1.1 本指南为使用小型环境试验箱测量室内材料和产品的挥发性有机化合物（VOCs）排放提供了指导。 1.2 本指南适用于完全封闭待测材料样品的腔室，不涉及其他发射腔室设计，如发射单元（参见实践 D7143 ). 1.3 作为ASTM标准，本指南描述了选项，但不推荐具体的行动方案。本指南不是标准测试方法，也不应如此解释。 1.4 使用小型环境试验箱来表征室内材料和产品中VOCs的排放仍在不断发展。随着该领域工作的进展，设备、测试程序和数据分析都会进行修改和变化。对于几种室内材料，现在已经制定了更详细的ASTM排放测试标准。如果存在更详细的ASTM标准实践或方法，它们将取代本指南，并应在其位置使用。在相关方就标准测试方案达成一致之前，方法上的差异将会出现。本指南将继续通过描述适用于测定室内材料有机排放的设备和技术来提供帮助。提供具体示例以说明现有方法；这些实施例并不旨在抑制将产生等同或更好结果的替代方法或技术。 1.5 小腔室有明显的局限性。通常，仅测试较大材料（例如地毯）的样品。小室不适用于测试完整的组件（例如家具）。小腔室也不适用于测试燃烧装置（例如煤油加热器）或活动（例如气溶胶喷雾产品的使用）。对于一些产品，小室测试可能仅提供感兴趣的发射曲线的一部分。例如，通过刷涂、喷涂、滚动等方式施加高溶剂材料(例如，油漆和蜡)的排放速率通常高于干燥过程期间的速率。小室测试不能用于评估涂层工艺的应用阶段。大型（或全尺寸）腔室可能更适合这些应用中的许多。有关室内材料排放物全尺寸室内试验的指导，请参阅实施规程 D6670 . 1.6 本指南没有为采样介质的选择或挥发性有机化合物的分析提供具体指导。这些信息是在实践中提供的 D6196 . 1.7 本指南没有提供确定复合木制品甲醛释放量的具体指导，因为此类释放量的室内测试方法已得到很好的开发和广泛使用。有关更多信息，请参阅测试方法 E1333 和 D6007 然而，该指南可以用于支持替代测试方法。 1.8 本指南不适用于测定材料/产品中半挥发性有机化合物（SVOCs）的排放，主要是由于这些化合物吸附在通常用于建造适用于VOC排放测试的试验箱的材料上。SVOC需要替代程序。例如，可以使用在高于正常室内条件的温度下操作的微型室来筛选材料的SVOCs排放（参见实践 D7706 ). 1.9 本指南适用于测定可能在室内使用的产品和材料的排放。排放的影响（例如毒性）没有得到解决，超出了指南的范围。指南 D6485 提供了一个评估给定材料VOC排放的急性和刺激影响的示例。关注的“目标”有机物质的规格同样超出了本指南的范围。随着特定室内污染物指南水平的发展，提供相关信息的排放测试协议也将发展。排放数据库和材料标签计划也将进行调整，以反映当前的知识状况。 1.10 与单个测试样本的获取、处理、调节、制备和测试相关的细节可能因特定研究目标而异。此处提供了排放测试这些方面的指南，未强制要求具体方向。本指南的目的是提高用户对通过小室测试评估室内材料/产品有机排放的可用技术的认识，确定必须控制和记录的排放测试的基本方面，从而提供可能导致进一步评估和标准化的信息。 1.11 在本节讨论的限制范围内，本指南的目的是描述使用s确定室内材料/产品有机排放率的方法和程序商场环境试验箱。所描述的技术对于制造商和测试实验室的常规产品测试以及室内空气质量（IAQ）研究人员的更严格评估都是有用的。 附录X1 提供广泛用于测量建筑物内部使用的材料和产品的挥发性有机化合物排放的标准参考。其中一些标准直接引用了本指南。 1.12 以SI单位表示的值将被视为标准值。本标准不包括其他计量单位。 1.13 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。1.14 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》中确立的国际公认的标准化原则制定的。 ======意义和用途====== 4.1 目标- 使用小室评估室内材料的VOC排放有几个目标: 4.1.1 开发VOC排放产品筛选技术； 4.1.2 确定环境变量（即温度、湿度、空气速度和空气变化率）对排放率的影响； 4.1.3 根据各种产品和产品类型的排放概况（例如，排放系数、排放的特定有机化合物）对其进行排名；4.1.4 提供关于各种有机来源的化合物特定数据，以指导实地研究并协助评估建筑物的室内空气质量； 4.1.5 为开发和验证用于预测室内有机化合物浓度的模型提供排放数据；和 4.1.6 开发对利益相关者和其他相关方有用的数据，用于评估产品排放和开发控制选项或改进产品。 4.2 传质考虑因素- 室内材料排放的小室评估需要考虑相关的传质过程。三个基本过程控制着室内材料有机蒸汽的排放率；从材料表面到上覆空气的蒸发传质、吸附化合物的解吸以及在材料内的扩散。关于发射传质理论的更详细的讨论可以在指南中找到 D8141 . 4.2.1 给定VOC从材料表面到上覆空气的蒸发传质可以表示为: 其中: 他 = 排放速率，mg/h， 一个 = 源区，m 2 , k 米 = 传质系数，m/h， 副总裁 s = 材料表面的蒸汽压，Pa， 副总裁 一个 = 地表上方空气中的蒸气压，Pa， MW = 分子量，mg/mol， R = 气体常数，8.314 J/mol-K或Pa m 3 /mol-K，和 T = 温度，K。 因此，排放速率与表面和上覆空气之间的蒸汽压差成比例。由于蒸气压与浓度直接相关，发射率与地表和上覆空气之间的浓度差成正比。传质系数是特定感兴趣化合物的扩散系数(在空气中)和整体流中湍流水平的函数。 4.2.2 吸附在材料上的化合物的解吸速率可以通过吸附分子的保留时间（或平均停留时间）来确定: 其中: T = 保留时间，s， T o = 常量，典型值为10 −12 s至10 −15 s，和 Q = 吸附的摩尔焓变化（或吸附能），J/mol。 保留时间越大，解吸速率越慢。 4.2.3 材料内的扩散传质是特定化合物的扩散系数(或扩散系数)的函数。给定化合物在给定材料内的扩散系数是该化合物的物理和化学性质(例如分子量、尺寸和极性)、温度和其中发生扩散的材料的结构的函数。混合物中单个化合物的扩散率也受混合物组成的影响。 4.2.4 影响传质的变量- 虽然传质理论的详细讨论超出了本指南的范围，但有必要在小室测试的背景下检查影响传质的关键变量: 4.2.4.1 温度影响有机化合物的蒸气压、解吸速率和扩散系数。因此，温度影响来自表面的传质（无论是通过蒸发还是解吸）和材料内的扩散传质。由于所有三个传质过程，温度升高导致排放增加。 4.2.4.2 换气率表示室内环境中发生的稀释和冲洗量。换气率越高稀释越大，假设室外空气越干净，室内浓度越低。如果表面的浓度不变，空气中较低的浓度通过增加表面和上覆空气之间的浓度差来增加蒸发传质。 4.2.4.3 空气速度- 表面空气速度是蒸发控制源的关键参数，如传质系数（ k 米 ）受边界层空气侧的空气速度和湍流的影响。一般情况下，空气速度和湍流越高，传质系数越大。在实际意义上，对于大多数VOCs来说，在一定的空气速度和湍流以上，通过边界层的传质阻力最小（即传质系数达到最大值）。在室内测试中，一些研究人员更喜欢使用足够高的空气速度，以最小化表面的传质阻力。例如，0.3 m/s至0.5 m/s的空气速度已被用于评估来自木制品的甲醛排放。这种空气速度高于Matthews等人在正常住宅环境中观察到的空气速度， 4 在六所房子里，他们使用全向加热球形风速计测量了风速，平均值为0.07米/秒，中值为0.05米/秒。因此，其他研究人员更喜欢将空气速度保持在室内通常发现的范围内。在任何一种情况下，在解释小室排放数据时，都需要了解空气速度对排放率的影响。 4.3 影响排放的其他因素- 室内材料和产品排放的大多数有机化合物是非反应性的，并且腔室被设计成减少或消除腔室表面上的反应和吸附（参见 5.3.1 ).然而，在一些情况下，可以发生表面吸附。一些相对高分子量、高沸点的化合物沉积在表面后可以发生反应（即与臭氧）。在这种情况下，腔室壁上的同时降解和积聚以及从腔室壁上的最终再发射会影响最终腔室浓度和发射分布的时间历史。除非这些因素得到适当考虑，否则将计算出不正确的排放率值（见 9.4 ).腔室吸附和反应效应的大小可以通过质量平衡计算来评估（见 9.5 ). 4.4 结果的使用- 需要强调的是，小室评估用于确定源排放率。然后在IAQ模型中使用这些速率来预测从测试材料中排放的化合物的室内浓度。可能需要咨询IAQ建模者，以确保小室测试制度与IAQ模型假设一致。在室内观察到的浓度不应用于替代在全尺寸室内环境中预期的浓度。

1.1 This guide provides direction on the measurement of the emissions of volatile organic compounds (VOCs) from indoor materials and products using small-scale environmental test chambers. 1.2 This guide pertains to chambers that fully enclose a material specimen to be tested and does not address other emission chamber designs such as emission cells (see instead Practice D7143 ). 1.3 As an ASTM standard, this guide describes options, but does not recommend specific courses of action. This guide is not a standard test method and must not be construed as such. 1.4 The use of small environmental test chambers to characterize the emissions of VOCs from indoor materials and products is still evolving. Modifications and variations in equipment, testing procedures, and data analysis are made as the work in the area progresses. For several indoor materials, more detailed ASTM standards for emissions testing have now been developed. Where more detailed ASTM standard practices or methods exist, they supersede this guide and should be used in its place. Until the interested parties agree upon standard testing protocols, differences in approach will occur. This guide will continue to provide assistance by describing equipment and techniques suitable for determining organic emissions from indoor materials. Specific examples are provided to illustrate existing approaches; these examples are not intended to inhibit alternative approaches or techniques that will produce equivalent or superior results. 1.5 Small chambers have obvious limitations. Normally, only samples of larger materials (for example, carpet) are tested. Small chambers are not applicable for testing complete assemblages (for example, furniture). Small chambers are also inappropriate for testing combustion devices (for example, kerosene heaters) or activities (for example, use of aerosol spray products). For some products, small chamber testing may provide only a portion of the emission profile of interest. For example, the rate of emissions from the application of high solvent materials (for example, paints and waxes) by means of brushing, spraying, rolling, etc. are generally higher than the rate during the drying process. Small chamber testing cannot be used to evaluate the application phase of the coating process. Large (or full-scale) chambers may be more appropriate for many of these applications. For guidance on full-scale chamber testing of emissions from indoor materials refer to Practice D6670 . 1.6 This guide does not provide specific directions for the selection of sampling media or for the analysis of VOCs. This information is provided in Practice D6196 . 1.7 This guide does not provide specific directions for determining emissions of formaldehyde from composite wood products, since chamber testing methods for such emissions are well developed and widely used. For more information refer to Test Methods E1333 and D6007 . It is possible, however, that the guide can be used to support alternative testing methods. 1.8 This guide is not applicable to the determination of emissions of semi-volatile organic compounds (SVOCs) from materials/products largely due to adsorption of these compounds on materials commonly used for construction of chambers suitable for VOC emissions testing. Alternate procedures are required for SVOCs. For example, it may be possible to screen materials for emissions of SVOCs using micro-scale chambers operated at temperatures above normal indoor conditions (see Practice D7706 ). 1.9 This guide is applicable to the determination of emissions from products and materials that may be used indoors. The effects of the emissions (for example, toxicity) are not addressed and are beyond the scope of the guide. Guide D6485 provides an example of the assessment of acute and irritant effects of VOC emissions for a given material. Specification of “target” organic species of concern is similarly beyond the scope of this guide. As guideline levels for specific indoor contaminants develop, so too will emission test protocols to provide relevant information. Emissions databases and material labeling schemes will also be expected to adjust to reflect the current state of knowledge. 1.10 Specifics related to the acquisition, handling, conditioning, preparation, and testing of individual test specimens may vary depending on particular study objectives. Guidelines for these aspects of emissions testing are provided here, specific direction is not mandated. The purpose of this guide is to increase the awareness of the user to available techniques for evaluating organic emissions from indoor materials/products by means of small chamber testing, to identify the essential aspects of emissions testing that must be controlled and documented, and therefore to provide information, which may lead to further evaluation and standardization. 1.11 Within the context of the limitations discussed in this section, the purpose of this guide is to describe the methods and procedures for determining organic emission rates from indoor materials/products using small environmental test chambers. The techniques described are useful for both routine product testing by manufacturers and testing laboratories and for more rigorous evaluation by indoor air quality (IAQ) researchers. Appendix X1 provides references to standards that are widely employed to measure emissions of VOCs from materials and products used in the interiors of buildings. Some of these standards directly reference this guide. 1.12 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.13 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. 1.14 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 ====== 4.1 Objectives— The use of small chambers to evaluate VOC emissions from indoor materials has several objectives: 4.1.1 Develop techniques for screening of products for VOC emissions; 4.1.2 Determine the effect of environmental variables (that is, temperature, humidity, air speed, and air change rate) on emission rates; 4.1.3 Rank various products and product types with respect to their emissions profiles (for example, emission factors, specific organic compounds emitted); 4.1.4 Provide compound-specific data on various organic sources to guide field studies and assist in evaluating indoor air quality in buildings; 4.1.5 Provide emissions data for the development and verification of models used to predict indoor concentrations of organic compounds; and 4.1.6 Develop data useful to stakeholders and other interested parties for assessing product emissions and developing control options or improved products. 4.2 Mass Transfer Considerations— Small chamber evaluation of emissions from indoor materials requires consideration of the relevant mass transfer processes. Three fundamental processes control the rate of emissions of organic vapors from indoor materials; evaporative mass transfer from the surface of the material to the overlying air, desorption of adsorbed compounds, and diffusion within the material. A more detailed discussion of emission mass transfer theory can be found in Guide D8141 . 4.2.1 The evaporative mass transfer of a given VOC from the surface of the material to the overlying air can be expressed as: where: ER = emission rate, mg/h, A = source area, m 2 , k m = mass transfer coefficient, m/h, VP s = vapor pressure at the surface of the material, Pa, VP a = vapor pressure in the air above the surface, Pa, MW = molecular weight, mg/mol, R = gas constant, 8.314 J/mol-K or Pa m 3 /mol-K, and T = temperature, K. Thus, the emission rate is proportional to the difference in vapor pressure between the surface and the overlying air. Since the vapor pressure is directly related to the concentration, the emission rate is proportional to the difference in concentration between the surface and the overlying air. The mass transfer coefficient is a function of the diffusion coefficient (in air) for the specific compound of interest and the level of turbulence in the bulk flow. 4.2.2 The desorption rate of compounds adsorbed on materials can be determined by the retention time (or average residence time) of an adsorbed molecule: where: τ = retention time, s, τ o = constant with a typical value from 10 −12 s to 10 −15 s, and Q = molar enthalpy change for adsorption (or adsorption energy), J/mol. The larger the retention time, the slower the rate of desorption. 4.2.3 The diffusion mass transfer within the material is a function of the diffusion coefficient (or diffusivity) of the specific compound. The diffusion coefficient of a given compound within a given material is a function of the compound's physical and chemical properties (for example, molecular weight, size, and polarity), temperature, and the structure of the material within which the diffusion is occurring. The diffusivity of an individual compound in a mixture is also affected by the composition of the mixture. 4.2.4 Variables Affecting Mass Transfer— While a detailed discussion of mass transfer theory is beyond the scope of this guide, it is necessary to examine the critical variables affecting mass transfer within the context of small chamber testing: 4.2.4.1 Temperature affects the vapor pressure, desorption rate, and the diffusion coefficients of the organic compounds. Thus, temperature impacts both the mass transfer from the surface (whether by evaporation or desorption) and the diffusion mass transfer within the material. Increases in temperature cause increases in the emissions due to all three mass transfer processes. 4.2.4.2 The air change rate indicates the amount of dilution and flushing that occurs in indoor environments. The higher the air change rate the greater the dilution, and assuming the outdoor air is cleaner, the lower the indoor concentration. If the concentration at the surface is unchanged, a lower concentration in the air increases the evaporative mass transfer by increasing the difference in concentration between the surface and the overlying air. 4.2.4.3 Air Speed— Surface air speed is a critical parameter for evaporative-controlled sources as the mass transfer coefficient ( k m ) is affected by the air speed and turbulence at the air-side of the boundary layer. Generally, the higher the air speed and turbulence, the greater the mass transfer coefficient. In a practical sense for most VOCs, above a certain air speed and turbulence, the resistance to mass transfer through the boundary layer is minimized (that is, the mass transfer coefficient reaches its maximum value). In chamber testing, some investigators prefer to use air speeds high enough to minimize the mass transfer resistance at the surface. For example, air speeds of 0.3 m/s to 0.5 m/s have been used in evaluating formaldehyde emissions from wood products. Such air speeds are higher than those observed in normal residential environments by Matthews et al., 4 where in six houses they measured air speeds using an omni-directional heated sphere anemometer with a mean of 0.07 m/s and a median of 0.05 m/s. Thus, other investigators prefer to keep the air speeds in the range normally found indoors. In either case, an understanding of the effect of air speed on the emission rate is needed in interpreting small chamber emissions data. 4.3 Other Factors Affecting Emissions— Most organic compounds emitted from indoor materials and products are non-reactive, and chambers are designed to reduce or eliminate reactions and adsorption on the chamber surfaces (see 5.3.1 ). In some cases, however, surface adsorption can occur. Some relatively high molecular weight, high boiling compounds can react (that is, with ozone) after being deposited on the surface. In such cases, the simultaneous degradation and buildup on and the ultimate re-emission from the chamber walls can affect the final chamber concentration and the time history of the emission profile. Unless such factors are properly accounted for, incorrect values for the emission rates will be calculated (see 9.4 ). The magnitude of chamber adsorption and reaction effects can be evaluated by way of mass balance calculations (see 9.5 ). 4.4 Use of the Results— It is emphasized that small chamber evaluations are used to determine source emission rates. These rates are then used in IAQ models to predict indoor concentration of the compounds emitted from the tested material. Consultation with IAQ modelers may be required to ensure that the small chamber test regime is consistent with the IAQ model assumptions. The concentrations observed in the chambers themselves should not be used as a substitute for concentrations expected in full-scale indoor environments.