extruded polycarbonate doors are available in unit sizes the
same as standard Series 250 and can be constructed of steel
or aluminum.
High Light Transmission - Extruded
polycarbonate sheet has approximately 90% the light transmission
of monolithic glass.
Light Weight - Extruded polycarbonate
sheet is almost 7 times lighter than double walled glass, and
less than half that of modified acrylic.
Ultraviolet-Resistant - Extruded
polycarbonate resists weathering and resultant yellowing 3 times
longer than untreated polycarbonate.
*FIREX is a registered trademark of Western
Canwell, LLC |
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Automatic or Manual Operations
- Unit opens automatically by parting of listed fusible link.
Unit can also be manually opened from roof or floor level.
Pressure Operation
- Doors open automatically by explosion, resistance to internal
pressure is factory adjustable in a wide range or pressure is
factory adjustable in a wide range or pressures of 45 PSF. Travel
of door for automatic self-triggering device may pre-set for
hair-trigger operations.
Heat, Smoke, Explosion Vents
- The economical venting system for restricting fire from spreading,
extracting heat and smoke, relieving explosive pressures, and
providing access for fire fighters.
Western Series 300 Firex* ventilators can be constructed of
galvanized steel or aluminum and furnished in all sizes as the
250 Series. Like the 250 Series the 300 series may be furnished
with extruded polycarbonate doors or spliced into multiple unit
runs.
Weathertight
- Door mating surfaces are gasketed to prevent the entrance
of water in the severest winds and rain. Two double wall doors
have 1" laminated insulation between steel walls to protect
against condensation and heat loss when closed.
Operating Mechanism
- All pivots, bearings, and operating mechanisms are constructed
of non-corrosive detail.
*FIREX is a registered trademark of Western
Canwell, LLC |
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