Patent Publication Number: US-10772981-B2

Title: Disinfection system

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of and claims the benefit of priority to U.S. patent application Ser. No. 15/478,147, filed Apr. 3, 2017, issued as U.S. Pat. No. 10,363,329 on Jun. 10, 2019, which is a continuation of U.S. Pat. No. 9,623,133, filed Jan. 30, 2015 and issued Apr. 18, 2017, the entire contents of both of which are incorporated herein by reference. 
    
    
     BACKGROUND INFORMATION 
     1. Field 
     The present disclosure relates generally to disinfection and, in particular, to disinfection of lavatories. Still more particularly, the present disclosure relates to a method and apparatus for disinfecting lavatories on vehicles using far-ultraviolet radiation. 
     2. Background 
     Pathogens may be spread between humans, between animals, or between humans and animals in many different ways. Consequently, there is an increasing need for the disinfection or sterilization of public areas and public spaces, particularly enclosed areas and spaces. As one example, a single aircraft may fly to multiple destinations on the same day. These destinations may include, for example, different airports, airstrips, or airfields in the same state, in different states, or in different countries. Any number of passengers and crewmembers may get on and off this single aircraft between flights. Further, the passengers and crewmembers onboard the aircraft during a single flight may be a diverse group coming from different backgrounds and environments. These conditions create the potential for the spread of pathogens onboard an aircraft. 
     One possible source for the spread of pathogens onboard an aircraft is inside the lavatory of the aircraft. Currently, the lavatories inside aircraft are cleaned manually. For example, one or more crewmembers or service personnel may clean the lavatories inside an aircraft between flights. Typically, disinfectant sprays, aerosols, or other types of cleaning solutions are used to disinfect surfaces. However, some of these materials may result in an undesired coating of material being left on the surfaces. The time required to dissipate certain types of aerosols or sprays may be longer than desired. Further, certain types of disinfectant materials may have odors that may be undesirable to some people. 
     Additionally, this type of manual disinfection of these lavatories may be more time-consuming than desired, may not be as effective as desired, or both. In some situations, performing this type of manual disinfection during flight may not be desirable or even feasible. Therefore, there may be a need for a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues. 
     SUMMARY 
     In one illustrative embodiment, an apparatus comprises a disinfection system and an activation system. The disinfection system emits far-ultraviolet radiation to perform a disinfection process inside a lavatory in a vehicle when the lavatory is not in use. The disinfection system is inactive when the lavatory is in use. The activation system controls activation and deactivation of the disinfection system. 
     In another illustrative embodiment, a method for disinfecting a lavatory is provided. A determination is made as to whether a set of criteria for activation of a disinfection system that emits far-ultraviolet radiation to perform a disinfection process inside a lavatory, has been met. In response to a determination that the set of criteria has been met, the disinfection system is activated, to perform the disinfection process inside the lavatory, using the far-ultraviolet radiation. 
     In yet another illustrative embodiment, a method for disinfecting a lavatory located inside an aerospace vehicle is provided. A determination is made as to whether the lavatory is unoccupied. In response to a determination that the lavatory is unoccupied, a determination is made as to whether the lavatory has been occupied a selected number of times since a previous disinfection of the lavatory. In response to a determination that the lavatory has been occupied the selected number of times since the previous disinfection of the lavatory, a determination is made as to whether a door to the lavatory is closed. In response to a determination that the door is closed, a disinfection system is activated to perform a disinfection process inside the lavatory using far-ultraviolet radiation. The disinfection system is deactivated after completion of the disinfection process. 
     The features and functions can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the illustrative embodiments are set forth in the appended claims. The illustrative embodiments, however, as well as a preferred mode of use, further objectives and features thereof, will best be understood by reference to the following detailed description of an illustrative embodiment of the present disclosure when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an illustration of a lavatory disinfection system in the form of a block diagram in accordance with an illustrative embodiment; 
         FIG. 2  is an illustration of an isometric view of a lavatory of an aircraft in accordance with an illustrative embodiment; 
         FIG. 3  is an illustration of another view of a lavatory in accordance with an illustrative embodiment; 
         FIG. 4  is an illustration of an isometric cut-away view of an aircraft in accordance with an illustrative embodiment; 
         FIG. 5  is an illustration of a process for disinfecting a lavatory in the form of a flowchart in accordance with an illustrative embodiment; 
         FIG. 6  is an illustration of a process for disinfecting a lavatory located in an aerospace vehicle in the form of a flowchart in accordance with an illustrative embodiment; 
         FIG. 7  is an illustration of an aircraft manufacturing and service method in the form of a block diagram in accordance with an illustrative embodiment; and 
         FIG. 8  is an illustration of an aircraft in the form of a block diagram in which an illustrative embodiment may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     The illustrative embodiments recognize and take into account different considerations. For example, the illustrative embodiments recognize and take into account that it may be desirable to have the capability of disinfecting the lavatories located in a vehicle, such as an aerospace vehicle. For example, it may be desirable to have the capability to disinfect a lavatory in an aerospace vehicle, such as an aircraft, during flight. Further, the illustrative embodiments recognize and take into account that it may be desirable to have a method and apparatus for disinfecting these lavatories to thereby reduce the need for a crewmember or some other type of person onboard the aircraft to perform the disinfection. 
     The illustrative embodiments recognize and take into account that ultraviolet radiation may be an effective form of disinfection. In particular, the illustrative embodiments recognize that far-ultraviolet (FUV) radiation may provide improved disinfection over other forms of ultraviolet radiation, such as, for example, without limitation, ultraviolet-C (UV-C) radiation. Far-ultraviolet radiation may be capable of destroying a greater number of pathogens and requires less exposure time for disinfection. Further, with respect to human exposure, far-ultraviolet radiation may be less harmful to humans as compared to ultraviolet-C radiation. 
     Thus, the illustrative embodiments provide a method and apparatus for disinfecting a lavatory using far-ultraviolet radiation. This disinfection may be performed in a manner that minimizes or prevents the exposure of humans to far-ultraviolet radiation. In one illustrative embodiment, an apparatus comprises a disinfection system and an activation system. The disinfection system emits far-ultraviolet radiation to perform a disinfection process inside a lavatory when the disinfection system is active. The disinfection system does not emit the far-ultraviolet radiation when inactive. The activation system controls activation and deactivation of the disinfection system. 
     Referring now to the figures and, in particular, with reference to  FIG. 1 , an illustration of a lavatory disinfection system is depicted in the form of a block diagram in accordance with an illustrative embodiment. In this illustrative example, lavatory disinfection system  100  may be used to disinfect lavatory  102 . 
     As depicted, lavatory  102  may be located in vehicle  104 . Vehicle  104  may take the form of aerospace vehicle  106 . Aerospace vehicle  106  may be selected from one of an aircraft, a spacecraft, a space shuttle, a space station, or some other type of aerospace vehicle. In other illustrative examples, vehicle  104  may take the form of a ground vehicle or a water vehicle, such as a ship. 
     Lavatory disinfection system  100  may include disinfection system  108  and activation system  110 . Depending on the implementation, disinfection system  108  and activation system  110  may be considered separate systems working in conjunction with each other to form lavatory disinfection system  100  or two systems that are integrated with each other to form lavatory disinfection system  100 . 
     Disinfection system  108  may use far-ultraviolet (FUV) radiation  112  to disinfect lavatory  102 . Activation system  110  may control when disinfection system  108  is activated and when disinfection system  108  is deactivated. When activated, disinfection system  108  enters active mode  116  where disinfection system  108  emits far-ultraviolet radiation  112 . When in inactive mode  114 , no far-ultraviolet radiation  112  is emitted until the disinfection system  108  is reactivated. In some cases, inactive mode  114  may be referred to as a “standby” mode, because disinfection system  108  remains inactive and on a temporal “standby” until the activation or the reactivation of disinfection system  108 . 
     In one illustrative example, disinfection system  108  includes ultraviolet radiation source  118 . Ultraviolet radiation source  118  may take the form of, for example, without limitation, far-ultraviolet light device  119 . 
     Ultraviolet radiation source  118  may be configured to emit far-ultraviolet radiation  112 , which may also be referred to as far-ultraviolet light. Far-ultraviolet radiation  112  may have a wavelength between about 150 nanometers (nm) and 240 nanometers (nm). In one illustrative example, far-ultraviolet radiation  112  may be selected as having a wavelength of about 222 nanometers. 
     Ultraviolet radiation source  118  may be mounted to any surface inside lavatory  102 , a surface within a vent or other access opening that opens into lavatory  102 , or some other type of surface. In particular, ultraviolet radiation source  118  may be mounted to a location that allows far-ultraviolet radiation  112  emitted by ultraviolet radiation source  118  to encounter the greatest number of surfaces inside lavatory  102 . As one illustrative example, ultraviolet radiation source  118  may be mounted to attachment location  121  inside lavatory  102 . 
     Attachment location  121  may be any location inside lavatory  102  or on any surface of lavatory  102 . In one illustrative example, attachment location  121  may be selected such that far-ultraviolet radiation  112  emitted by ultraviolet radiation source  118  reaches the largest portion of the greatest number of surfaces in lavatory  102  that need to disinfected. For example, without limitation, attachment location  121  may be on a top surface or ceiling of lavatory  102  or on a top portion of a side surface of lavatory  102 . As another example, attachment location  121  may be on the interior-facing side of door  134  that opens to lavatory  102 . 
     In some illustrative examples, ultraviolet radiation source  118  may emit far-ultraviolet radiation  112  in the form of one or more beams. These one or more beams may be focused beams. In some cases, ultraviolet radiation source  118  may be mounted to rotating device  120 . Rotating device  120  may be used to rotate ultraviolet radiation source  118  to rotate the one or more beams of far-ultraviolet radiation  112  such that far-ultraviolet radiation  112  becomes incident on more than one surface. 
     As depicted, disinfection system  108  may also include number of reflector devices  122 . As used herein, a “number of” items may include one or more items. In this manner, number of reflector devices  122  may include one or more reflector devices  122 . Each of number of reflector devices  122  may be positioned inside lavatory  102  such that far-ultraviolet radiation  112  that encounters the reflector device may be reflected. In particular, number of reflector devices  122  may be positioned such that far-ultraviolet radiation  112  is reflected onto at least one selected surface inside lavatory  102 . 
     In some illustrative examples, disinfection system  108  may also include reflective material  124 . In one illustrative example, reflective material  124  may take the form of reflective coating  125  applied to plurality of surfaces  128  inside lavatory  102  to reflect far-ultraviolet radiation  112  onto at least one selected surface inside lavatory  102 . In other illustrative examples, reflective material  124  may be part of the surface material of each of plurality of surfaces  128 . 
     Reflective material  124  may selectively reflect far-ultraviolet radiation  112 , but not electromagnetic radiation of human eye optical wavelengths. Consequently, reflective material  124  may be inconspicuous to the human user. For example, a human user of lavatory  102  may be unaware that reflective material  124  is present. In other words, reflective material  124  may not be noticeable to humans. 
     In this manner, far-ultraviolet radiation  112  emitted by ultraviolet radiation source  118  and far-ultraviolet radiation  112  reflected by number of reflector devices  122 , reflective material  124 , or both may be directed towards and encounter plurality of selected surfaces  126 . Once far-ultraviolet radiation  112  encounters plurality of selected surfaces  126 , far-ultraviolet radiation  112  begins disinfecting plurality of selected surfaces  126 . Disinfecting plurality of selected surfaces  126  comprises destroying potential pathogens that may be present on plurality of selected surfaces  126 . 
     Plurality of selected surfaces  126  may include any surfaces inside lavatory  102  that may need to be disinfected due to the potential for contact with at least one of a person, animal, or object carrying any number of pathogens. Plurality of selected surfaces  126  may include, for example, without limitation, surfaces on and around a toilet inside lavatory  102 , surfaces inside and around a sink inside lavatory  102 , a floor of lavatory  102 , one or more door handles, one or more drawer handles or cabinet knobs, other types of surfaces that can become infected through contact with at least one of a person, animal, object, or some combination thereof. 
     Activation system  110  may control whether disinfection system  108  is in active mode  116  or in inactive mode  114 . Active mode  116  may also be referred to as a disinfecting mode or an operational mode, in some cases. Activation system  110  may include sensor system  130  and controller  132 . Sensor system  130  may be used to detect when lavatory  102  is occupied or unoccupied and when door  134  to lavatory  102  is closed or open. 
     Sensor system  130  may include number of sensor devices  131  for monitoring the occupancy of lavatory  102  and whether or not door  134  is open or closed. Number of sensor devices  131  may include any number of different types of sensor types that are configured to detect and signal when the lavatory is occupied or empty. For example, without limitation, number of sensor devices  131  may include at least one of a motion sensor, an occupancy sensor, a thermal sensor, an open/close sensor, an infrared sensor device, an ultrasonic sensor device, a floor pressure sensor, or some other type of sensor. 
     As used herein, the phrase “at least one of,” when used with a list of items, means different combinations of one or more of the listed items may be used or only one of the items in the list may be used. The item may be a particular object, thing, or category. In other words, “at least one of” means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. 
     For example, “at least one of item A, item B, and item C” may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, “at least one of item A, item B, and item C” may mean, for example, without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination. 
     Sensor system  130  may monitor the occupancy of lavatory  102  and the status of door  134  with respect to being open or closed and generate information based on this monitoring. This information may take the form of, for example, without limitation, at least one of an electrical signal, a radio signal, an optical signal, some other type of wired signal, some other type of wireless signal, or some other type of signal. Sensor system  130  may send this information indicating whether or not lavatory  102  is occupied, and whether or not door  134  is open, to controller  132 . 
     Controller  132  may be implemented using hardware, firmware, software, or some combination thereof. Controller  132  may use the information received from sensor system  130  to determine whether set of criteria  136  has been met. In this illustrative example, set of criteria  136  may include lavatory  102  being unoccupied, door  134  to lavatory  102  being closed, lavatory  102  having been occupied a selected number of times since a previous disinfection of lavatory  102 , a selected amount of time having passed since a previous disinfection of lavatory  102 , a selected amount of time having passed since some reference point in time or event, some other type of criteria, or some combination thereof. 
     The selected number of times that lavatory  102  may need to be occupied since a previous disinfection of lavatory  102  may be, for example, without limitation, one time, two times, three times, or some other number of times. In some cases, no occupants may enter lavatory  102  after a previous disinfection. Consequently, in some cases, the selected number of times that lavatory  102  may need to be occupied since a previous disinfection of lavatory  102  may be set to zero times. 
     The selected amount of time that may need to pass since the previous disinfection of lavatory  102  may be, for example, without limitation, five minutes, ten minutes, thirty minutes, one hour, two hours, five hours, twenty-four hours, or some other period of time. When lavatory disinfection system  100  is being used for the first time, there may be no previous disinfection to consider. Consequently, the selected amount of time may be with respect to some other reference point in time. 
     In one illustrative example, set of criteria  136  may include a threshold level of pathogen presence, a threshold level of impurity presence, or both, within lavatory  102 . For example, without limitation, sensor system  130  may include at least one of an air sampling device, an air quality sensor, a pathogen detection system, or some other type of sensor device capable of detecting the level of pathogens, impurities, or both present in lavatory  102 . Pathogens may include pathogens on a surface, airborne pathogens, or both. Impurities may include, for example, inanimate contaminants on a surface, airborne inanimate contaminants, or both. This type of criterion may be met when the threshold level of pathogen presence, threshold level of impurity presence, or both has been met. 
     In these illustrative examples, set of criteria  136  may at least include that lavatory  102  be unoccupied such that disinfection system  108  is never in active mode  116  when lavatory  102  is occupied, for safety reasons. In response to controller  132  determining that set of criteria  136  has been met, controller  132  activates disinfection system  108 , thereby placing disinfection system  108  in active mode  116 . Upon entering active mode  116 , disinfection system  108  may begin performing disinfection process  138  to disinfect plurality of selected surfaces  126 . In some cases, far-ultraviolet radiation  112  may also be capable of disinfecting the air inside lavatory  102  by at least one of destroying or neutralizing pathogens, impurities, or both. 
     In some illustrative examples, door closing mechanism  135  may be associated with door  134 . When controller  132  determines that lavatory  102  is unoccupied and that all criteria in set of criteria  136  have been met except for door  134  being closed, controller  132  may engage door closing mechanism  135 . Door closing mechanism  135  closes door  134  automatically, such that the criterion of door  134  to lavatory  102  being closed, can then be met. 
     Disinfection process  138  may include, for example, without limitation, emitting far-ultraviolet radiation  112  from ultraviolet radiation source  118  for selected period of time  140 . In some cases, disinfection process  138  may include rotating ultraviolet radiation source  118  continuously or periodically during selected period of time  140 . 
     Exposure of plurality of selected surfaces  126  to far-ultraviolet radiation  112  for a short period of time may destroy, for example, without limitation, greater than about 95 percent or more of the pathogens present on plurality of selected surfaces  126 . Selected period of time  140  may be selected based on the minimum amount of time needed to fully disinfect lavatory  102  within selected tolerances. The minimum amount of time needed to disinfect within selected tolerances may be a function of, for example, without limitation, the energy of far-ultraviolet radiation  112  incident per square centimeter. 
     As one illustrative example, selected period of time  140  may be the minimum amount of time needed to fully disinfect plurality of selected surfaces  126  such that greater than about 99 percent of the undesired pathogens inside lavatory  102  are destroyed. Selected period of time  140  may be selected as, for example, without limitation, about 3, 5, 8, 10, 15, 20, 30, or some other number of seconds. 
     Once disinfection process  138  has been completed, controller  132  deactivates disinfection system  108 , thereby placing disinfection system  108  in inactive mode  114 . In some cases, door  134  to lavatory  102  may be opened during disinfection process  138 . If sensor system  130  detects the opening of door  134  during disinfection process  138 , then controller  132  deactivates disinfection system  108  to place disinfection system  108  in inactive mode  114 . 
     By using ultraviolet radiation source  118  that emits far-ultraviolet radiation  112 , the emission of far-ultraviolet radiation  112  from ultraviolet radiation source  118  may be halted substantially immediately upon deactivation of disinfection system  108 . For example, when disinfection system  108  is deactivated, ultraviolet radiation source  118  may be turned off such that the emission of far-ultraviolet radiation  112  is halted within less than a second. 
     Depending on the configuration of ultraviolet radiation source  118 , the emission of far-ultraviolet radiation  112  may be halted within milliseconds or microseconds. Using an electric arc-based source as ultraviolet radiation source  118  may enable the halting of the emission of far-ultraviolet radiation  112  within milliseconds or microseconds. 
     For example, ultraviolet radiation source  118  may be equipped with a controller switch that halts power supply to far-ultraviolet radiation source  118  within a desired, relatively short time following the opening of door  134  to lavatory  102 . In this manner, the safety of any person or animal that opens door  134  to lavatory  102  during disinfection process  138  may be ensured. 
     In some illustrative examples, indicator device  142  may be associated with an exterior of lavatory  102 . Indicator device  142  may display a visual indication of whether disinfection system  108  is in active mode  116  or in inactive mode  114 . As one illustrative example, indicator device  142  may be a digital display. In some cases, indicator device  142  or some other type of indicator device may be used to visually indicate when disinfection process  138  has been completed and lavatory  102  is ready for use. 
     In this manner, lavatory disinfection system  100  provides an effective and fast system for disinfecting lavatory  102 . Using far-ultraviolet radiation  112 , which has a shorter wavelength and higher frequency than other types of ultraviolet radiation, such as ultraviolet-C radiation, may be more effective than using lower-frequency, longer-wavelength ultraviolet radiation. Far-ultraviolet radiation  112  may be used to at least one of destroy or neutralize pathogens, impurities, or both. Pathogens may include bacteria, viruses, other types of microorganisms, or some combination thereof. A short-time exposure to far-ultraviolet radiation  112  may destroy a desired percentage of pathogens. For example, far-ultraviolet radiation  112  may enable destruction of substantially all contaminants present. Further, using far-ultraviolet radiation  112  as compared to other types of longer-wavelength ultraviolet radiation may reduce the amount of power required for lavatory disinfection system  100 . 
     Although the activation of disinfection system  108  is described above as being automated by activation system  110  based on set of criteria  136  being met, in some illustrative examples, disinfection system  108  may be capable of being manually activated. For example, without limitation, disinfection system  108  may have an additional manual activation switch device that may be operable by, for example, a human when the lavatory is unoccupied or vacant. 
     In other illustrative examples, lavatory disinfection system  100  may include one or more mechanical systems capable of physically moving one or more components inside lavatory  102  during disinfection process  138  to expose additional surfaces for disinfection. As one illustrative example, a mechanism may be associated with a toilet inside lavatory  102 . This mechanism may be used to lift a lid of the toilet to enable exposure of the toilet seat to far-ultraviolet radiation  112  during disinfection process  138 . In some cases, the mechanism may be used to lift the toilet seat of the toilet to enable exposure of other toilet surfaces to far-ultraviolet radiation  112  during disinfection process  138 . 
     Operation of these types of mechanisms may be triggered once disinfection process  138  begins. For example, these mechanisms may be triggered to operate after the lapse of a timer after disinfection process  138  begins or immediately after disinfection process  138  begins. 
     Lavatory disinfection system  100  may be implemented in such a manner that enables lavatory disinfection system  100  to be retrofitted in aerospace vehicle  106 . Using this type of system that can be either installed in lavatory  102  of aerospace vehicle  106  during manufacturing or retrofitted to aerospace vehicle  106  during maintenance, service, or repair may help reduce the overall costs associated with this type of disinfection system. 
     The illustration of lavatory disinfection system  100  in  FIG. 1  is not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. Other components in addition to or in place of the ones illustrated may be used. Some components may be optional. Also, the blocks are presented to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and divided into different blocks when implemented in an illustrative embodiment. 
     In other illustrative examples, lavatory disinfection system  100  may not include door closing mechanism  135 . In some illustrative examples, more than one door may provide access to lavatory  102 . Set of criteria  136  may include that all of the doors that provide access to lavatory  102  be closed. In still other illustrative examples, number of reflector devices  122  may be excluded and only reflective material  124  used to ensure that each of plurality of surfaces  128  will be reached by far-ultraviolet radiation  112 . 
     In some cases, lavatory disinfection system  100  may be used to disinfect a lavatory or restroom inside a building, a restaurant, a store, a mall, an office building, or some other type of structure. Further, although disinfection system  108  and activation system  110  have been described for use in disinfecting lavatory  102  inside aerospace vehicle  106 , at least one of disinfection system  108  or activation system  110  may be used for the disinfection of other areas inside aerospace vehicle  106 . 
     As one illustrative example, multiple disinfection systems implemented in a manner similar to disinfection system  108  may be positioned throughout aerospace vehicle  106 . For example, one or more disinfection systems may be positioned within at least one of a cabin area of aerospace vehicle  106 , a galley area of aerospace vehicle  106 , an interior of a duct or vent in aerospace vehicle  106 , or in some other area of aerospace vehicle  106 . Controller  132  or some other type of controller may be used to activate these disinfection systems between flights of aerospace vehicle  106  or during other times when there is no risk of humans or animals being exposed to far-ultraviolet radiation. 
     In still other illustrative examples, a system comprised of any number of disinfection systems implemented in a manner similar to disinfection system  108  and any number of activation systems implemented in a manner similar to activation system  110  may be used to disinfect other types of public areas. For example, this type of system may be used in airport baggage areas, airport waiting areas, airport gates, airport restrooms, airport restaurants, or some combination thereof. 
     With reference now to  FIG. 2 , an illustration of an isometric view of a lavatory of an aircraft is depicted in accordance with an illustrative embodiment. In this illustrative example, lavatory  200  may be an example of one implementation for lavatory  102  in  FIG. 1 . As depicted, lavatory disinfection system  202  is present inside lavatory  200 . Lavatory disinfection system  202  is an example of one implementation for lavatory disinfection system  100  in  FIG. 1 . 
     Lavatory disinfection system  202  includes disinfection system  204  and activation system  205 , which may be examples of implementations for disinfection system  108  and activation system  110 , respectively, in  FIG. 1 . Activation system  205  includes sensor system  208 , which may be an example of one implementation for sensor system  130  in  FIG. 1 . Sensor system  208  may include occupancy sensor  209  and an open/close sensor (not shown). 
     Disinfection system  204  includes far-ultraviolet light device  206 , which may be an example of one implementation for far-ultraviolet light device  119  in  FIG. 1 , and thereby, ultraviolet radiation source  118  in  FIG. 1 . Disinfection system  204  also includes number of reflector devices  210  and reflective material  218 . Number of reflector devices  210  may be an example of one implementation for number of reflector devices  122  in  FIG. 1 . Reflective material  218  may be an example of one implementation for reflective material  124  in  FIG. 1 . 
     Number of reflector devices  210  may include reflector device  212 , reflector device  214 , reflector device  215 , and reflector device  216 . As depicted, reflective material  218  may be applied to plurality of surfaces  220  inside lavatory  200 . 
     When disinfection system  204  is in an active mode, far-ultraviolet light device  206  emits far-ultraviolet radiation. This far-ultraviolet radiation may be emitted towards various surfaces inside lavatory  200 . The portion of far-ultraviolet radiation that encounters reflective material  218  and each of number of reflector devices  210  may be reflected. In particular, each of number of reflector devices  210  may be positioned to cause the reflection of far-ultraviolet radiation onto one or more selected surfaces inside lavatory  102 . In this manner, disinfection system  204  may be configured such that far-ultraviolet radiation reaches a plurality of selected surfaces inside lavatory  200  that need to be disinfected. 
     With reference now to  FIG. 3 , an illustration of another view of lavatory  200  from  FIG. 2  is depicted in accordance with an illustrative embodiment. In this illustrative example, door  300  to lavatory  200  may be seen. Open/close sensor  302  is associated with door  300 . Open/close sensor  302  is configured to detect when door  300  is open and when door  300  is closed. 
     Activation system  205  may use the information provided by sensor system  208  to determine when to place disinfection system  204  in an active mode and when to place disinfection system  204  in an inactive mode. Disinfection system  204  is only activated when door  300  to lavatory  200  is closed, when lavatory  200  is unoccupied, and when lavatory  200  has been occupied a selected number of times since a previous disinfection of lavatory  200 . 
     In addition, disinfection system  204  may be activated when a selected amount of time has passed since a previous disinfection of lavatory  200 , provided lavatory  200  is unoccupied. If lavatory  200  is occupied at the lapse of the selected amount of time since the previous disinfection, a controller, such as controller  132 , of disinfection system  204  may have an override capability to ensure that disinfection system  204  does not activate when lavatory  200  is occupied. 
     With reference now to  FIG. 4 , an illustration of an isometric cut-away view of an aircraft is depicted in accordance with an illustrative embodiment. Aircraft  400  may be an example of one implementation for aerospace vehicle  106  in  FIG. 1 . 
     In this illustrative example, aircraft  400  has wing  402  and wing  404  attached to body  406 . Body  406  may also be referred to as a fuselage. Aircraft  400  includes engine  408  attached to wing  402  and engine  410  attached to wing  404 . Body  406  has tail section  412 . Horizontal stabilizer  414 , horizontal stabilizer  416 , and vertical stabilizer  418  are attached to tail section  412  of body  406 . 
     Body  406  also has cockpit  420  and passenger cabin  422 . In this example, passenger cabin  422  may include passenger seating in seating area  424 . Further, seating area  424  in passenger cabin  422  may include storage areas, such as a number of overhead stowage bins. Passenger cabin  422  may include lavatory  426  and galley area  428 . 
     Lavatory  426  may be another example of an implementation for lavatory  102  in  FIG. 1 . In this illustrative example, lavatory  426  may be implemented in a manner similar to lavatory  200  in  FIGS. 2-3 . Further, a lavatory disinfection system, such as lavatory disinfection system  202  in  FIGS. 2-3 , may be installed in lavatory  426 . 
     In some illustrative examples, a system comprised of one or more disinfection systems implemented similarly to disinfection system  108  described in  FIG. 1  and one or more activation systems implemented similarly to activation system  110  in  FIG. 1  may be installed in aircraft  400  such that multiple areas throughout aircraft  400  may be disinfected. For example, this type of system may be used to disinfect galley area  428 , cockpit  420 , seating area  424  within passenger cabin  422 , the interior surfaces of storage areas within passenger cabin  422 , other areas inside passenger cabin  422 , other areas inside aircraft  400 , or some combination thereof. 
     The illustrations of lavatory  200  in  FIGS. 2-3  and aircraft  400  in  FIG. 4  are provided for purposes of illustrating one environment in which the different illustrative embodiments may be implemented. The illustrations in  FIGS. 2-4  are not meant to imply physical or architectural limitations as to the manner in which different illustrative embodiments may be implemented. 
     The different components shown in  FIGS. 2-4  may be illustrative examples of how components shown in block form in  FIG. 1  can be implemented as physical structures. Additionally, some of the components in  FIGS. 2-4  may be combined with components in  FIG. 1 , used with components in  FIG. 1 , or a combination of the two. 
     With reference now to  FIG. 5 , an illustration of a process for disinfecting a lavatory is depicted in the form of a flowchart in accordance with an illustrative embodiment. The process illustrated in  FIG. 5  may be implemented using, for example, lavatory disinfection system  100  in  FIG. 1 . 
     The process may begin by monitoring a lavatory (operation  500 ). In one illustrative example, operation  500  may be performed by monitoring occupancy of the lavatory and a door to the lavatory. The occupancy of the lavatory and the door the lavatory may be monitored in operation  500  using, for example, without limitation, a sensor system. 
     A determination may be made as to whether a set of criteria has been met (operation  502 ). The set of criteria may include the lavatory being unoccupied and at least one of, for example, without limitation, the door to the lavatory being closed, the lavatory having been occupied a selected number of times since a previous disinfection of the lavatory, or a selected amount of time having passed since the previous disinfection of the lavatory. The selected number of times that the lavatory must be occupied since a previous disinfection of the lavatory may be, for example, without limitation, one time, two times, three times, or some other number of times. The selected amount of time that needs to pass since the previous disinfection of the lavatory may be, for example, without limitation, five minutes, ten minutes, thirty minutes, one hour, two hours, five hours, twenty-four hours, or some other period of time. 
     If the set of criteria has not been met, the process returns to operation  500  as described above. Otherwise, if the set of criteria has been met, a disinfection system is activated to perform a disinfection process inside the lavatory using far-ultraviolet radiation (operation  504 ), with the process terminating thereafter. In this illustrative example, in operation  504 , the disinfection process may include emitting far-ultraviolet radiation for a selected period of time. For example, far-ultraviolet radiation may be emitted for about five seconds, ten seconds, or some other period of time. 
     With reference now to  FIG. 6 , an illustration of a process for disinfecting a lavatory located in an aerospace vehicle is depicted in the form of a flowchart in accordance with an illustrative embodiment. The process illustrated in  FIG. 6  may be implemented using, for example, lavatory disinfection system  100  in  FIG. 1 . 
     The process may begin by monitoring an occupancy of a lavatory and a door to the lavatory using a sensor system (operation  600 ). A determination may be made as to whether the lavatory is unoccupied (operation  602 ). If the lavatory is not unoccupied or, in other words, occupied, the process returns to operation  600  as described above. Otherwise, if the lavatory is unoccupied, a determination may be made as to whether the lavatory has been occupied a selected number of times since a previous disinfection of the lavatory (operation  604 ). 
     In operation  604 , the previous disinfection is the most recent performance of a fully completed disinfection process. In some illustrative examples, operation  604  may include determining whether a selected amount of time has passed since a previous disinfection of the lavatory in addition to or in place of the determination as to whether the lavatory has been occupied a selected number of times since a previous disinfection of the lavatory. 
     If the lavatory has not been occupied the selected number of times since the previous disinfection of the lavatory, the process returns to operation  600  as described above. Otherwise, a determination may be made as to whether the door to the lavatory is closed (operation  606 ). 
     In one illustrative example, the door to the lavatory may be considered closed when the door is fully closed. If the door to the lavatory is not closed, the process returns to operation  600  as described above. Otherwise, if the door to the lavatory is closed, a disinfection system is activated to perform a disinfection process inside the lavatory using far-ultraviolet radiation (operation  608 ). In operation  608 , activation of the disinfection system places the disinfection system in an active mode. 
     The door to the lavatory may be monitored during the disinfection process (operation  610 ). A determination may be made as to whether the door to the lavatory has been opened during the disinfection process or the disinfection process has been completed (operation  612 ). In operation  612 , the door may be considered open even if the door is only partially opened. 
     If either the door to the lavatory has been opened during the disinfection process or the disinfection process has been completed, the disinfection system is deactivated to place the disinfection system in an inactive mode (operation  614 ), with the process then returning to operation  600  as described above. However, if the door has not been opened and the disinfection process has not been completed, the process returns to operation  610  as described above. 
     The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatuses and methods in an illustrative embodiment. In this regard, each block in the flowcharts or block diagrams may represent a module, a segment, a function, and/or a portion of an operation or step. 
     In some alternative implementations of an illustrative embodiment, the function or functions noted in the blocks may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved. Also, other blocks may be added in addition to the illustrated blocks in a flowchart or block diagram. 
     For example, in some cases, a determination that the door to the lavatory is not closed in operation  606  in  FIG. 6  may cause a door closing mechanism to be automatically engaged instead of the process returning to operation  600 . Once engaged, the door closing mechanism may close the door to the lavatory and the process may then proceed to operation  608 . 
     The illustrative embodiments of the disclosure may be described in the context of aircraft manufacturing and service method  700  as shown in  FIG. 7  and aircraft  800  as shown in  FIG. 8 . Turning first to  FIG. 7 , an illustration of an aircraft manufacturing and service method is depicted in the form of a block diagram in accordance with an illustrative embodiment. During pre-production, aircraft manufacturing and service method  700  may include specification and design  702  of aircraft  800  in  FIG. 8  and material procurement  704 . 
     During production, component and subassembly manufacturing  706  and system integration  708  of aircraft  800  in  FIG. 8  takes place. Thereafter, aircraft  800  in  FIG. 8  may go through certification and delivery  710  in order to be placed in service  712 . While in service  712  by a customer, aircraft  800  in  FIG. 8  is scheduled for routine maintenance and service  714 , which may include modification, reconfiguration, refurbishment, and other maintenance or service. 
     Each of the processes of aircraft manufacturing and service method  700  may be performed or carried out by a system integrator, a third party, and/or an operator. In these examples, the operator may be a customer. For the purposes of this description, a system integrator may include, without limitation, any number of aircraft manufacturers and major-system subcontractors; a third party may include, without limitation, any number of vendors, subcontractors, and suppliers; and an operator may be an airline, a leasing company, a military entity, a service organization, and so on. 
     With reference now to  FIG. 8 , an illustration of an aircraft is depicted in the form of a block diagram in which an illustrative embodiment may be implemented. In this example, aircraft  800  is produced by aircraft manufacturing and service method  700  in  FIG. 7  and may include airframe  802  with plurality of systems  804  and interior  806 . Examples of systems  804  include one or more of propulsion system  808 , electrical system  810 , hydraulic system  812 , and environmental system  814 . Any number of other systems may be included. Although an aerospace example is shown, different illustrative embodiments may be applied to other industries, such as the automotive industry. 
     The apparatuses and methods embodied herein may be employed during at least one of the stages of aircraft manufacturing and service method  700  in  FIG. 7 . In particular, lavatory disinfection system  100  from  FIG. 1  may be installed on aircraft  800  during any one of the stages of aircraft manufacturing and service method  700 . For example, without limitation, lavatory disinfection system  100  from  FIG. 1  may be installed on aircraft  800  during at least one of component and subassembly manufacturing  706 , system integration  708 , routine maintenance and service  714 , or some other stage of aircraft manufacturing and service method  700 . Still further, lavatory disinfection system  100  from  FIG. 1  may be used while aircraft  800  is in service  712  in  FIG. 7 . 
     In one illustrative example, components or subassemblies produced in component and subassembly manufacturing  706  in  FIG. 7  may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft  800  is in service  712  in  FIG. 7 . As yet another example, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during production stages, such as component and subassembly manufacturing  706  and system integration  708  in  FIG. 7 . One or more apparatus embodiments, method embodiments, or a combination thereof may be utilized while aircraft  800  is in service  712  and/or during maintenance and service  714  in  FIG. 7 . The use of a number of the different illustrative embodiments may substantially expedite the assembly of and/or reduce the cost of aircraft  800 . 
     The description of the different illustrative embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different illustrative embodiments may provide different features as compared to other desirable embodiments. The embodiment or embodiments selected are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.