Air supported structure membrane configuration

An air supported structure including a wall portion having a membrane configuration comprising a structural substrate to which a plurality of coatings or films have been applied in a manner to provide a membrane configuration having improved heat flow properties, sound and light radiation and/or absorbing qualities, structural integrity, weather resistance, and design characteristics as desired or required according to the intended use of the air supported structure.

BRIEF BACKGROUND, FIELD AND OBJECTIVES OF THE INVENTION 
This invention relates to improvements in membrane configurations for air 
supported structures. 
The majority of air supported structures presently in use include a single 
membrane envelope which has been fabricated from commercially available 
high strength industrial fabric, providing a low cost portable or 
semi-permanent enclosure which is adequately serviceable under conditions 
where temporary collapse due to accidental damage or vandalism would not 
be of serious consequence; where heat flow through the membrane is of no 
major concern in terms of heat gain and/or loss; and/or where sound and 
light radiation and/or absorbing qualities are not of any particular 
consequence. 
Such previously provided air supported structures are generally fabricated 
as single skin, evenly stressed envelopes, having a wall comprising a very 
thin membrane, and in which the fabric of the membrane is a relatively 
good conductor of heat and is translucent to solar radiation. The same 
have also been historically extremely poor in sound characteristics, the 
generally highly stressed and evenly contoured single membrane thereof 
comprising a reflector of sound waves somewhat akin to the sound reflected 
from a drum head, frequently producing sound concentrations at various 
points in the interior of the structure and a "whispering wall" effect in 
which the sound produced at one point along the perimeter thereof travels 
thereabout and is magnified in a manner so that it is louder at a point as 
much as 200 to 300 feet away than at its origin. 
It is obvious that lighting fixtures cannot ordinarily be mounted on the 
walls of an air supported structure, but must be placed around the 
perimeter of the structure. Thus, air supported structures are generally 
indirectly lighted by way of ground supported light fixtures which are 
focused to project light rays against the membrane for reflection from the 
surface thereof and onto the floor of the air supported structure. 
Previously provided air supported structures have generally had very poor 
lighting characteristics, the uniform interior surface of the envelope 
thereof being highly reflective, concentrating the light at some areas of 
the floor while leaving other areas very poorly lighted. 
Also, since previously provided air supported structures were generally 
constructed to provide a low cost temporary enclosure, very little 
attention was given to designing the same for long term structural 
integrity and weather resistance. 
The primary object of this invention is the provision of a membrane 
configuration which is specifically constructed for use as a wall portion 
of an air supported structure, the same being designed to provide an air 
supported structure having long term structural integrity and weather 
resistance, with predetermined heat flow properties and sound and light 
radiation and/or absorbing characteristics according to the intended use 
thereof. 
In some instances it may prove desirable to provide a multiple membrane 
wall for the air supported structure. It is accordingly a further object 
of this invention to provide air supported structures which may be 
selectively of single and multiple membrane configurations having the 
desired total design characteristics. 
Other objects and advantages of the invention will become apparent from the 
following detailed description, taken in connection with the accompanying 
drawings, and in which drawings:

DETAILED DESCRIPTION 
In the drawings, wherein similar reference characters are used to designate 
corresponding parts throughout the several views, and wherein are shown 
various embodiments of the invention, the letter A may generally designate 
an air supported structure which may include a wall portion comprising a 
plurality of panels B which may be secured in position such as by 
restraining webs C that may be attached at one end thereof to ground 
anchors D and at the other end thereof to a restraining harness E. 
Air supported structure A is shown merely by way of example as to an air 
supported structure which may embody our invention. That is, this 
invention is not restricted to use in a square ended air supported 
structure such as is shown in FIG. 1, but may obviously be used in round 
ended air supported structures, circular air supported structures, and in 
air supported structures of various other designs. Neither is this 
invention restricted to an air supported structure of the particular seam 
design and anchor and harness relation shown for the air supported 
structure of FIG. 1. 
As shown, some panels B may comprise side wall portion panels 10 of air 
supported structure A, and others may comprise end wall portions 11. 
Restraining webs C may comprise a plurality of interconnected and/or 
interrelated webs 14 for resolving the resultants of aerodynamic and 
inflation pressure loads of air supported structure A. 
The letter F may generally designate a panel B of single membrane 
configuration; the letter G a panel B of double membrane configuration; 
and the letter H a panel B of triple membrane configuration. 
As respectively shown in FIGS. 2, 4 and 6, adjacent panels B of single 
membrane configuration F, double membrane configuration G and triple 
membrane configuration H may be interconnected together and to a web 14, 
such as by a double row of stitching 15, in a manner to provide a stress 
relieved seam. 
The structural improvements of the present invention become readily 
apparent in direct comparison of the construction of a typical membrane 
configuration for an air supported structure with the membrane 
configuration of the present invention. 
EXAMPLE I 
TRADITIONAL MEMBRANE CONFIGURATION 
The typical membrane configuration which is now generally in use for 
providing the wall portion of air supported structures comprises a 12-mil 
thick woven substrate, to the outer side of which is applied a 16-mil 
thick coating of white vinyl, and to the interior side of which is 
provided a 12-mil thick coating of white vinyl. 
As shown, single membrane configuration F preferably includes a single 
membrane 17 having an outer side 18, designed to form the exterior surface 
of a wall portion of the air supported structure, and an inner side 19, 
designed to form the interior surface of a wall portion of the air 
supported structure. 
Single membrane 17 preferably includes a structural substrate 20, which may 
comprise a woven nylon filament; a long wave opacity coating 23, which may 
comprise black vinyl, being applied to one side of structural substrate 
20; a short wave opacity coating 24 being applied over long wave opacity 
coating 21, which short wave opacity coating 24 may comprise the exterior 
surface of outer side 18 of single membrane configuration F, and which is 
thus preferably of wear and weather resistant material such as white 
polyvinyl fluoride; and the other side of structural substrate 20 being 
preferably provided with a long wave opacity and reflectivity coating 25, 
which may comprise an aluminum coating. It is sometimes difficult to 
obtain a good bond of an aluminum coating directly to a woven nylon 
substrate. Accordingly, when structural substrate 20 comprises a woven 
nylon filament and long wave opacity and reflectivity coating 25 comprises 
an aluminum coating, a coating bond 29 may be provided for bonding of the 
aluminum coating to the woven nylon filament. Coating bond 29 may comprise 
a white vinyl coating which, it will be noted, in addition to acting as a 
bonding medium, will also provide a short wave opacity coating on the 
inner side of structural substrate 20. 
EXAMPLE II 
SINGLE MEMBRANE CONFIGURATION F 
We have found that a suitable single membrane configuration F may be 
provided by using a 6-mil thick woven nylon filament, to the outer side of 
which is applied a 10-mil thick black vinyl coating, over which is applied 
a 1.5-mil thick white polyvinyl fluoride coating; the inner side of the 
woven nylon filament having applied thereto an 8-mil thick coating of 
white vinyl, over which is applied a 1-mil thick aluminum coating. 
As shown, double membrane configuration G preferably includes an outer 
membrane 30 and an inner membrane 31, there being provided a substantially 
dead air space 32 between spaced apart outer membrane 30 and inner 
membrane 31. Outer membrane 30 is provided with an outer side 34, designed 
to form the exterior surface of a wall portion of air supported structure, 
and an inner side 35. Inner membrane 31 has an inner side 37, designed to 
form the interior surface of a wall portion of the air supported 
structure, and an outer side 38. Outer side 38 of inner membrane 31 
confronts inner side 35 of outer membrane 30, defining a substantially 
dead air space 32 therebetween. 
Outer membrane 30 preferably includes a structural substrate 40, which may 
comprise a woven nylon filament; a long wave opacity coating 41, which may 
comprise black vinyl, being applied to one side of structural substrate 
40; a short wave opacity coating 42 being applied over long wave opacity 
coating 41, which short wave opacity coating 42 may comprise the exterior 
surface of outer side 34 of double membrane configuration G, and which is 
thus preferably of wear and weather resistant material such as white 
polyvinyl fluoride; and the other side of structural substrate 40 being 
preferably provided with a long wave opacity and reflectivity coating 44, 
which may comprise an aluminum coating. It is sometimes difficult to 
obtain a good bond of an aluminum coating directly to a woven nylon 
substrate. Accordingly, when structural substrate 40 comprises a woven 
nylon filament and long wave opacity and reflectivity coating 44 comprises 
an aluminum coating, a coating bond 46 may be provided for bonding of the 
aluminum coating to the woven nylon filament. Coating bond 46 may comprise 
a white vinyl coating which, it will be noted, in addition to acting as a 
bonding medium, will also provide a short wave opacity coating on the 
inner side of structural substrate 40. 
Inner membrane configuration 31 preferably includes a structural substrate 
50, which may comprise a woven nylon filament; a long wave opacity and 
reflectivity coating 53 being provided on the outer side 38 of inner 
membrane 31, which long wave opacity and reflectivity coating 53 may 
comprise an aluminum coating; and the other side of structural substrate 
50 being preferably provided with a short wave opacity coating 55, which 
may comprise white vinyl. Since, as previously discussed, it is sometimes 
difficult to obtain a good bond of an aluminum coating to a woven nylon 
substrate, when structural substrate 50 comprises a woven nylon filament 
and long wave opacity and reflectivity coating 53 comprises an aluminum 
coating, a coating bond 56 may be provided for bonding of the aluminum 
coating to the woven nylon filament. Coating bond 56 may comprise a white 
vinyl coating which, it will be noted, in addition to acting as a bonding 
medium, will also provide a short wave opacity coating on the outer side 
of structural substrate 50. 
EXAMPLE III 
DOUBLE MEMBRANE CONFIGURATION G 
We have found that a suitable double membrane configuration G may include: 
an outer membrane 30 comprising a 6-mil thick woven nylon filament, to the 
outer side of which is applied a 10-mil thick black vinyl coating, over 
which is applied a 1.5-mil thick white polyvinyl fluoride coating, the 
inner side of the woven nylon filament having applied thereto an 8-mil 
thick coating of white vinyl, over which is applied a 1-mil thick aluminum 
coating; and 
an inner membrane configuration 31 comprising a 4-mil thick woven nylon 
filament, to the outer side of which is applied a 2-mil thick coating of 
white vinyl, over which is applied a 1-mil thick aluminum coating, the 
inner side of the woven nylon filament having applied thereto a 4-mil 
thick coating of white vinyl. 
As shown, triple membrane configuration H preferably includes an outer 
membrane 60, a center membrane 61, and an inner membrane 62, there being 
provided a substantially dead air space 64 between spaced apart outer 
membrane 60 and center membrane 61; and a substantially dead air space 65 
between spaced apart center membrane 61 and inner membrane 62. Outer 
membrane 60 is provided with an outer side 67, designed to form the 
exterior surface of a wall portion of the air supported structure, and an 
inner side 68. Center membrane 61 has an outer side 69 and an inner side 
70. Outer side 69 of center membrane 61 confronts inner side 68 of outer 
membrane 60, defining a substantially dead air space 64 therebetween. 
Inner membrane 62 is provided with an inner side 72, designed to form the 
interior surface of a wall portion of the air supported structure, and an 
outer side 74. Outer side 74 of inner membrane 62 confronts inner side 70 
of center membrane 61, defining a substantially dead air space 65 
therebetween. 
Outer membrane 60 preferably includes a structural substrate 76, which may 
comprise a woven nylon filament; a long wave opacity coating 77, which may 
comprise black vinyl, being applied to one side of such structural 
substrate 76; a short wave opacity coating 79 being applied over long wave 
opacity coating 77, which short wave opacity coating 70 may comprise the 
exterior of outer side 67 of triple membrane configuration H, and which is 
thus preferably of wear and weather resistant material such as white 
polyvinyl fluoride; and the other side of structural substrate 76 being 
provided with a long wave opacity and reflectivity coating 80, which may 
comprise an aluminum coating. It is sometimes difficult to obtain a good 
bond of an aluminum coating direct to a woven nylon substrate. 
Accordingly, when structural substrate 76 comprises a woven nylon filament 
and long wave opacity and reflectivity coating 80 comprises an aluminum 
coating, a coating bond 81 may be provided for bonding of the aluminum 
coating to the woven nylon filament. Coating bond 81 may comprise a white 
vinyl coating which, it will be noted, in addition to acting as a bonding 
medium, will also provide a short wave opacity coating on the inner side 
of structural substrate 76. 
Center membrane configuration 61 preferably includes a structural substrate 
85, the outer side 69 of which is provided with a long wave opacity and 
reflectivity coating 86, which may comprise an aluminum coating; and the 
inner side 70 thereof being provided with a long wave opacity and 
reflectivity coating 88, which may comprise an aluminum coating. As 
previously discussed, since it is sometimes difficult to obtain a good 
bond of an aluminum coating to a woven nylon substrate, when structural 
substrate 85 comprises a woven nylon filament and long wave opacity and 
reflectivity coatings 85 and 86 comprise aluminum coatings, coating bonds 
89 and 90 may be provided for respectively bonding the aluminum coating of 
the outer and inner sides thereof to the woven nylon filament. Coating 
bonds 89 and 90 may comprise a white vinyl coating which, it will be 
noted, in addition to acting as a bonding medium, will also provide a 
short wave opacity coating on the inner and outer sides of structural 
substrate 85. 
Inner membrane configuration 62 preferably includes a structural substrate 
92, which may comprise a woven nylon filament; a long wave opacity and 
reflectivity coating 94 being provided on the outer side 74 of inner 
membrane 62, which long wave opacity and reflectivity coating 94 may 
comprise an aluminum coating; and the other side of structural substrate 
92 being preferably provided with a short wave opacity coating 96, which 
may comprise white vinyl. Since, as previously noted, it is sometimes 
difficult to obtain a good bond of an aluminum coating to a woven nylon 
substrate, when structural substrate 92 comprises a woven nylon filament 
and long wave opacity and reflectivity coating 94 comprises an aluminum 
coating, a coating bond 97 may be provided for bonding of the aluminum 
coating to the woven nylon filament. Coating bond 97 may comprise a white 
vinyl coating which, it will be noted, in addition to acting as a bonding 
medium, will also provide a short wave opacity coating on the outer side 
of structural substrate 70. 
EXAMPLE IV 
TRIPLE MEMBRANE CONFIGURATION H 
We have found that a suitable triple membrane configuration H may include: 
an outer membrane configuration comprising a 6-mil thick woven nylon 
filament, to the outer side of which is applied a 10-mil thick black vinyl 
coating, over which is applied a 1.5-mil thick white polyvinyl fluoride 
coating, the inner side of the woven nylon filament having applied thereto 
an 8-mil thick coating of white vinyl, over which is applied a 1-mil thick 
aluminum coating; 
a center membrane comprising a 4-mil thick woven nylon filament, to each 
side of which is applied a 2-mil thick coating of white vinyl, and over 
each of which is applied a 1-mil thick aluminum coating; and 
an inner membrane comprising a 4-mil thick woven nylon filament, to the 
outer side of which is applied a 2-mil thick coating of white vinyl, over 
which is applied a 1-mil thick aluminum coating, and to the inner side of 
which is applied a 4-mil thick coating of white vinyl. 
Using the membrane configurations of Examples I-IV, a direct comparison may 
be made of the thermal performance of the traditional membrane 
configuration with those of the single, double and triple membrane 
configurations of the present invention. 
In the case of some air supported structures, such as those used for 
storage, a traditional membrane configuration will likely suffice. 
However, in the case of air supported structures intended for use as an 
enclosure for recreational pursuits, such as tennis and swimming, the 
membrane configurations thereof are preferably provided with heat flow 
characteristics which will facilitate heating an air supported structure 
in the winter and air conditioning in the summer. A determination of the 
total coefficient of heat transmission for the wall portion of the air 
supported structure (U value) is necessary so that heat flow properties 
can be reasonably calculated and the heating and/or air conditioning 
equipment therefor be of an appropriate size and capacity. The total 
coefficient of heat transmission can be determined by finding the thermal 
resistance of a given portion of the wall portion and converting the 
reciprocals of the summed resistances to the U value according to the 
relationship: 
EQU U = 1/R 
the coefficients, resistances, emissivities and methods of computation of 
the following comparative analyses are based on data contained in the 
"ASHRAE Guide"; the total resistance (R) of a given portion of the wall 
being the sum of the resistances (r); and wherein the "dead air space" is 
based upon an averaged 4-inch depth of entrapped and substantially 
motionless air between respective membrane configurations. 
______________________________________ 
DETERMINATION OF 
COEFFICIENT OF HEAT TRANSMISSION DOWNWARD 
(SUMMER CONDITION) 
______________________________________ 
TRADITIONAL MEMBRANE OF EXAMPLE I 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.25 
r.sub.m (white vinyl/structural substrate/white vinyl) 
.06 
r.sub.i (interior air film) 
.92 
##STR1## 
##STR2## 
##STR3## 
= .81 BTU/HR./SQ.FT./.degree. F 
______________________________________ 
SINGLE MEMBRANE CONFIGURATION OF EXAMPLE II 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.25 
r.sub.m (white polyvinyl fluoride/black vinyl/ 
structural substrate/white vinyl/aluminum) 
.28 
r.sub.i (interior air film) 
.92 
##STR4## 
##STR5## 
##STR6## 
= 0.69 BTU/HR./SQ. FT./.degree. F 
______________________________________ 
DOUBLE MEMBRANE CONFIGURATION OF EXAMPLE III 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.25 
r.sub.om (white polyvinyl fluoride/black vinyl/ 
structural substrate/white vinyl/aluminum) 
.28 
r.sub.da (dead air space) 2.33 
r.sub.im (aluminum/white vinyl/structural substrate/ 
white vinyl) .26 
r.sub.i (interior air film) 
.92 
##STR7## 
##STR8## 
##STR9## 
= 0.25 BTU/HR./SQ.FT./.degree. F 
______________________________________ 
TRIPLE MEMBRANE CONFIGURATION OF EXAMPLE IV 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.25 
r.sub.om (white polyvinyl fluoride/black vinyl/ 
structural substrate/white vinyl/aluminum) 
.28 
r.sub.da (dead air space) 2.33 
r.sub.cm (aluminum/white vinyl/structural substrate/ 
white vinyl/aluminum 0.6 
r.sub.da (dead air space) 2.33 
r.sub.im (aluminum/white vinyl/structural substrate/ 
white vinyl) .26 
r.sub.i (interior air film) 
.92 
##STR10## 
##STR11## 
##STR12## 
= 0.16 BTU/HR./SQ.FT./.degree. F 
______________________________________ 
______________________________________ 
DETERMINATION OF 
COEFFICIENT OF HEAT TRANSMISSION UPWARD 
(WINTER CONDITION) 
______________________________________ 
TRADITIONAL MEMBRANE OF EXAMPLE I 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.17 
r.sub.m (white vinyl/structural substrate/white vinyl) 
.06 
r.sub.i (interior air film) 
.61 
##STR13## 
##STR14## 
##STR15## 
= 1.19 BTU/HR./SQ.FT./.degree. F 
______________________________________ 
SINGLE MEMBRANE CONFIGURATION OF EXAMPLE II 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.17 
r.sub.m (white polyvinyl fluoride/black vinyl/ 
structural substrate/white vinyl/aluminum) 
.28 
r.sub.i (interior air film) 
.61 
##STR16## 
##STR17## 
##STR18## 
= 0.94 BTU/HR./SQ.FT./.degree. F 
______________________________________ 
DOUBLE MEMBRANE CONFIGURATION OF EXAMPLE III 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.17 
r.sub.om (white polyvinyl fluoride/black vinyl/ 
structural substrate/white vinyl/aluminum 
.28 
r.sub.da (dead air space) 1.71 
r.sub.im (aluminum/white vinyl/structural substrate/ 
white vinyl) .26 
r.sub.i (interior air film) 
.61 
##STR19## 
##STR20## 
##STR21## 
= 0.33 BTU/HR./SQ.FT./.degree. F 
______________________________________ 
TRIPLE MEMBRANE CONFIGURATION OF EXAMPLE IV 
______________________________________ 
Resistance 
r.sub.e (exterior air film) 
.17 
r.sub.om (white polyvinyl fluoride/black vinyl/ 
structural substrate/white vinyl/aluminum) 
.28 
r.sub.da (dead air space) 1.71 
r.sub.cm (aluminum/white vinyl/structural substrate/ 
white vinyl/aluminum) .06 
r.sub.da (dead air space) 1.71 
r.sub.im (aluminum/white vinyl/structural substrate/ 
white vinyl) .26 
r.sub.i (interior air film) 
.61 
##STR22## 
##STR23## 
##STR24## 
= 0.21 BTU/HR./SQ.FT./.degree. F 
______________________________________ 
______________________________________ 
TABLE OF "U" VALUES 
______________________________________ 
Heat Flow Shown in BTU/HR./SQ.FT./.degree. F 
______________________________________ 
HEAT FLOW HEAT FLOW 
DOWNWARD UPWARD 
CONFIGURATION (SUMMER) (WINTER) 
______________________________________ 
Traditional 0.81 1.19 
Single Membrane 
0.69 0.94 
Double Membrane 
0.25 0.33 
Triple Membrane 
0.16 0.21 
______________________________________ 
From the above comparisons it will be seen that the membrane configurations 
of the present invention have a coefficient of heat transmission which is 
on the order of from 1/5 to 1/8 of those inherent in the typical 
traditional membrane configuration. Accordingly, considering the present 
day rapidly increasing energy costs, it is estimated that any extra costs 
necessitated in designing and furnishing an air supported structure having 
a membrane configuration according to the present invention, over the cost 
of a traditional air structure, will be reimbursed to the buyer within 
less than 2 years' time by way of savings from the operation of heating 
and air conditioning equipment. 
Various changes in the forms of the invention herein shown and described 
may be made without departing from the spirit of the invention or the 
scope of the following claims.