1.1 这种做法 2. 描述了使用相衬显微镜和可选的透射电子显微镜来评估在个人呼吸区的膜过滤器上收集的颗粒材料，或通过在特定位置的区域采样来确定纤维浓度，以每毫升空气中此类纤维的数量表示。本实践基于国际标准化组织（ISO）标准ISO 8672中提供的核心程序 ( 1. ) , 3. 国家职业健康研究所（NIOSH）分析方法手册，NIOSH 7400 ( 2. ) ，以及职业安全与健康管理局（OSHA）ID 160 ( 3. ) . 本规程指出了这些方法不同的要点，并提供了有关差异的信息，这将允许用户为特定应用选择最合适的程序。 然而，从不同发布的方法中选择部分过程通常需要用户报告他们使用了对方法的修改，而不是声称他们使用了书面方法。 1.2 本规程用于常规测定工作场所中空气中纤维的职业暴露指数。工作场所被视为工人接触空气中纤维（包括石棉）的场所。ASTM小组委员会E06目前正在审议的《含石棉材料管理空气监测标准实施规程》（WK 8951）中提供了关于石棉减排项目的采样策略、样本采集（包括校准）和样本结果使用的其他信息。 24、针对矿山和采石场中的气载纤维采样和计数的特定目的，批准了另一种做法（做法 D7200 )，尽管本文中的实践也可用于此目的。当已知石棉纤维时，可将当前做法用作监测职业接触石棉纤维的手段 先验的 存在于空气中的灰尘中。实践中给出了空气中纤维浓度的指标。本规程可与电子显微镜一起使用（参见 附录X1 )以帮助识别纤维。本规程可用于其他材料，如纤维玻璃或人造矿物纤维，使用替代计数规则（见 附件A4 ). 1.3 本实施规程规定了对个人呼吸区内的大气进行采样的设备和程序，以及在适当的呼吸过程中确定滤膜上累积的纤维数量的设备和程序- 选定的采样周期。该方法也可用于对建筑物特定位置或房间的大气进行采样（区域采样），这可能有助于评估工人接触含纤维产品的情况。 1.4 该测试实践的理想工作范围为100根纤维/毫米 2. 至1300根纤维/毫米 2. 过滤面积的。对于1000升空气样品，这对应于约0.04至0.5纤维/毫升（或纤维/厘米）的浓度范围 3. ). 通过减少或增加收集的空气量，可以测量纤维浓度的高低范围。然而，当本规程适用于对其他非石棉粉尘的采样时，如果生产的过滤器具有适当的纤维负载以进行纤维计数，则总悬浮颗粒物的水平可能会对可采样的空气体积施加上限。 1.5 用户应在实践中使用该程序确定自己的检测极限 D6620 . 作为参考，NIOSH 7400方法的检测极限为7根纤维/毫米 2. 过滤面积的。对于1000 L空气样品，这对应于0.0027纤维/毫升（或纤维/厘米）的检测极限 3. ). 对于OSHA ID 160检测极限为5.5纤维/毫米 2. 过滤面积的。对于1000 L空气样品，这对应于0.0022纤维/毫升（或纤维/厘米）的检测极限 3. ). 1.6 如果这种做法产生的纤维浓度不超过特定规定纤维品种的职业极限值，则可能无需采取进一步行动。如果纤维浓度超过特定纤维品种的职业限值，并且有理由怀疑特定纤维品种与不在同一标准或法规范围内的其他纤维混合，则采用 附录X1 可用于测量规定品种的已计数纤维的浓度或比例。 1.7 本实践中使用的安装介质的折射率约为1.45。折射率在1.4到1.5之间的光纤对比度会降低，可能难以检测。 1.8 直径小于约0.2μm的纤维将无法通过本规程检测到 ( 4. ) . 1.9 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.10 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户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。 有关具体的预防说明，请参阅第节 7. . 1.11 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本规程的使用者必须自行确定所述规程是否符合管理石棉或其他纤维危害的地方或国家当局的要求。 5.2 英国石棉研究委员会描述了这种做法的变化 ( 8. ) ，石棉国际协会（AIA）RTM 1 ( 9 ) ，NIOSH 7400，OSHA ID 160和ISO 8672。如果后三种方法的计算规则不同，请在正文中注明。 5.3 优势: 5.3.1 该技术针对纤维。PCM是一种纤维计数技术，从分析中排除非纤维颗粒。 5.3.2 该技术价格低廉，但需要专业知识来进行总纤维数的分析，至少在法规通常要求分析员参加特定培训课程（例如NIOSH 582或同等课程）的情况下。 5.3.3 该分析快速，可在现场进行，以快速测定空气中纤维的浓度。 5.4 限制: 5.4.1 PCM的主要局限性是无法识别光纤。 计算指定尺寸范围内的所有纤维。有时可以使用差异纤维计数来区分石棉纤维和形态明显不同的纤维，如纤维素和玻璃纤维。在大多数情况下，如果没有额外的阳性识别，则无法使用差异纤维计数来充分区分石棉和非石棉纤维，以符合法规。如果需要对石棉进行阳性识别，则必须通过偏振光或电子显微镜技术，使用过滤器的不同部分进行。 5.4.2 另一个限制是，PCM可见的最小纤维直径约为0.2μm，而最细的石棉纤维可能小至0。 直径02μm。 5.4.3 如果纤维浓度的计算结果超过了监管标准，则假设不符合要求，除非可以证明计数的纤维不属于该标准监管的纤维组的一个或多个成员。

1.1 This practice 2 describes the determination of the concentration of fibers, expressed as the number of such fibers per millilitre of air, using phase contrast microscopy and optionally transmission electron microscopy to evaluate particulate material collected on a membrane filter in the breathing zone of an individual or by area sampling in a specific location. This practice is based on the core procedures provided in the International Organization for Standardization (ISO) Standard ISO 8672 ( 1 ) , 3 the National Institute for Occupational and Health (NIOSH) Manual of Analytical Methods, NIOSH 7400 ( 2 ) , and the Occupational Safety and Health Administration (OSHA) ID 160 ( 3 ) . This practice indicates the important points where these methods differ, and provides information regarding the differences, which will allow the user to select the most appropriate procedure for a particular application. However, selecting portions of procedures from different published methods generally requires a user to report that they have used a modification to a method rather than claim they have used the method as written. 1.2 The practice is used for routine determination of an index of occupational exposure to airborne fibers in workplaces. Workplaces are considered those places where workers are exposed to airborne fibers including asbestos. Additional information on sampling strategies, sample collection (including calibration) and use of sample results for asbestos abatement projects is provided in a standard Practice for Air Monitoring for Management of Asbestos-Containing Materials (WK 8951) currently being considered by ASTM subcommittee E06.24. A further practice has been approved for the specific purpose of sampling and counting airborne fibers in mines and quarries (Practice D7200 ), although the practice herein may also be used for this purpose. The current practice may be used as a means of monitoring occupational exposure to asbestos fibers when asbestos fibers are known a priori to be present in the airborne dust. The practice gives an index of airborne fiber concentration. This practice may be used in conjunction with electron microscopy (see Appendix X1 ) for assistance in identification of fibers. This practice may be used for other materials such as fibrous glass, or man-made mineral fibers by using alternate counting rules (see Annex A4 ). 1.3 This practice specifies the equipment and procedures for sampling the atmosphere in the breathing zone of an individual and for determining the number of fibers accumulated on a filter membrane during the course of an appropriately-selected sampling period. The practice may also be used to sample the atmosphere in a specific location or room of a building (area sampling), where this may be helpful in assessing exposure to workers handling fiber-containing products. 1.4 The ideal working range of this test practice extends from 100 fibers/mm 2 to 1300 fibers/mm 2 of filter area. For a 1000-L air sample, this corresponds to a concentration range from approximately 0.04 to 0.5 fiber/mL (or fiber/cm 3 ). Lower and higher ranges of fiber concentration can be measured by reducing or increasing the volume of air collected. However, when this practice is applied to sampling the presence of other, non-asbestos dust, the level of total suspended particulate may impose an upper limit to the volume of air that can be sampled if the filters produced are to be of appropriate fiber loading for fiber counting. 1.5 Users should determine their own limit of detection using the procedure in Practice D6620 . For Reference the NIOSH 7400 method gives the limit of detection as 7 fibers/mm 2 of filter area. For a 1000 L air sample, this corresponds to a limit of detection of 0.0027 fiber/mL (or fiber/cm 3 ). For OSHA ID 160 the limit of detection is given as 5.5 fibers/mm 2 of filter area. For a 1000 L air sample, this corresponds to a limit of detection of 0.0022 fiber/mL (or fiber/cm 3 ). 1.6 If this practice yields a fiber concentration that does not exceed the occupational limit value for the particular regulated fiber variety, no further action may be necessary. If the fiber concentration exceeds the occupational limit value for a specific fiber variety, and there is reason to suspect that the specific fiber variety is mixed with other fibers not covered under the same standard or regulation, the optional method specified in Appendix X1 may be used to measure the concentration or proportion of the fibers counted that are of the regulated variety. 1.7 The mounting medium used in this practice has a refractive index of approximately 1.45. Fibers with refractive indices in the range of 1.4 to 1.5 will exhibit reduced contrast, and may be difficult to detect. 1.8 Fibers less than approximately 0.2 μm in diameter will not be detected by this practice ( 4 ) . 1.9 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.10 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. For specific precautionary statements, see Section 7 . 1.11 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 Users of this practice must determine for themselves whether the practices described meet the requirements of local or national authorities regulating asbestos or other fibrous hazards. 5.2 Variations of this practice have been described by the Asbestos Research Council in Great Britain ( 8 ) , the Asbestos International Association (AIA) RTM 1 ( 9 ) , NIOSH 7400, OSHA ID 160, and ISO 8672. Where the counting rules of the latter three methods differ, this is noted in the text. 5.3 Advantages: 5.3.1 The technique is specific for fibers. PCM is a fiber counting technique that excludes non-fibrous particles from the analysis. 5.3.2 The technique is inexpensive, but requires specialized knowledge to carry out the analysis for total fiber counts, at least in so far as the analyst is often required under regulations to have taken a specific training course (for example, NIOSH 582, or equivalent). 5.3.3 The analysis is quick and can be performed on-site for rapid determination of the concentrations of airborne fibers. 5.4 Limitations: 5.4.1 The main limitation of PCM is that fibers are not identified. All fibers within the specified dimensional range are counted. Differential fiber counting may sometimes be used to discriminate between asbestos fibers and fibers of obviously different morphology, such as cellulose and glass fiber. In most situations, differential fiber counting cannot be used to adequately differentiate asbestos from non-asbestos fibers for purposes of compliance with regulations without additional positive identification. If positive identification of asbestos is required, this must be performed by polarized light or electron microscopy techniques, using a different portion of the filter. 5.4.2 A further limitation is that the smallest fibers visible by PCM are about 0.2 μm in diameter, while the finest asbestos fibers may be as small as 0.02 μm in diameter. 5.4.3 Where calculation of fiber concentration provides a result exceeding the regulatory standard, non-compliance is assumed unless it can be proven that the fibers counted do not belong to a member or members of the group of fibers regulated by that standard.