AU2006339489A1 - Integrated decontamination system - Google Patents

Description

WO 2007/102798 PCT/US2006/000781 INFLATABLE DECONTAMINATION SYSTEM

BACKGROUND

[00011 The present invention relates to the field of environmental decontamination. It finds particular application in conjunction with a portable enclosure for microbial, biological or chemical decontamination of large pieces of equipment, and will be described with particular reference thereto. It should be appreciated, however, that the invention is also applicable to the decontamination, treatment, or isolation of other items, both large and small.

[0002] Small pieces of equipment used in medical, pharmaceutical, food, and other applications are frequently sterilized or otherwise microbially decontaminated prior to use or reuse. Concerns arise, however, when larger pieces of equipment, such as vehicles, food and pharmaceutical processing equipment, mail handling equipment, and the like become contaminated with chemical or biological contaminants, such as harmful organisms or other species. Such equipment is often too large or is unsuited to being transported to a decontamination system, such as a sterilizer. Further, there is often concern that transporting the contaminated equipment around a facility or to an offsite decontamination system may pose hazards to those transporting the equipment or may spread the contamination around the facility or to transportation equipment.

[0003] US Published Application No. 2003/0133834 to Karle discloses an enclosure assembly includes a framework formed from structural members and a flexible transparent enclosure which provides an enclosed space for isolation and or treatment of patients, equipment, and the like. A treatment material, such as hydrogen peroxide or other gaseous or vapor sterilant, may be fed to the enclosure to microbially decontaminate or otherwise treat the equipment. The enclosure is quickly assembled and disassembled after use, making it suitable for treatment of large pieces of equipment which are not readily moved or which are too large to be accommodated conventional sterilization equipment.

[00041 The system of Karle is suited to smaller enclosures where the height of the framework makes assembly feasible. Due to the large number of components, there is a risk that an important part of the frame may be lost if the assembly has been used previously and repacked without care.

WO 2007/102798 PCT/US2006/000781 -2- [0005] The present invention provides a new and improved portable environmental enclosure and method of use which overcome the above-referenced problems and others.

BRIEF DESCRIPTION [0006] In accordance with one aspect of the present exemplary embodiment, a decontamination system for decontaminating an item includes an enclosure comprising an inflatable structure which, when inflated, defines an interior space for receiving the item to be decontaminated. A source of a decontaminant is fluidly connected with the interior space. The source supplies the decontaminant to the interior space for decontaminating the item.

[0007] In accordance with another aspect of the present exemplary embodiment. a method of'decontaminating an item is provided. The method includes inflating inflatable structural elements to form an enclosure with an interior space to hold the enclosure erect and transporting an item into the interior space. The item is sealed in the enclosure and a gaseous decontaminant is introduced to the interior space to decontaminate the item.

[0008] One advantage of at least one embodiment is that the decontamination system is readily transported to a site at or close to the location at which contamination has occurred or is recognized.

[0009] Another advantage of at least one embodiment is that the system is employed operational in a short period of time.

[0010] Another advantage of at least one embodiment is that the system can be stored, when not in use, in a small volume.

[0011] Another advantage of at least one embodiment is that the passages which form the enclosure are heated by inflation air, reducing condensation of the decontaminant between the decontaminant source and the enclosure interior.

[0012] Another advantage of at least one embodiment is that the enclosure is temperature controlled on all sides.

[0013] Still further advantages will be apparent from a reading of the following description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS [0014] The drawings illustrate embodiments of the invention and are not intended to limit it. Further embodiments will occur to those of ordinary skill in the art on reading and WO 2007/102798 PCT/US2006/000781 -3following Detailed Description. The invention is to be construed as including all such further embodiments which come within the scope of the depended claims or their equivalents.

[0015] FIGURE 1 is a perspective view of a decontamination system according to the present invention; [0016] FIGURE 2 is a top plan view of the decontamination system of FIGURE 1; [0017] FIGURE 3 is a perspective view of the decontamination system of FIGURE 1 with the front doors open; [0018] FIGURE 4 is a cross sectional view of the enclosure; and [0019 FIGURE 5 is an enlarged perspective view of a portion of a side wall of the enclosure of FIGURE 1.

DETAILED DESCRIPTION [0020] With reference to FIGURE 1, a portable decontamination system A includes a portable enclosure 10 which is suitable for temporarily isolating and decontaminating large items. The enclosure 10 is readily erected when needed for isolation of a contaminated or potentially contaminated item from the surrounding environment and for subsequently decontaminating the item with a gaseous or liquid decontaminant. The gaseous decontaminant may be in the form of a gas, vapor, mist, aerosol, or fog. Suitable gaseous decontaminants include oxidizing agents, in particular, peroxides, such as hydrogen peroxide, ozone, or a combination of hydrogen peroxide with a co-agent, such as ammonia or UV radiation. Other suitable gaseous decontaminants include high temperature air and other gaseous decontaminants which are capable of destroying, inactivating, or otherwise rendering the contaminant less harmful. While particular reference is made to vapor hydrogen peroxide, it will be appreciated that other gaseous decontaminants and combinations of decontaminants are also contemplated.

[0021] The term "decontamination," as used herein, encompasses microbial decontamination-the destruction or inactivation of biological contaminants, including living microorganisms and harmful replicating biological substances, such as prions. The term also encompasses chemical decontamination-the destruction or inactivation of chemical agents which are harmful to humans at low levels below about 10 ppm.), such as chemical warfare agents. It is not intended to encompass solely ,the physical removal of such contaminants, without destruction or inactivation, as in a cleaning process, WO 2007/102798 PCT/US2006/000781 -4although a decontamination process may also effect cleaning. A "decontaminant," as used herein, is a substance which is capable of effecting decontamination. The enclosure 10 is configured for performing decontamination processes, particularly chemical and microbial decontamination processes, such as sterilization or lesser forms of decontamination, including disinfection and sanitization.

[0022] Items which can be isolated and decontaminated in the enclosure 10 include motorized passenger and goods transport vehicles, such as ambulances, cars, trucks, buses, and other road vehicles, military vehicles, such as tanks and personnel and munitions carriers, aircraft, food and beverage processing equipment, such as cooking, processing, chilling, slicing, packaging and bottling equipment, and pharmaceutical equipment. Other equipment can also be treated, such as medical and veterinary equipment contaminated with body fluids or other sources of microorganisms, including beds, chairs, washing facilities, and the like. Pharmaceutical processing equipment, mail-handling equipment, and other equipment may be isolated and treated. The item is typically one which is known or suspected of being contaminated with a chemical or biological contaminant which is harmful to humans, such as chemical warfare agents, biological warfare agents, and naturally occurring chemical and biological contaminants. The item is readily isolated and treated without moving the item to a permanent, purpose-built isolation unit, reducing the chance that harmful microorganisms or other contaminants will be spread around a facility.

Additionally, some equipment which is too heavy or too large for convenient movement can be cleaned in place.

[0023] The enclosure 10 includes a flexible inflatable structure 12. When inflated with an inflation fluid, such as air, as shown in FIGURE 1, the inflated structure 12 provides a rigid freestanding walled enclosure. The structure 12 is self-supporting, without the need for a framework of support members formed from a rigid material, although such a framework may be employed if desired. With reference also to FIGURE 2, the inflatable structure 12 includes a plurality of inflatable walls 14, 16, 18. While the enclosure 10 is illustrated with an inflatable rear wall 14 and inflatable sidewalls 16, 18 which extend and arch upwardly to form a roof 20 of the structure 12 (FIGURE it will be understood that any number of walls may be employed as long as the enclosure is inflatable for its desired purpose. One or more of the walls 14, 16, 18 or potions of the walls may include noninflatable portions. For example, the rear wall 14 may alternatively be formed of a single or double layer. The walls 14, 16, 18 define an inflatable support structure formed by a set of WO 2007/102798 PCT/US2006/000781 tubular members or other suitably shaped structural elements 21 which define interconiected inflation passages 22. Once inflated, and tied or otherwise anchored down, as necessary, the enclosure is capable of withstanding wind speeds of up to about 100 miles/hr. The enclosure 10 optionally includes a floor 24, suitable for positioning on a support surface 26. In one embodiment, the floor is thermally insulated to facilitate accurate temperature control. Alternatively, the support structure 12 is taped or otherwise sealed to the support surface 26 and has cross structures, as necessary to help maintain the base of the walls in the proper location. The enclosure 10 is light weight and, prior to inflation, can be stored in a valise 28 of suitable size.

[0024] As shown in FIGURE 2, an interior space 30 within the enclosure 10 can be sealed from the surrounding atmosphere to create a substantially airtight isolation chamber for carrying out a decontamination process. Specifically, the floor 24 of the enclosure is sealed to the walls adjacent a lower end thereof. The rear wall 14 is sealed, around its perimeter, to the adjacent side walls 16, 18. An access opening 32, at an end of the enclosure opposite the rear wall 14 is sealed, during decontamination, by a closure comprising an interior door 34 and an exterior door 36 which define an antechamber 38 therebetween. The doors 34, 36 each comprise a set of closure members in the form of flexible panels 40, 42, 44 (FIGURE which may be formed from the same material as the inflatable structure 12. The panels are folded, rolled, or otherwise drawn aside as shown in FIGURE 3, to provide access to the enclosed space 30. Fastening members 46, along edges of the panels 40, 42, 44 allow the panels to be sealed to each other and to the floor when in the closed position. Suitable fastening members 46 include hook and loop tape ChicoTM hook and loop tape, available from Stretchline (Textiles) Ltd, Tetbury, Gos., UK, or VelcroTM tape). Other suitable fastening members include zippers, and Ziploc® types of closure. ChicoTM hook and loop tape, for example, is a fire retardant tape formed from 100% nylon. It has a cushioning effect which both insulates and reduces vibrations and, when firmly closed, acts as an effective dust filter and, in one embodiment, is snow and sand proof.

[0025] In FIGURE 1, the exterior door has a center panel 40, which includes a transparent portion 48 for providing a window to the interior space 30. The center panel may be rolled upward, from the floor, and held by tapes or ties 50 attached to a fixed panel 52 (FIGURE 3) for access to the interior 30. Two side panels 42, 44, are also drawn aside WO 2007/102798 PCT/US2006/000781 -6and held by suitably positioned tapes or straps 54 attached to the inflatable structure 12.

The interior door 34 can be similarly constructed.

[0026] With continued reference to FIGURES 1 and 2, an inflation system 60 is connected with the interconnected inflation passages 22 prior to inflation. The inflation system 60 includes a compressor 62 or other suitable air blower which pressurizes atmospheric air. Suitable blowers are electrically operated pumps, although a manually operated pump is alternatively used. The inflation system optionally also includes heating and/or cooling equipment 64 for heating/cooling the air prior to entering the passages 22.

The compressor 62 may have two or more operating speeds to provide low and high air flow rates. The high flow rate is used for initially inflating the structure 12 and a lower rate is used for sustaining the inflation structure.

[0027] The temperature controlled air enters the passages 22 and provides a temperature adjustable air blanket around the interior space 30, which enables the appropriate temperature for effective decontamination to be maintained within the interior space. In the case of hydrogen peroxide vapor, a suitable temperature is one which eliminates or minimizes condensation of the hydrogen peroxide vapor on the walls of the enclosure or on items to be decontaminated and is generally above that of the surrounding exterior environment. A switch (not shown) or the like is optionally provided on the pump 62, which enables a user to change the pump from an inflation mode to a deflation mode. The inflation system 60 typically operates at about 1-300 m 3 /min. Depending on the size of the blower and the size of the inflatable structure, the enclosure can be erected in a relatively short period of time, typically in under about an hour. For larger enclosures, a plurality of blowers can be employed to increase the rate of inflation.

[0028] The inflation-system 60 is connected with the interior 30 via an inlet port 70 of the inflatable enclosure. As shown, a thermally insulated air conduit 72 extends between the inflation system and the wall 18 of the enclosure. In one embodiment, the end of the air conduit is fitted with a suitable coupling member 74 for quickly coupling with a corresponding coupling member 76 extending from the inlet port 70. Alternatively, a permanent connection may be provided between the conduit 72 and the wall inlet port The inflation system 60 optionally also supplies fresh air to the antechamber 38 via an inlet or inlets 78. The air may be heated or cooled as for the air in the passages, thus ensuring a temperature controlled environment on all sides of the enclosure WO 2007/102798 PCT/US2006/000781 -7- [0029] As illustrated in FIGURE 2, the walls 14, 16, 18 and roof 20 of the enclosure are formed from inner and outer panels 80, 82 of flexible material, which are arranged generally parallel to one another. The panels 80, 82 are connected to each other by vertically extending connecting members 84, which may be formed from the same material.

Together, the inner and outer layers and connecting members form the tubular members which define the through passages 22. The walls 14, 16, 18 may be vertical or slope generally inward, towards their upper ends, adjacent the roof portion 20, as illustrated in FIGURE1. The passages 22 which define the side walls 16, 18 and roof portion 20 thus extend generally vertically from the floor 24 to form the first side wall 16, span the roof portion 20, and continue down the other wall 18 to the floor. The connecting members 84 define apertures 86, which enable the air to flow throughout the passages and equalize the pressure. An outlet check valve 88 in the outer panel 82 of the wall 16 opposite to the inlet allows the release of excess pressure above a preselected maximum pressure and allows the passages to be continuously or intermittently replenished with heated or cooled air, if desired.

[0030] The panels 40, 42, 44, 80, 82 are sealed together at their edges to provide an airtight, or substantially airtight interior space 30. It will be appreciated that each panel may be formed from two or more separate panels which are sealed together at their respective edges. 'By substantially airtight it is meant that if air at a pressure equivalent to about 3.8 cm of water is supplied to the enclosure and allowed to equilibrate for 2 minutes, and then the air pressure supply is disconnected, the pressure within the enclosure after a further 5 minutes is at least about 2 cm of water, in one embodiment, at least about 2.5 cm of water. The enclosure may be leak tested, prior to use, to check that the enclosure is substantially airtight, for example, by pressurizing the enclosure to about 1.5 cm water, equilibrating for 1 minute, and testing to ensure that an acceptable pressure level is maintained, such as a pressure of 1.0 cm water after 2 minutes.

[0031] The floor 24 of the enclosure is optionally heated for heating the interior space For example, as shown in FIGURE 4, the floor comprises lower and upper layers of flexible material 90, 92. A flexible resistance heating element 94 or other heat source is located in a gap 96 between the two layers. In one embodiment, the floor 24 comprises sections, each section having its own associated heat source.

[0032] A mobile source 100 of gaseous decontaminant supplies a gaseous decontaminant to the interior space 30. As shown in FIGURE 2, the source 100 is located WO 2007/102798 PCT/US2006/000781 -8exterior to the enclosure, although it is contemplated that the source is alternatively transported into the interior, prior to decontamination. A suitable source 100 for supplying vapor hydrogen peroxide includes a source 102 of liquid hydrogen peroxide in solution, such as a reservoir of aqueous hydrogen peroxide at a concentration of about 20-40% by weight hydrogen peroxide. The hydrogen peroxide liquid is fed by a pump 104 to a vaporizer 106, where the hydrogen peroxide and water components are vaporized on a heated surface (not shown). The vapor is carried in a carrier gas, such as air or other flow medium, suppliedby a source of carrier gas 108, such as a blower or pressurized reservoir.

The blower 108 may operate at about 1-300 m 3 /min. For larger enclosures, a plurality of mobile sources 100 may be employed. The air is optionally dehumidified in a dehumidifier 110 and heated by a heater 112 prior to combining with the hydrogen peroxide vapor.

[0033] One suitable mobile'source 100 of sterilant is a STERIS VHP 1000TM hydrogen peroxide vapor generator. Other suitable vaporizers are disclosed in U.S. Patent No.

6,734,405 to Centanni, et al., and U.S. Published Application No. 2002/0159915 to Zelina, et al. Other suitable misting, fogging, or aerosol generating equipment for generating the gaseous decontaminant is also contemplated. Alternatively, the gaseous decontaminant is generated in situ, within the enclosure or is supplied from a pressurized container (as in the case, for example, of ozone).

[0034] The vaporizer 106 -is connected by one or more thermally insulated supply conduits 114 which pass through corresponding access ports 116 in the enclosure wall 16, 18 and are carried within or through the passages 22 to the interior 30. Within the interior, the conduits 114 may branch to provide a gaseous decontamination distribution network 118. The ports 116 are sealed around the conduits to reduce leakage. Alternatively the conduit(s) 114 and network 118 may be selectively connectable by releasable connection members, as for the air supply conduit 72.

[0035] The distribution network 118 includes a plurality of flexible conduits 120, which can be collapsible. The conduits 120 transport the gaseous decontaminant to a plurality of decontaminant supply inlets 122 in the form of vents or nozzles spaced around the interior The heated air within the passages 22 assists in preventing or limiting condensation of hydrogen peroxide or other vapor decontaminant between the source 100 and the nozzles 122. The nozzles 122 feed the gaseous decontaminant into the interior space 30. The nozzles may be directional to assist in circulating the decontaminant. One or more fans 124 or other circulation devices optionally assist in distributing the gaseous decontaminant WO 2007/102798 PCT/US2006/000781 -9throughout the interior. The conduits 120 can be built into the passages 22, in which case they may fold flat, or be held in place, within the interior, by suitably positioned clips or ties 126.

[0036] To ensure that the decontaminant contacts portions of an item that are poorly accessible to the decontaminant, flexible hoses 128 communicate between the vaporizer and the interior 30 through selectively operable ports 130 formed in the interior and exterior panels 80, 82 as best shown in FIGURE 5. The flexible hoses 128, which can be routed into the poorly accessible areas, for example, through windows of a vehicle to be decontaminated. In the illustrated embodiment, the ports 130 are covered, when not in use by closures 132 such as flexible flaps formed from ChicoTM or VelcroTM hook and loop tape or other suitable sealing members. The flexible hoses 128 are fed through the sidewall 16, 18, when needed, so that they extend between the interior and exterior. The ports 130 are configured to grip the hoses tightly, minimizing leakage from the interior 30. Additional sealing material, such as duct tape is optionally used to assist in sealing around the hoses 128 at the ports 130. Alternatively, distribution tubes built into passages 22 terminate at operable/sealable connection ports along the interior.

[0037] With reference to FIGURE 4, sensors 140 within the enclosure detect one or more parameters of the interior space 30, such as temperature, humidity, concentration of decontaminant hydrogen peroxide concentration), concentration of a contaminant anthrax spores or a chemical warfare agent), concentration of a product of a reaction of a contaminant with the decontaminant (such as the product of a reaction of a chemical warfare agent with hydrogen peroxide), and the like. In one embodiment, several sensors 140 of each type are located around the interior space 30. The sensors are hung from suitably positioned hangars or straps 142 mounted to the interior panels 80 and communicate with a monitoring and control system 144, such as a microprocessor, located exterior to the enclosure 10 by suitable optical or electrical connectors 146. Biological and/or chemical indicators 148 are optionally located within the enclosure and examined, after the decontamination process. Suitable biological indicators include a population of spores or other hard to kill microorganisms. The presence of residual live spores, after decontamination, is an indication that the decontamination process was inadequate.

Suitable chemical indicators exhibit a visual or otherwise detectable change in response to a preselected minimum concentration of the decontaminant.

WO 2007/102798 PCT/US2006/000781 [0038] The monitoring and control system 144 includes a monitoring function 150 which records inputs from the sensors and determines/stores values of the sensed parameters. The system 144 also includes a control function 152 which provides feedback control to the source 100 of decontaminant in response to the sensed parameters. The control function 152 uses the information provided by the monitoring function 150 to control variables, such as the rate of hydrogen peroxide vaporization, the carrier gas flow rate, the carrier gas temperature, the inflation gas temperature and flow rate, power to the heater 94, and other operating parameters in order to maintain desired conditions for decontamination within the enclosure.

[0039] For example, where the hydrogen peroxide concentration detected in the interior is outside a preselected range, the control function 152 instructs the source 100 of decontaminant to increase or lower the rate of production of hydrogen peroxide.

Alternatively or additionally, the control function 152 provides feedback control to other components of the system. For example if the temperature within the enclosure is outside a preselected range, the control function 152 instructs the heater 64 to adjust the temperature of air entering the passages, its introduction rate, or instructs the floor heater 94 to adjust the temperature of the floor to bring the temperature to within the preselected range. In this way, the system components can be adjusted to maintain a hydrogen peroxide concentration within the interior space 30 within a preselected range, such as from about 0.1-5 mg/L (72- 3600ppm), from 0.1-2.0 mg/L and avoid saturation concentrations being reached. In one embodiment, the hydrogen peroxide concentration is at least about 0.7 mg/L (400+ppm). A temperature in the interior space 30 of about 15-120'C may be used, at least 25°C. The vapor hydrogen peroxide concentration is selected to be below the saturation point, which is a function of the temperature in the interior space [0040] As shown in FIGURE 2, the spent vapor, mixed with air from the interior optionally exits the enclosure 10 through an outlet conduit 154 connected with an outlet port 156 and is advantageously transported to a catalytic converter 158 or other destroyer before being released to the atmosphere. A filter system 160 in the outlet conduit removes traces of residual contaminants in the exiting air. For example, the filter system 160 includes a HEPA filter which traps microorganisms. A chemical filter is optionally included which removes certain harmful chemical agents. A pump 162 is used, in the illustrated embodiment, to actively withdrawn the spent vapor. One or more outlet vents 164 are WO 2007/102798 PCT/US2006/000781 -11located in the wall of the antechamber 38 and are connected with the outlet conduit 154 by suitable flexible hoses 165 for withdrawing air from the antechamber.

[0041] Alternatively or additionally, all or a portion of the vapor is recirculated through the vaporizer via a return line 166, optionally after passing through a catalytic converter 168, the dehumidifier 110 and heater 112 (FIGURE 2).

[0042] Hydrogen peroxide is a particularly effective decontaminant for many airborne microorganisms and other toxic materials including chemical and biological warfare agents.

It shows effectivity against a wide range of vegetative and endospore forming bacteria anthrax); fungi; viruses; yeasts, and prions. It is also effective against many chemical warfare agents, including organosulfur agents, such as mustard gas HD, HS); G-series nerve agents (organophosphate nerve agents), such as tabun sarin soman (GD), and cyclosarin V-series nerve agents, such as VX, VE, VG, VM and V-gas, particularly when used in combination with ammonia in a ratio of hydrogen peroxide: ammonia of between 1:1 and 1:0.0001. The spores responsible for Anthrax and other microbial contamination, for example, are readily destroyed using a short exposure period to hydrogen peroxide of a few minutes. Destruction of chemical warfare agents may take several hours. In one embodiment, the decontaminant reduces the population of live microorganisms or concentration by weight of the harmful chemical agent to less than 1% of the original value and in one embodiment, reduces the contaminant to undetectable levels.

[0043] Ozone has also been found to neutralize most known biological and chemical contaminants. Chemical and biological contaminants may also be treated with another decontaminant, such as UV radiation, or the like.

[0044] Prior to introducing the vapor, a slight negative pressure can be applied to the interior 30 of the enclosure to speed up the introduction and dispersal of the vapor.

[0045] The enclosure 10 is capable of maintaining an interior pressure which is slightly above atmospheric pressure or slightly below atmospheric pressure. Below atmospheric pressures are preferred when it is desirable to minimize any leakage of airborne contaminants from the enclosure. In one embodiment, for vapor hydrogen peroxide decontamination, the enclosure is able to withstand approximately three times a normal operating pressure of 2-5 cm of water to provide a margin of safety.

[0046] In one embodiment, the enclosure 10 is formed from a flexible sheet material, which is airtight and water resistant, such as vinyl or polyvinyl chloride (PVC). It is also WO 2007/102798 PCT/US2006/000781 -12resistant to chemical decontaminants, such as hydrogen peroxide. One suitable material is sold under the tradename V3F Polytarp, and is a woven polyester fabric of 77g/m 2 weight which is laminated on both sides with flexible PVC, yielding a material of about 580 g/m 2 This material is resistant to cracking to temperatures of about -25°C and above. The enclosure can thus be used for decontamination in indoor or outdoor variable temperatures between about -50 and [00471 As illustrated in FIGURES 1 and 5, in one embodiment, portions of the walls 14, 16, 18 are transparent to provide operators outside the enclosure with a view of what is taking place inside. For example, windows 170 are formed in the walls by forming midportions 172, 174, 176 of the inner and outer panels 80, 82 and connecting members 84 from panels of a transparent material, such as a clear PVC sheeting. One suitable PVC sheet material has a thickness of 0.5 mm and a weight of 646 g/m 2 is sold under the tradename VelbexTM by Wardle Storeys Ltd., Earby, Colne, Lancashire, UK. Seams between the various sheeting panels can be double lapped and sewn, adhesively joined, thermally fused together, or the like. The interior panels 80 of the walls may be coated with an antifungal, UV stabilized, water repellant coating. The water repellant ingredients resist condensation of the vapor on the walls of the enclosure, while the antifungal components inhibit the growth of fungus on the enclosure during storage.

[0048] The size of the enclosure 10 is variable, depending on the size of the item to be decontaminated. Typically, the interior volume can be from about 20m 3 to about 10,000m 3 For example, for decontaminating vehicles, such as ambulances, the interior may define a volume of about 10m x 8m x 4m. For larger vehicles, such as aircraft, the enclosure may be significantly larger. For larger enclosures, above about 500-1000m 3 the structure 12 may not be fully self supporting, in which case, an interior or exterior frame (not shown) of metal poles or the like is constructed and the enclosure supported thereon.

[0049] Additionally or alternatively to enabling supply of gaseous decontaminant to the interior, the enclosure 10 is optionally adapted to facilitate treatment of an item in other ways. For example, as shown in FIGURE 4, a liquid conduit 180 is optionally connected with one or more spray nozzles 182 within the interior space 30 for washing or otherwise treating the item to remove solid contaminants which are removable with water, detergents, liquid decontaminants, or combinations thereof. A drain 184 is formed in the floor and the enclosure positioned to allow the used liquid and associated dirt and contaminants to flow into a sump 186 formed in the support surface. The fluids collected in the sump are WO 2007/102798 PCT/US2006/000781 -13ooptionally bagged and disposed of by a hazardous waste treatment facility or otherwise treated appropriately to remove contaminants.

[0050] The enclosure 10 is particularly suited to treatment of vehicles and items which can be transported on a vehicle, for example on a wheeled cart or conveyor, into the enclosure.

[0051] A typical decontamination proceeds as follows. A contaminating event, such as a release of chemical or biological warfare agents, occurs and is communicated to an operator who transports the deflated enclosure 10 and all or a portion of the associated equipment 60, 100, 158, 160, etc. to a site at which decontamination of contaminated or potentially contaminated items which were exposed to the contaminating event is to take place. For example, the enclosure 10, vapor generator 100, blower 60, and the like are loaded onto a truck and transported to an indoor or outdoor site or facility at or close to the location of the contaminating event. This minimizes the risk of spreading of contamination.

[0052] The enclosure 10. is removed from its valise 28 and spread out, ready for inflation. The blower 60 is connected to the port 70 and inflation is commenced, optionally also with heating/cooling of the air and/or floor. As soon as the enclosure has reached a sufficiently stable inflated state, the vehicle, or other item(s) to be decontaminated, is transported into the enclosure by personnel dressed in hazard material protective clothing.

Doors, windows, etc. of the vehicle are opened to allow access to the decontaminant.

Sensors 140 and chemical /biological indications 148 are suspended from the enclosure or otherwise located within the interior space 30. Ends of the flexible tubes 120, 128 are pushed through their respective ports, for example, from the interior to the exterior, and connected with the decontaminant source 100. The flexible tubes 128 are positioned so that their outlets are located in less accessible parts of the vehicle while tubes 120 are suspended from clips 126. The inner and outer doors 34, 36 of the enclosure are closed and the hook and loop tapes 46 sealed together, prior to beginning introduction of the gaseous decontaminant. The pressure in the interior space 30 may be reduced to slightly below atmospheric pressure, to minimize leakage of contaminants and to speed introduction of the decontaminant.

[0053] If a washing operation or liquid decontamination is to be performed, this is optionally carried out prior to the gaseous decontamination, although it could alternatively be performed after or in place of the gaseous decontamination.

WO 2007/102798 PCT/US2006/000781 -14- [0054] The gaseous decontaminant is introduced to the interior space 30 to achieve a concentration which is sufficient to ensure decontamination of the item to an acceptable level within a preselected period of time, such as from a few minutes to several days. In the case of hydrogen peroxide, for example, a concentration of about 400-1000 ppm at a temperature of 20-50'C is generally sufficient to reduce microbial contamination by a 6 log reduction a population of 106 spores is reduced to 1 or less) in under about two hours, and generally in about 30 minutes or less. Similar concentrations, and temperatures may be used for destroying chemical agents or reducing their activity, to a level at which they are not considered hazardous. Longer times may be needed, however. Once the decontamination period is complete, the interior space 30 is aerated, for example, by switching off the vaporizer 106 and introducing dehumidified, exterior air with the blower 108 while withdrawing air from one or more vents 156.

[0055] Alternatively or additionally, vents 188 in the inflation passages 22 release air into the enclosure. The vents 188 may be closed, when not in use, by flaps covered with ChicoTM or VelcroTM hook and loop tape, in a similar manner to the vents 132. To hold the flaps open, the hook and loop tape may be temporarily attached by hook and loop tape to corresponding hook and loop fabric attached to the inner wall 80. A mesh screen 190 covers the vent and allows air to pass freely through. The aeration is. continued until the decontaminant concentration within the enclosure is low enough for operators to reenter. In the case of hydrogen peroxide, a safe level is considered to be about lppm, or less. The aeration phase may last several hours, or longer. The vehicle or other decontaminated item may be subjected to tests for residual contaminant before it is returned to service. Or, if appropriate, the item may be disposed of.

[0056] After use, the inflatable enclosure 10 may be deflated and repackaged in a carrying bag 28 for a subsequent reuse. Prior to repackaging, the enclosure is optionally subjected to a suitable decontamination process, such as a gaseous decontamination process, for example with hydrogen peroxide vapor. Such a decontamination process may be used to decontaminate both outer and interior surfaces of the enclosure. Alternatively, the enclosure is used one time and then disposed of, using an appropriate safe disposal method.

[0057] It will be appreciated that, depending on the size of the item and the size of the enclosure, a plurality of items may be decontaminated simultaneously within the enclosure.

Claims (21)

1. A decontamination system for decontaminating an item characterized by: an enclosure (10) comprising an inflatable structure (12) which, when inflated defines an interior space (30) for receiving the item to be decontaminated; and a source (106) of a decontaminant fluidly connected with the interior space which supplies the decontaminant to the interior space for decontaminating the item.

2. The decontamination system of claim 1, further characterized by: the source of a decontaminant including a source of gaseous decontaminant.

3. The decontamination system of claim 2, further characterized by: the source of gaseous decontaminant including a source of hydrogen peroxide.

4. The decontamination system of any one of claims 1-3, further characterized by: the source of decontaminant being located exterior to the enclosure and communicating with the interior space through a wall (14, 16, 18) of the enclosure. The system of any one of claims 1-4, further characterized by: an inflation system connected with the enclosure for inflating the inflatable structure.

6. The system of claim 5, further including a heater associated with the inflation system, for heating air supplied to inflate the structure.

7. The decontamination system of any one of claims 1-6, further characterized by: a closure (34, 36) for selectively sealing the interior space. WO 2007/102798 PCT/US2006/000781 -16-

8. The decontamination system of claim 7, further characterized by: the closure including interior and exterior doors (34, 36) which define an antechamber (38) therebetween, the antechamber spacing the interior space from the exterior environment.

9. The decontamination system of any one of claims 1-9, further characterized by: the inflatable structure including inflatable tubular elements (21) that define side walls (16, 18) and a roof (20) of the enclosure. The decontamination system of claim 9, further characterized by: the inflatable structure, when inflated, defining an inflated rear wall (14) of the enclosure which is connected with the side walls and the roof.

11. The decontamination system of claim 9 or 10, further characterized by: at least a portion of the tubular elements being constructed of transparent materials that define windows (170).

12. The decontamination system of any one of claims 9-11, further characterized by: the enclosure further including a floor (24) connected with the side walls (16, 18) of the enclosure.

13. The decontamination system of claim 12, further characterized by: the floor including a drain (184).

14. The decontamination system of claim 12 or 13, further characterized by: the floor including a heater (94). WO 2007/102798 PCT/US2006/000781 -17- The decontamination system of any one of claims 1-14, further characterized by: the inflatable structure defining a plurality of interconnected inflatable passages (22) which passages, when inflated, define structural elements (21) which support the structure.

16. The decontamination system of claim 15, further characterized by: the source of decontaminant being fluidly connected with the interior space by at least one conduit (114), the conduit being carried through at least one of the interior passages of the inflatable structure.

17. The decontamination system of claim 16, further characterized by: a vent (188) mounted in an interior panel 80 which defines a wall of one of the inflatable passages.

18. The decontamination system of claim 17, further characterized by: the vent including: a flexible flap (132); and a hook and loop fabric for holding the flap open.

19. The decontamination system of any one of claims 1-18, further characterized by: a sensor (140), supported by the inflatable structure, for detecting a parameter within the interior space. The decontamination system of claim 19, further characterized by: a monitoring and control system (144), connected with the sensor, which controls the source of decontaminant in accordance with the sensed parameter.

21. The system of any one of claims 1-18, further characterized by: the interior space being sized to accommodate a motor vehicle.

22. A method for decontaminating an item characterized by: WO 2007/102798 PCT/US2006/000781 -18- transporting an item into the interior space (30)of the enclosure (10) of claim 1; and supplying the decontaminant to the interior space to decontaminate the item.

23. The method of claim 22, further characterized by: adjusting the temperature of an inflation gas; and inflating the inflatable structure with the inflation gas, whereby a temperature of the interior space is adjusted.

24. The method of claim 22 or 23, further characterized by: the enclosure including a floor (24) attached to the inflatable structure, the method further including: adjusting a temperature of the floor of the enclosure, whereby a temperature of the enclosure is adjusted. The method of any one of claims 22-24, further characterized by: sensing a parameter within the interior space; and controlling the source of a decontaminant in accordance with the detected parameter.

26. A method for decontaminating an item comprising: inflating inflatable structural elements (21) of an enclosure (10) with an interior space (30) to hold the enclosure erect; transporting an item into the interior space; sealing the item in the enclosure; and introducing a gaseous decontaminant to the interior space to decontaminate the item.