Patent Publication Number: US-2007094972-A1

Title: Wind protection system and roof ballast module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      The application claims priority to U.S. Provisional Patent Application No. 60/725,159 filed Oct. 11, 2005, which is expressly incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates to apparatuses and methods to secure and protects buildings and rigid roofs from high winds, and more particularly to a wind protection system and a roof ballast module to protect a building from high winds, such as hurricane winds.  
     BACKGROUND OF THE INVENTION  
      Storm winds, such as hurricane winds, present a unique problem in the protection of buildings. Any breach in the walls, doors, windows, or the roof of a building can lead to a complete significant damage to a building. Maintaining the security of the roof is of particular importance in protecting a building from damage. Roof structures can be susceptible to at least three forces tending to separate a roof from a building. Wind forces may act under the eaves of a roof tending to separate the roof from the building at its point of attachment. If windows, doors, or any part of the walls of a building are compromised, wind entering the building will place an uncontrollable positive pressure inside the building and thus under the roof. Finally, the movement of high winds across the top of the roof creates a reduced pressure at the top surface of the roof due to Bernoulli&#39;s principle, thus tending to lift the roof off of the building. Once a roof is breached, the interior of a building is susceptible to a greater extent of damage from wind, debris, and water. Therefore, adequate building protection requires securing both the building and the roof from these forces.  
      In addition to these three forces, hurricane force winds present additional problems compared to other types of wind storms. First, hurricane winds are more turbulent and sustained than other wind storms. Hurricane winds can last hours at a time while permitting gusts that are 25%-50% higher than the maximum sustained winds. In a hurricane with sustained winds at 150 mph, gusts can exceed 200 mph. Also, hurricane winds generate a larger quantity of debris than other wind storms. The debris is carried by the strong winds, which multiply the potential damage that can be caused by the debris. For example, in a 100 mph wind, a 4 ft. by 8 ft. sheet of plywood could be thrown with up to 1100 lbs. of force. Thus, even the smallest debris increases the risk of compromise to the walls, doors, and windows of a building. If just small portions of the building walls, doors, or windows are compromised, the pressure inside the building (and thus against the underside of the roof) can quickly increase. Hurricane winds also change slowly in direction, which increases the probability that winds will achieve a critical angle of attack against a building or roof, thus maximizing the forces tending to remove the roof from the building. Ultimately, all of these factors contribute to a chain reaction compromising the building and the roof, possibly leading to the total destruction of the building.  
      Recent studies have demonstrated that fastening equipment and building protection could reduce the amount of property damage. In particular, the National Association of Homebuilders (NAHB) Research Center concluded that, in one observed hurricane, the use of fastening equipment could have reduced the loss of roof sheathing from 64% to 15% or less. Therefore, there is a need for systems and methods to protect buildings and roofs from wind damage in general, and more particularly hurricane wind damage.  
     SUMMARY OF THE INVENTION  
      A wind protection system, a roof ballast module, and a method for protecting a building from high winds are therefore provided. In one embodiment, the wind protection system includes a plurality of roof ballast modules disposed across a planar section of a rigid roof. The roof ballast modules have a plurality of elongate liquid impermeable bladders. The bladders have a port on one end permitting the interior of the bladder to be filled with a liquid, such as water. Channels may be provided between the bladders permitting fluid communication therebetween.  
      The wind protection system of one embodiment includes a protective shield to protect the building from airborne objects carried by high winds. At the upper end, the protective shield may be secured to roof ballast modules or to the building itself, for example extending from a fascia below the roof. At the lower end the protective shield may be secured to the ground by an anchor system or one or more anchors. The anchors may include ground screws, weighted bladders, and/or ground pillars, among other devices that may be used to secure the protective shield against high winds.  
      A roof ballast module according to one embodiment of the invention may include a plurality of elongate liquid impermeable bladders. The roof ballast module may include a first port on a top end of one of the bladders permitting the interior of the bladder to be filled with a liquid. An example of one type of port used in the invention may be a valve. Several channels may be provided between the bladders to permit fluid communication between the bladders.  
      Embodiments of the roof ballast module may include a drain valve disposed at the bottom end of a bladder. A second port may be disposed near the top end of another of the elongate bladders to permit fluid spillover from the interior of the bladder to another roof ballast module. In this way several roof ballast modules may be connected and filled through the spillover from the adjacent roof ballast modules.  
      According to one embodiment, the roof ballast modules and bladders may be formed from first and second panels sealed to one another along a common periphery. Additionally, grommets may be disposed about a periphery of the roof ballast modules for securing the roof ballast modules to one another or the roof. Furthermore, the ports may include threaded water hose connectors in order to facilitate connection to common water hose sources.  
      With respect to a method of protecting a building from high wind, one embodiment of the invention includes placing a plurality of water impermeable bladder panels on a rigid roof to ballast the roof. The impermeable bladders are filled with a liquid, such as water. Embodiments of the method may also include attaching a protective shield to a periphery of a building. The protective shield is anchored to the ground to secure the protective shield in place against high winds.  
      Therefore, a new wind protection system and roof ballast module is provided to more effectively protect a roof and a building from high winds, such as hurricane and other storm force winds. Generally, the roof ballasts may be filled with a liquid over a large area of the roof to add substantial mass to the roof. The added mass overcomes the lifting forces applied to the roof by high winds to maintain the integrity of roof and the building.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:  
       FIG. 1  is perspective view of a building having a wind protection system including roof ballast modules and a wind screen according to one embodiment of the invention;  
       FIG. 2  is a plan view of a rigid roof depicting several roof ballast modules distributed about a roofing surface according to one embodiment of the invention;  
       FIG. 3  is a plan view of a roof ballast module according to one embodiment of the invention;  
       FIG. 4  is an end view of a roof ballast module according to the  FIG. 3  embodiment of the invention; and  
       FIG. 5  is a perspective view of bladder for securing a protective shield according to one embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the inventions are shown. The inventions may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey embodiments within the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.  
      Referring now to  FIG. 1 , one embodiment of a wind protection system  10  is illustrated for a building. The wind protection system includes a plurality of roof ballast modules  20  distributed about the surface of a planar section of a rigid roof  22 . As shown in  FIG. 1 , other planar sections  24  of the roof may include additional ballast modules  20 . The ballast modules (one embodiment of which is described in more detail below) are modules of liquid impermeable bladders filled with a liquid, such as water. The ballasts are therefore secure to the roof by the weight of the liquid in the bladders. Although any mass of liquid may be used according to embodiments of the inventions described herein, water is a prevalent and readily available source. Water is therefore described throughout this description for filling the bladders by way of illustration and not limitation.  
       FIG. 2  illustrates the distribution of various shapes and sizes of roof ballast modules  20  distributed about several sloping planar surfaces of a rigid roof  22 ,  24 . The modules include various sizes so that they may be distributed across substantially the entire planar area of the roof surface. As an example of different sized embodiments, the roof ballast modules may comprise 4 ft. by 8 ft. modules  20 , which may be comprised of five approximately 8 ft. elongate bladders. Also 4 ft. by 4 ft. square roof ballast modules  25 , and 2 ft. by 8 ft. roof ballast modules  21 , 2 ft. by 4 ft. roof ballast modules  27 , and triangular 2 ft. roof ballast modules  23  are depicted in  FIG. 2 . By covering substantially the entire surface of the roof, the roof is ballasted to protect from the different types of lifting forces on the roof, including negative pressure from wind shear above the roof, positive pressure from wind under the eaves of the building, and wind forces that may penetrate the building and create positive pressure from inside the building. For example, the 4 ft. by 8 ft. embodiment of the roof ballast modules may be expected to hold up to 1,100-1,200 lbs. of water, thus securing it to the rigid roof by its weight by way of static friction.  
      Returning to  FIG. 1 , a protective shield  30  is also provided to protect the building from airborne objects carried by storm winds. The protective shield may be attached to the ballast modules or may be attached to the building, such as at the fascia below the roof. The protective shield may be secured to the ground by way of any of various types of anchors  36  that will hold the protective shield in place against expected high winds. A protective shield must be sufficiently strong to repel flying objects at speeds generated by storm force and hurricane force winds. A protective shield  30  may be made of a light weight and flexible material, typically a net or mesh. The protective shield may be cinched down to the anchors  32 ,  34 ,  36 . Such attachment may be by way of latches  35 , ratcheting devices, bolts, swivels (not shown), and other devices known to those of ordinary skill for securing objects.  
      The protective shield may comprise nylon, blended composites of nylon, rubber, plastic, carbon fiber, or natural materials such as high strength weaves of cotton, wool, jute, etc. One example of a protective shields for this purpose includes polypropylene netting having a mesh size of about ⅜th inch square. As the protective shield netting protects the exterior of a building, it may be desirable to employ UV stabilized material to avoid degradation from ultraviolet light. The protective shield  30  may have a series of protective panels  38  at places near windows, doors, etc.  
      In the example provided in  FIG. 1 , one type of anchor illustrated includes ground pillars  34  such as cement/concrete pillars disposed under the ground and including a fastener or latch  35  to connect the protective shield  30  to the ground pillars  34 . Another embodiment of the anchor illustrated includes ground screws  36  including a latch  35  to attach the protective shield to the anchor. A third embodiment of the anchors includes liquid bladders  32  (described in more detail below) that hold large masses of water or other mass such as sand, gravel, etc., or combinations of sand, gravel, water, or other mass.  
       FIGS. 3 and 4  illustrate one particular embodiment of a roof ballast module  20 . In this embodiment, the roof ballast modules  20  includes five elongate bladders  54  disposed parallel to one another. The bladders  54  are in fluid communication with one another by way of communication channels  64  between each of the adjacent bladders. The communication channels  64  are disposed near one end, which is referred to herein as the top end  58  of the bladders  54 . Disposed just above the communication channels (nearer the top end), are first and second valves  50 ,  52  which are ports that permit connecting the interior of the bladders. Although the ports described herein are valves, other ports are within the scope of the invention, for example, capped tubes or sealable fittings may be employed as ports within the scope of the invention. The first valve  50  generally permits filling the interior of the bladder with water. Accordingly, the valve (by way of a hose [not shown] and threaded connector  51 , if desired) allows the first bladder to be filled, while water spills over to the next bladder through the communication channel  64 . The communication channels  64  allow each bladder to spillover to fill the next until the last bladder is filled. The second valve  52  (when open) permits water to flow out of the last bladder upon completion of the filling all of the bladders through the first valve  50 . In this regard, the second valve  52  may be connected to a first valve (not shown) of another similar roof ballast module (such as shown in  FIG. 2 ) allowing the spillover to fill successive roof ballasts. Thus, several roof ballasts  20  ( FIG. 2 ) may be daisy-chained about the planar surface of a roof  22 , and filled though a single liquid supply to one or more of the roof ballast modules  20 . The first and second valves may include threaded male  51  and female  53  couplings for connecting to one another and to a water source.  
      Additionally, the ballast modules may be used on sloping roofs (as shown in  FIG. 1 ), as well as flat roofs. Returning to  FIG. 1  and in conjunction with  FIG. 3 , the roof ballast modules  20  may be disposed about the planar surface of a sloping roof such the top end  58  of the bladders is higher than the lower end  60  the bladders. In this way, liquid filling first bladder fills the bladder up to the communication channel first, then spilling over to the next bladder. As such, the first and second valve  50 ,  52  may be disposed nearer the top end of the roof ballast than the communication channels  64  to permit gravity drain from the first valve  52  through the communication channels.  
      When disposed on sloping rigid roofs  22 ,  24 , the plurality of elongate bladders  54  may be disposed such that the axial length of the bladders proceeds from a higher elevation to a lower elevation on the roof. By doing this, the weight of the water mass in the interior of each bladder is distributed at different elevations to reduce the moment of inertia of water at the lower elevation of the bladders. For example, if the plurality of elongate bladders  54  were distributed horizontally, the moment of inertia would be higher due to a larger mass in a single bladder being at the at the lower elevation of the bladder. Thus the bladder would be more likely to rotate and roll the roof ballast modules down the roof. Distributing the bladders axially from a higher elevation to a lower elevation therefore redistributes the water mass to overcome the rolling effect, and is a preferred arrangement. However, other arrangements, including horizontal arrangements are also within the scope of the invention.  
      Other features of the roof ballast may include grommets  70  disposed about the periphery of the roof ballast module. Grommets permit securing the roof ballast modules to one another, or to the roof itself. For example, any or all of the adjacent modules shown in  FIG. 2  may be secured to one another. Some examples of securing the modules to one another includes the use of zip-ties between grommets, while locks, looped wire, ring latches, and other methods of connection are known to those of ordinary skill. Alternatively, the modules could be designed to have interlocking surfaces that permit mating one module to another without additional connectors. In addition, modules on either side of a rood line may be secured together, which can assist in keeping the modules in place. For example, modules  81  and  82  in  FIG. 2  can be connected across the roof line  83 , as can any or all other similarly situated modules.  
      Furthermore, each elongate bladder  54  may also include a drain valve  72  disposed at the lower end of the bladders. The drain valve  72  therefore permits gravity drain of water effluent when the roof ballasts are no longer needed for wind protection.  
      As is understood by those of ordinary skill in the art, there are numerous processes and methods by which to construct a bladder. For a flexible bladder, one particular method known to those of ordinary skill includes radio frequency (RF) sealing and heat sealing of thermoplastic sheets of liquid impermeable materials. Referring back to  FIGS. 3 and 4 , two panels  76 ,  78  may be sealed about the periphery  56  of the module and lengthwise through the inner part of the module to form the plurality of elongate bladders  54  of the roof ballast modules. In this regard, the communication channels  64  may also be formed by the absence of sealing the panels together between bladders. One example of a material having liquid water impermeability and high strength properties for this application includes UV stabilized polyvinylchloride (PVC) coated nylon mesh. A coating of 24 mil and a weave of about 0.6 mm square has high strength properties for holding the mass of water as described in the above embodiments of 4 ft. by 8 ft. modules of five elongate bladders. Other bladders, both rigid and flexible, are known to those of skill in the art, such as plastic tubing, containers, and PVC pipes.  
      In other embodiments, it may be desirable to use potable water as the liquid for filling the roof ballast modules so that adequate supplies of water remain after storms, hurricanes, etc., when regular water supplies may be limited. In this regard, materials that may be used can include thermoplastics that are approved by the Food and Drug Administration for contact with food substances. Other materials and embodiments of bladders and construction of liquid impermeable bladders are known and may be used, and these examples are given without limitation.  
      Some examples of valves for filling and draining the bladders may include valves with threaded fittings to attach to common household water hoses or other water supply systems. The valves may include plugs, ball valves, check valves, etc. (not shown), to permit filling and retaining water in modules. Additionally, the modules may support various attachments for ancillary uses of the water. For example, a shower head attachment can be provided to permit showering water after a storm in the event that regular water supplies are not available.  
      Referring now to  FIG. 5 , a liquid bladder for use as an anchor for the protective shield  30  is illustrated. Similar to the roof ballast modules, the liquid bladder may comprise thermoplastic panels that are RF or heat sealed. Furthermore, the liquid bladder may also employ thermoplastic materials that are approved by the Food and Drug Administration for contact with food substances so that potable water may be used to fill the liquid bladders. A single fill and drain valve  42  may be included for filling the bladder. Like the roof ballast, the fill and drain valve may include male or female threaded  43  connections for compatibility with regular water hoses. A latch or connector  46 , is included to attach the protective shield to the bladder.  
      A wind protection system in accordance with an embodiment of the invention may be installed relatively simply by placing the unfilled ballast modules on the roof and, is desired, securing them together. Then, once in place on the roof, the ballast modules can be filled with water. Filling may be accomplished, for example, with regular water hoses. thus, the system can be installed at low weight and filled to the desired weight once in place.  
      Many modifications and other embodiments of the inventions will come to mind to one skilled in the art to which these inventions pertain, having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.