1. Scope

1.Scope 1.1This practice is limited to the basic principles for operating a low pressure mercury lamp apparatus to assess degradation of materials due to exposure to UVC light; on its own, it does not deliver a specific result. 1.2It is intended to be used in conjunction with a practice or method that defines specific exposure conditions for an application along with a means to evaluate changes in material properties. This practice is intended to reproduce the photodegradation effects that occur when materials are exposed to artificial light sources that emit radiation primarily in the UVC wavelength band, particularly in the range of 240-280 nm. This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure. Note: A common use of UVC light sources is for the disinfection of surfaces and air, a process known as ultraviolet germicidal irradiation (UVGI). 1.3Specimens are exposed to UVC light controlled to a specified irradiance level under controlled temperature conditions. 1.4Specimen preparation and evaluation of the results are covered in ASTM methods or specifications for specific materials. General guidance is given in Practice G151. 1.5The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Keywords

germicidal

Rationale

The COVID-19 pandemic has dramatically increased the use of ultraviolet germicidal irradiation (UVGI) for disinfection of air and surfaces in public and private spaces. Wavelengths in the UVC portion of the spectrum are well-known to kill or deactivate a variety of microorganisms, including all bacteria and viruses. Low pressure mercury lamps have a peak output at 254 nm, and the effectiveness of this wavelength is about 90% of the peak as published in scientific literature and standards. Due to its effectiveness and long history of manufacture, this particular light source dominates the current market for UVGI devices. With increased utilization of UVGI devices, material degradation due to repeated UVC light exposures is a growing concern. Paints, plastics, and textiles are all subjected to this problem. However, because UVC light is not present in terrestrial sunlight, these materials are not commonly tested or designed for resistance to UVC wavelengths. This standard is intended to provide a practical, repeatable, and reproducible tool for testing and product development. Germicidal UVC lamps are effectively the same as standard fluorescent lamps, except they are manufactured without the fluorescent phosphors. This leads to a logical adaptation of the G154 technology to test materials for durability to UVC exposures. It is proposed that a new standard for UVC exposures is developed and modeled after Standard Practice G154.

The title and scope are in draft form and are under development within this ASTM Committee.