Note: Descriptions are shown in the official language in which they were submitted.
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FIRESTOP BLOCK AND THERMAL BARRIER SYSTEM
FOR FLUTED METAL DECKS
FIELD OF THE INVENTION
The present invention relates to firestop blocks and a thermal barrier system
for building
structures, and more particularly to thermal barriers for "head-of-wall" joint
assemblies
between tops of walls and ceilings or floors.
BACKGROUND OF THE INVENTION
Firestops are thermal barrier materials or combinations of materials used for
filling gaps and
openings such as in the joints between fire-rated walls and/or floors of
buildings. For example,
firestops can be used in walls or floors to prevent fire and smoke from
passing through the
gaps or openings required for cables, pipes, ducts, or other conduits.
Firestops are also used to
fill joint gaps that occur between walls, between a ceiling and the top of a
wall ("head-of-wall"
joints), and between a floor and vertical wall ("perimeter" joints).
So-called "head-of-wall" joints pose a number of challenges for the
firestopping industry.
Walls are generally made of concrete block or other type of fire resistant
block. Ceilings (or
floors) are increasingly being made by pouring concrete onto fluted steel.
Walls are also
increasingly being made of gypsum wallboard affixed to a framework of metal
studs capped
by a horizontally extending track. Although the distance between the concrete
block wall or
horizontally extending track at the top of the wall is often fixed in
relationship to the ceiling,
the concrete block and gypsum wallboards are subject to expansion and
contraction due to
motion of other building components, ground settling, or other causes.
For such head-of-wall joints, it is known to use mineral wool batt as a
thermal resistant
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firestop material due to its ability to provide for cyclic movements in the
wallboard material.
Mineral wool batt is also used at the head.-of-wall joints for block walls.
See, e.g., U.S. Pat.
No. 4,756,945. The mineral wool is cut into separate sheets that are
appropriately sized
depending on the specific geometry of the fluted steel ceiling. The sheets
need to be stacked
and compressed (e.g., a minimum 50%) when packed into the joint gap. In some
situations, a
fireproofing material is spray-applied into the spaces of the fluted ceiling
to supplement the
mineral wool in the joint. In either case, the mineral wool approach requires
labor and time.
After packing of the mineral wool batt into place above the wall, the
construction worker must
then spray an elastomeric coating, using a minimum one-eighth inch thickness,
against the
exposed side surfaces of the compressed mineral wool layers. The coating must
overlap a
minimum of one half inch onto the ceiling and wall surfaces. Thus, the use of
mineral wool
batt and elastomeric spray coating provides for the ability of the resultant
firestop to
accommodate some cyclic movement (compression and extension) in various
components
such as the gypsum wallboards on either side of the head-of-wall joint.
In addition, a thermal barrier and method is known that employs introducing
into the opening
or gap at least one (empty) thermal barrier molding bag to receive a flowable
firestop material
that is to expand the bag within the hole or joint gap and harden within the
bag; thereby
molding a thermal barrier within the hole; or joint gap. See U.S. Pat. No.
7,043,880. This
method is inconvenient, labor intensive and time-consuming, and therefore
quite costly.
One objective of the present invention is to provide a more convenient and
cost-effective
method for installing a thermal barrier in shaped openings and joint gaps such
as are found in
"head-of-wall" joints.
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Another objective of the invention is to provide novel thermal barriers that
may be used
conveniently and safely in hard-to-reach building or ship vessel joint gaps or
holes. For
example, the location of a head-of-wall joint next to an elevator shaft or
crawl space would
render difficult the installation of mineral wool/coating systems, because the
task of coating
both sides would be complicated by the lack of convenient access. With the
present invention,
a thermal barrier for both sides could be completed while the wall is being
built, thereby
obviating this problem.
A still further objective of the invention is to enhance safety of
installation. An applicator must
climb up and down ladders on a frequent basis when working on head-of-wall
joint
assemblies. In the first instance, there is the fitting and hand-packing of
mineral wool material
into the joint gap. In the second instance, there is the coating of
elastomeric material to create
a continuous surface between the ceiling, firestop, and wall. In both cases,
the ladder may
require frequent repositioning, and this is especially the case where joint
gaps extend lengthy
distances of ten to twenty feet or more. Frequent climbing up and down ladders
would also be
required in "perimeter barrier" systems if it were desired to apply an
elastomeric coating onto
the bottom face of a mineral wool firestop that has been packed between a
floor and a wall,
because the installer would need to go to the floor below the firestop to coat
the bottom face of
the mineral wool material. With the present invention, it is not necessary to
repeatedly access
the work area.
In view of the prior art disadvantages, novel thermal barriers and methods are
believed to be
needed.
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SUMMARY OF THE INVENTION
In surmounting the disadvantages of the prior art, the present invention
provides a method and
system for installing a thermal barrier in openings and gaps in or between
building structures
such as walls, ceilings and floors. In so doing, the present invention
provides increased
convenience, effectiveness and safety in comparison to the prior art mineral
wool/coating and
other methods. The thermal barriers of the present invention have the ability
to conform to the
openings and gap spaces between the tops of walls and fluted metal decks. The
thermal
barriers also have the ability to permit movement of the various building
structures around the
openings or gaps. In particular, protection on both sides of "head-of-wall"
joint assemblies
(arising between a wall and ceiling), may be conveniently accomplished by the
thermal
barriers and methods of the present invention.
In one aspect, there is provided a building, joint structure, comprising: a
thermal barrier in a
joint gap between a first structure comprising a wall and a second structure
comprising a
ceiling or floor, said thermal barrier comprising at least one firestop block,
the firestop block
comprising cementitious or intumescent fire resistant material as recognized
in the U.L. Fire
Resistant Directory and that is configured to conform to the shape and depth
dimensions of the
joint gap.
In another aspect, there is provided a firestop block made of cementitious or
intumescent fire
resistant material as recognized in the U.L. Fire Resistant Directory and
having a top surface, a
bottom surface, side surfaces and end surfaces, and wherein said firestop
block is configured
to conform to the shape and depth dimensions of a joint gap between a first
structure
comprising a wall and a second structure comprising a ceiling or floor.
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In another aspect, there is provided a method of creating a thermal barrier in
a building joint
gap between a first structure comprising a wall and a second structure
comprising a ceiling or
floor, comprising the step of: inserting into said joint gap at least one
firestop block
comprising cementitious or intumescent fire resistant material as recognized
in the U.L. Fire
5 Resistant Directory that is configured to conform to the dimensions of the
joint gap.
An exemplary method of the present invention comprises providing a first and
second
structure which define therebetween a gap, such as the joint gap between a
wall and a fluted
ceiling, introducing into the opening or gap at least one firestop block that
is constructed of
firestop material and configured to be slideably inserted into the fluted
opening between the
wall and the floor. A flexible firestop material, such as an elastomeric
sealant, silicone,
polyethylene or polyurethane foam backer rod, or spray, as are commercially
available, is
supplied as a sealant of filler between any remaining space between the
firestop block and the
wall or fluted metal ceiling, thereby forming a molded a thermal barrier
within the fluted hole
or gap.
The firestop blocks of the invention can be made of any dense, firestop
material as recognized
in the UL Fire Resistance Directory, 2007 ed., but cementitious materials such
as concrete
blocks (CAZT) or pre-cast concrete units (CFTV) are preferred. In addition,
the firestop
blocks may be made of fire resistant intumescent materials, which expand when
they are
heated, as by a fire. Intumescent materials, however, may be more expensive
than cementitous
materials. Although the firestop blocks can be of any shape to match the shape
of the fluted
metal deck, they are generally configured as trapezoidal shaped bars and are
dimensioned to
be slidably inserted into the openings created at the tops of walls and the
fluted metal deck
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setting on top of the wall. The base and height of the firestop blocks may be
of any dimension
as required by the shape of the flutes on the metal deck, but are generally
about 4-6 inches
wide, with about 5 inches being preferred, are generally 1-4 inches high, with
2'/2 inches being
preferred. The firestop blocks may also be of any length, but generally, 16 to
18 inches is
preferred.
Typically, both the floor and fluted metal ceiling of the structure are in
place when the walls
are constructed. The walls are thus built up to the fluted metal ceiling,
leaving a space at the
top, particularly with respect to the position of the flutes. The firestop
blocks are then set on
the tops of the walls and, in the case of cement block walls, are held in
place by mortar on the
underside of the firestop blocks. Where the wall is made of gypsum and is
capped by a metal
track, fire resistant adhesive can be used to attach the firestop block to the
metal track. The
spaces that remain on the top and sides of the firestop block and the fluted
metal deck can be
filled or sealed using intumescent fillers, caulks or sealers as are available
commercially, e.g.,
such as hydratable cementitious slurry, an intumescent material, a
superabsorbent polymer;
silicone; polyurethane (foam); hydrated silica gel; inorganic dessicants
(e.g., molecular sieves
such as zeolites; silica gel; calcium oxide; calcium sulfate; calcium
chloride; barium oxide;
phosphorous pentoxide); fibers; mineral wool; fiber glass; or mixture thereof.
Firestop barriers made in accordance with the above-described in-situ methods
of the present
invention provide excellent fire resistance and sealing ability as well as
smoke and acoustic
barrier properties that also provides for flexibility. They are also
sufficiently strong to resist
dislodgement from the gap or opening due to pressure (e.g., force from a water
hose) and are
highly amenable to visual inspection.
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Further features and advantages of the invention are described in detail
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
The following detailed description of exemplary embodiments may be more
readily
appreciated in conjunction with appended drawings, wherein:
FIG. 1 is a perspective view of a so-called "head-of-wall" joint assembly for
a gypsum wall
(PRIOR ART);
FIG. 2 is a perspective view of a so-called "head-of-wall" joint assembly for
a block wall
(PRIOR ART);
FIG. 3 is a perspective diagram of a mineral wool batt firestop "head-of-wall"
joint assembly
(PRIOR ART);
FIG. 4 is a perspective view of a firestop block for a fluted metal deck;
FIG. 5 is an elevation sectioned view of a firestop block for a fluted deck in
use on a concrete
masonry ("CMU") wall illustrating deck flutes perpendicular to the CMU wall;
and
FIG. 6 is an elevation sectioned view of a firestop block for a fluted deck in
use on a CMU
wall illustrating deck flutes parallel to the CMU wall.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings wherein the showings are for purposes of
illustrating different
embodiments of the present invention and not for purposes of limiting the
same, FIG. 4
perspectively illustrates a firestop block 10 configured to be slidably
inserted into a fluted
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opening 42 (see FIG. 1) of a fluted metal deck 40.
The present invention employs one or more thermal barrier firestop blocks 10
that may be
conveniently placed in openings in a structure, such as a wall, ceiling, or
floor, or conveniently
placed in gaps such as are defined in the joints between walls, ceilings,
and/or floors. The
firestop blocks are placed in the hole or joint gap formed between the head of
a wall and a
fluted metal deck. A flexible firestop material is introduced around the
firestop block, thereby
filling and sealing the space within the hole or joint gap and the fluted
deck, and the
filler/sealant firestop material is then allowed to harden within the hole or
joint gap to provide
a strong thermal barrier.
As shown in FIG. 1, a "head-of-wall" joint gap fluted opening 42 appears
between the top of a
vertical wall 44 and fluted metal ceiling or deck 40 (PRIOR ART). In this
case, the wall is
made by attaching a horizontal metal track 46 or runner to a fluted metal
ceiling 40 which runs
in a perpendicular manner to the wall 44. The fluted metal ceiling 40 has
fluted portions 40B
which are somewhat lower than the top ceiling portion 40A, and thus a fluted
opening 42 is
defined between the top ceiling portion 40B and the top of the wall, which in
this case is the
horizontal track 46. Metal studs 48 are attached to the horizontal track 46
and connected to the
floor below. Gypsum wallboards can be affixed on either side of the studs 48
to complete the
wall assembly (PRIOR ART), and gaps 49 are typically left between the tops of
the horizontal
track 46 to permit movement of the wallboards. Typically, the fluted joint gap
openings 42 can
be about 5 inches wide at its narrowest point and about 6 inches wide at its
widest point,
although these dimensions may vary. Also, the height of the fluted joint gap
openings 42 can
vary, but generally is about three inches.
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Similarly, FIG. 2 illustrates a "head-of-wall" joint for a concrete block wall
where gap fluted
joint gap openings 42 appear between the top of the concrete block wall 45 and
fluted metal
ceiling or deck 40 (PRIOR ART). The fluted metal ceiling 40 has fluted
portions 40B which
are somewhat lower than the top ceiling portion 40A, and thus a fluted joint
gap opening 42 is
defined between the top ceiling portion 40B and the top of the wall. Metal
studs 48 are
attached to the horizontal track 46 and connected to the floor below. Gaps 49
are typically left
between the tops of the concrete block wall 45 and the fluted metal deck 40.
As illustrated, the
fluted joint gap openings 42 can be about 6 inches wide and the height of the
fluted joint gap
openings 42 is about 3 inches.
FIG. 3 illustrates the prior art mineral wool batt system used to fill the
fluted joint gap opening
42 and gaps 49. There, the mineral wool batt is folded into the desired
thickness and inserted
into the corresponding openings.
As shown if FIG. 4, an exemplary firestop block 10 of the invention. The
firestop blocks of the
invention are made of any dense, firestop (or fire resistant) material as
recognized in the UL
Fire Resistance Directory, 2007 ed. Cementitious materials such as concrete
blocks (CAZT) or
pre-cast concrete units (CFTV) are preferred. Hydratable cementitious
materials are also
preferred. In addition, the firestop blocks may be made of fire resistant
intumescent materials,
which expand when they are heated, as by a fire.
The firestop blocks 10 of the invention are configured to conform to fluted
joint gap openings
42. Specifically, firestop block 10 is shaped as an elongated trapezoid,
having a width
dimension 12, a height dimension 14 and a length dimension 16. These
dimensions are
designed to generally conform to the corresponding dimensions of fluted joint
gap openings
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42, but are sufficient to allow a space between the firestop block 10 and the
fluted metal deck
40. The base and height of the firestop block 10 may be of any dimension as
required by the
shape of the flutes 40A and 40B on the metal deck 40, but generally, the width
12 of firestop
block 10 is about 4-6 inches, with about 5 inches being preferred. The height
14 of the firestop
5 blocks 10 are generally about 1-4 inches, with 2'/2 inches being preferred.
The firestop blocks
10 may also be of any length 16, but generally, about 16 or 18 inches is
preferred. In addition,
the firestop blocks 10 of the invention may contain scoring 18 on the upper
surface 17 of the
block 10, so that the length 16 of the blocks 10 can be easily shortened by
breaking the blocks
at the scoring points in, in a manner known by masons. The scorings 18 can be
located in any
10 desired position on the upper surface 17 of the blocks, but are preferred
to be in the center and
in "quarter" positions so that the blocks 10 can be broken into 12 inch, 8
inch and 4 inch
blocks to match the width of a CMU wall.
As shown in FIG. 5, an exemplary thermal barrier 1 of the invention is made by
inserting at
least one firestop block 10 at the top of a CMU wall 30 between the top of the
wall 32 and top
ceiling portion 40A of the fluted metal ceiling 40. As seen in FIG. 5, the
direction of the wall
30 is perpendicular to the direction of the fluted joint gap openings 42 of
the fluted metal
ceiling 40. In this embodiment, the firestop blocks 10 can be inserted
lengthwise into the
fluted joint gap openings 42, after the length 16 is adjusted to the width of
the wall 30, if
necessary. The fluted metal ceiling 40 is connected to the top 32 of wall 30
by applying a
mortar material 50 to the top of the wall 30. Thus, the fluted metal ceiling
40 is on the top of
mortar 50 on top of wall 30. When the firestop blocks 10 are inserted into the
fluted joint gap
openings 42, the firestop blocks rest on top of the mortar 50 and are held in
place when the
mortar 50 hardens.
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A flexible sealant or filler material 20 is then introduced into the remaining
gap 22 in the
fluted joint gap opening 42 between the firestop block 10 and the fluted
ceiling 40, which is
generally about '/2 of an inch. Both the mortar 50 and the sealant material 20
protect the
exposed fluted joint gap opening 42, so that heat and smoke do not penetrate
through the wall
at the top portion.
The sealant material 20 can be made of any flexible spacer material, such as
intumescent
fillers, caulks or sealers as are available commercially, e.g., such as
hydratable cementitious
slurry, an intumescent material, a superabsorbent polymer; silicone;
polyurethane (foam);
hydrated silica gel; inorganic dessicants (e.g., molecular sieves such as
zeolites; silica gel;
calcium oxide; calcium sulfate; calcium chloride; barium oxide; phosphorous
pentoxide);
fibers; mineral wool; fiber glass; or mixture thereof.
As shown in FIG. 6, another exemplary thermal barrier 1 of the invention can
be made when
the fluted metal ceiling 40 is oriented in the same direction as, or parallel
to, the CMU wall 30.
In this case, the firestop blocks 10 are positioned on top of the wall 30
parallel to the direction
of the wall. Enough firestop blocks 10 are inserted to fill the entire length
of the fluted joint
gap opening 42. Thus, no fluted joint gap opening 42 appears on top of the
wall in this case
(because the spaces defined between ceiling surfaces 40A and 40B do not appear
on either
side of the wall). However, firestop sealant material 20 is introduced along
the edges, such that
a thermal firestop barrier is formed at the top of the wall 30.
Thus, an exemplary method of the invention comprises inserting at least one
firestop block 10
into the fluted joint gap opening 42 between two structures, such as a wall
and ceiling, affixing
the firestop blocks 10 on its bottom surface using a mortar material, then
introducing a firestop
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sealant material into the spaces 22 (FIG. 5) between the top and sides of the
firestop block 10
and the fluted ceiling 40, allowing the mortar and sealant material to harden
inside the fluted
joint gap openings 42, whereby a thermal barrier is formed.
The thermal barriers of the invention are contemplated primarily for use in
joint assemblies
(e.g., floor-to-floor joint systems, wall-to-wall joint systems, floor-to-wall
joint systems, and
head-of-wall joint systems).
The term "hydratable cementitious" material as used herein refers to material
that comprises at
least one cementitious binder that begins to harden when mixed with water.
Such a binder may
be Portland cement, masonry cement, or mortar cement, gypsum, stucco, Plaster
of Paris,
aluminous cement, pozzolanic cement, magnesium oxychloride, magnesium
oxysulfate,
calcium silicate-hemihydrate, as well as materials such as limestone, hydrated
lime, fly ash,
blast furnace slag, and silica fume. The hydratable cementitious materials may
in addition
optionally include fine aggregates (e.g., sand), coarse aggregates (e.g.,
crushed stone, gravel,
carbon flakes), or other fillers. Further exemplary cementitious materials may
optionally
contain, in addition to the cementitious binder, an intumescent material as
will be further
described hereinafter.
Exemplary hydratable cementitious materials used as flexible firestop
materials in the present
invention may further include one or more admixtures or additives, such as set
accelerators,
set retarders, water reducers (including superplasticizers and fluidity
enhancing agents),
rheology modifiers, air entraining agents, pigments or colorants, porous
aggregates (e.g.,
shredded expanded polystyrene, expanded vermiculite, perlite, etc.), fibers,
rheopectic agents
(e.g., granular attapulgite, sepiolite, or mixtures thereof), surfactants, and
other admixtures as
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conventionally known in the art.
Numerous patents and publications have disclosed intumescent compositions
containing one
or more polymeric materials in combination with phosphate-containing materials
and
carbonific or carbon-yielding materials, and such compositions, as known in
the art, are
believed to be suitable for use as firestop materials of the present
invention. See, e.g., U.S. Pat.
No. 3,513,114 of Hahn et al.; U.S. Pat. No. 5,487,946 of McGinniss et al.;
U.S. Pat. No.
5,591,791 of Deogon; U.S. Pat. No. 5,723,515 of Gottfried; PCT Publication No.
WO
94/17142 (PCTIUS94/00643) of Buckingham; and PCT Publication No. WO 98/04639
(PCT/US96/12568) of Janci.
Other exemplary intumescent materials include graphite flakes impregnated with
sulfuric or
nitric acids. Inorganic material flakes capable of exfoliation when heated
include vermiculite
and perlite.
When installed in the joint gap of a building structure, the in-situ thermal
barriers of the
invention are tightly conformed to the shape of the structure or structures
surrounding/defining
the joint gap. It is envisioned that preferred thermal barriers of the
invention, when installed in
joint assemblies, are capable of passing fire endurance tests and hose stream
tests in
accordance with the "UL Standard for Safety for Tests for Fire Resistance of
Building Joint
Systems, UL 2079," Third Edition, Dated Jul. 31, 1988, (Underwriters
Laboratories, Inc.,
Northbrook, Ill.).
The foregoing discussion and examples are provided for illustrative purposes
and not intended
to limit the scope of the invention as claimed.
