Patent Publication Number: US-2023158185-A1

Title: Systems and methods for uv decontamination of respirators

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 17/356,383, filed Jun. 23, 2021, which claims the benefit of U.S. Provisional Application No. 63/043,446, filed Jun. 24, 2020, the entire contents of each of which are incorporated herein by reference. 
    
    
     FIELD 
     This disclosure is related generally to decontamination of personal protective equipment and, more specifically, to decontamination of respirators. 
     BACKGROUND 
     Filtering Facepiece respirators (FFRs) are respiratory protective devices designed to cover the nose and mouth and achieve a close facial fit and efficient filtration of airborne particles. An N95 respirator is a disposable FFR that blocks at least 95 percent of small (0.3 micron) test particles. N95 respirators are worn by health care personnel during patient encounters to protect both the patient and health care personnel from the transfer of microorganisms, body fluids, and particulate material. The surfaces of an N95 respirator may become contaminated while filtering the inhalation air of the wearer during exposures to pathogen-laden aerosols. The pathogens on the filter materials of an N95 respirator may be transferred to the wearer upon contact with the respirator during activities such as adjusting the respirator, doffing the respirator improperly, and performing a user-seal check when redoffing a previously worn respirator. To mitigate the risk of infection from pathogens accumulating on the filter materials, N95 respirators are intended to be discarded after a single patient encounter and, thus, are commonly referred to a single-use respirators. 
     In the midst of a pandemic, such as the COVID-19 pandemic, the supply chain for respiratory protective devices, such as N95 respirators, can be substantially stressed due to demand exceeding supply. During shortages of respirators, healthcare facilities may choose to re-use single use N95 respirators under the recommendation of government agencies, such as the CDC. To mitigate the contact transfer of pathogens from the respirator to the wearer during reuse during the COVID-19 pandemic, for example, the CDC recommended issuing five respirators to each healthcare worker who may care for patients with suspected or confirmed COVID-19. The healthcare worker wears one respirator each day and stores it in a breathable paper bag at the end of each shift. The order of respirator use is repeated with a minimum of five days between each respirator use. However, this strategy poses significant risks due to the potential build-up of pathogens over the course of a day. 
     SUMMARY 
     According to various embodiments, a counter-top decontamination system is configured for a wearer to personally reduce the pathogen contamination on their own respirator multiple times throughout a day, for example while the wearer is taking other protective sanitation actions such as hand-washing, hand sanitizer use, or changing gloves. According to some embodiments, the decontamination device delivers an effective dose of ultraviolet (UV) light to the exterior surfaces of both sides of the respirator, including the straps, in a short period of time. 
     According to various embodiments, a filtering facepiece respirator decontamination device includes an enclosure defining a UV irradiation chamber; at least one UV lamp positioned in the irradiation chamber; a moveable drawer comprising a platform for positioning a respirator, wherein the moveable drawer can move to a closed position in the respirator positioned on the platform is located in the irradiation chamber; a switch for detecting that the drawer is in the closed position; and a controller for activating the at least one UV lamp based on the switch detecting that the drawer is in the closed position. 
     In any of these embodiments, the at least one UV lamp can include a first set of UV lamps positioned beneath the drawer and a second set of UV lamps positioned above the drawer. 
     In any of these embodiments, the device can include at least one reflector surrounding at least a portion of the at least one UV lamp for reflecting UV light toward the respirator. 
     In any of these embodiments, the platform can include a plurality of quartz rods. 
     In any of these embodiments, the drawer can include a plurality of quartz posts that project from the platform for locating straps of the respirator. 
     In any of these embodiments, the device can be configured to decontaminate a single respirator at a time. 
     In any of these embodiments, he device can be configured to deliver a UV dosage the respirator of 1 J/cm2 in one minute or less. 
     In any of these embodiments, the controller can be configured to activate the at least one UV lamp automatically in response to receiving a signal from the detector indicating that the drawer is in the closed position. 
     In any of these embodiments, the controller can be configured to deactivate the at least one UV lamp automatically in response to receiving a signal from the detector indicating that the drawer has moved away from the closed position. 
     In any of these embodiments, the enclosure can include a front aperture that is shaped to indicate the proper positioning of a respirator on the platform. 
     In any of these embodiments, the at least one UV lamp can be configured for generating UVC light. 
     According to various embodiments, a method of decontaminating a filtering facepiece respirator includes positioning the respirator on the platform of a drawer of a decontamination device; closing the drawer; activating, by the device, one or more UV lamps of the device based on the device detecting that the drawer has been closed; and deactivating, by the device, the one or more UV lamps after a pre-programmed decontamination period has elapsed. 
     In any of these embodiments, the method can include delivering a dosage of UV light of 1 J/cm2 to the respirator. 
     In any of these embodiments, the pre-programmed decontamination period can be a minute or less. 
     In any of these embodiments, the method can further include, in response to detecting that the drawer has been opened while the one or more UV lamps are activated, automatically deactivating the one or more UV lamps. 
     In any of these embodiments, the UV lamps can be configured to generate UVC light. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG.  1    illustrates a respirator decontaminate device, according to some embodiments; 
         FIG.  2    illustrates is a rear view of a respirator decontaminate device with the top portion of the enclosure removed, according to various embodiments; 
         FIGS.  3 A and  3 B  are side and front elevation views, respectively, of a respirator decontaminate device, according to various embodiments; 
         FIGS.  4 A- 4 D  are cross sectional views through various portions of a respirator decontaminate device, according to various embodiments; 
         FIG.  5    illustrates the loading of a respirator on the platform of the drawer of a respirator decontaminate device, according to various embodiments; 
         FIG.  6    is a functional block diagram of device  100 , according to various embodiments; and 
         FIGS.  7 A and  7 B  illustrate examples of information that can be displayed to the user. 
     
    
    
     DETAILED DESCRIPTION 
     Systems and methods, according to various embodiments, include a UV device that is configured irradiate a filtering facepiece respirator (referred to herein as simply a respirator), such as an N95 respirator, with UV light to deactivate pathogens that have accumulated on the respirator during use. The UV device includes a platform for positioning at least one respirator and a plurality of UV lamps positioned around the platform for irradiating the respirator with UV light. A wearer may easily place his or her own respirator in the device and initiate a decontamination cycle during which the respirator is irradiated with a sufficient amount of UV light to deactivate one or more target pathogens on the respirator. The decontamination cycle time may be relatively short, enabling a wearer to quickly and easily decontaminate the wearer&#39;s respirator, which can encourage wearers to decontaminate their respirators multiple times throughout their shift. By enabling multiple decontaminations throughout a wearer&#39;s shift, the UV device can prevent the excessive accumulation of pathogens on a wearer&#39;s respirator that can occur when respirator re-use is needed, such as during respirator shortages. 
     According to various embodiments, the respirator decontamination system includes an enclosure and a UV irradiation chamber within the enclosure for positioning a respirator for UV irradiation. The chamber includes a platform for supporting the respirator and a plurality of UV lamps arrayed around the chamber such that UV light from the lamps reaches substantially of the exterior surfaces of the respirator. In some embodiments, one or more UV lamps are positioned below the platform and one or more UV lamps are positioned above the platform. In some embodiments, one or more reflectors or reflective surfaces are positioned outwardly of the UV lamps to reflect UV light toward the respirator in the center of the chamber. In some embodiments, the UV lamps and reflectors are positioned to ensure that there is no shadowing—that substantially all of the external surface of the respirator, including the straps, are simultaneously irradiating with UV light. 
     In some embodiments, the platform is a movable platform that can be moved outwardly from the enclosure to enable a user to easily place the user&#39;s respirator on the platform. For example, the platform may be a portion of a drawer that slides out to enable access to the platform by the user. In some embodiments, the platform includes a grating for supporting the respirator and allowing light to pass through the platform to the respirator from lamps located beneath the respirator. In some embodiments, the grating is a plurality of parallel members that are substantially transparent to the UV light, or to at least a band of UV light used to decontaminate the respirator. For example, in some embodiments, the parallel members are quartz rods. In some embodiments, the platform includes strap positioning features for positioning the straps of a respirator in repeatable positions that ensure that the straps do not fold on themselves or cover the respirator body, which would otherwise cause shadowing. In some embodiments, the strap positioning features are posts, such as made of quartz, that project upwardly from the platform. 
     The enclosure may include a front aperture that is configured so that one or more respirators can move into and out of the enclosure as the drawer is moved in and out. The drawer can include a front panel that covers the aperture when the drawer is in a closed position so that UV light does not escape the enclosure. In some embodiments, the device includes a detector that detects when the drawer is in its closed position. Operation of the UV lamps may be based on the detector detecting whether the drawer is in the closed position. For example, the UV lamps may be disabled when the detector detects that the drawer is not in its closed position. In some embodiments, the detector can be any suitable sensor and/or switch, including a Hall Effect sensor or a limit switch. 
     According to various embodiments, the respirator decontamination system can be configured to irradiate a respirator with UV light for a predefined decontamination cycle time that is preselected to provide at least the UV dosage that testing has shown to be sufficiently effective at destroying or deactivating one or more target pathogens on the exterior surfaces of the respirators. For example, the UV dosage provided during a decontamination cycle may be sufficient to provide at least a 3-log reduction in one or more target viruses, such as SARS-CoV-2, accumulated on the respirator. The cycle time is generally inversely proportional to the power of the UV lamps such that embodiments with higher power lamps may have shorter decontamination cycles than embodiments with lower power lamps. 
     According to various embodiments, the respirator decontamination system is used by opening the drawer, positioning the respirator on the platform of the drawer, and closing the drawer. The device may then enter a decontamination cycle, for example, either automatically in response to detecting that the drawer has been closed and/or in response to a user input. Upon initiation of the decontamination cycle, the lamps may be activated and remain activated for the predefined cycle time, such as a minute or less. In some embodiments, the device may be configured to shut off the lamps upon detecting that the drawer has been opened, such as to prevent exposure of the user to UV light. Upon expiration of the cycle time, the lamps may be deactivated. The device may provide an indication to the user that the decontamination cycle is complete, and in response, the user may open the drawer and remove the decontaminated respirator. The user may then don the respirator and go about their work. Thus, the respirator decontamination system can be used by a wearer to quickly and easily decontaminate the wearer&#39;s own respirator, enabling the wearer to decontaminate their respirator multiple times throughout their shift. 
     During a shortage of respirators, such as during the COVID-19 pandemic, emergency use guidance (such as issued by the CDC) allowed the re-use and rationing of respirators. However, re-use and rationing can result in the same respirator being worn for many hours and over many patient interactions. Such long term wear can lead to high pathogen loads occurring on the patient-facing surface of the respirator, posing a high risk for both the wearer and patients. According to various embodiments, the respirator decontamination system allows the wearer (such as healthcare personnel) to personally reduce the bioburden on their own respirator after each patient visit (or regularly throughout the day) with minimal risk and while establishing similar benefits for the wearer and patients as the standard of care during non-emergency periods, which includes using a new respirator after each patient visit/interaction. 
     As used herein, a filtering facepiece respirator is a negative pressure particulate respirator with a filter as an integral part of the facepiece or with the entire facepiece composed of the filtering medium. According to various embodiments, a decontamination system according to the principles described herein can be used and/or configured to decontaminate filtering facepiece respirators of any type and/or any model, including N95 respirators, KN95 respirators, and FFP2 masks. According to various embodiments, the decontamination system can be used and/or configured for decontaminating devices other than respirators, including surgical masks, mobile phones, pagers, remote controls, writing utensils, keys, gloves, stethoscopes, and any other device that can be placed in the decontaminator. 
     In some embodiments, the decontamination system can be configured to perform the decontamination process differently for different types and/or models of devices. For example, the decontamination system may deliver a lower dose of UV light for a device with hard surfaces, such as a mobile phone, than a device with porous surfaces, such as a respirator. In some embodiments, the decontamination system may deliver a different dosage depending on the model of the respirator. 
     The decontamination system can determine the types of device in various ways. In some embodiments, the decontamination system includes a user interface for a user to input a type of device. For example, a user can navigate through a list of devices via the user interface, with each devices in the list having an associated preprogrammed decontamination process. Any suitable user interface can be used, including, for example, a touch screen, an app on a smartphone that is communicatively coupled to the decontamination system, voice commands, or gestures. In some embodiments, the UV dosage provided during a decontamination cycle may be user-selectable along with or irrespective of differences in device type. For example, the user may select a low, medium, or high dosage setting, resulting in different dosages pre-programmed into the decontamination system. In some embodiments, different decontamination cycles can be selectable for different purposes. For example, the decontamination system may be pre-programmed with decontamination cycles for sanitizing, bioburden reduction, decontamination, sterilization, etc. According to some embodiments, the availability of decontamination cycle options such as these could be determined by the user, or may be required by policy (such as of the medical facility), by regulation, or by the device configuration. 
     In some embodiments, the decontamination system can automatically detect a type and/or model of a device to be decontaminated using, for example, feature recognition on one or more images generated by a camera of the decontamination system, by a bar code scanner, by an RFID reader, or any other suitable method. In some embodiments, a camera may be positioned in the decontamination system for imaging a device placed therein and one or more images of the device can be analyzed using image processing to detect the type of device. The decontamination system may then execute a decontamination process that is based on the type of device. In some embodiments, the type and/or model of the device may be indicated on a display of the decontamination system for confirmation by the user. In some embodiments, the decontamination system may prevent execution of a decontamination cycle and/or may provide a warning based on its determination of the device model and/or type. For example, the decontamination system may be configured to not decontaminate and/or provide a warning when an unapproved respirator model is placed in the device. In some embodiments, the decontamination system may be configured to detect soiling or damage to a respirator and may provide a warning and/or may block execution of a decontamination cycle. 
     According to various embodiments, the decontamination system can be configured to perform different decontamination procedures, such as for different types of respirators and/or for different types of devices, as discussed above. Differences between decontamination procedures can include different amounts of time for which the UV lights are active, different operating power for one or more UV lights, different combinations of UV light activations (for example, only a subset of the UV lights active), or any combination of these. 
     According to various embodiments, individual UV light sources can power on for various time periods, such as to optimize the uniformity of the UV dose or to target higher dosage in certain areas (for example to address shadowing). In some embodiments, one or more UV light sources can move to a different position, such as to deliver uniform dosage or target specific areas. In some embodiments, one or more UV light sources can move depending on a type of the device, such as to accommodate a different device shape (e.g., a respirator versus a smartphone). One or more UV light sources may move prior to and/or during a decontamination cycle, independently or in conjunction with the cycles for individual lamps. Movement can be on a different axis (including rotating). In some embodiments, the drawer is configured to rotate the device, such as via a rotatable platform, instead of or in addition to the UV light sources moving. 
     According to some embodiments, the decontamination system may be configured to track the user of the device. This can be based on a scan of an employee&#39;s badge, an RFID, a barcode, and/or a Bluetooth connection to an external camera system (such as for facial recognition), a fingerprint sensor, and/or other biometric sensor. In some embodiments, the decontamination system may track the number of cycles a user has decontaminated their device. The decontamination system may be configured to log decontamination activity per user to validate that the necessary decontamination is occurring. In some embodiments, policies by shift/workday could be enforced (for example, at the beginning of a shift or after lunch, a specific cycle would be required). In some embodiments, users can be notified via an APP and/or text message that they need to decontaminate. 
     According to various embodiments, the decontamination system can be configured to provide information to a user, such as on a display of the decontamination system. The information can include information on the types and/or models of devices that the decontamination system is intended to decontaminate, the history of previous cleaning cycles and recommendation or requirement for the next cycle (for example, display that a device has had 10 quick sanitize cycles, and new requires or recommends the next cycle be a long sterilization cycle), the picture or info of the owner of the device being decontaminated, and/or the location of an another available decontamination system, such as when the decontamination system is not functioning or is being used. 
     In the following description of the disclosure and embodiments, reference is made to the accompanying drawings in which are shown, by way of illustration, specific embodiments that can be practiced. It is to be understood that other embodiments and examples can be practiced, and changes can be made, without departing from the scope of the disclosure. 
     In addition, it is also to be understood that the singular forms “a,” “an,” and “the” used in the following description are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is also to be understood that the term “and/or”,” as used herein, refers to and encompasses any and all possible combinations of one or more of the associated listed items. It is further to be understood that the terms “includes, “including,” “comprises,” and/or “comprising,” when used herein, specify the presence of stated features, integers, steps, operations, elements, components, and/or units, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, units, and/or groups thereof. 
       FIG.  1    illustrates a respirator decontaminate device  100 , according to some embodiments. The device  100  can be sized to fit on a countertop and can be used by a wearer of a respirator to personally decontaminate their own device using UV radiation. For example, healthcare personnel in medical facilities, such as doctors, nurses, and aides, can personally decontaminate their own N95 respirators, post-patient contact while they wait—for example, during the time the healthcare personnel washes his or her hands. 
     The device  100  includes an enclosure  102  that encloses UV lamps (discussed further below) and a drawer  104  is used to load a respirator  180  into a UV irradiation chamber within the enclosure  102 . The drawer  104  includes a platform  106  for placing at least one respirator  180 . The drawer  104  may be mounted to the enclosure  102  via telescoping rails  108  that enable the drawer  104  to be opened and closed. A front panel  110  of the enclosure  102  includes an aperture  112  that is shaped to accommodate the platform  106  and the at least one respirator  180  positioned on the platform  106 . In some embodiments, the shape of the aperture  112  may indicate the proper positioning of the respirator  180  on the platform  106 . For example, the respirator may be properly positioned with its patient-facing surface  182  facing upward and the aperture  112  may match the shape of the respirator  180  when placed in its proper position on the platform  106 . In some embodiments, the aperture  112  and/or drawer  104  is configured to limit the number of respirators that can be loaded into the device  100 . In some embodiments, the aperture  112  and drawer  104  are configured to limit the number of respirators that can be loaded into the device  100  to just a single respirator, which can help prevent cross-contamination between respirators and can prevent a user from accidentally switching their respirator with another user&#39;s (loss of custody), which is of particular concern in medical facilities such as hospitals. In some embodiments, the drawer  104  includes a front panel  120  that is sized to cover the aperture  112  so that UV light does not escape the enclosure  102  during use. 
     According to some embodiments, the platform  106  may be formed as a grating that allows UV light to pass from underneath the platform to the respirator  180 , as discussed further below. In some embodiments, the grating is formed of a plurality of spaced apart members  114 . In some embodiments, the plurality of spaced apart members  114  are formed of a material that transmits UV light or at least a band of UV light that is selected for decontaminating the respirator. In some embodiments, the members  114  are parallel quartz rods configured to transmit UV light in the UVC band. In some embodiments, the quartz rods are mounted to mounts  118  that are, in turn, mounted to the rails  108 . In some embodiments, the mounts  118  are also made of quartz or another material that transmits at least a portion of UV light. 
     In some embodiments, the platform  106  includes one or more respirator strap positioning members  116  that can be used to position the straps in substantially defined positions, ensuring that the straps do not fold on themselves or cover the respirator body. In some embodiments, the respirator strap positioning members  116  are four quarts posts that project from the platform  106 . 
     The drawer  104  may include a handle or other feature that enables a user to open and close the drawer  104 . In some embodiments, the drawer  104  is powered so that it can open and close under its own power. The device  100  may include a button or touchscreen for a user to provide an open/close command and the drawer  104  may open/close in response to the user&#39;s command. In some embodiments, the device  100  includes a proximity sensor that can sense a user, such as a user&#39;s hand placed near the device  100 , without the user touching the device. The device may open/close in response to detecting the user without the user having to touch the device  100 , which can reduce the risk of cross-contamination through touching of the device. 
     In some embodiments, the device  100  includes a display screen  122  for displaying information to the user. Examples of information that may be displayed include, the status of the device (e.g., that the UV lamps are warming, that the device is ready for decontamination of a respirator, that a cycle has begun, the remaining time in a cycle, that a cycle is complete, any errors, or any other suitable information). In some embodiments, the display screen  122  is a touch-screen that enables user input. In some embodiments, the device  100  includes a separate user input device, such as one or more switches, selectors, or other suitable user input device (not shown). 
       FIG.  2    illustrates is a rear view of the device  100  with the top portion  124  of the enclosure  102  removed, according to various embodiments. The rear portion  126  of the enclosure  102  may accommodate electrical and/or electronic components of the device  100 , such as the ballast(s) for UV lamps, one or more controllers, cooling features, etc. In some embodiments, the device is actively cooled and a cooling fan, motor, or other cooling system features are located in the rear portion  126 . In some embodiments, the device is passively cooled. Located centrally within the enclosure is an upper reflector  128  that defines an upper portion of the irradiation chamber where the respirator is located during the decontamination cycle. The reflector  128  can be made of various materials, including PTFE and/or highly polished aluminum. 
       FIGS.  3 A and  3 B  are side and front elevation views, respectively, of the device  100 , illustrating the relative size of the device  100  according to various embodiments. In some embodiments, the device  100  is less than 20 inches in height and width and less than 30 inches in depth. In some embodiments, the device  100  is no more than 24 inches in depth, enabling the device  100  to fit on a standard size countertop, preferably no more than 20 inches in depth, more preferably no more than 18 inches in depth. 
       FIGS.  4 A- 4 D  are cross sectional views through various portions of the device of  FIGS.  3 A and  3 B , according to various embodiments, with a respirator  180  positioned in the irradiation chamber  130 . According to various embodiments, the chamber  130  may be configured to accommodate just a single respirator. This can discourage multiple respirators from being decontaminated together, which would otherwise pose risks of cross-contamination of respirators. In some embodiments, the chamber  130  is configured to accommodate more than one respirator. 
     A plurality of UV lamps  132  are arrayed around the irradiation chamber  130 . The UV lamps  132  are illustrated in the drawings as configured as fluorescent lamps. However, the term lamp as used herein refers broadly to any artificial UV light source. Suitable UV light generating technology can include, for example, fluorescent lamps, LEDs, gas-discharge lamps, broad-spectrum light sources with filters that are separate from the lamps positioned in front of the lamps, or any suitable combination of different light sources. According to some embodiments, a lower set  132 A of UV lamps are positioned in the lower portion of the irradiation chamber  130  such that they are beneath the platform  106  and an upper set  132 B of UV lamps are positioned in the upper portion of the irradiation chamber  130  such that they are positioned above the platform  106 . The upper reflector  128  extends around the upper set  132 B of lamps in an arcuate shape to reflect light toward the outward-facing side of the respirator  180 . A lower reflector  134  is positioned beneath the lower set  132 A of lamps and is shaped to reflect light toward the wearer-facing side of the respirator  180 . 
     The device  100  can include any suitable configuration of UV lamps  132 . The illustrated embodiment includes four UV lamps in the upper set  132 B and two UV lamps in the lower set  132 A. The illustrated UV lamps each include two tubes  140  extending from a base  136 . The lamps  132  are mounted in sockets  138  located toward the rear of the enclosure. The lamps  132  and upper and lower reflectors  128  and  134  may be arranged to provide UV light to all exterior surfaces of the respirator at the same time. According to some embodiments, the lamps  132  are arranged to generally uniformly irradiate the respirator. In some embodiments, the upper and lower set of lamps are the same. In other embodiments, the power of the upper set of lamps is less than the power of the lower set of lamps to account for a different in the relative number of lamps. For example, the lower set of lamps can include two 18 watt lamps and the upper set of lamps can include four 9 watt lamps, which can provide approximately a uniform irradiation of all sides of the respirator. 
     The UV lamps can be configured to generate a desired bandwidth of UV radiation. In some embodiments, the UV lamps generate UV light in the UVC wavelength band. In some embodiments, the UV lamps generate UVC light centered around 254 nm. In some embodiments, the lamps are doped so that UV light below 254 nm will be substantially blocked, such as to prevent the release of ozone producing 185 nm ozone producing light. The power of the lamps  132  can vary based on the number of UV lamps, the desired UV dosage, and the desired decontamination cycle time. Generally, the lower the total UV lamp power, the proportionally greater the cycle time. 
     According to various embodiments, the device  100  uses two 18 W UVC lamps positioned beneath the drawer and either four 18 W or four 9 W UVC lamps positioned above the drawer. Examples of suitable 18 W UVC lamps are PHILLIPS 18 W TUV PL-L 18 W/4P and OSRAM 18 W GFT18DL/2G11/SE/OF. Examples of suitable 9 W UVC lamps are PHILLIPS 9 W PL-S9W/TUV or OSRAM 9 W GCF9DS/G23/SE/OF. 
     According to various embodiments, the arrangement of the lamps in device, combined with the reflectors surrounding the lamps, maximizes uniformity of radiation within the irradiation chamber  130 , and thus minimizes fluctuations in dose received by the various respirator surfaces. Under these conditions, it is more accurate to address the incident power density at a location on a respirator in terms of the fluence rate, rather than intensity (or irradiance), since some light can impinge on a point in the fabric of the respirator from multiple directions, including directions associated with some light backscattered from “below” (diffuse reflectance) within the respirator material. Common optical detectors respond to light intensity impinging within a solid angle of ˜π steradians (sr). So, the detector-measured values are an underestimate of the actual total exposure fluence rate, leading to a conservative estimate of the time-integrated radiant exposure, or fluence (J). The SI units for intensity and fluence rate are the same (W/m2), but fluence rate includes photons impinging from all directions over 4π steradians of solid angle, whereas intensity (irradiance) is defined as light incident from one side, over 2π sr (and common detectors only sense from ˜πsr). 
     According to various embodiments, the device is configured to irradiate a respirator light at intensities at the respirator that are in the range of 5-50 mW/cm 2 , preferably 5-40 mW/cm 2 , more preferably 8-25 mW/cm 2 , more preferably 10-15 mW/cm 2 . In some embodiments, the device is configured to irradiate a respirator with 11-14 mW/cm 2 . 
       FIG.  4 D  illustrates a detector  150  for detecting that the drawer  104  is in a closed position. In some embodiments, the detector  150  is a magnetic switch that detects when the drawer  104  is closed and may also provide a small holding force to the drawer  104  in the closed position. 
       FIG.  5    illustrates the loading of a respirator  180  on the platform  106  of the drawer  104 , according to various embodiments. The respirator  180  is positioned with its wear-facing surface on quartz rods  152  of the platform  106 . The straps  184  of the respirator  180  are positioned around quartz posts  154  located at the four corners of the drawer  104 . 
       FIG.  6    is a functional block diagram of device  100 , according to various embodiments. The device  100  includes a controller  160  that activates and deactivates the UV lamps  132  vie one or more lamp drivers  162  (such as ballasts) that each drive one or more UV lamps  132 . The controller includes one or more processor, memory, and one or more programs stored in the memory for execution by the one or more processors for controlling the device  100 , such as according to the methods described further below. 
     The controller  160  is communicatively coupled to a drawer positional detector  150  that detects when the drawer is in its closed position. The controller  160  may control the activation/deactivation of the lamps  132  based on signals from the detector  150 , as discussed further below. For example, the controller  160  may start or stop a decontamination cycle based on the detector  150  detecting that the drawer is in its closed position or has moved away from its closed position. 
     In some embodiments, the device  100  includes one or more UV sensors  164  for sensing the UV intensity in the irradiation chamber. According to various embodiments, the controller  160  may use the information from the UV sensor  164  as a diagnostic to determine whether the UV irradiation is within an acceptable level and/or may adjust a decontamination cycle time to ensure that a predefined minimum UV dosage is delivered to the respirator. 
     The device  100  includes a display  122  for displaying information to a user. Examples of suitable information include the readiness of the device  100 , that the device is performing a decontamination cycle, the amount of time that has elapsed or is remaining in a cycle, the completion of a cycle, the cumulative usage of the lamps, and/or any other useful information.  FIG.  7 A and  7 B  illustrate examples of information that can be displayed to the user, with the display in  FIG.  7 A  showing that the decontamination cycle is in progress with 11 of 60 seconds having elapsed and the display of  FIG.  7 B  showing that the 60 second decontamination cycle is complete. In some embodiments, the device  100  includes one or more user inputs  166 , which can be used for various purposes, such as to initiate a decontamination cycle, to select information for viewing on the display, for altering one or more decontamination cycle parameters, such as cycle time, or for any other suitable purpose. 
     According to various embodiments, the controller  160  activates and deactivates the UV lamps  132  based on the input from the detector  150  and a pre-programmed decontamination cycle time. The pre-programmed cycle may automatically begin when the drawer  104  is closed. The controller  160  may automatically activate the lamps  132  and initiate a cycle timer. The controller  160  may display the amount of cycle time remaining to the user on the display  122 . Once the preset cycle time has elapsed, the lamps  132  may be automatically deactivated by the controller  160  and an indication that the cycle is complete may be displayed on the display  122 . In some embodiments, the drawer locks during the cycle time to prevent a person from opening the drawer while the lamps are activated. In some embodiments, the door does not lock but should it be opened at any point during a cycle, the lamps are automatically deactivated in response to the detector  150  detecting that the drawer has moved from its closed position. In some embodiments, the controller  160  tracks the total number of hours of use of the lamps and can display this information to the user via the display. 
     In some embodiments, the controller  160  is configured to detect a failure in a lamp and provide an indication of the failure, which can be, for example, provided on the display and/or can be provided to an external system via a network connection. In some embodiments, the controller  160  is configured to alter a cycle time based on a detected lamp failure and/or lamp degradation. For example, where the lamps are determined by the controller  160  to be delivering half their rated UV light output, the controller  160  may double the cycle time. 
     According to various embodiments, the device executes a decontamination cycle any time the drawer is closed (and the device is powered on). Therefore, according to various embodiments, the only user action required for using the device is closing and opening the drawer. According to various embodiments, any time the drawer is closed, the lamps will activate for only the preset cycle period, after which they will deactivate. Therefore, the lamps will not be continuously active for more than a single cycle period. In other words, the lamps will not operate continuously and will not be continuously activate for more than a single pre-programmed cycle period. 
     According to various embodiments, the device  100  decontaminates N95 respirators by supplying a sufficient amount of UVC germicidal irradiation. UVC (254 nm) light can deactivate viruses by cleaving RNA and/or DNA. In particular, studies have shown that 1 J/cm 2  of UVC light on the exterior surfaces of the respirator can provide greater than 3-log reduction in the viral load on N95 respirators. According to various embodiments, the device  100  is configured to provide a dosage of 1 J/cm 2  of UV light to all exterior surfaces of a single N95 respirator. In some embodiments the dosage is provided in under 10 minutes, preferably in under 5 minutes, more preferably in under 2 minutes, more preferably in a minute or less. 
     According to various embodiments, a method of decontaminating a respirator includes the user doffing the user&#39;s own N95 respirator and inspecting the respirator for visible signs of damage or contamination by excessive mucous, blood, or other soiling. If the respirator is visibly damaged or soiled, then the respirator should be discarded. If the respirator is not visibly damaged or soiled, the user places the respirator on the platform of the drawer of the device, such as device  100 , with the outer-facing surface of the respirator facing upward. If the drawer of the device is closed, the user first opens the drawer, such as using the drawer handle. To avoid cross contamination from touching the drawer handle, the user can use a disposable tissue, wipe, or glove to grasp the handle. The user places each strap of the respirator around two respective quartz posts, which keeps the straps from folding or covering any portion of the respirator during UV irradiation. The user closes the drawer of the device, such as using a disposable tissue or with gloves. In some embodiments, the closing of the drawer is detected and the decontamination cycle is automatically initiated via activation of the UV lamps. In various embodiments, the drawer may not lock during the decontamination cycle but should the user open the drawer the UV lamps may be automatically deactivated by the controller, ensuring that the user is not exposed to UV light. 
     According to various embodiments, the LUV Device may be pre-programmed with the cycle time required for delivering a dosage of 1 J/cm 2  or less of UVC irradiation to the respirator given the UVC lamp configuration. According to various embodiments, the device tracks the amount of time remaining in the cycle and may indicate the remaining time (or elapsed time) to the user on the display screen, including when the cycle is complete. The controller may automatically deactivate the UV lamps at the end of the cycle. Upon observing that the cycle is complete, the user can open the drawer, such as by grasping the drawer handle with a disposable tissue, wipe, or glove to avoid cross contamination from the drawer handle. The user retrieves the decontaminated respirator and follows standard precautionary measures to reuse the respirator. The drawer can remain open for the next use. Should the drawer be closed, the lamps may activate for only the pre-programmed cycle period and then deactivate until the next use. 
     In some embodiments, the device includes a powered drawer that opens and closes without user force. The user may press a button or otherwise provide a user command that causes the drawer to close and/or open. In some embodiments, upon the completion of a decontamination cycle, the drawer may automatically open for the user to retrieve the respirator. 
     According to various embodiments, the decontamination device can be configured to provide a UVC dosage to all portions of the exterior surfaces of a respirator of at least 0.1 J/cm 2 , preferably at least 0.3 J/cm 2 , more preferably at least 0.5 J/cm 2 , more preferably at least 0.9 J/cm 2 . In some embodiments, the decontamination device can be configured to provide a UVC dosage to all portions of the exterior surfaces of a respirator of less than 10 J/cm 2 , preferably less than 3 J/cm 2 , more preferably less than 1.5 J/cm 2 , more preferably less no more than 1 J/cm 2 . In some embodiments, the device is configured to provide a dosage of UVC effective to decontaminate a respirator of one or more target pathogens in less than 10 minutes, preferably less than 5 minutes, more preferably less than 2 minutes, and more preferably no more than 1 minute. In some embodiments, the device is configured to decontaminate a respirator of one or more target pathogens by delivering a dosage of UVC light to all surfaces of the respirator that is effective to provide at least a 3-log reduction of at least one enveloped virus, such as SARS-CoV-2, more preferably, at least one non-enveloped virus. In some embodiments, the device is capable of providing a dosage of UVC light of 1 J/cm 2  in 1 minute or less. 
     According to various embodiments, the device  100  may include network communication technology, which can include wired and/or wireless network communication capability, and can be connected to a network, such as a hospital internal network, a cloud network, or any other suitable network. According to various embodiments, the device  100  can receive software updates via the network connection, can receive user commands via the network (such as through an APP on a user&#39;s smartphone), can upload usage statistics, operational status, errors codes, or other information to a server system, and/or communicate any other suitable information. 
     The foregoing description, for the purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the techniques and their practical applications. Others skilled in the art are thereby enabled to best utilize the techniques and various embodiments with various modifications as are suited to the particular use contemplated. 
     Although the disclosure and examples have been fully described with reference to the accompanying figures, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosure and examples as defined by the claims. Finally, the entire disclosure of the patents and publications referred to in this application are hereby incorporated herein by reference.