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适用范围：<p><span class="italic"><span class="italic">Objectives</span>8212;</span>The use of small chambers to evaluate organic emissions from indoor materials has several objectives:</p> <p>Develop techniques for screening of products for organic emissions;</p> <p>Determine the effect of environmental variables (that is, temperature, humidity, air exchange) on emission rates;</p> <p>Rank various products and product types with respect to their emissions profiles (for example, emission factors, specific organic compounds emitted);</p> <p>Provide compound-specific data on various organic sources to guide field studies and assist in evaluating indoor air quality in buildings;</p> <p>Provide emissions data for the development and verification of models used to predict indoor concentrations of organic compounds; and</p> <p>Develop data useful to manufacturers and builders for assessing product emissions and developing control options or improved products.</p> <p><span class="italic"><span class="italic">Mass Transfer Considerations</span>8212;</span>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. For more information, refer to Bird, Stewart, and Lightfoot (1960) and Bennett and Myers (1962) in X1.1.</p> <p>The evaporative mass transfer of a given organic compound from the surface of the material to the overlying air can be expressed as:<p id="s00164">1.1 This guide provides guidance on determination of emissions of organic compounds from indoor materials and products using small-scale environmental test chambers.</p> <p id="s00165">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 <a href="http://myastm.astm.org/SUBSCRIPTION/NewValidateSubscription.cgi?D7143-HTML">D7143</a>).</p> <p id="s00166">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.</p> <p id="s00002">1.4 The use of small environmental test chambers to characterize the organic emissions of 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.</p> <p id="s00003">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) via brushing, spraying, rolling, etc. are generally higher ......