Note: Descriptions are shown in the official language in which they were submitted.
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
NOVEL FIRE STOP AND TTS USE
The present invention relates to devices for use in making fire stops in
buildings,
and to a method of using the devices.
Partitions in general, including walls, floors and ceilings in buildings, may
have
holes in them for passage of items such as vent pipes, drain pipes, plumbing
pipes, gas
pipes, electrical wiring, conduits to contain electrical telephone and
computer wiring,
optical fibre, air conditioning ducts, heating ducts and the like. One hole
may
accommodate one or several such items. Annular spaces between the hole and the
item
passing through the hole create passages through which heat and fire can
spread, especially
if a pipe collapses or burns under the influence of heat. It is therefore
desired to provide
means for filling or blocking these spaces to prevent the spread of heat and
fire through the
holes. There are devices and materials known for this purpose. These have the
disadvantages as they are cumbersome to apply, require tools and skills for
their
installation, and may require use of metal frames and screws or grout or
caulking for their
permanent installation. They may require that a seal to prevent passage of
heat and fire is
formed at the moment of installation. Such devices and materials make re-entry
to repair or
to retro-fit piping and cabling systems difficult. Furthermore, in many cases
subsequent
visual inspection does not readily reveal whether the device or material has
been properly
2 0 installed or not.
It is an object of the present invention to alleviate some or all of the above-
mentioned disadvantages.
Summary of the Invention
2 5 The present invention provides a device that comprises a material that
intumesces
on exposure to heat, a patch of an adhesive connected to one surface of the
intumescent
material and a liner that covers the adhesive and is readily detachable from
the adhesive by
means of a pull, to expose the adhesive.
In another aspect the invention provides a method of providing a fire stop in
a space
3 0 between a hole in a partition and an item passing through the hole, which
method
comprises wrapping around the item a device as defined above, sliding the
device along the
- 1 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
item into the hole and pulling on the pull tab to expose adhesive and anchor
the device
permanently on the item by means of the adhesive.
Description of Preferred Embodiments of the Invention
In the description of preferred embodiments that follows, for purposes of
illustration reference is made to a pipe passing through a hole. It should be
appreciated
that the pipe is merely representative of items that may pass through a hole,
and examples
of such items are mentioned above.
When the device is in place in a hole and heat from fire is encountered, the
intumescent material swells markedly, thereby blocking the hole and preventing
passage of
heat, flame, smoke and the like. Suitable intumescent materials include
flexible fire barner
felts that are disclosed in United States Patent No. 5,830,319, the disclosure
ofwhich is
incorporated by reference. The felt comprises an organic polymeric binder,
organic fibres
having pendant hydroxyl groups, for example cellulosic fibres, a heat
absorbing compound
that is suitably an intumescent compound, for example intercalated graphite,
mica, perlite,
vermiculite, hydrated sodium silicate, and a phosphorus compound.
One such intumescent material that is suitable for use in the present
invention is a
flexible fire barrier felt that is available from 3M under the trade-mark
Interam Ultra GS. It
is available in strips about 2 inches wide and about - inch thick, in any
length. When
exposed to temperatures of at least 300°F (149°C) it intumesces
rapidly, expanding up to
approximately 25 times its original volume. It turns into a hard char that
impedes or
prevents passage of heat, fire, smoke and gases. The material exerts
substantial pressures
on items in the hole so that it compresses piping and wiring materials, thus
further effecting
a seal of the hole against fire, heat, smoke and the like. It also releases
chemically bound
2 5 water that helps to slow temperature rise.
In one simple embodiment of the invention, suitable for use with small holes
and
small pipes, the patch of adhesive is present directly on a surface of a strip
of an
intumescent fire barrier felt. The liner is removed from the patch of
adhesive, the felt is
flexed to permit it to be pushed into the hole and the adhesive attaches
either to the exterior
3 0 surface of the pipe or the interior surface of the hole, where it is held
permanently in place.
In another simple embodiment the intumescent felt strip is contained in a
coating of, for
- 2 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
example, a plastic sheet, woven fabric or, preferably, aluminum foil and the
adhesive patch
is on the coating. The intumescent felt material and the adhesive are
operatively connected
to each other via the coating, although not in direct physical contact. The
coating contains
the intumescent material when it first encounters heat and intumesces, so that
the expanded
material remains contained in the hole and blocks the hole, rather than
perhaps being blown
around by a fire draught and leaving the hole unblocked. These embodiments are
more
suited for use with small pipes, up to about 1 inch nominal diameter, and
small holes, up to
about 1'/z inch nominal diameter.
For use with pipes larger than 1 inch and holes larger than 1'h inch it is
preferred to
enclose the intumescent material in a container.
The container surrounding the intumescent material is preferably flexible and
has a
certain degree of strength. Suitable materials for the flexible container
include plastics
materials and mention is made of polyolefins, particularly polyethylene, which
heat will melt
and may assist in sealing. Another flexible container material that can be
used is a metal
foil, such as aluminum foil. Yet another material is a fabric, for instance
woven fibres of
polyamide, polyester, polyolefin, polyacrylate, glass or ceramic or the like.
A preferred
container, particularly for more stringent conditions, is composed of a thin
aluminum sheet
or foil attached to a fabric or fiber reinforcing material made of, for
instance, polyamide,
polyester, glass, ceramic or the like. Suitable materials include fabric net
reinforced
2 0 aluminum foils with polyethylene heat seal layer available from Alpha
Associates, Inc., of
Woodbridge, New Jersey, U.S.A. particularly the foil available under the
designation Alpha
Style 4413-VLSTM.
To make a device for use with pipes sizes of about 1'/2 inch nominal and
greater, the
flexible container, when laid flat, is normally elongate and in use is folded
to bring one end
2 5 into contact with the other to form an annulus. In a preferred embodiment
the two ends are
held in contact by some means. The particular means for holding the ends is
not critical.
Persons skilled in the art will be able to suggest many possible means for
this purpose, for
instance a clip or clamp, or tape, or Velcro. Preferred is an adhesive covered
with a
detachable liner, so that the annulus can be readily made simply by detaching
the detachable
3 0 liner and pressing the two ends of the container together to be held by
the adhesive. The
demands on this adhesive are not particularly stringent, and suitable
adhesives are available
- 3 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
from 3M under the designation ScotchTM 467 HiPerformance Adhesive and 468
HiPerformance Adhesive.
A device of the invention can be made by taking a sheet of the flexible
material that
will form the container. The sheet should be of the approximate length
required for the
maximum length of the container when flat, plus, if necessary, an allowance
for sealing at
each end to enclose the intumescent material. It should be of a width
sufficient to
encompass both the width and the height of the unexpanded intumescent
material, plus
again, if necessary, an allowance for sealing along one edge. The material can
then be
folded over the unexpanded intumescent material and sealed along one side and
both ends,
to form the required enclosure. One suitable way of doing this is by heat
sealing, although
it is again clear that this could be done by many other means, for instance
use of adhesive
or even stitching. The flexible container should not be a tight fit over the
intumescent
material, so that when the intumescent material does swell some of that
swelling is
accommodated before the flexible container becomes stressed by the swelling.
It is
important that the flexible container contain the intumescent material as it
first swells on
encountering the heat, so that the intumescent material stays in place and is
trapped in the
hole, surrounding the pipe that passes through the hole. The container holds
the swelling
material for at least this brief initial period of time. Even if a seal bursts
or the container
subsequently tears the expansion of the intumescent material in the confined
space will hold
2 0 at least the bulk of the expanded material in place
and form an effective fire stop.
In order to locate the device permanently around the pipe and in a hole that
is to be
blocked, use is made of the patch of adhesive that is on one exterior surface
of the
container. That adhesive can be on the surface that becomes the inner surface
when the
2 5 device is formed into an annulus. The installation of the device is not
particularly critical,
provided that it adheres to the pipe, as the seal is not formed on
installation but is formed
only when heat causes the intumescent material to intumesce. On installation
the device is
wrapped around a pipe to form an annulus, or collar, using the adhesive or
other sealing
means at either end of the container to form the annulus, then thrust into the
hole. Once
3 0 the device is in the desired location a pull tab, which attaches to or is
integral with the liner
on the adhesive patch and projects from the hole, is pulled to remove the
liner from over
- 4 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
the adhesive patch. During insertion of the device in a hole there is usually
some degree of
friction between the inner surface of the device and the pipe that tends to
help in holding
the device in place before the exposure of the adhesive patch to form the
permanent bond.
The adhesive then comes in contact with the pipe and the device is held
permanently by the
adhesive at the desired location. The pull tab and liner, which at its one end
is permanently
attached to the container, projects from the hole and serves as a flag or
marker to indicate
that the device is in place. At this stage, or at any subsequent inspection,
the hole can
readily be examined visually to see that the device is in place in the hole,
as indicated by the
flag. Adhesion between the strip of adhesive on the inner surface of the
annulus and the
outer surface of the pipe can also be checked, of course.
Also within the scope of the invention is a device similar to that described
in the
immediately preceding paragraph, but differing in having the adhesive patch on
the surface
that becomes the outer surface when the device is formed into an annulus. With
this device
the adhesive attaches to the inside of the hole, rather than the exterior of
the pipe. One
application of this device is in a partition wall composed of studs faced on
both sides with
gypsum wallboard. For effective fire-stopping it is necessary to use two fire
stops, one in
each piece of wallboard, or to insert a sleeve that extends through the two
pieces of
wallboard and spans the gap that is equal to the width of the studs. In this
case one fire
stop can be inserted in the sleeve, which is, for example, of PVC or of 24 or
28 gauge sheet
2 0 metal. The device can be held in place by the adhesive patch adhering the
outer surface of
the device to the inner surface of the sleeve.
As stated above, with the device of the invention the seal to prevent passage
of
heat, smoke, flame, etc. is not formed on installation, but is formed on
exposure to heat
causing rapid expansion of the intumescent material. The rapidly expanding
intumescent
2 5 material occupies whatever space is available, so it accommodates awkward
shapes with
ease. For instance, sometimes in a hole there is a pipe in which there is an
elbow or a
coupling between two pipes of different diameter, or two or more small pipes
passing
through one hole. These create awkward shapes and present problems for fire
stops
composed of rigid material and designed to form a seal immediately on
installation. They
3 0 present no problem with the fire stop of the present invention, however,
as the intumescent
material expands into whatever shape of space is available to form the
required seal.
- 5 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
The intention is that the adhesion between a surface of the fire stop device
and the
outer surface of the pipe, or the inner surface of the hole, as the case may
be, shall be
permanent, and shall therefore be able to withstand variations in temperature,
exposure to
conditions of moisture, lack of humidity, vibration, exposure to gases and any
other
condition which might tend to reduce or break the adhesion. The demands on
this adhesive
material are therefore greater than the demands on the material joining the
two ends of the
container to form an annulus. If the latter adhesion should fail this is of no
effect, because
the device is still retained in place. In contrast, the adhesive holding the
device to the pipe
must remain in place and should therefore have the capacity of adhering to
materials that
have low surface energy. Suitable adhesives are known, for instance, from U.
S. Patents
Nos. 5,602,221; 5,616,670 and 5,654,387 the disclosures of which are
incorporated herein
by reference. One adhesive for this purpose is available from 3M under the
trade-mark
Scotch 300LSE HiStrength Adhesive. It should be borne in mind that fire stop
devices of
the same construction might be used on pipes made of many different materials,
such as
various plastic materials, including but not limited to cellular core PVC
(ccPVC), PVC,
crosslinked PVC (CPVC), fire resistant polypropylene (FRPP), PVDF, ccABS and
ABS,
steel, galvanized steel, aluminum, copper or mild steel which may have an anti-
corrosive oil
finish, or be painted, and the adhesive should attach permanently and firmly
to any of these
materials.
2 0 Pipes and conduits used in buildings tend to be of certain nominal sizes.
There is
some variation in external diameter, because diameters quoted are often
internal diameters
and different pipes for different purposes have different wall thicknesses.
The outer
diameters of pipes encountered in buildings are clustered in various fairly
narrow
dimensional ranges, however, and a device of appropriate size is made for each
range.
2 5 Alternatively, or in addition to sizing devices with regard to the pipe
size it is
possible to size them with regard to the hole size.
Usually in construction a hole to accommodate a pipe passing through it is
sized so
that the diameter of the pipe is about SO to 80% of the diameter of the hole.
In this case
one appropriately sized device of the invention is all that is needed to form
a fire stop. In
30 some instances, however, it is necessary to insert a fire stop where the
hole is much larger
than the pipe. This is the case particularly when retrofitting, when, say, a 3
inch pipe may
- 6 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
have been removed from a hole and in the retrofit a 1 inch pipe is passed
through the hole.
In such a case it is possible to use two devices of the invention. Immediately
around the I
inch pipe is placed a device appropriately sized for 1 inch pipe, and around
that there is
placed a second, larger device of the invention. Alternatively the hole can be
partially filled
with some non-combustible material, for example mineral wool.
As stated above, after installation of the device the pull tab can serve as a
flag. The
flags can be coded to indicate the size of the device, for instance with
different colours.
The invention is further illustrated in the accompanying drawings showing, by
way
of example, preferred embodiments of the invention, of which:
Figure 1 illustrates certain characteristics of a liner- covered adhesive that
are taken
advantage of in some preferred embodiments of the invention;
Figure 2 shows a flexible container in accordance with the invention in plan
view;
Figure 3 shows a device of the invention in longitudinal section;
Figure 4 shows a device of the invention in cross section;
Figure S shows a device in process of installation; and
Figure 6 shows detail of a liner and pull tab.
Figure 1 shows a substrate 1 on the surface of which is applied an adhesive
material
2 covered with a liner 3 which extends to form a pull tab 4. If a pull is
exerted on the pull
tab in the direction indicated as 0° in the figure then the shear force
resisting removal of the
2 0 pull tab will be very great and it is more likely that the pull tab will
tear than that the
adhesive will release. If the pull is in the direction indicated as
90°, i.e., perpendicular to
the surface bearing the adhesive, then the force required to remove the liner
is considerably
less. If the pull is in the direction indicated as 180° the resistance
to removal of the liner is
also less. The embodiment of the invention that is illustrated in Figures 2 to
5 takes
2 5 advantage of this phenomenon.
Figures 2, 3 and 4 show a device in accordance with the invention before
installation. A flexible container 5 encloses strips 10 of intumescent
material, the container
being closed by a heat-sealed strip 7. At one end of the container is a strip
of adhesive 6,
temporarily covered by a releasable liner 6a, that will adhere to the other
end of the
3 0 container to hold the two ends when the flexible container is formed into
an annulus.
Attached to one surface of the flexible container is a pull tab 8 that, over
part of its length,
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
act as a liner over a patch of double-sided adhesive 9 that is on the surface
of the container
that forms the inner surface when the container forms an annulus. As can be
seen from
Figure 4, the liner and pull tab 8 is looped over so that when a pull on the
pull tab in the
direction of the arrow it is initially at about 180° to the adhesive
surface, so that the liner is
released relatively easily. As the point of attachment of the liner approaches
the edge of the
flexible container then the angle approaches 90° and the resistance to
release increases. As
more of the liner is removed the angle approaches 0° and the resistance
to release increases
yet further as discussed above. At the point that this further increase in
resistance is
encountered the patch of adhesive that will contact the pipe is exposed. The
adhesive
contacts and attaches to the pipe. The pull tab extends from the hole and
serves as a flag
indicating that a device has been inserted. The device will therefore remain
in place. It will
be appreciated that its insertion has involved no use of tools, no particular
skills, no use of
screws, grout or caulking to hold it in place, and it is clearly very easily
capable of rapid
visual inspection, to determine that it has been installed properly.
The intumescent material inside the container is shown as two strips of
intumescent
material 10. As stated above, each device is designed for use with pipe of a
particular size,
and the device shown in Figures 2, 3 and 4 is intended for pipe whose external
diameter is
approximately 2 inches. The intumescent material Interam Ultra GS is available
in strips
that are approximately 2 inches wide and 1/8 of an inch thick. For a device
for use with 2
2 0 inch pipe two strips of this material are used, one approximately 7 1/2
inches in length and
the other approximately 8 1/4 inches in length. The one is laid on top of the
other and the
strips are free to move relatively to each other, although they are, of
course, confined
within the flexible container. The shorter length of intumescent material is
adjacent that
side of the foil container that, on its outer surface, bears the adhesive
patch 9 and liner 8.
2 5 As the device is wrapped around a pipe the two layers of intumescent
material move
relatively to each other to accommodate the formation of the annulus. For 2
inch pipe, the
flexible container is formed from a sheet that is approximately 10 1/4 inches
long by 7
inches wide, when laid flat. The two layers of intumescent material are laid
on this sheet.
The sheet is then folded over lengthwise to enclose the intumescent material
and heat-
3 0 sealed along one edge, and to form seal 7 at either end. Adhesive 6 and
liner 6a are applied
to the one end and the adhesive patch 9 and liner 8 attached thereafter. For 4
inch pipe the
_ g _
CA 02368073 2001-10-24
WO 00/67849 PCT/L1S00/12034
flexible container is suitably about 19 1/2 inches long and contains four
strips of the
Interam Ultra GS intumescent material, the shortest of which is about 14 3/8
inches long
and the longest of which is about 17 inches long.
Figure 5 shows schematically the device in place before removal of the liner
8. A
pipe 11 extends through a hole in a concrete wall 12. In the space between the
exterior
surface of the pipe and the interior of the hole in the concrete there is
placed the device of
the invention. As can be seen, a pull on the liner in the direction of the
arrow will expose
the adhesive which then attaches to the pipe. The liner 8 is not completely
detached from
the device but remains in place and serves as a flag to indicate that the
device has been
installed.
It is clear from the above description that the adhesive that attaches the
device of
Figures 2 to 6 to the pipe need not extend all around the inner circle of the
annulus of the
adhesive. The area of the adhesive should be such that, when in place, it
occupies a sector
of at least about 25° preferably about 50°. The size of this
sector does depend to some
extent on the size and weight of the device and the pipe around which it is to
be wrapped.
With a larger device and larger diameter pipe the sector subtended by the
adhesive patch
can be smaller. Particularly for use in a hole in a floor or ceiling, where
gravity will tend to
pull on the device, the amount and tenacity of the adhesive should be
sufficient to support
the weight of the device permanently in a non-friction mode, i.e., without
reliance on
2 0 friction, on a low energy surface.
Figure 6 shows detail of a preferred embodiment of the liner and pull tab 8,
in its
orientation after it has been pulled from the adhesive patch 9. The liner and
pull tab is
composed of a silicone release coated paper 1 S, i.e., paper coated on both
sides with low
surface energy silicone so that it will readily release from the adhesive
patch 9. As the pull
2 5 tab 8 is to remain in place as a permanent flag or marker it is necessary
that it shall not
release from the device as a whole. To enhance the adhesion between the
surface of the
container 5 and the paper 15 there is used a double-sided adhesive, available
from 3M as
Double Sided Adhesive 9731. This is composed of a scrim, on one side of which
is a layer
16 of Scotch 300LSE HiStrength Adhesive, which adheres well to the silicone
release
3 0 coated paper 1 S. On the other side of the scrim is a layer 15 of an
acrylate adhesive that
adheres well to the fabric of container 5. At the other end of the strip of
paper 15 there is a
- 9 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
strip of plastic sheet 18 that is attached to the paper 15, again using 3M's
Double Sided
Adhesive 9731, with the 300LSE HiStrength Adhesive in contact with the paper
15 and the
acrylate in contact with the plastic sheet 18.
It will be appreciated that the invention can be embodied in some ways
different
from that described above with reference to the drawings. For instance, with
larger pipe
diameter a larger device will be needed and there may be used 3 or 4 or even 5
or more
strips of the 1/8 inch thick material Interam Ultra GS. The intumescent
material could be in
pulverulent form, rather than solid strip form. The manner of sealing the
flexible container
to contain the intumescent material is not critical, provided that the sealing
material does
withstand the initial force to sufficient extent to ensure that at least the
bulk of the
intumescent material remains in place in the annulus between the pipe and the
hole and does
in fact form a fire stop. The liner and pull tab may be formed of the same
material, or, of
course, may be made of a composite of several different materials. Suitable
materials are
sheet plastic and paper, or a combination of the two; clearly the selection of
material for
this purpose is not critical. The liner and pull tab remain attached to the
device, and this
can be done by means of adhesive, as described above, or the liner can be
anchored at its
one extreme end by any other suitable means, for instance stitching, or by
making the
flexible container of a material which is shaped so that when it is folded to
enclose the
intumescent material there is a tail extending from one surface of the
container material,
2 0 which tail can be folded over to cover the adhesive and serve as liner and
pull tab.
Another variant of the embodiment of Figures 2 to 6 is to dispense with the
pull tab
8 and adhesive batch 9, and to locate the adhesive along the lengthwise strip
of the heat-
sealed area 7. The adhesive would be covered with a release liner until used.
In use the
release liner would be removed, the device wrapped around the pipe and slid
carefizlly into
2 5 the hole and, when properly located, the adhesive on the heat- sealed
strip 7 would be
pressed either against the exterior of the pipe or the interior of the hole,
as required. It will
be realised that this embodiment does not provide the flag to indicate
installation of the
device. Also, as in this embodiment the adhesive is exposed before the device
is located,
care must be exercised in sliding the device along the pipe to the required
location.
3 0 In yet another variant, inside the flexible container and partially
surrounding the
intumescent material is a member of, for example, thick foil or thin metal
that directs
- 10 -
CA 02368073 2001-10-24
WO 00/67849 PCT/US00/12034
expansion and flow of expanding material in a particular direction.
- 11 -
