Note: Descriptions are shown in the official language in which they were submitted.
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PASSIVE FIRE PROTECTION SYSTEMS FOR CONDUITS
The present invention relates generally to the design of a passive fire
protection
system and more particularly, to an insulative and fire resistant/retardant
wrap suitable for
protecting conduits, cable trays, support rods, structural and other
components from
destruction during a fire.
S I~ACKC1_R_OLTNT~ OF THE INVENTT_ON
The following are three types of materials that have been used to protect
conduits,
cable trays, support rods, structural steel, and other construction materials
from excessive
heat during a fire and to retard the fire itself:
(1) insulation wraps,
(2) endothermic wraps, and
(3) intumescent coatings and materials.
Each category of these insulative materials has its drawbacks.
There are two primary problems with insulation wraps such as alumina silica
blankets or mineral wool blankets. In order to achieve suitable fire
protection in a severe
total environment type fire, viz, a hydrocarbon fire, the material has to be
very thick and
as a result causes the two problems inherent in such systems. First, the fact
that the
material is thick causes problems with clearances between the protected item
and adjacent
or interfering items. Secondly, insulation systems cause a problem during
normal
operations because of the insulating factor. This problem is called "ampacity
derating,"
which means that the heat generated by electrical cables within the conduit or
cable tray is
restricted from escape and causes the safe operating level of current
allowable in said
cables to be reduced or overheating will occur. The more severe the fire
protection
requirement, the more difficult this "Catch 22" becomes because the only way
to increase
the fire protection effect is to make the system thicker.
When this option is used to try to solve fire problems, it is common for the
user to
. have to reduce the amperage rating of the system within the conduit or cable
tray, thus
losing efficiency originally designed into the systems.
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Endothermic materials are composed of compounds that activate in a fire
situation
by breaking down at the molecular level and releasing trapped water which then
cools the
protected item. The most common example of this is alumina tri-hydrate, which
is a dry
white powder that releases large amounts of water at about 1,100°F. A
well known
endothermic product is the INTERAMTM E-SO series flexible wrap systems
available from
3M Fire Protection Products, St. Paul, Minnesota.
Endothermic wrap materials have proved to be useful in fire protection in that
some of the "thickness" problems inherent in insulation systems is somewhat
lessened, but
endothermics have their own problems. Due to the fact that the material has
water
molecules trapped in dry form, the total system package tends to be quite
heavy. Also,
there is still a problem with inherent insulative properties in products such
as the 3M
INTERAMTM E-50 wrap system because the system is generally installed in
several layers
with careful sealing requirements at all seams to hold in the water that will
be released in
a fire. The net effect of this is that, in every day operations, heat is still
trapped within
the system leading to ampacity derating.
Endothermics, such as 3M's INTERAMTM E-SO wrap system are also generally
difficult to install, with very high associated labor costs. Also, once
installed, these
systems are extremely difficult to remove and replace in order to do
maintenance work on
electrical conduits or cable trays.
Intumescent products have gained a high level of interest recently because of
the
problems associated with insulations and endothermics as outlined above.
Intumescent
materials are products that "grow" or "thicken" only when exposed to heat,
creating an
insulation layer that separates the protected item from the fire.
One major advantage of intumescent materials is that the unreacted material is
very
thin and non-insulative. This characteristic makes intumescent materials ideal
for
insulating conduits and cable trays since these materials do not require
ampacity derating
as the insulation and endothermic systems do. Furthermore, these materials are
simpler to
install than insulation or endothermic systems. In fact, intumescent materials
are often
applied as a light weight coating over the area to be protected. In general,
intumescent
coatings are a preferred insulative material because they are thin, non-
insulative (except in
a fire), and light weight.
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However, there are two severe problems with using intumescent products which
make it difficult to provide consistent insulative protection. These two
problems are:
(1) The carbonaceous "foam" that results when the intumescent materials
expand upon exposure to heat is always very fragile and is generally damaged
by the
turbulence of a fire. Furthermore, expanded intumescent materials will
commonly fall off
of the coated surfaces due to the pull of gravity. This fragile nature of
intumescent
materials leads to the formation of "fissures" in the material which allow
heat to penetrate
to the protected surfaces. These fissures appear randomly and give the system
a quality of
unpredictability that is undesirable for fire protection systems. These
"fissures" are
particularly prominent where the intumescent materials have been used on
curved surfaces
or at the corners of sharp turns.
(2) In addition to fissure formation, when expanded intumescent materials are
exposed to direct fire and heat in a hydrocarbon fire Exposure Test, the outer
carbonaceous foam that is in direct contact with the fire tends to erode, thus
exposing
lower layers of the materials. The lower layers also erode, causing a
geometric reduction
of the effectiveness of the product over time. This eroding effect magnifies
the
unpredictability of the system. Furthermore, this erosion of the materials
accelerates the
growth of the above mentioned "fissures," once formed.
Thus, there exists a need for a fire protective system that can take advantage
of the
favorable qualities of intumescent materials, while providing a means of
stabilizing the
carbonaceous foam resulting from the reaction of the intumescent materials
with heat.
It is therefore an object of the present invention to provide a system which
can
stabilize expanded intumescent materials.
A further object of the present invention is to provide a fire protective
system that
is easily customized to meet the specific fire protective needs of different
environments.
It is another object of the present invention to provide a fire protective
flexible
wrap that can be easily installed, removed, or replaced on conduits, cable
trays, support
rods, and structural members.
It is yet another object of the present invention to provide a thin, light
weight, low
ampacity derating fire protective system.
Still yet another object of the present invention is to provide a fire
protective
system that can be easily custom fitted to any size or shape structure.
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SUMMARY OF THE INVENTION
The present invention fulfills the need discussed above by disclosing a multi-
layered
containment system for intumescent materials.
In accordance with one aspect of the present invention, a fire protective
system is
provided that contains multiple layers of fire resistant materials with
intumescent materials
located between the layers of fire resistant materials. The resultant multi-
layered material
provides a flexible wrap that provides stability to expanded intumescent
materials.
In accordance with another aspect of the present invention, a fire protective
system is
provided that includes alternate layers of fire resistant materials and
intumescent material that is
designed to expand one layer at a time and that will expand in all directions
to provide a
consistent and effective fire protective system.
In one particular embodiment there is provided a fire protection system
comprising: a
folded sheet of fire resistant material, said folded sheet having a plurality
of folds running
substantially parallel to each other; a flexible layer of heat resistant
material; and a layer of an
I S intumescent material localized between said folded sheet and said flexible
layer, said
intumescent material expanding when subjected to elevated temperatures;
wherein said folded
sheet will unfold in response to the expansion of said intumescent material to
provide stability to
said expanded intumescent materials.
One feature and advantage of the present invention is that it provides a thin,
light weight
fire protective system with a low ampacity derating.
Another feature and advantage of the present invention is that it provides a
fire protective
system that takes advantage of the favorable qualities of intumescent
materials and stabilizes the
carbonaceous material that results from the expansion of the intumescents in
response to heat.
Another feature and advantage of the present invention is that it provides a
fire protective
system that can be optimized to meet the fire protective needs of different
environments.
Another feature and advantage ofthe present invention is that it is easily
installed,
removed, and/or replaced on conduits, cables, trays, support rods, and any
other structural
members.
Yet another feature and advantage of the present invention is that it allows
the
intumescent material to expand evenly in all directions, no matter what
configuration is being
protected.
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Still yet another feature and advantage of the present invention is that it
provides a fire
protective system that can be custom fitted to any size or shape structure.
An additional feature and advantage of the present invention is that it
provides a fire
protective system that is non-toxic to plants and animals, contains no
petroleum derivatives, and
generates essentially no smoke during exposure to fire or heat.
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The foregoing has outlined rather broadly the features and technical
advantages of
the present invention in order that the detailed description of the invention
that follows
may be better understood. Additional features and advantages of the invention
will be
described hereinafter which form the subject of the claims of the invention.
It should be
appreciated by those skilled in the art that the conception and the specific
embodiments
disclosed may be readily utilized as a basis for modifying or designing other
structures for
carrying out the same purpose of the present invention. It should also be
realized by those
skilled in the art that such equivalent constructions do not depart from the
spirit and scope
of the invention as set forth in the appended claims.
For a more complete understanding of the present invention, and the advantages
thereof, reference is now made to the following DETAILED DESCRIPTION OF THE
INVENTION taken in conjunction with the accompanying drawings, in which:
FIGURE 1 shows a side view of a preferred embodiment of the mufti-layered
material used in the present invention;
FIGURE 2 is a side view of one embodiment of the invention, illustrating the
manner in which the layers of material are folded;
FIGURE 3 is a side view of an alternative embodiment of the invention,
illustrating
the manner in which the layers of material are folded;
FIGURE 4 is a rear view of one embodiment of the mufti-layered material,
showing a method used to secure both sides of the material during manufacture;
FIGURE 5 is an end view of an insulative strip showing one embodiment that
allows joints to overlap during installation of the strip;
FIGURE 6 is a cut-away drawing of two overlapping strips illustrated in FIGURE
5.
FIGURE 7 is an end view of a preferred embodiment of the present invention
installed around a typical conduit;
FIGURE 8 shows a typical completed installation of a preferred embodiment of
the
present invention on an electrical conduit;
FIGURE 9A is a side view of one embodiment of the present invention installed
around a cable tray;
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FIGURE 9B is an end view of an embodiment of the present invention installed
around a cable tray; and
FIGURE 10 illustrates the stages of growth of one embodiment of the present
invention during a fire situation.
The present invention relates to the design and manufacture of an improved
passive
fire protection system used to protect conduits, cable trays, support rods,
and structural
steel against the flame and heat of a total environment-type fire, such as a
hydrocarbon
fire.
Referring now to the drawings, and initially to FIGURE l, it is emphasized
that the
Figures, or drawings, are not intended to be to scale. For example, purely for
the sake of
greater clarity in the drawings, layer thicknesses and spacings are not
dimensioned as they
actually exist in the assembled embodiments.
FIGURE 1 illustrates one embodiment of a flexible, mufti-layered (or
laminated)
material 10 that is used to construct a fire protective or insulative wrap.
For example, the
embodiment illustrated in FIGURE 1 is comprised of four layers of heat
resistant
materials. An exploded view of those layers is seen on the left side of FIGURE
1. The
component layers of this mufti-layered material 10 may be composed of the same
heat
resistant materials or different heat resistant materials. Interspersed
between the layers of
fire-resistant materials is a high-level intumescent material which will
expand significantly
during a fire.
Although any flame resistant material can be used in the present invention,
preferred embodiments will include metal foils, fire-resistant fabrics, or a
combination of
materials such as aluminum foil, stainless steel foil, fiberglass, or alumina
silica fabric. A
preferred embodiment of the present invention is illustrated in FIGURE 1. In
this
embodiment, layers of fire-resistant material numbered 11,12, and 13 in FIGURE
1 are
made of thin sheets of aluminum foil (such as a 0.002 or 0.003 gauge foil) and
folded
layer 14 is made of a fiberglass material. Preferred embodiments of the fire
protective
system include at least one layer of folded material. The material may be
folded in any
number of configurations. It may be S-folded, accordion folded or pleated, as
demonstrated in FIGURE 1 by pleats 17. The number and size of pleats 17 is
variable.
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Such variations being dependent upon the degree of 5re protection roqt>ired.
Preferred
embodiments of the p~ese~ invention have pleats 17 in folded layer 14 rtnmmg
leogthwiae
in the mufti-layered material 10.
Examples of preferred intumescent materials that can be used in the pad
inve~ion to hold these layerod materials together are 3M's C! 25 int~esoeat
material that can be obtained from 3M Fire Protection Ptoduets, St. Paul,
Minnesota, or a
FX-100 costing material available ~rom Flame Seal Product, Inc., Housto~,
Tams. Thous,
the embodiment of the present invention illustrated is FIGURE 1 has font
layers of heat
resistant material bald together with three layers of intumescent materials.
The gteamer the
expansion capacity of the intumescent materials utilized in the inve~ion the
grey the
fire protective ability of the insulative wrap. Preferred intumesoent
materials will have an
expansion capability of 700°Y. or more. However, materials having
lesser degrees of
~wpansion may suffce in arr$in applications depending on the quanttty of
intumesoent
used between layers, the number of layers, the size of the folds, and the
distancx betvueen
the folds.
A preferred embodiment of tlx; present inve~on utilizes two Iowa layers of
.002
gauge aluminum foil, one middle layer of extreme heat-resistant fiberglass,
nerd a top layer
of .003 gauge aluminum foil. The top layer uses a heavier .003" foil to
increase the
strength and durability of the insu>ative wrap during installation and
everyday use. The
lower layers use a thinner foil since the lower layers are protected during
everyday use
and the thinner foil lowers the total weight of the insulative wrap. The outer
lays of foil
is sacrificial in a fire and is ~s~tially or sublimated af3tr about 3-5 miau~.
The
laminated mufti-layered material 10 described above is feather pleated or
folded when
made into a 5rt protective or insulabve wrap. These pleats or folds 15, shown
on the
right side of FIGURE 1, run sideways across the mufti-layered material 10
approximately
perpendicular to pleats 17 in folded layer 14. Such folds 15 may be simple
pleats or
S-folds as shown in FIGURE 1. The number, configuration, a~ size of folds 15
can be
varied according to the degrre of fire protection required, the expansion
capacity of the
intumescent materials, and t~ size and shape of the protected sta<s~e.
~ The primary containment of the iatumescent materials is accomplished by the
system design of the iasulative wrap. Folds 15 in the mufti-layered material
will typically
expand, or unfold, during the first 10-15 minutes of a fire. Pleats l7 in
folded layer 14
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will also contribute significantly to the containment of the expanded
intumescent materials.
Folds 15 and pleats 17 allow for linear growth of the insulative wrap as the
intumescent
material expands thereby allowing the expanded insulative wrap to expand
around
interfering structures and banded joints. These folds and pleats also allow
the system to
expand to seal any penetrations of the system. The ability of the present
invention to
expand in a fairly uniform diameter around protected structures during a fire
minimizes
the heat exposure of the protected structure at all points in the system
including sharp
corners, banded joints, and points of intersecting structures.
FIGURES 2 and 3 show side views of preferred folded configurations into which
the above laminated material 10 is formed. Folds 15 are shown as being a width
X and
spaced at a distance Y from the center of one fold 15 to the center of the
adjacent fold 15.
An example of folds 15 in the configuration illustrated in FIGURE 2 would be
folds I S
that are one inch in width and spaced at approximately two inches from the
center of one
fold to the center of the adjacent fold. FIGURE 3 illustrates an alternative
configuration
where a similar one inch wide fold 15 would be spaced such that the distance
from the
center of one fold to the center of the adjoining fold would be approximately
one inch.
The width of folds 15 and the distance between folds 15 determine the
"unfolded" length
of the material and contributes to the final size of the perimeter of the
expanded insulative
wrap exposed to a fire. For example, a one inch spacing between the center of
adjacent
one inch wide folds, as illustrated in FIGURE 3, yields an expansion capacity
of three
times the original circumference (or perimeter) of the protected item. Two
inch spacings
between one inch wide folds, as illustrated in FIGURE 2, yield an expansion
capacity of
two times the original circumference (or perimeter).
FIGURE 4 illustrates how the folds 15 in a preferred embodiment of the
insulative
wrap are secured to maintain the shape of the insulative wrap for installation
and everyday
use. The folded configuration of the mufti-layered material 10 is secured by
using an
adhesive, such as an epoxy or a contact glue, between the surfaces of folds
15. When
folds 1 S are S-folds, as shown in FIGURE 4, adhesive is placed on both sides
of the
middle section 42 of fold I5. The adhesive will hold the insulative wrap in
its desired
configuration during normal use, yet will release the layers of the S-fold as
each layer
reaches a certain temperature and melts or softens the adhesive to allow that
layer of the
S-fold to expand and separate from the next layer.
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Preferred embodiments of the insulative wrap also have an adhesive fire
resistant
material 46, such as an industrial aluminum or stainless steel tape, running
along the
length of the bottom (or inner) side of the insulative wrap. The bottom
adhesive material
46 can be trimmed to the proper length to fit the dimensions of the protected
item or
surface.
This bottom adhesive material 46 serves two purposes. One purpose is to help
hold the insulative wrap in its everyday configuration. The other purpose is
to ensure that
the insulative material is held snugly against the protected item or structure
during the
expansion process in a fire. The bottom adhesive material 46 will continue to
secure the
insulative wrap to the protected surface during a fire because the insulative
wrap will
protect the protected surface from the type of elevated temperatures that
would cause the
adhesive material to soften and allow the insulative wrap to disengage from
the protected
surface.
By keeping the insulative wrap firmly in place around the protected surface
the
expanded intumescent material will compact as each subsequent layer begins its
expansion.
The bottom adhesive material 46 will thus allow the insulative material to
expand in
response to extremely elevated temperatures in an approximately symmetrical
manner. As
the insulative wrap is exposed to heat, its outer layers will expand away from
the
protected surface as described in more detail below. This symmetrical
expansion prevents
the system from obtaining a "bell shaped" configuration during a fire which
could result in
localized pressure points along the external surface of the insulative wrap
and lead to
fissures in the insulative wrap. The bottom adhesive material thus contributes
to the
ability of the insulative wrap to undergo a uniform expansion in all
directions adding to
the efficient operation of the fire protective system.
The insulative wrap may be made in any number of configurations, shapes and
sizes to fit any shape or size of surface or structural item. However, one
convenient
embodiment of the insulative wrap is produced in strips 50 of any desired
length as
illustrated in FIGURE 5. Folds 15 run along the length of the strip 50. One or
both ends
of strip SO may have a narrow area, typically one inch wide, where the mufti-
layered
material 10 was constructed with a minimal amount of intumescent material so
as to
provide a thinner area, approximately one-half the regular thickness of the
insulative wrap.
This thinner area 55, as shown in FIGURE S, provides a means of overlapping
two strips
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50 and securing that overlap with a heat resistant securing device 68, such as
a stainless
steel band as shown in FIGURE 6. When the insulative wrap expands during
exposure to
a fire the intumescent materials will expand around the securing device 68 to
protect the
securing device 68 and avoid the production of "hot spots" on the protected
surface. The
ability to overlap thinner areas SS provide an easy means of protecting
surface 62.
FIGURE 7 illustrates one method of joining the sides of the insulative wrap
where
it has been wrapped around an electrical conduit 72 containing electric cables
75. If the
insulative wrap has been constructed such that it has a space between folds
15, the
insulative wrap is easy to cut in such a space and to join together using
fasteners 78, such
as stainless steel hog rings. Typically when the insulative wrap is installed
on an
electrical conduit 72, a fastener 78 is placed every 1/2 to one inch apart
along the linear
seams of the insulative wrap such as illustrated in FIGURE 8. The site where
fastener 78
secures two sides of insulative wrap together may be covered with an adhesive
metal tape.
Although not essential, this tape adds to the appearance of the fire
protective system and
1 S helps reduce moisture accumulation on fasteners 78.
FIGURE 8 shows the insulative wrap installed on a typical electrical conduit.
FIGURES 9A and B show a strip SO of the insulative wrap installed on a typical
electrical
cable tray 92.
Turning now to the operation of the insulative material, FIGURE 10 is a series
of
five drawings showing the growth stages of the described preferred embodiment
of the
insulative material during exposure to a fire. FIGURE l0A shows the insulative
wrap
illustrated in FIGURE 1 before it has been exposed to a fire. FIGURE lOB shows
the
initial activation of the fire protective system. In FIGURE lOB folds 15 have
been
released and have risen to approximately a 90° angle as internal
pressures from the
expanding intumescent materials begin to exert their effect. The resultant
pressures from
the expanding intumescent materials will seek an equilibrium state, and
therefore, due to
this design, will yield a symmetrical expansion around the protected surface.
A major
advantage of the present invention is that even if the insulative wrap is
breached or eroded
at one point the pressure of the expanding intumescents will cause the
expanded material
to fill the breach in the system, therefore providing a self healing system.
During this
initial stage of activation the outer layer of aluminum foil will burn off and
expose the
layer of intumescent material protecting the folded fiberglass layer.
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FIGURE lOC shows the early expansion process under way when the first layer of
intumescent material has expanded. The expanded intumescent material will
insulate the
lower layers of intumescent material and delay their expansion. In FIGURE lOD,
two
layers of intumescent material are shown expanding. The outer layer of
intumescent
material and the first layer under the folded fiberglass layer are moving
toward a state of
equilibrium. FIGURE l0E shows the final configuration of the expanded
insulative wrap.
At this point folds 1 S and pleats 17 have expanded to their design limit, the
top two layers
of intumescent material have expanded to a state of equilibrium, the bottom
layer of
intumescent material remains in its original state against the protected
surface, and the
expanded intumescent material has compacted and reached a state of equilibrium
with a
common density throughout the system.
One advantage of the present invention is that it is designed to include
sufficient
intumescent material that even after it has fully expanded it has residual
expansion ability.
This design feature essentially eliminates the problem of fissure formation
since the
1 S expanded intumescent material will always be in the process of
"compacting" during a fire
situation as additional intumescent material expands.
Once the entire system has completely expanded and all intumescent material
has
reacted and reached an equilibrium, the expanded insulative wrap will act as
any other
insulative material. This fact is but one of the considerations that is taken
into account
when deciding how thick the final system must be after expansion is complete.
The fire protective effectiveness of the present invention has been tested for
the
preferred embodiment described above. The insulative wrap was installed around
a one
inch conduit and the wrapped conduit was placed in a furnace. Two teflon
jacketed
thermocouples (T/C 1 and T/C 2 in Table 1) were placed in the furnace to
record the
furnace temperature and two thermocouples (T/C 3 and T/C 4 in Table 1 ) were
placed
along the surface of the conduit underneath the insulative wrap to measure the
temperature
of the conduit surface during the testing procedure. The furnace was lit and
within 7
minutes had reached 2000°F and was maintained at approximately that
temperature for 30
minutes as recorded by T/C 1 and T/C 2 and set forth in Table 1. The surface
of the
conduit was efficiently protected from the flames and the 2000°F heat.
In fact, the surface
of the conduit (as recorded by T/C 3 and T/C 4) was consistently less than
250°F
throughout the entire 30 minute test as seen in Table 1.
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The design of the present invention, a five-protective and insulative wrap,
utilizes
the ability of intumescents to expand in volume during a fire, when protection
is needed.
Thus the insulative wrap can be installed as a thin, light-weight, and non-
insulative
material. Further, the present invention solves existing problems with the use
of
intumescent coatings (i.e., the formation of fissures and the tearing away of
the expanded
carbonaceous material by the turbulence of a fire). The present invention
contains the
intumescent material within the system as it expands, much as the foil design
contains
expanding popcorn in the product TIFFY POPTM.
The design can be varied according to the severity of the fine protection
requirement by adjusting the amount of intumescent material in the layers,
adding more
layers and by adjusting the size and dimension of the S-folds to yield a
larger expanded
diameter.
An enhancement of the insulative effect of this invention is realized when
progressive, separate "layers" of intumescent materials are designed to grow
outward
1 S toward the fire or heat one at a time, thereby protecting and delaying the
successive lower
layers from expanding outward. This delayed effect on the inner intumescent
layers
creates an endothermic effect, in addition to the insulative and heat
absorptive properties
of expanding intumescent materials. The protected lower layers, during the
expansion of
the upper layers of intumescent materials, release water in the slowed process
of heat
exposure and growth, thereby cooling the protected item with greater
efficiency. During
the exposure and growth of successive layers outward toward the fire, lower
layers are
protected by three mechanisms operating at the same time.
1. The reaction temperature of most intumescent products is 350°F to
500°F.
As long as there is any unreacted product within the system, the layer
directly below the
reacting product will not reach its reaction temperature.
2. As carbonaceous foam forms and grows, an increasingly thicker insulation
layer is formed and acts purely as an insulator.
3. As the temperature increases, the exposure of inner layers of intumescent
material to moderate temperatures will release water producing an endothermic
effect,
thereby temporarily preventing the temperature of the inner layers of the
insulative wrap
from surpassing 212°F due to the boiling point of water. The present
invention will also
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temporarily trap any steam that is formed which will also lessen the rate of
temperature
increase above 212°F.
In summary, the growing material insulates lower layers and slows them from
reacting or growing. As the heat builds up and reacts the first layer of
intumescent
materials the second layer is protected from the heat. Once the heat gets
through the first
layer of intumescent material, or the insulative wrap has completed its first
phase of
growth, the next layer of intumescent material reacts and grows outward
further
compacting the carbonaceous foam resulting from the expansion of the first
layer of
intumescents. The expansion of the second layer of intumescents protects the
third layer
of intumescents from reacting or expanding to the heat, and so on until the
entire system
is expanded to its final size and all intumescent materials within are
compacted within the
containment system provided by the heat resistant materials that are layered
throughout the
system. This entire process, plus the above described endothermic effects and
successive
reaction processes, takes time to complete as the entire process is cyclic in
nature. Once
1 S the system has completely reacted and expanded to its full extent the
resultant insulative
wrap will act strictly as an insulative material of considerable thickness.
Although the present invention has been disclosed in connection with conduits,
cable trays, support rods, and structural steel in a petrochemical
environment, the present
invention may be used wherever fire protection is needed such as in a home or
an office
building. The configuration of the insulative material is easily customized to
surround any
circular, square, rectangular, or irregularly shaped item.
As described earlier, the design uses layers of metallic foils and fire
resistant
fabrics to contain the intumescent materials and protect them from direct
contact with the
fire environment. However, modifications can be made to resist more severe
situations
such as explosions or jet fires by using a stainless steel foil outer layer
and a stainless
steel mesh lower layer for stronger system integrity.
13
CA 02235740 1998-04-23
WO 97/15444 PCT//1JS96/17016
The invention provides industry with an ideal product for fire protection of
conduits, cable trays, support rods, and structural steel as it has the
following properties:
(1) Thin
(2) Light weight;
S (3) Low ampacity derating (non-insulative except in a fire);
(4) Easy to install (one layer; simple techniques);
(5) Can be removed, and re-installed;
(6) Safe and environmentally friendly; and
(7) Easily custom fitted to any size and shape structure.
Having described preferred embodiments of the present invention, it is
believed
that other modifications, variations and changes will be suggested to those
skilled in the
art in view of the description set forth above. It is therefore to be
understood that all such
variations, modifications and changes are believed to fall within the scope of
the invention
as defined in the appended claims.
14
CA 02235740 1999-03-29
TABLE 1
THERMOCOUPLE TEMPERATURE READINGS
TIME T/C 1 TIC 2 T/C 3 T/C 4
MINUTES FURNACE FURNACE CONDUIT CONDUIT
--
I 1037 1289 82.8 82.4
-
-
2 ~ 1299 82.8 80
193
3 1335 1484 83 82.6
4 1615.6 ~ 1700 83.4 83.2
--
1742 1839 84.8 84.4
6 1887 1938 87.6 - 87
7 2032 2036 90.4 89.6
8 1982 2010 94.8 93.8
9 1970 1980 100.4 g9.8
2008 1992 108.6 109.8
II 1973 1974 122.6 124.2
12 1966 1990 148.4 147.2
13 1922 1926.6 164 176.4
14 1904 1900 166 180.4
1995 2052 173.2 183.6
16 1934 1938 178.4 183.8
17 2005.6 2014.4 183.6 183.4
18 1950 1948.4 187.4 184.4
I 9 1965 1964.8 190.4 190.4
1988 1993 195 197.8
21 1987 1987.8 198 201.8
22 2020.4 2022.2 201.8 203
23 1922.2 1921.8 206.4 204.6
24 2024.4 2019.4 209.8 206.2
1976.8 1986 211 209.6
26 2004.2 2002.8 213 210.3
27 1987.4 1987 216.4 210.6
28 1968.4 1968,6 219.2 211.2
29 1878 1878 223.6 213.4
1968 ~ 1962.6 230.4 221.8
14a
