1.1 该实践仅限于操作低压汞灯设备以评估由于暴露于UVC光而导致的材料降解的基本原理；就其本身而言，它并没有带来具体的结果。 1.2 它旨在与定义应用特定暴露条件的实践或方法以及评估材料财产变化的方法一起使用。这种做法旨在再现当材料暴露于主要发射UVC波段辐射的人工光源时，特别是在240波长范围内时发生的光降解效应 nm至280 纳米。 这种做法仅限于获得、测量和控制暴露条件的程序。 注1: 实践 G151 描述了在使用实验室光源的加速测试设备中暴露材料时使用的一般程序。 注2: 紫外线光源的常见用途是对表面和空气进行消毒，这一过程被称为紫外线杀菌照射（UVGI）。使用紫外线光源的水消毒应用已经使用了几十年。 1.3 此做法不包括其他光源（例如。 g.LED、准分子灯等）或主要发射波长在 1.2 . 1.4 在受控温度条件下，将样品暴露于控制在规定辐照度水平的紫外线下。 1.5 试样制备和结果评估包含在特定材料的ASTM方法或规范中。《实践》中给出了一般指导 G151 . 1.6 单位- 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。 本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 由于使用紫外线杀菌照射（UVGI）来减缓传染病的传播，暴露于人造UVC光源引起的材料对光降解的抵抗力越来越令人担忧。 5.2 用于阳光直射的材料和产品通常被设计成能够抵抗到达地球表面的UVA和UVB光的影响，但通常不会对它们进行测试，以确定暴露在被大气过滤掉的UVC下的影响。 5.3 与电磁光谱中UVA和UVB区域的光相比，当UVC光被材料吸收时，可以导致光降解以不同的速率和通过不同的机制进行，并将降解限制在较薄的表面层。 5.4 室内材料和产品通常不能承受显著的紫外线照射，当暴露在紫外线下时，其过早降解的风险更大。 5.5 本规程旨在引起与暴露于人造紫外线光源的材料所经历的性质变化一致的性质变化，人造紫外线光源具有与本规程中规定的类似的光谱辐照度分布。

1.1 This 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. 1.2 It 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 nm to 280 nm. This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure. Note 1: Practice G151 describes general procedures to be used when exposing materials in accelerated test devices that use laboratory light sources. Note 2: A common use of UVC light sources is for the disinfection of surfaces and air, a process known as ultraviolet germicidal irradiation (UVGI). Water disinfection applications using UVC light sources have been in use for many decades. 1.3 This practice does not cover other light sources (e.g. LEDs, excimer lamps, etc.) or any lamps that emit wavelengths primarily outside the range in 1.2 . 1.4 Specimens are exposed to UVC light controlled to a specified irradiance level under controlled temperature conditions. 1.5 Specimen preparation and evaluation of the results are covered in ASTM methods or specifications for specific materials. General guidance is given in Practice G151 . 1.6 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 This 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Material resistance to photodegradation caused by exposure to artificial UVC light sources is a growing concern due to the use of ultraviolet germicidal irradiation (UVGI) to mitigate the spread of infectious diseases. 5.2 Materials and products intended for direct sunlight exposure are typically designed to resist the effects of the UVA and UVB light reaching the earth’s surface, but generally they are not tested to determine the effects of exposure to UVC, which is filtered out by the atmosphere. 5.3 Compared to light in the UVA and UVB regions of the electromagnetic spectrum, UVC light, when absorbed by a material, can cause photodegradation to proceed at different rates and by different mechanisms as well as confining degradation to a thinner surface layer. 5.4 Indoor materials and products, which typically are not designed to withstand significant ultraviolet light exposure, are at even greater risk of premature degradation when subjected to UVC exposure. 5.5 This practice is intended to induce property changes consistent with those experienced by materials exposed to artificial UVC light sources with a similar spectral irradiance distribution to those specified in this practice.