Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVED FIRE, ACOUSTIC, AND THERMAL RESISTANT
CONSTRUCTION
BackQround of the Invention
(1) Field of the Invention
The present invention relates generally to a structure having a fire
resistance
rated, area separation wall and, more particularly, to a fire resistance
rated, area
separation wall for a structure which also provides acoustic attenuation and
thermal
resistance without adversely affecting the fire resistance of the area
separation wall.
(2) Description of the Prior Art
Multi-family residential constructions typically include a separation wall
constructed of wood members and having a material barrier between the units.
These
wood members may include dual two-by-four framing with a drywall surface on
both
sides of the framing. In most cases, this type of construction requires that
the drywall
be attached to the interior surface of the framing before the framing is
placed upright
to serve as a wall. After the framing is placed upright, insulation material
may be
positioned in the framing, and later an additional drywall membrane is
fastened to the
outside of the framing to complete an interior wall. This process is
expensive, labor-
intensive and time consuming.
One purpose of such a dual membrane construction of an area separation wall
is to provide a fire resistance separation between adjacent spaces to meet
federal, state
and local regulations concerning the fire resistance of such a construction.
Underwriters Laboratories Inc. (UL), an independent, not-for-profit product
safety
testing and certification organization, has been testing products for public
safety for
more than a century. Because UL has an undisputed reputation as the leader in
U.S.
product safety and certification, it is advantageous to obtain classification
of a
building product by UL. One UL test, ANSI/UL 263 (ASTM E119 and NFPA 251),
involves rating such a separation wall for fire resistance. If a separation
wall
including only outer membranes could be developed that is sufficiently fire
resistant
to gain UL classification for more than two hours, such a separation wall
would be
less costly to construct than a conventional separation wall. Additionally,
there is a
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need for providing walls that provide acoustic attenuation, especially as more
and
more condominiums and townhouses having shared walls are built.
Another purpose of such a dual membrane construction of an area separation
wall is to provide improved acoustic and thermal resistance.
Thus, there is a need for a structure having an arca separation wall, the
structure including a first and second building units and an area separation
wall
having at least one outer membrane. There is also a need for an area
separation wall
that provides acoustic attenuation and improved thermal resistance without
adversely
affecting the fire resistance of the area separation wall.
Summary of the Invention
The present invention is directed to a structure having an area separation
wall
including: a first building unit; a second building unit; and an area
separation wall
having only outer membranes. The area separation wall provides improved fire,
thermal, and sound resistance. The outer membranes provide acoustic
attenuation
without adversely affecting the fire resistance of the area separation wall.
In an embodiment, the area separation wall includes: an interior support
structure; at least one outer membrane on each side of the interior support
structure,
the outer membranes providing acoustic attenuation; and a substantially
organic
thermal material barrier between the outer membranes, The structure may
further
include a tying structure connecting the area separation wall to the first
unit and the
second unit.
In an embodiment, the tying structure may include a top plate attached to the
top edge of said area separation wall and a bottom plate attached to the
bottom edge
of said area separation wall. The tying structure and said top plate may form
a double
top plate. The top plate and said bottom plate may be less than about 10 feet
apart.
In an embodiment, the first building unit is an occupiable space and the
occupiable space is residential. The residential occupiable space may be a
town
home. The second building unit may be an occupiable space. In an embodiment,
the
occupiable space is residential. The residential occupiable space is a town
home.
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The interior. support structure may include at least two structural interior
support members. The structural interior support members may include a
plurality of
vertical members. The plurality of vertical members may be spaced apart. The
plurality of vertical members are spaced apart no more than about 24 inches.
Preferably, the plurality of vertical members are 2x4 wood. The plurality of
vertical
members may be 2x4 metal.
The plurality of vertical members may be 2x10 or less thickness dimension of a
material selected from the group consisting of wood, metal, other materials,
and
combinations thereof. The plurality of vertical members further include cross
bracing
at about the mid height of said plurality of vertical members. There may be a
physical
gap between said structural interior support members.
In a preferred embodiment, the outer membranes are fire resistant wallboard.
Preferably, the fire resistant wallboard is a gypsum wallboard (GWB) Type X or
Type
C as defined in ASTM C11. The gypsum wallboard conforms to ASTM Test C-36-
96. Preferably, the substantially organic material barrier is selected from
the group
consisting of fibrous material, granular material, pellet material, aggregated
material,
agglomerated material, closed cell foam, open cell foam, fire retardants,
binders and
mixtures thereof. The substantially organic material barrier may be a natural
material.
The natural material is cellulosic. In an embodiment, the substantially
organic
material barrier includes an inorganic material. The inorganic material is
selected
from the group consisting of fiberglass, rock wool, pearlite, mineral wool,
asbestos,
cementitious materials, fire retardants, binders, and mixtures thereof.
Preferably, the
substantially organic material barrier is an acoustically transmission
resistive material.
In an embodiment, there are an unequal number of like outer membranes. The
outer membranes may be of unequal thickness. The outer membranes may be made
of unlike materials. In an embodiment, the outer membranes may be made of
unlike
materials and are of unequal thickness.
Accordingly, one aspect of the present invention is to provide a structure
having an area separation wall. The structure may include: a first building
unit; a
second building unit; and an area separation wall having only outer membranes,
the
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outer membranes also providing acoustic attenuation. The area separation wall
provides improved fire, thermal and sound resistance and combinations thereof.
Another aspect of the present invention is to provide an area separation wall
for a structnre. The area separation wall may include: an interior support
structure;
and at least one outer membrane on each side of the interior support
structure. The
outer membranes provide acoustic attenuation; and a substantially organic
material
barrier between the outer. membranes. The area separation wall also provides
improved fire, thermal and sound resistance and combinations thereof.
Still another aspect of the present invention is to provide a structure having
an
area separation wall. The structure may include: a first building unit; a
second
building unit; and an area separation wall. The area separation wall may
include: (i)
an interior support structure; (ii) at least one outer membrane on each side
of the
interior support structure, and (iii) a substantially organic material barrier
betwecn the
outer membranes; and a tying structure connecting the fire resistance rated,
area
separation wall to the first unit and the second unit. The outer membranes may
provide acoustic attenuation. The area separation wall also provides improved
fire,
thermal and sound resistance and combinations thereof.
These and other aspects of the present invention will become apparent to those
sldlled in the art after a reading of the following description of the
preferred
embodiment when considered with the drawings.
Brief Description of the Drawinns
Figure 1 is a front perspective view of a structure having an area separation
wall constructed according to the present invention;
Figure 2 is a side view of the area separation wall for a sttvcture shown in
Figure 1 including a tying structure;
Figure 3 is a side view of the area separation wall for a structure shown in
Figure 1 without a tying structure;
Figure 4 is a side view of an embodiment of the area separation wall for a
structure shown in Figure 1 without a tying structure and with an additional
outer
membrane on a side of the area separation wall;
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CA 02642214 2008-10-29
Figure 5 is a side view of an embodiment of the area separation wall for a
structure shown in Figure 1 without a tying structure and with an additional
outer
membrane on each side of the area separation wall; and
Figure 6 is a cross-sectional, side view of the confined space showing the
organic material between the outer membranes in locations where an interior
support
structure is not located.
Description of the Preferred Embodiments
In the following description, like reference characters designate likc or
corresponding parts throughout the several views. Also in the following
description,
it is to be understood that such terms as "forward," "rearward," "left,"
"right,"
"upwardly," "downwardly," and the like are words of convenience and are not to
be
construed as limiting terms.
As used herein "improved" fire, sound or thermal resistance refers to a
measurable increase in fire resistance, sound resistance or thermal resistance
when
comparing the present invention with only outer membranes to a conventional
area
separation walls as described herein. Moreover, "low-conductivity", "thermally
resistive", "acoustically transmission resistant", "electrically non-
conductive", and the
like are relative to conventional area separation walls which are composed of
more
than outer membranes.
Referring now to the drawings in general and Figure 1 in particular, it will
be
understood that the illustrations are for the purpose of describing a
preferred
embodiment of the invention and are not intended to limit the invention
thereto. As
best seen in Figure 1, a structure having an area separation wall, generally
designated
10, is shown constructed according to the present invention. In the preferred
embodiment, the area separation wall is a fire resistance rated, area
separation wall.
More preferably, the fire resistance rated, area separation wall is a 2-1/2,
3, 3-1/2 or 4
hour or longer rated firewall according to ASTM E119-2003.
The structure having an area separation wall includes a first building unit 12
and a second building unit 14. Additional building units 16 may also be part
of the
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CA 02642214 2008-10-29
structure 10. The first building unit 12 and second building units 14 may be
occupiable spaces, which may be residentially occupiable spaces, such as town
homes. A town house is generally defined by the 2000 International Residential
Code
as a single-family dwelling unit constructed -as a group of three or more
attached units
in which each unit extends from foundation to roof with open space on at least
two
sides. An area separation wall 18, constructed according to the present
invention, is
located between each building unit 12, 14, 16..
Figure 2 is a side view of one embodiment of the area separation wall 18
including an interior support structure 22 having at least one outer membrane
24 on
each side of the interior support structure 22, and a material barrier 26
between the
outer membranes 24.
In an embodiment, there are only outer membranes. In other words, the outer
membranes are on the outside of the wall studs rather than having a membrane
on
each side of both wall studs.
In a preferred embodiment, the material barrier 26 is a substantially organic
material barrier.
The interior support structure 22 includes at least two structurally
independent
interior support members 28. The structurally independent interior support
members
28 include a plurality of vertical members such as conventiona12x4. The 2x4
may be
made of wood or metal. Altematively, the plurality of vertical members may be
2x 10
or less thickness dimension and constructed of wood, metal, or other
materials. The
plurality of vertical members may be spaced apart less than about 24 inches
and may
include cross bracing 30 at about their mid height. The area separation wal118
includes a physical gap 32 between the structurally independent interior
support
members 28. The plurality of vertical members may be staggered to aid in
acoustic
transmission resistance.
Sound travels as a compression wave through air. When sound strikes a
barrier such as a wall, vibrations occur. Thus, wall studs can act as a
conduit for
acoustic transmission. Ilowever, by staggering the wall studs, acoustic
transmission
resistance is increased.
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CA 02642214 2008-10-29
A tying structure 34 connects the fust unit 12 and the second unit 14. The
tying structure 34 may be a conventional W. The tying structure is overlaid
top
plates 37 that is attached to the top edge of the interior support members 28.
A
bottom plate 36 is attached to the bottom edge of the interior support members
28.
Also, the maximum height of the area separation wall prcferably is 10 feet,
whereupon another wall would begin.
In other embodiments, other tying structures may be used. For instance, other
tying structares may be necessary where the occupiable spaces are staggered
either
horizontally or verdcally. Also, other membrane configurations may exist
where, for
example, part of the fire rated area separation wall is exposed as an exterior
wall on
one side, and not exposed, or as an interior wall, on the other side. Such a
configuration may occur when two adjoining town homes or other structures
connected to either side of a fire rated area separation wall are staggered
vertically or
horizontally, thus exposing part of the wall to the exterior environment on
one side
with no exterior exposure on the other side. This would likely result in the
membranes on the exterior side consisting of exterior cladding, building paper
and
other materials not normally associated with fire wall construction and
performance.
The outer membranes 24 preferably are a fire resistant wallboard, including
Type X or Type C gypsum wallboard (GWB) as defined in ASTM C11. The gypsum
wallboard preferably conforms to ASTM Test C-36-96. However, other types of
wallboard may be used. A single outer membrane may be placed on either side of
the
interior support structure. However, as seen in Figure 5, two or more outer
membranes may be placed on either side of the interior support structure. As
seen in
Figure 4, unequal numbers of outer mcmbranes may be placed on either side of
the
interior support structure. For instance, a single outer membrane 24 may be
placed on
one side of the interior support structure. In a preferred embodiment, two or
more
outer membranes 24 may be placed on each side of the interior support
structure. The
use of multiple outer membranes 24 on each side of the interior support
structure aids
in acoustic transmission resistance, fire resistance and thermal resistance.
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The outer membranes may be of unequal thicknesses on either side of the
interior support sttucture. In an embodiment, the outer membrane on either
side of
the interior support structure may be of different materials.
The substantially organic material barrier 26 between the outer membranes 24
may be selected from the group consisting of fibrous material, granular
material,
pellet material, aggregated material, agglomerated material, closed cell foam,
open
cell foam, fire retardants, binders and mixtures thereof. The substantially
organic
material barrier 26 may be a natural material. The natural material may be
cellulosic.
The substantially organic material barrier 26 may be an acoustically
transmission
resistant material.
The substantially organic material barrier 26 may also include inorganic
materials. The inorganic material is selected from the group consisting of
fiberglass,
rock wool, pearlite, mineral wool, asbestos, cementitious materials, fire
retardants,
binders, and mixtures thereof.
In the embodiment of Figure 6, the substantially organic material barrier
completely fills the area between the outer membranes.
Figure 3 is a side view of the preferred embodiment of the area separation
wall
18 that does not include a tying structure 34 connecting the first unit 12 and
the
second unit 14. Instead, the area separation wall 18 described in Figure 3
includes a
separate top plate 37 attached to another top plate 37 that is attached to the
top edge of
the interior support members 28. In both embodiments, a bottom plate 36 is
attached
to the bottom edge of the interior support members 28. Also, in both
embodiments,
the maximum height of the area separation wall preferably is 10 feet,
whereupon
another wall would begin.
As can be seen, the top of the area separation wall can be formed either by a
top plate 37 overlaid with a tying structure 34 or by a top plate 37 overlaid
with a
second top plate 37 separated by an inch. Thus, there are two configurations.
One is
with a single top plate 37 and a tying structure 34 that joins the two walls
(shown in
Fig. 2) and the other is two separate top plates with a space between them
(shown in
Fig. 3). In either case, this results in a double top plate being formed.
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As best seen in Figure 6, the material barrier 26 may completely fill the area
between the outer membranes 24 as well as the area between the interior
support
structure 22 as seen in Figure 2.
Certain modifications and improvements will occur to those skilled in the art
upon a reading of the foregoing description. It should be understood that all
such
modifications and improvements have been deleted herein for the sake of
conciseness
and readability but are properly within the scope of the following claims.
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