Note: Descriptions are shown in the official language in which they were submitted.
CA 02550234 2006-06-12
INSULATION SYSTEM WITH VARIABLE POSITION VAPOR RETARDER
TECHNICAL FIELD AND INDUSTRIAL
APPLICABILITY OF THE INVENTION
The present invention relates generally to an insulation system that contains
a
vapor retarder and more particularly to an insulation system in which the
vapor retarder is
variably positioned between insulative layers depending on geographic location
and/or
condensation potential.
BACKGROUND OF THE INVENTION
Fiber insulation is typically formed of mineral fibers (e.g., glass fibers) or
organic
fibers (e.g., polypropylene fibers), bound together by a binder material. The
binder
material gives the insulation product resiliency for recovery after packaging
and provides
stiffness and handleability so that the insulation product can be handled and
applied as
needed in insulation cavities of buildings. During manufacturing, the fiber
insulation is
cut into lengths to form individual insulation products, and the insulation
products are
packaged for shipping to customer locations. One typical insulation product is
an
insulation batt, which is suitable for use as wall insulation in residential
dwellings or as
insulation in the attic and floor insulation cavities in buildings.
Most insulation products have a vapor retarder on one side of the insulation
product to retard or prohibit the movement of water vapor through the
insulation product.
Insulation products that contain a vapor retarder facing are installed with
the vapor retarder
side placed flat on the edge of the insulation cavity. Water vapor moves from
an area of
high vapor pressure to an area of low vapor pressure. Thus, in winter months,
when the
outside air is cooler than the inside air, the water vapor drive is from the
interior of the
building to the exterior of the building. In summer months, when the air
conditioned air is
cooler than the external air, the water vapor drive is from the exterior to
the interior.
In winter months, when the vapor drive is from the interior to the exterior,
it is
desirable to place the vapor retarder on the inside of the insulation cavity
(e.g., toward the
inside of the building) to prevent condensation within the insulation product.
However,
during the summer months when the outside air is warmer than the inside air,
this internal
placement of the vapor retarder may result in condensation collecting in the
insulation
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CA 02550234 2006-06-12
product. Consequently, in summer months, it is desirable to place the vapor
retarder on
the exterior side of the insulation cavity (e.g., toward the outside of the
building) to reduce
the amount of water vapor entering the building during the air conditioning
season.
However, this external placement of the vapor retarder may result in the vapor
cooling and
condensing within the insulation in the winter. Thus, in geographic locations
that have
seasonal temperature changes, a;ingle vapor retarder placed on either the
inside or the
outside of the insulation cavity may result in condensation of water vapor
into the
insulation at some time during the year.
It has been proposed by some building researchers to place a vapor retarder on
both
the inside and the outside of the insulation cavity to reduce condensation in
both the winter
and the summer months. (Yost, et al., Basement Insulation Systems, Building
Science
Corporation, 2002, page 7). Although this dual vapor retarder approach is
effective in
reducing the amount of condensation that occurs in both the winter and the
summer
months, if moisture does enter the insulation, such as by a rip or tear in the
vapor retarder
that may occur during the installation of the insulation product, the water
vapor becomes
trapped between the opposing vapor retarders, and the dual vapor retarders
prevent the
moisture in the insulation from drying to either the inside or the outside of
the building.
Another approach that may be used to reduce condensation is to install a water-
permeable vapor retarder on either the interior or the exterior of the
insulation. The water-
permeable vapor retarder allows water to escape in humid conditions. In dry
conditions,
the water-permeable vapor retarder retains its vapor retarding abilities.
(1997 ASHRAE
Handbook Fundamentals, Inch-Pound Edition, American Society of Heating,
Refrigerating
and Air Conditioning Engineers, Inc., chapter 23, page 8). Thus, the water-
permeable
vapor retarder permits a wall to remove condensation from the insulation in
the summer
months. Although such a vapor retarder may be able to remove some condensation
from
within the insulation, water-permeable vapor retarders are very costly and
thus impractical.
Water vapor condensing and collecting in the insulation product results in a
damp
insulation product, which causes mold, mildew, and decay of the wood studs in
the
framing of the building, and a loss in their insulting properties. Thus, there
exists a need
in the art for an insulation system that reduces the condensation of water
vapor in
insulation products in various geographical locations.
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CA 02550234 2006-06-12
SUMMARY OF THE INVENTION
An object of the invention is to provide a method for positioning a continuous
vapor retarder within an insulation system to reduce condensation. First, the
temperature
differential between the exterior temperature and the interior temperature of
the building is
calculated. This temperature differential is then divided by the R-value of
the insulation to
obtain the approximate amount of temperature increase/decrease per single R-
value of
insulation (e.g., "the incremental R-value temperature change"). Thus, for
each R-value of
insulation, the temperature of a vapor retarder will increase or decrease in
temperature
from the internal or external temperature in an amount approximately equal to
the
incremental R-value temperature change as the vapor retarder is moved through
the
insulation.
Various possible temperatures of the vapor retarder within the insulation
system
may then be determined using the incremental R-value temperature change. The R-
values
of the insulation layers on either side of the vapor retarder may be
determined by a
condensation potential analysis for the particular geographic region. To
reduce
condensation, the vapor retarder is positioned at a location between a first
layer of
insulation and a second layer of insulation where its temperature remains
above the
interior dew point in the winter and above the outside dew point temperature
in the
summer. Preferably, the vapor retarder is positioned within the insulation
system such that
the vapor retarder temperature is above the interior dew point in the summer
and above the
outside dew point temperature in the winter for the entire year.
In some geographic locations, the placement of the vapor retarder may result
in a
small amount of condensation within the insulation system at some point during
the year.
An analysis of the amount of daily condensation that occurs may be conducted.
The
amount of condensation that may occur within the insulation system depends on
the
temperature difference between the dew point temperature and the vapor
retarder
temperature and the length of time that the temperature of the vapor retarder
is below the
dew point temperature. By positioning the vapor retarder within the insulation
system
such that the amount of time that the temperature of the vapor retarder is
below the dew
point temperature is reduced, the amount of condensation will also be reduced.
By conducting an analysis of the condensation potential for an insulation
system 24
hours a day for 365 days, the total condensation potential for the entire year
for a given
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CA 02550234 2006-06-12
vapor retarder position may be determined for a given climate. This
condensation
potential may then be quantitatively compared to the condensation potentials
for vapor
retarders at other positions within the insulation system and an optimum
location for the
vapor retarder at that geographic location may be determined which reduces the
overall
condensation potential of the insulation system over an entire year for that
given
geographical location. Preferably, a computer program is used to conduct these
yearly
condensation potential calculations.
Another object of the present invention is to provide an insulation system
that
contains a continuous vapor retarder that is variably positioned between a
first insulation
layer having a first thickness and a second insulation layer having a second
thickness. The
thicknesses of the first and second insulation layers may be determined by the
analysis
described above. The first layer of insulation is affixed to a wall, which is
preferably a
wall that does not contain a wood or metal stud framing structure. In a
preferred
embodiment, the first layer of insulation is a foam board or high density
fiberglass
insulation that has sufficient strength and durability to support a vapor
retarder and
subsequent layer of insulation. Mechanical fasteners or adhesives may be used
to fasten
the first layer of insulation to the wall. The first layer of insulation may
be applied in a
step-wise fashion until the wall is covered. A continuous vapor retarder is
then attached to
the first layer of insulation. Alternatively, a vapor retarder may be pre-
applied to the first
layer of insulation. When the vapor retarder is pre-applied to the first layer
of insulation,
the joints between the first insulation layers may be taped to provide a
substantially
continuous vapor retarder.
Lineals are then horizontally and vertically affixed to the vapor retarder to
form
insulation spaces. Lineals may be formed of a base member and two vertically
projecting
arms. The second layer of insulation is placed into the insulation spaces
adjacent to the
vapor retarder. Preferably, the second layer of insulation contains a
permeable finished
surface that provides an aesthetic appearance and which meets functional
requirements
such as damage resistance and fire resistance. If the second layer of
insulation does not
contain a finished surface, a separate finished surface may be attached to the
second layer
of insulation. It is preferred that the finished surface does not act as a
second vapor
retarder. Trim pieces are then attached to the lineals over the finished
surface to complete
the insulation system.
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CA 02550234 2006-06-12
The foregoing and other objects, features, and advantages of the invention
will
appear more fully hereinafter from a consideration of the detailed description
that follows,
in conjunction with the accompanying sheets of drawings. It is to be expressly
understood,
however, that the drawings are for illustrative purposes and are not to be
construed as
defining the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is a schematic elevational illustration of a masonry wall;
FIG. lb is an end view of the schematic illustration depicted in FIG. la;
FIG. 2a is a schematic elevational illustration of the placement of a first
sheet of
the first layer of insulation on the concrete block wall depicted in FIG. 1 a;
FIG. 2b is an end view of the schematic illustration depicted in FIG. 2a;
FIG. 3a is a schematic elevational illustration of the placement of a second
sheet of
the first layer of insulation;
FIG. 3b is a an end view of the schematic illustration depicted in FIG. 3a;
FIG. 4a is a schematic elevational illustration of the placement of the
lineals on the
first layer of insulation;
FIG. 4b is an end view of the schematic illustration depicted in FIG. 4a;
FIG. 5a is an end view that depicts the cross-sectional configuration of a
lineal for
use with the insulation system of the present invention;
FIGS. 5b - 5f are end views that depict the cross-sectional configurations of
various trim pieces for use with the insulation system of the present
invention;
FIG. 6a is a schematic elevational illustration of the placement of the second
layer
of insulation between the lineals;
FIG. 6b is an end view of the schematic illustration depicted in FIG. 6a;
FIGS. 7a - 7d are schematic elevational illustrations of various placements of
the
vapor retarder within a modular insulation system;
FIG. 8a is a schematic elevational illustration of the placement of a vapor
retarder
in Experimental Insulation System 1;
FIGS. 8b - 8c are graphical illustrations depicting the outside temperature,
the
outside dew point temperature, and the vapor retarder temperature vs. the time
of day for
Experimental Insulation System 1;
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CA 02550234 2006-06-12
FIG. 9a is a schematic elevational illustration of the placement of a vapor
retarder
in Experimental Insulation System 2;
FIGS. 9b - 9c are graphical illustrations depicting the outside temperature,
the
outside dew point temperature, and the vapor retarder temperature vs. the time
of day for
Experimental Insulation System 2;
FIG. I Oa is a schematic elevational illustration of the placement of a vapor
retarder
in Experimental Insulation System 3;
FIGS. 10b - 10c are graphical illustrations depicting the outside temperature,
the
outside dew point temperature, and the vapor retarder temperature vs. the time
of day for
Experimental Insulation System 3;
FIG. 11 a is a schematic elevational illustration of the placement of a vapor
retarder
in Experimental Insulation System 4;
FIGS. l lb - l lc are graphical illustrations depicting the outside
temperature, the
outside dew point temperature, and the vapor retarder temperature vs. the time
of day for
Experimental Insulation System 4;
FIG. 12a is a schematic elevational illustration of the placement of a vapor
retarder
in Experimental Insulation System 5; and
FIGS. 12b - 12c are graphical illustrations depicting the outside temperature,
the
outside dew point temperature, and the vapor retarder temperature vs. the time
of day for
Experimental Insulation System 5.
DETAILED DESCRIPTION AND
PREFERRED EMBODIMENTS OF THE INVENTION
Unless defined otherwise, all technical and scientific terms used herein have
the
same meaning as commonly understood by one of ordinary skill in the art to
which the
invention belongs. Although any methods and materials similar or equivalent to
those
described herein can be used in the practice or testing of the present
invention, the
preferred methods and materials are described herein. It is to be noted that
like numbers
found throughout the figures refer to like elements.
The present invention relates to an insulation system that contains a vapor
retarder
that is variably positioned between insulative layers depending on geographic
location
and/or condensation potential. In particular, the vapor retarder is positioned
with a first
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CA 02550234 2006-06-12
insulation layer having a first thickness located on one side of the vapor
retarder and a
second insulation layer having a second thickness located on the opposing side
of the
vapor retarder. The first and second thicknesses may be equal to each other,
or one
thickness may be greater than the other.
Temperatures of the vapor retarder vary depending upon its location in the
insulation system. For example, a vapor retarder placed on the exterior side
of a wall with
all of the insulation placed towards the interior will have a temperature that
matches or
nearly matches the outside air temperature. Similarly, a vapor retarder placed
on the
interior side of a wall with all of the insulation placed towards the exterior
will have a
temperature that is the same or nearly the same as the temperature of the
interior of the
building. On the other hand, if tlie vapor retarder is placed internally
within the insulation
system such that insulation is located on both sides of the vapor retarder,
the temperature
of the vapor retarder is insulated. from both the interior and exterior
temperatures. As a
result, the temperature of the vapor retarder will have a temperature that is
between the
interior temperature and the exterior temperature.
Approximate temperatures of the vapor retarder at various locations within the
insulation system at any geographic location may be easily calculated. First,
the
temperature differential between the exterior temperature and the interior
temperature of
the building is calculated. The temperature differential between the exterior
temperature
and the interior temperature is then divided by the R-value of the insulation.
The resulting
number is the approximate amount of temperature increase or decrease per
single R-value
of the insulation (hereinafter referred to as "the incremental R-value
temperature change").
The thickness of the insulation is generally proportional to the insulative
effectiveness, or
R-value of the insulation. Thus, for each R-value of insulation, the vapor
retarder will
increase or decrease in temperature from the internal or external temperature
in an amount
approximately equal to the incremental R-value temperature change as the vapor
retarder
is moved at different locations through the insulation.
For example, in the summer, when the internal temperature is less than the
external
temperature, the vapor retarder temperature will increase in an amount
approximately
equal to the incremental R-value temperature change for each R-value of
insulation as the
vapor retarder is moved from the interior of the building toward the exterior
of the
building. On the other hand, when the external temperature is below the
interior
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CA 02550234 2006-06-12
temperature, as in the winter, the vapor retarder temperature will decrease in
an amount
approximately equal to the increinental R-value temperature change as the
vapor retarder
is moved from the interior of the building toward the exterior of the building
one R-value
at a time.
Once the temperature increase/decrease per R-value of insulation is
calculated, the
various possible temperatures for the vapor retarder within the insulation at
that
geographic location may be determined using the incremental R-value
temperature change.
The R-values of the insulation layers on either side of the vapor retarder may
then be
determined by a condensation potential analysis for the particular geographic
region.
Condensation occurs when the temperature of the vapor retarder is below the
dew
point temperature. In the summer, condensation occurs when the temperature of
the vapor
retarder is below the exterior dew point temperature. In the winter,
condensation occurs
when the temperature of the vapor retarder is below the interior dew point
temperature.
Thus, to reduce condensation, the vapor retarder may be positioned between the
first
insulation layer and the second insulation layer at a location where its
temperature remains
above the interior dew point in the winter and above the outside dew point
temperature in
the summer for a majority of the time. Preferably, the vapor retarder is
positioned within
the insulation system such that the vapor retarder temperature is above the
interior dew
point in the winter and above the outside dew point temperature in the summer
for the
entire year.
As one illustrative example, consider an R-13 insulation system in a building
at a
northerly location where the interior temperature and interior dew point
temperature
remain a constant 65 F and 40 F, respectively, throughout the year, the
external winter
temperature is 16 F, and the external winter dew point temperature is 11 F,
the external
summer temperature is 84 F, and the external summer dew point temperature is
71 F.
By placing the vapor retarder on the interior of the insulation system with
all of the
insulation towards the exterior of the building, as in conventional systems,
the temperature
of the vapor retarder will remain approximately 65 F (the interior
temperature). Thus, in
the winter, the temperature of the vapor retarder will remain above the
interior dew point
temperature of 40 F. As a result, there would be no condensation in the
winter with this
insulation system. This internal placement of the vapor retarder, however, is
not optimal
for the summer climatic conditions at this geographic location, because in the
summer, the
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CA 02550234 2006-06-12
temperature of the vapor retarder would be below the exterior dew point
temperature (i.e.,
65 F < 71 F). As a result, condensation would occur in the summer.
To reduce this potential summer condensation, the vapor retarder may be
positioned within the insulation at a location where the temperature of the
vapor retarder is
above the exterior summer dew point temperature. Thus, in order to reduce
condensation
in the summer, the vapor retarder temperature needs to be raised from 65 F to
at least
71 F, . i. e., the temperature of the vapor retarder maybe raised at least 6
F. To determine
the R-values of insulation surrounding the vapor retarder, the incremental R-
value
temperature change is calculated. First, the temperature differential between
the external
summer temperature and the internal temperature is calculated (i.e., 84 F -
65 F = 19
F). This temperature differential is then divided by the R-value of the
insulation (13) to
obtain the incremental R-value temperature change (1.46 F/R-value).
To obtain at least a 6 F temperature increase in the vapor retarder in the
summer,
the vapor retarder may be placed at least four R-values of insulation from the
interior.
(e.g., 6 F = 1.46 F/R-value = approximately 4 R-values). Moving the vapor
retarder a
total of four R-values toward the exterior of the building results in a vapor
retarder
temperature of approximately 71 F in the summer. A similar calculation for
the
temperature of the vapor retarder with R-4 insulation on the interior
determines that the
vapor retarder would have a temperature of approximately 49.9 F in the
winter, which is
above the internal dew point temperature of 40 F. Therefore, the vapor
retarder may be
placed with R-4 insulation on the interior side of the vapor retarder and R-9
insulation on
the exterior side to reduce condensation in both the summer and the winter
months. A
further analysis of the temperatures of the vapor retarder compared to the dew
point
temperatures determines that the placement of R-5 insulation on the interior
side and R-8
insulation on the exterior side also reduces condensation in both the winter
and the
summer.
Although the above description considers two temperature extremes, namely,
summer and winter, for a given climate, if a more detailed analysis is
desired, daily or
hourly climatic data may be obtained and calculated, preferably with the aid
of a computer
program. In such a computer program, annual climatic data for a given location
and the
thermal properties of the insulation system (e.g., R-value, heat capacity,
vapor permeance,
internal dew point temperature, etc.) may be input and the condensation
potential
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CA 02550234 2006-06-12
calculated for any length of time. In a preferred embodiment, the computer
program
would also factor in the benefit of the drying potential resulting from the
reversal of the
vapor drive from summer to winter and vice versa.
Although it is preferred that the placement of the vapor retarder eliminate
the
potential for condensation throughout the year, it is possible that in some
geographic
locations, the placement of the vapor retarder, may result in a small amount
of
condensation within the insulation at some point during the year. Because the
inventive
insulation system contains one vapor retarder between two layers of
insulation, this small
amount of condensation is able ti-) dry out of the insulation as the vapor
drive changes from
the exterior to the interior of the building in the summer and from the
interior to the
exterior of the building in the winter.
In a preferred embodiment, an analysis of the amount of daily condensation
that
occurs is conducted. The amount of condensation that may occur within the
insulation
system depends on the temperature difference between the dew point temperature
and the
vapor retarder temperature and the length of time that the temperature of the
vapor retarder
is below the dew point temperature (i.e., the length of time that the
condensation occurs).
For example, for a particular geographic location, the placement of the vapor
retarder may
result in the temperature of the vapor retarder being 5 F below the dew point
temperature
for 8 hours in one day. Thus, the condensation potential for this location
would be 40
F=hour (8 hours = 5 F). If the vapor retarder is placed at a location where
the temperature
is 2 F below the dew point temperature for 4 hours, the condensation potential
becomes 8
F=hour (4 hours = 2 F). Therefore, by positioning the vapor retarder within
the insulation
so that amount of time that the temperature of the vapor retarder is below the
dew point
temperature is reduced, the amount of condensation will also be reduced.
By continuing the analysis of the condensation potential for the insulation
system
24 hours a day for 365 days, the total condensation potential for the entire
year for a given
vapor retarder position may be determined for a given climate. This
condensation
potential may then be quantitatively compared to the condensation potentials
for vapor
retarders at other positions within the insulation system and an optimum
location for the
vapor retarder at that geographic location may be determined which reduces the
overall
condensation potential of the insulation system over an entire year for that
given
geographical location. A computer program may be used to conduct these
calculations.
CA 02550234 2006-06-12
Preferably, the computer program factors in the drying potential resulting
from the reversal
of the vapor drive, the transient effects of changing exterior temperature and
humidity, the
variation of the interior temperature and humidity throughout the year, the
effects of solar
load on the insulation system, and the moisture diffusion properties of the
insulation and
the vapor retarder.
An exemplary embodiment of an insulation system according to the present
invention is illustrated in FIGS. 1 a - 6b. In particular, FIGS. 1 a - 6b
illustrate the
application of an insulation system of the present invention to a masonry
wall. Although a
masonry wall is used as one example for the application of the inventive
insulation system,
any wall that does not provide substantial thermal insulation could be
utilized. In FIGS. 1 a
and lb, the masonry wall is a concrete block wall 10. However, the wall could
also be
poured concrete, or any other suitable building material including stud
framing. A plate 20
and joists 30 are shown for illustrative purposes to place the masonry wall in
context with
the framing structure.
Turning to FIGS. 2a - 2b, a first layer of insulation 50 having a first
thickness
determined by the analysis described above is affixed to the concrete block
wall 10. Any
suitable mechanical fasteners (e.g., concrete nails) or adhesives may be used
to fasten the
first layer of insulation 50 to the concrete block wall 10. The first layer of
insulation 50
may be any type of insulation known to those of skill in the art, such as, but
not limited to,
fiberglass insulation, a fiberglass board, rock wool glass board, or a mineral
board. In a
preferred embodiment, the first layer of insulation 50 is a foam board or high
density
fiberglass insulation that has sufficient strength and durability to support a
vapor retarder
60 and a subsequent layer of insulation. The foam may be formed of extruded
polystyrene,
molded polystyrene, polyisocyanurate, phenolic foam, polyurethane, or other
similar foam
insulations identified by one of skill in the art.
The first layer of insulation 50 may be applied in a step-wise fashion, as
illustrated
in FIG. 2a and 3a, until the concrete block wall 10 is covered by the first
layer of insulation
50 (not shown). As shown in FIG. 2b, the first layer of insulation 50 may
include a vapor
retarder 60. Alternatively, the vapor retarder 60 may be applied to the first
layer of
insulation 50 after the first layer of insulation 50 has been affixed to the
concrete block
wall 10 (not shown). When the vapor retarder 60 is pre-applied to the first
layer of
insulation 50, or if the first insulation layer has inherent vapor retarder
properties (such as
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CA 02550234 2006-06-12
extruded polystyrene), such as is illustrated in FIG. 2b, the joints between
first insulation
layers 50 may be sealed by tape 61 or caulk (not shown) to form a
substantially continuous
vapor retarder. The vapor retarder 60 may be a sheet of plastic film (e.g.,
polyethylene,
nylon, or a rubber membrane (EPDM)) or a foil (e.g., aluminum foil)) having a
low vapor
permeance.
Next, lineals 70 may be vertically and horizontally affixed to the vapor
retarder 60
as depicted in FIGS. 4a and 4b, and are preferably spaced along the vapor
retarder 60 to
form insulation spaces that are substantially equal to the size of the second
layer of
insulation. Preferably, the lineals 70 are spaced approximately every 4 feet
vertically
across the concrete block wall 10. Optionally, lineals 70a may be affixed
horizontally
across the concrete block wall 10 as shown in FIGS. 4a - 4b to provide an
optional trim
such as a chair rail or the like. The lineals 70a may have a structure that is
identical to
lineals 70 illustrated in FIG. 5a.
As shown in FIG. 5a, the lineal 70 is formed of a base member 71 and two
vertically projecting arms 72. The base member 71 of the lineal 70 is affixed
to the vapor
retarder 60 by any suitable mechanical fastening devices, such as, but not
limited to, nails
and screws, or adhesives such that the arms 72 project inwardly from the vapor
retarder 60.
The lineals 70, 70a may be affixed to the concrete block wall 10 through the
vapor
retarder 60 and the first layer of insulation 50. Alternatively, the lineals
70, 70a may be
affixed to the vapor retarder 60 via an adhesive.
Turning now to FIGS. 6a and 6b, a second layer of insulation 80 having a
second
thickness as determined by the analysis described above is placed in the
insulation space
formed by the lineals 70 adjacent to the vapor retarder 60. It is to be noted
that the arms
72 of the lineals 70, 70a may vary in length to correspond to the thickness of
the second
insulation layer 80. The second layer of insulation 80 may be a high density
fiberglass
board, and may be the same or different than the first layer of insulation 50.
Preferably, the second layer of insulation 80 contains a permeable finished
surface
that provides an aesthetic appearance and which meets functional requirements
such as
damage resistance and fire resistance. If the second layer of insulation 80
does not contain
a finished surface, a separate finished surface (not shown) may be attached to
the second
layer of insulation 80. However, such a separate finished surface requires an
additional
step of attaching the finished surface to the second layer of insulation 80.
It is preferable
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CA 02550234 2006-06-12
that the finished surface does not act as a second vapor retarder which would
trap moisture
within the insulation system. A fire resistant fabric covering is a preferred
finished surface
because it provides an aesthetic and durable covering that is highly
permeable. Preferably,
the fabric is a polyolefin woven fabric having a basis weight of 1.3 oz/ft2
with an integral
Teflon surface treatment and a porous acrylic latex coating having a basis
weight of 0.37
oz/ft2 on the backside of the fabric. Further suitable examples of a
decorative, permeable
finished surface include, but are _iot limited to, woven polymers, glass mats
(e.g.,
fiberglass mats), glass veils, non-woven polymers, and woven polyolefins.
To complete the insulation system, a trim piece 85 is attached to the lineals
70 over
the finished surface. Suitable examples of trim pieces 85 are illustrated in
FIGS. 5b - 5f.
For example, 5b depicts an outside corner trim piece 73, 5c depicts a cove 74,
5d depicts a
batten 75, 5e depicts a base 76, and 5f depicts a casing 77. Battens 75 may be
placed in
the lineals 70 that are positioned vertically on the vapor retarder 60 to hold
the second
layer of insulation 80 in place. The cove 74, the base 76, and the casing 77
may be
positioned in the lineals 70, 70a depending upon the desired aesthetic
appearance. Each of
the trim pieces 85, e.g., the outside corner trim piece 73, the cove 74, the
batten 75, the
base 76, and the casing 77, contain a flange member 78. To attach the trim
piece 85 to the
lineal 70, 70a, the flange member 78 is inserted between the two arms 72 and
snapped into
place. Such interlocking construction provides for easy and quick
installation.
In one embodiment of the present invention, the insulation system may be
provided
in modular insulation members with one modular insulation member containing a
vapor
retarder. An illustrative example of an insulation system formed of modular
insulation
members is set forth in FIGS. 7a - 7d. In the illustrative example shown in
FIGS. 7a - 7d,
the total amount of insulation present in the insulation system is divided
into four modular
members of substantially the same thickness, namely a first modular insulation
member 81
that contains the vapor retarder 60, a second modular insulation member 82, a
third
modular insulation member 83, and a fourth modular insulation member 84. The
total
thickness of each of the modular insulation members 81, 82, 83, and 84
corresponds to the
total R-value of the insulation. It is to be noted that the illustrative
example set forth in
FIGS. 7a - 7d contain four modular members for ease of discussion. However,
any
number of modular members may be present in the insulation system depending on
how
many locations for the vapor retarder are desired within the insulation
system. For
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CA 02550234 2006-06-12
example, if R- 13 insulation is used in the insulation system, it may be
desirable to form
thirteen modular insulation members, each modular insulation member being
substantially
equal to each R-value of insulation. Such a division of the insulation would
provide 14
optional positions for the vapor retarder (i.e., an interior position, an
exterior position, and
12 interior positions).
Turning back to FIGS. 7a - 7d, it can be seen that the modular members may be
placed in any order to place the vapor retarder 60 at a desired location
within the
insulation. For example, if the analysis set forth above determines that the
preferred
location for the vapor retarder 60 is located substantially at the center of
the insulation,
such as is shown in FIG. 7a, the second modular insulation member 82 (or any
modular
insulation member that does not contain the vapor retarder 60) may be placed
on the
concrete block wall 10. The first modular insulation member 81 is then placed
such that
the vapor retarder 60 is positioned toward the interior of the building. The
lineals 70, 70a
may then be attached to the vapor retarder 60. The remaining modular
insulation members
83, 84 may be sequentially placed over the vapor retarder 60 in the insulation
spaces
formed by the lineals 70, 70a. Trim pieces 85 may then be attached to complete
the
insulation system.
As shown in FIGS. 7b - 7d, the vapor retarder 60 may be positioned at other
incremental locations by placing the modular members on the concrete block
wall 10 in
various orders. In FIG. 7b, the vapor retarder is positioned with the vapor
retarder 60
located off-center towards the interior of the building with a majority of the
insulation
towards the exterior such as, for example, by placing modular insulation
members 82, 83,
sequentially on the concrete block wall 10. The first modular insulation
member 81 is
then placed on modular insulation member 83 with the vapor retarder 60 facing
the interior
of the building. The lineals 70, 70a may then be attached to the vapor
retarder 60 and tlhe
fourth modular insulation member 84 is placed in the insulation spaces formed
by the
lineals 70, 70a. FIG. 7c illustrates an example of the placement of the vapor
retarder 60 on
the exterior adjacent to the concrete block wall 10. To place the vapor
retarder 60 on the
concrete block wall 10, the first modular insulation member 81 is oriented
with the vapor
retarder 60 facing the exterior of the building. This orientation of the first
modular member
81 is opposite than the orientation of the first modular insulation member 81
depicted in
FIGS. 7a, 7b, and 7d. FIG. 7d illustrates an example of the positioning of the
vapor
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CA 02550234 2006-06-12
retarder 60 off-center towards the exterior of the building with a majority of
the insulation
towards the interior of the building.
Such modular insulation systems such as are described above may be pre-
packaged
to include the modular insulation members, lineals, trim pieces, and
instructions for
assembling the modular insulation members to place the vapor retarder at the
optimal
location for a particular geographic climate.
Having generally described this invention, a further understanding can be
obtained
by reference to certain specific examples illustrated below which are provided
for purposes
of illustration only and are not intended to be all inclusive or limiting
unless otherwise
specified.
EXAMPLE
Determination of the Optimal Placement of a Vapor Retarder in Columbus, Ohio
Based on Condensation Potentia'
Five separate experimental insulation systems are constructed in Columbus,
Ohio,
each experimental system having R- 13 insulation placed a concrete block wall
with a
vapor retarder placed on or within the insulation at a chosen location. Each
of the five
experimental insulation systems are discussed in detail below and are shown
schematically
in FIGS. 8a, 9a, 10a, l l a, and 12a. The interior of the building for each of
the
experimental systems has a temperature of 65 F and a relative humidity of
40%.
The outside temperature and the outside dew point temperature on both January
1,
2002 and August 1, 2002 are obtained, such as from hourly climatic data, and
the
temperature of the vapor retarders in each of the experimental systems are
calculated.
Graphs for the data for each of the five experimental systems are depicted in
FIGS. 8b -8c,
9b - 9c, lOb - lOc, 1 lb - I Ic, and 12b - 12c. In each of the graphs, the
outside
temperature is represented by a dotted line 92, the dew point temperature is
depicted by a
solid line 94, and the vapor retarder temperature is illustrated by a phantom
line 96.
Experimental Insulation System 1
In Experimental Insulation System 1, shown in FIG. 8a, a layer of R- 13
insulation
90 is placed on a concrete block wall 100 in a residential building. A vapor
retarder 110 is
affixed to the R- 13 insulation 90 toward the interior of the building. In
this experimental
CA 02550234 2006-06-12
system, the vapor retarder 110 is placed in the "warm in winter" side of the
insulation
system with all of the insulation towards the exterior of the building.
A graphical analysis of the outside temperature, the outside dew point
temperature,
and the temperature of the vapor retarder 110 vs. the time of day for August
1, 2002 is
shown in FIG. 8b. Because the vapor retarder 110 is located toward the
interior of the
building, the temperature of the vapor retarder 110 remains substantially
constant at 65 F
(the interior temperature). As illustrated in FIG. 8b, when the temperature of
the vapor
retarder 110 (phantom line 96) is less than the outside dew point temperature
(solid line
94), condensation occurs. In FIG. 8b, condensation is depicted by the hashed
regions. The
condensation potential for each hour is the amount of the difference between
the vapor
retarder temperature and the dew point temperature (e.g., A temperature =
hour). Thus, the
total condensation potential for one day is calculated by adding the
individual hourly
condensation potentials over a twenty-four hour period. From the data
obtained, the
condensation potential is calculated to be 56.9 F=hour.
A graphical analysis of the outside temperature, the outside dew point
temperature,
and the temperature of the vapor retarder 110 vs. the time of day for January
1, 2002 is
shown in FIG. 8c. As illustrated in FIG. 8c, the temperature for the vapor
retarder 110
(phantom line 96) remains above the dew point temperature (solid line 94) for
the entire
time period. Consequently, no condensation occurs. Thus, the condensation
potential on
January 1, 2002 is zero. The total condensation potential for both August 1,
2002 and
January 1, 2002 is 56.9 F=hour.
Extperimental Insulation System 2
In Experimental Insulation System 2, shown in FIG. 9a, a first layer of R-9
insulation 120 is placed on a concrete block wall 100 in a residential
building. A vapor
retarder 110 is affixed to the first layer of R-9 insulation 120 toward the
interior of the
building. A second layer of R-4 insulation 130 is affixed to the vapor
retarder 110, thus
placing the vapor retarder 110 between the two layers of insulation. As can be
seen in
FIG. 9a, the vapor retarder 110 is positioned off-center towards the interior
of the building.
As in Experimental Insulation System 1, the total insulation in the system is
R- 13.
Graphical analyses of the outside temperatures, the outside dew point
temperatures,
and the temperatures of the vapor retarder 110 vs. the time of day for August
1, 2002 and
January 1, 2002 are depicted in FIGS. 9b and 9c respectively. As shown in FIG.
9b, the
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CA 02550234 2006-06-12
vapor retarder temperature (phantom line 96) is below the outside dew point
temperature
(solid line 94) during the early morning. This is when the condensation
occurs. The
condensation potential for August 1, 2002 is calculated to be 21.0 F=hour.
Because the
temperature of the vapor retarder does not drop below the outside dew point
temperature
on January 1, 2002, no condensation occurs, as is illustrated in FIG. 9c.
Thus, there is no
condensation potential. The total condensation potential for both August 1,
2002 and
January 1, 2002 is 21.0 F=hour.
Experimental Insulation System 3
In Experimental Insulation System 3, shown in FIG. 10a, a first layer of R-6.5
insulation 140 is placed on a concrete block wall 100 in a residential
building. A vapor
retarder 110 is affixed to the first layer of R-6.5 insulation 140 toward the
interior of the
building. A second layer of R-6.5 insulation 150 is affixed to the vapor
retarder 110, thus
placing the vapor retarder 110 between two equal layers of insulation. The
total insulation
in the system is R- 13.
Graphical analyses of the outside temperatures, the outside dew point
temperatures,
and the temperatures of the vapor retarder 110 vs. the time of day for August
1, 2002 and
January 1, 2002 are depicted in FIGS. lOb and lOc respectively. As seen in
FIGS. 10b and
l Oc, there is slight condensation in the early morning hours for both days.
The
condensation potential for August 1, 2002 is calculated to be 7.5 F=hour and
the
condensation potential for January 1, 2002 is calculated to be 8.0 F=hour.
Thus, the total
condensation potential for both August 1, 2002 and January 1, 2002 is 15.5
F=hour.
Experimental Insulation System 4
In Experimental Insulation System 4, shown in FIG. 11 a, a first layer of R-4
insulation 160 is placed on a concrete block wall 100 in a residential
building. A vapor
retarder 110 is affixed to the first layer of R-4 insulation 160 toward the
interior of the
building. A second layer of R-9 insulation 170 is affixed to the vapor
retarder 110, thus
placing the vapor retarder 110 between the two layers of insulation. As shown
in FIG.
l la, the vapor retarder 110 is positioned off-center towards the exterior of
the building.
The total insulation in the system is R-13.
Graphical analyses of the outside temperatures, the outside dew point
temperatures,
and the temperatures of the vapor retarder 110 vs. the time of day for August
1, 2002 and
January 1, 2002 are depicted in FIGS. l lb and l lc respectively. As shown in
FIG. l lb,
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CA 02550234 2006-06-12
there is very slight condensation in the early morning hours on August 1,
2002. The
condensation potential is calculated to be 1.0 F=hour. Because the vapor
retarder
temperature (phantom line 96) is below the outside dew point temperature
(solid line 94)
for the entire day, there is a large amount of condensation on January 1, 2002
(FIG. 11 c).
The condensation potential for January 1, 2002 is calculated to be 131.5
F=hour. Adding
the condensation potentials for both days yields a total condensation
potential of 132.5
F=hour.
Experimental Insulation System 5
In Experimental Insulation System 5, shown in FIG. 12a, a vapor retarder 110
is
placed directly on a concrete block wall 100 and covered with a layer of R-13
insulation
180. In this experimental system, the vapor retarder 110 is placed in the
"warm in
summer" side of the insulation system with all of the insulation towards the
interior of the
building.
Graphical analyses of the outside temperatures, the outside dew point
temperatures,
and the temperatures of the vapor retarder 110 vs. the time of day for August
1, 2002 and
January 1, 2002 are depicted in FIGS. 12b and 12c respectively. On August 1,
2002, the
temperature of the vapor retarder 110 (phantom line 96) remains above the dew
point
temperature (solid line 94). As a result, no condensation occurs and the
condensation
potential is zero (FIG. 12b). As shown in FIG. 12c, the temperature of the
vapor retarder
110 is below the outside dew point temperature for the entire day on January
1, 2002,
resulting in severe condensation. The condensation potential is calculated to
be 424.9
F=hour. Adding the condensation potentials for both days yields a total
condensation
potential of 424.9 F=hour.
Comparing the total condensation potentials for each of the five experimental
systems, it is determined that Experimental Insulation System 3 has the lowest
total
condensation potential. Thus, in Columbus, Ohio, the optimal location for the
vapor
retarder 110 in R-13 insulation is near the mid-point, such as with R-6.5
insulation
positioned on both sides of the vapor retarder. Experimental Insulation System
2 had a
total condensation potential that is slightly greater than Experimental
Insulation System 3.
Thus, the vapor retarder 110 may alternatively be placed with R-4 insulation
to the
exterior and R-9 insulation to the exterior of the vapor retarder 110.
18
CA 02550234 2006-06-12
The invention of this application has been described above both generically
and
with regard to specific embodiments. Although the invention has been set forth
in what is
believed to be the preferred embodiments, a wide variety of alternatives known
to those of
skill in the art can be selected within the generic disclosure. The invention
is not
otherwise limited, except for the recitation of the claims set forth below.
19
