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Welcome
to the FAQ forum of our web site.
We will hopefully answer any or all of your questions about our
product line, however if the answer to your question is not offered here,
simply send us a note at info@firedetectiondevices.com
and we will respond no later than the next business day.
1.
What
is a THERMOFLEX heat detector? "THERMOFLEX" is the brand name for a series of automatic Heat Detectors that form an integral part of a Fire Alarm System. They are connected to a fire alarm panel as an Alarm Initiating Device in conjunction with other devices such as smoke detectors, flame detectors, pull stations and water flow switches.
The
THERMOFLEX heat detector
is designed to initiate an alarm condition if it detects a rate of
temperature increase of 15 Fahrenheit degrees (8.4 Celsius degrees) over
one minute, at the ceiling. This
is referred to as the "rate-of-rise" function.
The
unit will also initiate an alarm condition if the ceiling temperature
reaches a pre-determined temperature.
This is referred to as the "fixed temperature" function. The standard heat detector is the combination rate-of-rise and fixed temperature unit.
3.
How
Does the Rate-of-Rise function operate? The
air chamber of the unit is sealed, with the exception of a small orifice.
As the ceiling temperature increases, the expanding air trapped in
the chamber is allowed to escape through this orifice.
The rate at which the air escapes is governed by a calibrated
restrictor. If the temperature
increases at a rate of 15
Fahrenheit degrees (8.4 Celsius degrees) per minute, the air inside the
chamber expands faster than it can escape.
The increasing pressure inside the chamber begins to depress a thin
diaphragm which, in turn, pushes a contact against a fixed contact point.
This contact closure initiates a fire alarm condition.
4.
How
does the Fixed Temperature function operate? Every THERMOFLEX unit has a back-up device that provides for fail-safe operation. Should the ceiling temperature rise at a rate less than the prescribed rate, a spring-loaded plunger held in place by a special alloy, will release at a specific temperature. The plunger strikes the contacts and holds them closed. This contact closure initiates a fire alarm condition.
5.
What
is the standard Fixed Temperature setting? The
standard releasing temperature is 135 degrees F., or 57 degrees C.
6.
What
are the other Fixed Temperature settings? There
are many instances where ceiling temperatures are normally much higher
than usual, e.g. furnace and laundry rooms, paint shops and foundries.
THERMOFLEX offers three fusible settings that are higher than the standard
135 degrees Fahrenheit.
These are:
7.
What if the ceiling temperature fluctuates drastically, even under normal
conditions? In
some instances, rapid (yet
normal) temperature increases would cause the rate of rise portion of the
detector to operate, resulting in a false fire alarm.
Examples of this type of location are boiler rooms, janitor closets
with hot water sinks, kitchens, saunas, etc. For
these situations, the "Fixed Temperature Only" unit should be
used. In this unit, the rate
of rise function is disabled in such a way that the construction of the
thermostat is virtually unchanged. The expanding air is allowed to vent to
atmosphere, which prevents a pressure build-up in the air chamber. Although
Fixed Temperature Only units fulfill a specific need, as explained above,
they should be regarded as the exception to the rule, with the combination
rate-of-rise & fixed temperature unit considered as the standard
detector.
8.
What
sets the THERMOFLEX detector apart from the Competition? In
a word: reliability. As
a life safety device, it is extremely important that the THERMOFLEX
detector be designed and manufactured to maximize its ability to sense and
respond to a specific rate of temperature increase. This important
tracking capability must not change with time.
With the THERMOFLEX series, calibration
procedures at the time of manufacture ensure that repeated field testing
of the detector will not affect its capability to respond properly to a
temperature increase. The quality of a detector is determined by its
ability to maintain its calibrated settings over long periods of time
without "wandering". It
is a well-known fact that the THERMOFLEX line of heat detectors have
performed unfailingly in the North American market for over three decades,
and is the unit selected by alarm installers and electrical contractors
who are interested in supplying the most reliable heat detector in
safety-to-life situations. The
reason for this popularity is simple; the unit does not change its
operational characteristics over time but remains stable test after test,
year after year. There
is no "shelf life" for a properly installed THERMOFLEX heat
detector.
9.
How
does one identify the different types of units? Affixed
to the heat collecting fin are differently coloured, round dots that can
be seen from the floor.
The colour code for these dots is:
10.
Is
the detector with the aluminum cover plate still available? Yes.
For our existing customers who wish to continue using the aluminum-appearance
detector, Fire Detection Devices will continue to manufacture the unit
with the aluminum cover plate and adapter plate.
The
new appearance featuring a white plastic cover and cage (see Spec. Sheet
#1 under the "Products" button), will be replacing the older style
as time goes on.
11.
Can
the THERMOFLEX detector be protected from damage? Yes.
Fire Detection Devices offers two types of guards for protection of
the unit, which can be added during or after installation.
Model # 150, is a welded wire cage that encloses the entire unit,
offering complete protection from damaging blows from broom handles,
hockey sticks, basketballs, etc. Model
# 152, consists of a wire cage which is fastened to a standard cover
plate. This unit is
satisfactory for less hazardous locations, such as kitchens and stock
rooms. (See Spec. Sheet #7 under the "Products" button). Please Note: The newest design for the THERMOFLEX detector incorporates an attractive guard protecting the shell and heat fin from damage.
12.
How does one interpret model numbers? The
prefix "CR" means the unit is the Combination Rate-of-Rise &
Fixed Temperature type. The prefix "CF" means the unit is a
"Fixed Temperature Only" type. After
the prefix, a temperature setting relating to the fusible alloy is given
in
Fahrenheit degrees ...135, 165, 200 or 285. We
then indicate what type of contact configuration is in the unit,
namely:
The
next component of the Model Number is the Special Environment suffix,
namely:
The
final component of the Model Number is:
13.
What
Authorities have approved or listed the THERMOFLEX product line?
14.
What
are the Installation Considerations for THERMOFLEX detectors? The
listed Standard Spacing Parameters are described as follows:
Variables: A)
Ceiling Height An
increase in the ceiling height will diminish the effect of the heat plume
generated in a fire condition. The
density of Fire Detectors, (including heat detectors) on a ceiling surface
must therefore increase as the ceiling goes higher.
This ratio is expressed as a change in spacing (% decrease), versus
a change in height (increase). For
Example:
B)
Sloped
Ceiling Detectors are required to be installed at a distance of 35 inches (900mm) from the peak of the ceiling, measured horizontally. Other detectors are installed in accordance with the "flat ceiling" ratio described above, with the height taken to be the height of the peak. C)
Interrupted
Ceiling If
a ceiling is divided by solid obstructions such as beams, the spacing of
detectors is subject to change.
D)
Wall Mounting In
cramped, shallow areas such as hallway communication closets, ceiling
installation of the detector may not be practical.
A detector may be mounted on a wall providing that it is between 4
inches and 12 inches (100mm and 300mm) from the ceiling surface.
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