1.1 这些试验方法包括按一般要求的准确度测定木材和木基材料的密度和比重（相对密度），以及不同尺寸、形状和含水量条件的试样。方法标题表示使用的程序或特定使用区域。 部分 测验 方法 A卷 通过 测量 7. 测验 方法 B-体积 通过 水 浸没 8. 测验 方法 C-浮选 管 9 测验 方法 D-Forstner公司 一点 10 测验 方法 E-增量 果心 11 测验 方法 F芯片 12 1.2 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和健康实践，并确定监管限制的适用性。 ====意义和用途====== 5.1 密度和比重是帮助定义木材和木质产品许多有用特性的基础术语。这些术语指定了具有不同定义的概念，尽管它们与相同的特性（单位体积中的质量）有关。通常，在美国和加拿大，木材密度是根据 比重 或 相对密度 . 在树林里- 基于复合材料行业和国际上的术语密度通常是首选。 5.2 这个 基本密度 和 基本比重 木材在林业中用于计算各种木材品种的已知木材体积中所含木材纤维的烘干重量。因此，它可以作为可以生产的木浆量、材料的可加工性或其运输重量的指标。这些信息在各种资源中都有引用，包括《木材手册》。 5. 请注意，比重在树内、树之间和物种之间都会发生变化。由于所有物种的木材细胞壁物质的比重实际上是恒定的（约为1。 53），很明显，单个比重值指示存在的木材细胞壁物质的数量。它为选择特定用途的木材提供了一种快速而有价值的方法。在美国和加拿大建筑规范中 烘干比重 与木制品的各种强度特性相关（例如，垂直于纹理的压缩、剪切强度和紧固件保持能力）。 5.3 通常需要知道活树的密度或比重、已就位的结构构件、原木横截面、研究元素的一段或早材或晚材层。 因此，试样的形状可能是大的或小的，规则的或不规则的，含水量也可能不同。这些试验方法给出了包括所有这些变量的程序，并提供了按通常需要的精度计算密度和比重值的方法。 5.4 在木基复合材料行业，产品密度或比重也提供了潜在产品属性的重要指标。对于木质材料，使用相同的试验方法；然而，测量通常将木材物质的质量与材料中存在的任何树脂、蜡或其他固体添加剂结合起来。 这些属性不能混淆 当量比重 用于表征其紧固件承载能力的结构复合木材的 D5456 .

1.1 These test methods cover the determination of the density and specific gravity (relative density) of wood and wood-based materials to generally desired degrees of accuracy and for specimens of different sizes, shapes, and moisture content conditions. The method title is indicative of the procedures used or the specific area of use. Section Test Method A—Volume by Measurement 7 Test Method B—Volume by Water Immersion 8 Test Method C—Flotation Tube 9 Test Method D—Forstner Bit 10 Test Method E—Increment Core 11 Test Method F—Chips 12 1.2 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 5.1 Density and specific gravity are cornerstone terms that help define many useful properties of wood and wood-based products. These terms designate concepts that have distinct definitions though they relate to the same characteristic (mass in a unit volume). Generally, in the US and Canada, density of wood is measured in terms of specific gravity , or relative density . In the wood-based composites industry and internationally the term density is often preferred. 5.2 The basic density and basic specific gravity of wood are used in the forestry industry for calculating the oven-dry weight of wood fiber contained in a known wood volume of various wood species. Thus, it serves as an indicator of the amount of wood pulp that could be produced, the workability of the material or its shipping weight. This information is referenced in various resources, including Wood Handbook. 5 Note that specific gravity varies within a tree, between trees, and between species. Since the specific gravity of wood cell wall substance is practically constant for all species (approximately 1.53), it is apparent that individual specific gravity value is indicative of the amount of wood cell wall substance present. It affords a rapid and valuable method for selection of wood for specific uses. In US and Canadian building codes, the oven-dry specific gravity is correlated to various strength characteristics of wood products (e.g., compression perpendicular to grain, shear strength and fastener holding capacity). 5.3 It is often desirable to know the density or specific gravity of a living tree, a structural member already in place, a log cross section, a segment of a research element, or the earlywood or latewood layer. Therefore, it is possible that specimens will be large or small, regular or irregular in shape, and at a variety of moisture contents. These test methods give procedures that include all of these variables and provides for calculation of density and specific gravity values to degrees of precision generally needed. 5.4 In the wood-based composites industry, the product density or specific gravity also provides an important indicator of potential product attributes. For wood-based materials, the same test methods are used; however, the measurements typically combine the mass from the wood substance with any resin, wax, or other solid additives present in the material. These properties are not to be confused with equivalent specific gravity of structural composite lumber used to characterize its fastener-holding capacity determined in accordance with D5456 .