Abstract:
An apparatus and methodology for abating fungi in a building supported on a ground surface and having an upper enclosed living space and a lower enclosed space beneath the upper enclosed space and proximate or beneath the ground. The apparatus includes a blower positioned in the lower enclosed space and having an air inlet and an air exhaust; a plurality of intake conduits having inlet ends adapted to open in the lower enclosed space proximate a lower boundary of that space and outlet ends connected to the inlet of the blower; a plurality of exhaust conduits having inlet ends connected to the exhaust of the blower and outlet ends discharging into the lower enclosed space; a plurality of ultraviolet lamps establishing germicidal killing zones intercepting and cleansing air moving from the lower enclosed space to the inlet of the blower; and a condenser positioned between the outlet ends of the intake conduits and the blower inlet, forming a part of a refrigerant loop, and serving to dehumidify the air moving from the outlet ends of the intake conduits to the inlet of the blower.

Description:
RELATED APPLICATIONS  
       [0001]     This continuation-in-part application claims the priority of U.S. Provisional Patent Application Nos. 60/435,390 and 60/448,071, filed on Dec. 20, 2002 and Feb. 18, 2003, respectively and U.S. patent application Ser. No. 10/733,904, filed on Dec. 11, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to fungus abatement and more particularly to a system for use in preventing fungus from forming in a building structure such as a home or an office building.  
         [0003]     Fungus is increasingly a problem in homes and office buildings. The fungus typically develops in unconditioned areas of the building such as basements or crawl spaces and is then spread by a natural upward flow of air and/or by the HVAC system to conditioned areas of the building where it contaminates the conditioned areas and generates occupant discomfort and health hazards.  
       SUMMARY OF THE INVENTION  
       [0004]     The invention provides a method of maintaining a structure free of fungi. According to the invention method, a flow of air is created from an enclosed space within the structure, the flow of air is treated in a germicidal fashion, and the flow of air is treated in a dehumidifying fashion. This basic air handling and treating process results in a continual cleansing and dehumidifying of the air in the enclosed space to preclude contamination of other areas of the structure.  
         [0005]     According to a further feature of the invention methodology, the flow of air is returned to the enclosed space after the germicidal treating step and after the dehumidifying treating step. The germicidal cleansing and the dehumidifying of the air conditions the air to a point where it is suitable for return to the enclosed space.  
         [0006]     According to a further feature of the invention methodology, the germicidal treating step comprises creating a fungi killing zone in the enclosed space and passing the flow of air through the killing zone. This specific germicidal treating step effectively removes fungi from the air.  
         [0007]     According to a further feature of the invention methodology, the killing zone comprises a zone in which the flow of air is subjected to radiant energy. This methodology provides a convenient means of creating the killing zone to destroy the fungi. In the disclosed embodiments of the invention the radiant energy comprises ultraviolet radiation.  
         [0008]     In one embodiment of the invention methodology, the flow of air moves through the killing zone prior to its movement through the dehumidifier. In another version of the invention methodology, the air flows through the dehumidifier prior to its movement through the killing zone.  
         [0009]     The invention also provides an apparatus for abating fungi in a structure having boundary walls defining a first enclosed space intended for human occupancy and a second enclosed space proximate the first enclosed space. The abatement apparatus comprises a blower unit, a source of radiant energy, and a dehumidifier. The blower unit has an air inlet and an air exhaust and is adapted to be positioned within the structure with the air inlet communicating with the second enclosed space, actuation of the blower unit being operative to create a flow of air from the second enclosed space into the blower unit inlet and thereafter discharge the air through the blower unit air exhaust. The source of radiant energy is adapted to be positioned to establish a fungi killing zone to intercept the flow of air moving from the second enclosed space to the inlet of the blower unit, and the dehumidifier is adapted to be positioned to intercept the flow of air moving from the second enclosed space to the inlet of the blower unit. This apparatus provides a ready and continuous cleansing and dehumidifying of the air in the second enclosed space and insures that all of the exhausted air is thoroughly dehumidfied and throughly treated with radiant energy to remove the fungi from the air.  
         [0010]     In one embodiment of the invention apparatus, the radiant energy source comprises a series of ultraviolet lamps positioned in spaced locations within the second enclosed space and arranged to irradiate the air prior to its movement to the dehumidifier. In another embodiment of the invention apparatus, a housing is provided receiving the blower unit and the dehumidifier and the source of radiant energy is provided in the housing between the dehumidifier and the inlet of the blower unit so that the flow of air moving from the second enclosed space to the blower unit passes first through the dehumidifier and then through the killing zone established by the source of radiant energy.  
         [0011]     Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:  
         [0013]      FIG. 1  is a perspective, fragmentary view of building having a crawl space employing a fungus abatement system according to the invention;  
         [0014]      FIGS. 2, 3 ,  4  and  5  are perspective, plan, side elevation, and end views of a blower unit employed in the fungus abatement system;  
         [0015]      FIG. 6  is a plan view of the fungus abatement system;  
         [0016]      FIGS. 7 and 8  are cross-sectional views of germicidal lamp assemblies utilized in the fungus abatement system;  
         [0017]      FIG. 9  is a wiring diagram for a fungus abatement system according to the invention;  
         [0018]      FIG. 10  is a perspective view showing the fungus abatement system of the invention utilized in a building having a full unfinished basement;  
         [0019]      FIGS. 11-13  are fragmentary views showing the fungus abatement system of the invention utilized in a building having a full finished basement;  
         [0020]      FIGS. 14, 15  and  16  are plan, side elevational, and perspective views of a modified form of the invention employing a dehumidifying apparatus; and  
         [0021]      FIGS. 17 and 18  are side elevational and cross-sectional views of a further modified form of the invention also employing a dehumidifying apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     The invention fungus abatement system is seen in  FIGS. 1 and 6  installed in a building  10  of the type including an upper enclosed living area space  12 , bounded by a floor  14 , and a lower enclosed crawl space  16  beneath the upper enclosed space. Upper enclosed space  12  is defined by walls  12   a  and  12   b  as well as by floor  14  and crawl space  16  is defined by walls  16   a  and  16   b  as well as by a ground surface  18 .  
         [0023]     The fungus abatement system, broadly considered, includes a blower assembly  20 , a plurality of air inlet conduits  22 ,  24 ,  26  and  28 , a pair of exhaust conduits  30  and  32 , and a plurality of germicidal units  34 ,  36 ,  38  and  40 .  
         [0024]     Blower assembly  20  includes a housing  42  and a pair of squirrel cage blowers  44  and  46 .  
         [0025]     Housing  42  ( FIG. 2-5 ) has a sheet metal construction and is secured to the underface of floor  14  centrally within the crawl space  16 . Housing  42  includes a main body portion  42   a  defining exhaust ports  42   b  and  42   c , and a plenum chamber  42   d  positioned against main body portion  42   a  and defining intake ports  42   e ,  42   f ,  42   g  and  42   h.    
         [0026]     Squirrel cage blowers  44  and  46  are commonly driven by a central electric motor  48  positioned in housing main body portion  42   a  and may each comprise a unit available from Penn Zepher as Part Number Z102. Each blower  44 ,  46 , will be understood to have an exhaust communicating with a respective exhaust port  42   b ,  42   c  and an intake communicating with plenum chamber  42   d . Blower assembly  20  is preferably provided with a germicidal filter  49  positioned at the interface of plenum chamber  42   d  and the intakes of the blowers  44  and  46 .  
         [0027]     Intake conduits  22 ,  24 ,  26  and  28  each have an outlet end  22   a ,  24   a ,  26   a , and  28   a  connected respectively to a housing port  42   e ,  42   f ,  42   g  and  42   h ; an inlet end  22   b ,  24   b ,  26   b  and  28   b  positioned respectively in the four corners of the crawl space; and an intermediate portion  22   c ,  24   c ,  26   c  and  28   c  interconnecting the inlet end and the outlet end of each conduit. Inlet ends  22   b ,  24   b ,  26   b  and  28   b  will be seen to be vertically disposed and will be seen to terminate in an inlet port  22   d ,  24   d ,  26   d  and  28   d  positioned proximate but spaced slightly above the ground surface  18 . Intermediate portions  22   c ,  24   c ,  26   c  and  28   c  will be seen to comprise horizontal runs extending beneath floor  14  and interconnecting the respective inlet end and the respective outlet end of the respective conduit.  
         [0028]     Exhaust conduits  30 ,  32  each define an inlet end  30   a  and  32   a  connected to a respective port  42   b ,  42   c  of housing  42  and an outlet end  30   b  and  32   b  communicating with a register or vent  50  positioned in opposite crawl space sidewalls  16   b.    
         [0029]     Germicidal units  34 ,  36 ,  38  and  40  are positioned on the underface of floor  14  in association with the inlet port of a respective intake conduit. Each germicidal unit may comprise, for example, a 15 watt ultraviolet germicidal lamp of the type available from Sylvania company as Part Number G15T8. Each germicidal lamp in known manner emits ultraviolet radiation in the wave length of 254 nm which has the effect of establishing a killing zone around each germicidal unit which will effectively kill any fungi carried by air passing through the killing zone. Each germicidal lamp comprises an elongated tube  51  and a base  52  to which the tube is suitably mounted. If desired, an overhead directional reflector may be provided with respect to at least certain of the lamps. The reflector may, for example, have an inverted trough configuration as seen at  53  in  FIG. 7  or a gull wing configuration as seen at  54  in  FIG. 8 , depending upon the shape and size of the killing field that it is desired to establish in the vicinity of the tube  51 . Preferably, however, no reflectors would be utilized in the crawl space embodiment of  FIGS. 1-6 . Rather, sufficient germicidal lamps would be provided to essentially flood the crawl space area with radiant energy.  
         [0030]     The fungus abatement system of the invention further includes a motion detector  58 , a control panel  60 , a plurality of humidistats  62 , and a controller  64 .  
         [0031]     Motion detector  58  may be installed in the crawl space  16  beneath the floor  14  and preferably has a 180° sweep. The detector may be of the type available from Desa International as Part Number 5411-ASL-5407A. This is a motion-on detector and is therefore used with a relay  65  to reverse the action of the motion detector to a motion-off detector. Relay  65  may be a 5 pin 6C895-7 type and may snap into a 5 pin base of the 6C898-1 type.  
         [0032]     Control panel  60  may be positioned in upper enclosed living space  12  on wall  12   a  for ready access by occupants of living space  12 .  
         [0033]     A humidistat or humidistat trigger  62  may be installed in crawl space  16  proximate the inlet port  22   d ,  24   d ,  26   d  and  28   d  of each of the intake conduits whereby to sense the humidity of the air entering each of the intake conduits.  
         [0034]     Controller  64  may be mounted, for example, in a controller housing  68  secured to a side face of blower housing  42 .  
         [0035]     As seen in the wiring diagram of  FIG. 9 , a lead  64  interconnects lamp  34  and motion detector  58 ; a lead  66  interconnects lamp  36  and lamp  40 ; a lead  68  interconnects lamp  40  and motion detector  60 ; a lead  70  interconnects lamp  38  and motion detector  60 ; a lead  72  interconnects motion detector  60  and controller  64 ; leads  74  and  76  interconnect thermostats  62  and controller  64 ; and a lead  78  interconnects control panel  60  and controller  64 .  
       Operation  
       [0036]     With control panel  60  calling for operation of the fungus abatement system, and assuming that the motion detector  58  does not detect the presence of anyone in the crawl space, the controller  64  functions to turn on the system and specifically functions to turn on the blowers  44 ,  46  and the lamps  34 ,  36 ,  38  and  40 . Actuation of the blowers has the effect of drawing air from the crawl space  16  into the inlet ports  22   d ,  24   d ,  26   d  and  28   d  of the intake conduits for passage through the conduits to the plenum chamber  42 d and thence through the squirrel cage blowers for discharge via the conduits  30  and  32  through the grills  50  to the exterior of the building. As the air moves respectively toward the inlet ports  22   d ,  24   d ,  26   d  and  28   d  of the intake conduits, the air passes through killing zones  80  established around each of the lamps  34 ,  36 ,  38 ,  40  so that effectively all of the air entering the inlet ports  22   d  of all of the conduits is first passed through a killing zone where the air is irradiated by the germinating lamp to kill any fungus or other contaminants carried by the air. The air passing through the intake conduits in turn passes through germicidal filter  49 . The air thereafter moved outwardly through the exhaust conduits is thus essentially free of fungus and the air in the crawl space  16  is continuously purged of fungus so that the crawl space air, rather than rising upwardly laden with fungal contaminants into the conditioned air living area space above the crawl space, is cleansed within the crawl space and carried to a location outside of the building. Alternatively, the system may be programmed to cycle on and off dependent upon the readings provided by the humidistats  62 . Specifically, as the humidity of one or more of the humidistats reaches a predetermined upper limit the controller functions to turn on the system and as the humidity reaches a predetermined lower limit as determined by the humidistats the blowers are turned off. Desirably, the ultraviolet lights remain on for a measured period of time following cessation of blower operation to insure that the stagnant air remaining in the crawl space is cleansed of fungi.  
         [0037]     It will be understood that, depending upon the construction and porosity of the building, air will also be sucked downwardly from the conditioned air space  12  into the crawl space for discharge through the intake conduits and the exhaust conduits to the exterior of the building, thereby reversing the normal flow of air within the building.  
         [0038]     It will further be understood that the efficiency of ultraviolet radiation is directly proportional to the density or the humidity of the air being treated. The denser or more humid the air, the slower the ultraviolet travel. Accordingly, by lowering humidity the efficiency of the germicidal units increases. In some scenarios involving exceptionally high humidity, it may be necessary to provide a separate dedicated dehumidifier to assist the invention system in maintaining a desired humidity level.  
         [0039]     It will further be understood that, if the motion detector  58  detects movement in the crawlspace, the controller is appropriately signaled to turn off the system to preclude harm to living creatures in the crawlspace.  
       Alternate Embodiments  
       [0040]     The fungus abatement system seen in  FIG. 10  is intended for use with a building  10 ′ having a full unfinished basement  82  including a floor  84 . The system of  FIG. 12 , for use with a full unfinished basement, is identical to the system of  FIG. 1 , for use with a crawl space, except that the intake conduit lower ends  22   b ′,  24   b ′,  26   b ′, and  28   b ′ are extended vertically downwardly to position the conduit inlet ports  22   d ′,  24   d ′,  26   d ′ and  28   d ′ proximate the floor  84 , and the humidistats  62  are moved downwardly to retain their positions proximate the inlet ports of the respective intake conduits whereby to monitor the humidity of the air entering the respective conduits. As with the crawl space configuration, sufficient germicidal lamps would be provided to essentially flood the basement area with radiant energy or, alternatively, at least certain of the ultraviolet lamps would be provided with directional reflectors. Lamps  34 ,  36 ,  38  and  40  are preferably mounted on the underface of floor  14 .  
         [0041]      FIGS. 11-13  illustrate an arrangement for use in a full finished basement including a drop ceiling  86 , studs  88  mounted against foundation wall  90 , and dry wall or other paneling  92  mounted on the studs and defining dead air spaces  94  between the paneling and the foundation wall. Suitable HVAC equipment is provided so that the lower area within the paneling is provided year round with conditioned air, either heated or cooled. The fungus abatement system for the full finished basement of  FIGS. 11-13  includes a plurality of vertical intake conduits  96  positioned between selected studs  88  with the open lower ends  96   a  spaced above the sills  98  and a plurality of germicidal lamp units  100  positioned above the drop ceiling proximate to the perimeter of the basement. For example, and as shown, intake conduits  96  may be positioned around the perimeter of the basement on  48 ″ centers and a germicidal lamp  100  may be provided in association with each intake conduit. Each germicidal lamp  100  may include an elongated tube  102 , a base  104 , and a reflector  106 . Each lamp may be centered on a stud  88  and the reflector  106  may be notched at  106   a  to fit over the stud. Each reflector  100  may be of the type available from Simkar Corporation as Part Number ARW20-SR and will be seen to provide an angled reflector surface  106   b  which is operative to direct rays from the tube  102  downwardly into the dead air spaces  94  on either side of the stud over which the reflector is fitted so as to establish germicidal killing zones in the dead air spaces on either side of the stud over which the reflector is fitted.  
         [0042]     It will be understood that the blower unit  20  in this finished basement embodiment is positioned centrally above the drop ceiling, that each conduit  96  is suitably connected to the intake of the blower unit, and that suitable humidistats (not shown) might be provided proximate the intake of the various conduits  96 . In operation, following actuation of the blower unit and the germicidal lamps, any fungal matter in the dead air spaces  94  is killed by exposure to the ultraviolet killing zones established in the dead air spaces and the cleansed air is sucked upwardly through conduits  96  for discharge by the blower unit outside of the building. Since the studs  88  do not sealingly interface with the foundation wall but rather define significant spacing at the interface, air is free to move laterally from the dead air spaces in which a conduit is not positioned into a dead air space in which a conduit is positioned for entry into that conduit and discharge from the building. As the air moves laterally toward the intake of a conduit, it moves through a killing zone and is cleansed of fungal matter.  
         [0043]     The forms of the invention heretofore described are open systems in which the conditioned air is exhausted outside of the associated building structure. The modified form of the invention seen in  FIGS. 14-16  employs a dehumidifying apparatus to allow the unit to operate in a closed loop fashion with the blower discharge being returned to the enclosed space defined by a finished basement, for example, rather than being exhausted outside of the building structure.  
         [0044]     The apparatus seen in  FIGS. 14-16  is generally similar to the apparatus seen in  FIG. 10  and as such includes intake conduits  22 ,  24 ,  26  and  28  defining intake conduit lower ends  22   b ′,  24   b ′,  26   b ′ and  28   b ′ positioned proximate the floor of the associated enclosed space (for example a finished basement of a housing structure); a plurality of ultraviolet lamps  34 ,  36 ,  38  and  40  mounted at spaced locations on the underface of the floor of the enclosed space of the housing structure overlying the finished basement and establishing respective killing zones  80  positioned to intercept air moving from the finished basement space into the respective intake conduit lower ends, and a housing  42 ′ receiving the outlet ends of the intake conduits  22 ,  24 ,  26  and  28  and housing the blowers  44  and  46 .  
         [0045]     However, and as best seen in  FIG. 15 , housing  42 ′ also receives a dehumidifying apparatus  110  positioned within the housing between filter  49  and blowers  44 ,  46 .  
         [0046]     Dehumidifying apparatus  110  includes an evaporator  112 , a compressor  114 , and a condenser  116 .  
         [0047]     Evaporator  112 , in known manner, may comprise a single continuous smooth wall tube  112   a  extending in sinusoidal fashion within the housing  120   b  of the evaporator and condenser  116 , in known manner, may comprise a single continuous finned tube  116   a  extending in sinusoidal fashion within the housing  116   b  of the condenser. Compressor  114  may, for example, comprise a unit available from Danfoss as Model Number SE 15FPX; condenser  116  may, for example, comprise a unit available from Tecumseh as Model Number 508; the evaporator  112  may be formed of a length of {fraction (5/16)}″ OD copper tubing received in a suitable housing; and the refrigerant may be R  134   a . The refrigerant moves through the dehumidifier apparatus as indicated by the arrows and, specifically, leaves the outlet  114   a  of the compressor as a high pressure vapor, moves through a conduit  120  to the inlet of the condenser, is transformed in the condenser to a liquid, flows as a liquid through a conduit  122  to the inlet of the evaporator, is transformed in the evaporator to a low pressure vapor, and moves through a conduit  118  to the inlet  114   b  of the compressor to complete the refrigerant loop.  
         [0048]     In the operation of the embodiment of  FIGS. 14-16 , a flow of irradiated air from the enclosed space defined by the finished basement is delivered to plenum chamber  42   d ′ of the housing  42 ′ via intake conduits  22 ,  24 ,  26  and  28 ; thereafter moves through the filter  49 ; thereafter moves through evaporator  112  where it is cooled by the evaporation of the refrigerant and the resulting condensate collected in a drain pan  124  for discharge and collection via a drain tube  126 ; the cooled and dehumidified air thereafter moves through the condenser  116  where it serves to extract the superheat from the refrigerant and is heated; and the irradiated and dehumidified air flow is thereafter delivered to the blower units  44 ,  46  for discharge through exhaust conduits  32 ′ which, rather than extending as in the  FIG. 10  embodiment to registers  50  for discharge outside of the building, are configured to deliver the dehumidified and irradiated air back to the enclosed space via exhaust tube outlet ends  32   a.    
         [0049]     The modified apparatus as seen in  FIG. 17  and  18  corresponds to the apparatus of  FIGS. 14-16  with the exception that the killing zone for irradiation is established within the housing  42 ″ between the dehumidifying apparatus  110  and the blower units  44 ,  46 .  
         [0050]     Specifically, the dehumidifying air leaving the dehumidifying unit  110 , rather than flowing directly to the blowers  44 ,  46  as in the  FIGS. 14-16  embodiment, instead is directed through a reduced diameter housing conduit  42   a ″ where it is exposed to a series of ultraviolet lamps positioned within the conduit  42   a ′″ so that the flow of air arriving at the blowers  44 ,  46  is irradiated to remove fungi with the irradiation in this case taking place within the housing of the blower unit rather than taking place outside of the housing within the general area of the enclosed space as in the previous embodiments. Specifically, the flow of air leaving the dehumidifying unit first passes through a first killing zone established by a first series of circumferentially spaced ultraviolet lamps  128  positioned within the conduit  42   a ″ and thereafter passes through a second killing zone established by a second series of circumferentially spaced ultraviolet lamps  130  positioned within the conduit  42   a ″. As in the case of the 14-16 embodiment, the irradiated and dehumidified air leaving the blowers  44 ,  46  is returned via conduits  32 ′ to the enclosed space rather than being discharged outside of the building. As noted, in the embodiment of  FIGS. 17 and 18  the ultraviolet lamp  34 ,  36 ,  38  and  40  and their associated killing zones  80 , are eliminated since the irradiation is now performed within the blower unit housing.  
       Specifications  
       [0051]     The number sizing and location of the various components of the mold abatement system will of course depend on whether a crawl space is being treated or a full basement is being treated and will of course in each case further depend on the size of the crawl space or the full basement.  
         [0052]     As an example, for a crawl space with dimensions of 26′ wide by 42′ long and 36″ deep for a total of 3,276 cubic feet, the blower assembly  20  would have a 638 cfm capacity and would serve to establish a system static pressure of 0.375 inches, and would operate on 3.6 amps. This arrangement would serve to change the air within the crawl space ten times per hour. As previously noted, blowers  44  and  46  in this crawl space configuration may comprise units available from Penn Zepher as Part Number Z102. These blower units would also be satisfactory for use in the full finished basement embodiment of  FIGS. 11-13 .  
         [0053]     As a further example, for a full unfinished basement 8′ deep by 26′ wide by 42′ long, resulting in 8,736 cubic feet of space, a 950 cfm blower assembly  20  would be required operating at 0.8375 inches system static pressure. This arrangement would serve to change the air within the basement 5.868 times per hour. Blowers  44  and  46  in this full basement configuration may comprise units available from Penn Zepher as Part Number Z121.  
         [0054]     The invention would seem to provide an efficient and inexpensive means of precluding the contamination of the living areas of a building by fungi. The embodiments of the invention illustrated in  FIGS. 1-13 , where the irradiated air is exhausted to a location outside of the building structure, are best suited for crawl space applications or applications where the basement, while full size, is not primarily used for human habitation, and the embodiments seen in  FIGS. 14-18 , where the air is dehumidified prior to discharge from the blower units, are best suited for use in full basements that are finished and where regular human habitation is contemplated.  
         [0055]     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law. For example, the term fungi as used in the specification and appended claims will be understood to include germs, parasites, spores, bacteria, mold, rust, mildew, smuts, mushrooms and other airborne contaminants. As a further example, the particular reflector configuration, if any, employed in association with the ultraviolet lamps will vary depending upon the nature and configuration of the space being treated. As a yet further example, although the invention has been described with reference to the germicidal treatment of air in a lower enclosed space of a building, it also has applicability in certain situations to the germicidal treatment of air in an upper enclosed space of a building. As a yet further example, although the invention has been described with reference to treatment of air in a building, it may also have applicability to the treatment of air in structures other than buildings.