Photochromic indicator and a method of documenting decontamination of an object using a photochromic indicator
Provided is a method and an apparatus for indicating minimum exposure of a surface to UVC light emitted by a source during a decontamination process to achieve a desired level of pathogen reduction. The apparatus includes a photochromic material to be applied to, or applied adjacent to the surface. The photochromic material is to exhibit a visible response to receiving the minimum exposure to the UVC light, and exhibit the visible response to a lesser extent after the photochromic material ceases to be exposed to the UVC light emitted by the source. A protective layer of material that is substantially transparent to the UVC light emitted by the source is positioned over the photochromic material to be disposed between the source and the photochromic material during the decontamination process.
1. An apparatus for indicating exposure of a surface to at least a predetermined dose of UVC light emitted by a source during a decontamination process, the apparatus comprising:
a photochromic material to be applied to, or applied adjacent to the surface, wherein the photochromic material exhibits a visible response to receiving the predetermined dose of the UVC light and, after the photochromic material ceases to be exposed to the UVC light emitted by the source, an appearance of the photochromic material returns to an original appearance that was visible before exposure of the photochromic material to the UVC light;
a second material that exhibits a visible response to being exposed to light having a wavelength outside of range of wavelengths constituting UVC light; and
a protective layer of material that is substantially transparent to the UVC light emitted by the source positioned over the photochromic material to be disposed between the source and the photochromic material during the decontamination process.
2. The apparatus of claim 1 , wherein the photochromic material is substantially transparent before being exposed to the UVC light and is substantially opaque and/or changes color as the visible response to receiving the predetermined dose of the UVC light.
3. The apparatus of claim 1 further comprising a second photochromic material that exhibits a different visible response than the visible response of the photochromic material to indicate different exposures to the UVC light.
4. The apparatus of claim 1 , wherein the visible response of the photochromic material is visibly perceptible by an observer for at least a predetermined period of time after the photochromic material ceases to be exposed to the UVC light emitted by the source.
5. The apparatus of claim 4 , wherein the predetermined period of time comprises at least four minutes.
6. The apparatus of claim 4 , wherein the predetermined period of time comprises at least ten minutes.
7. The apparatus of claim 1 further comprising a visible identifier that indicates a general vicinity of the photochromic material in an original state before the photochromic material exhibits the visible response.
8. The apparatus of claim 1 further comprising an adhesive that adheres the apparatus to the surface.
9. The apparatus of claim 1 further comprising a backing layer, wherein the photochromic material is disposed between the backing layer and the protective layer.
10. A method of evaluating progress of a decontamination process, the method comprising:
applying a photochromic indicator to a surface to be rendered pathogen reduced during the decontamination process, the photochromic indicator comprising a photochromic material that exhibits a visible response to being exposed to at least a predetermined dose of UVC light and, after the photochromic material ceases to be exposed to the UVC light, an appearance of the photochromic material returns to an original appearance that was visible before exposure of the photochromic material to the UVC light;
applying a second material that exhibits a visible response to being exposed to light having a wavelength outside of a range of wavelengths constituting UVC light adjacent to the photochromic indicator;
exposing the photochromic material to the UVC light impinging on the surface during the decontamination process for a length of time expected to be suitable for achieving pathogen reduction of the surface to a desired extent during the decontamination process; and
after expiration of the length of time, using a light source that emits the light with the wavelength outside of the range of wavelengths constituting UVC light to cause the second material to exhibit the visible response, and determining an extent to which the decontamination process was completed based on whether the photochromic material exhibits the visible response.
11. The method of claim 10 , wherein said determining the extent to which the decontamination process was completed comprises observing a plurality of photochromic materials provided to the photochromic indicator, and making a determination of the extent to which the decontamination process was completed based on a different visible response exhibited by each of the plurality of photochromic materials.
12. The method of claim 10 , wherein said determining comprises making a determination, based on the visible response, that the desired level of pathogen has not been achieved, and said method further comprises reactivating a source of the UVC light to achieve the desired level of pathogen reduction.
13. The method of claim 10 , wherein the second material is combined with the photochromic material and applied concurrently with application of the photochromic material.