1.1 本规程介绍了一种实验室程序，用于确定模拟稳态冬季条件下阁楼隔热系统的热阻。该做法仅适用于面向开放式阁楼空气空间的阁楼隔热系统。 1.2 隔热层的热阻是根据天花板系统的测量值计算得出的，天花板系统由与所研究系统一致的组件组成。例如，这样的系统可能由石膏板或胶合板天花板、木天花板托梁和阁楼隔热层组成，其顶部暴露在露天空间中。 施加在石膏板或胶合板上的温度应在18-24°C[64-75°F]的范围内。隔热层上方的空气温度应符合冬季条件，范围为-46°C至10°C【-51至50°F】。石膏板或胶合板天花板应密封，以防止系统的暖侧和冷侧之间的直接气流。 1.3 本规程适用于各种松散填充或毯子隔热产品，包括玻璃纤维、岩棉/矿渣棉或纤维素纤维材料；颗粒类型，包括蛭石和珍珠岩； 造粒产品；以及气动安装或浇注到位的任何其他绝缘材料。该实践考虑了对结构传热的影响，特别是天花板托梁、基底，例如石膏板、空气膜，以及可能的饰面、薄膜或与隔热层结合使用的其他材料。 1.4 本规程测量阁楼/天花板系统的热阻，其中隔热材料已根据材料规范进行了预处理 C549 ， C665 ， C739 和 C764 。 1.5 本标准中概述的试样制备技术不包括用于封闭应用的松散填充材料的特性。 1.6 本规程用于表征受控稳态实验室条件下的材料行为，旨在模拟实际使用温度条件。该做法不模拟强制气流条件。 1.7 以国际单位制或英寸磅单位表示的数值应单独视为标准。每个系统中规定的值可能不是完全相等的； 因此，每个系统应独立使用。将两个系统的值合并可能导致不符合标准。 1.7.1 除非客户另有规定，否则所有数值均应以国际单位制和英寸磅为单位进行报告。 1.8 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。 1.9 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====== 4.1 天花板系统的热阻用于表征其稳态热性能。 4.2 绝缘材料的热阻与绝缘材料的密度和厚度有关。 热阻的测试数据是在代表最终用途应用的厚度和密度下获得的。此外，由于系统结构和材料的原因，隔热系统的热阻将与单独隔热的热阻不同。 4.3 之所以需要这种做法，是因为一些可渗透阁楼隔热材料在冬季条件下的使用热阻不同、更低或更高 R ，而不是在模拟室温条件下或接近模拟室温条件时使用小规模测试测量的，在小规模测试中，绝缘材料夹在温差（ΔT）为20至30°C[36至54°F]的两块等温不渗透板之间。 当这种隔热材料安装在阁楼上，安装在由石膏板或胶合板等普通建筑材料组成的天花板上，敞开的顶面暴露在阁楼的空气空间中时，由于自然对流的额外传热，在热流上升和温差较大的冬季条件下的热阻明显较小。 图1 说明了小规模测试和在这种实践条件下的测试结果之间的差异。参见参考文献 ( 1- 12 ) 以讨论这一现象。 3. 图1 模拟冬季条件下可渗透阁楼隔热材料的热阻示意图（热流向上） 注1: 恒定的热侧温度( T ，hot），并且温差随着冷侧温度的升高而增加( T ，冷）减少。看见 5.1.6 空气空间大小的要求。 4.4 在正常使用中，绝缘产品的厚度范围为75 mm[3 In.]至500 mm[20 In.]。安装密度取决于产品类型、安装厚度、使用的安装设备、安装技术和绝缘空间的几何形状。 4.5 在冬季条件下，自然对流的开始是某些材料试样厚度的函数。就本规程而言，应在使用产品的厚度下进行试验。 4.6 由于这种做法模拟冬季条件，热流方向应垂直向上。 4.7 试样的制备方式应符合预期的安装程序。气动安装产品应采用气动方式（吹制），现场浇筑安装产品应浇筑到位。 看见 5.2 。

1.1 This practice presents a laboratory procedure to determine the thermal resistance of attic insulation systems under simulated steady-state winter conditions. The practice applies only to attic insulation systems that face an open attic air space. 1.2 The thermal resistance of the insulation is inferred from calculations based on measurements on a ceiling system consisting of components consistent with the system being studied. For example, such a system might consist of a gypsum board or plywood ceiling, wood ceiling joists, and attic insulation with its top exposed to an open air space. The temperature applied to the gypsum board or plywood shall be in the range of 18 to 24°C [64 to 75°F]. The air temperature above the insulation shall correspond to winter conditions and ranges from –46°C to 10°C [–51 to 50°F]. The gypsum board or plywood ceiling shall be sealed to prevent direct airflow between the warm and cold sides of the system. 1.3 This practice applies to a wide variety of loose-fill or blanket thermal insulation products including fibrous glass, rock/slag wool, or cellulosic fiber materials; granular types including vermiculite and perlite; pelletized products; and any other insulation material that is installed pneumatically or poured in place. The practice considers the effects on heat transfer of structures, specifically the ceiling joists, substrate, for example, gypsum board, air films, and possible facings, films, or other materials that are used in conjunction with the insulation. 1.4 This practice measures the thermal resistance of the attic/ceiling system in which the insulation material has been preconditioned according to the material Specifications C549 , C665 , C739 , and C764 . 1.5 The specimen preparation techniques outlined in this standard do not cover the characterization of loose-fill materials intended for enclosed applications. 1.6 This practice is be used to characterize material behavior under controlled steady-state laboratory conditions intended to simulate actual temperature conditions of use. The practice does not simulate forced air flow conditions. 1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.7.1 All values shall be reported in both SI and inch-pound units unless specified otherwise by the client. 1.8 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. 1.9 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 The thermal resistance of a ceiling system is used to characterize its steady-state thermal performance. 4.2 The thermal resistance of insulation is related to the density and thickness of the insulation. Test data on thermal resistance are obtained at a thickness and density representative of the end use applications. In addition, the thermal resistance of the insulation system will be different from that of the thermal insulation alone because of the system construction and materials. 4.3 This practice is needed because the in-service thermal resistance of some permeable attic insulations under winter conditions is different, lower or higher R , than that measured at or close to simulated room temperature conditions utilizing small-scale tests in which the insulation is sandwiched between two isothermal impermeable plates that have a temperature difference (ΔT) of 20 to 30°C [36 to 54°F]. When such insulation is installed in an attic, on top of a ceiling composed of normal building materials such as gypsum board or plywood, with an open top surface exposed to the attic air space, the thermal resistance under winter conditions with heat flow up and large temperature differences is significantly less because of additional heat transfer by natural convection. Fig. 1 illustrates the difference between results from small scale tests and tests under the conditions of this practice. See Ref ( 1- 12 ) for discussions of this phenomenon. 3 FIG. 1 Schematic of Thermal Resistance for a Permeable Attic Insulation Under Simulated Winter Conditions (Heat Flow Up) Note 1: A constant hot-side temperature ( T , hot) is used for both tests and the temperature difference increases as the cold side temperature ( T , cold) is decreased. See 5.1.6 for requirements on size of air space. 4.4 In normal use, the thickness of insulation products ranges from 75 mm [3 in.] to 500 mm [20 in.]. Installed densities will depend upon the product type, the installed thickness, the installation equipment used, the installation technique, and the geometry of the insulated space. 4.5 The onset of natural convection under winter conditions is a function of specimen thickness for some materials. For purposes of this practice, the tests shall be carried out at thicknesses at which the product is used. 4.6 Since this practice simulates winter conditions, the heat flow direction shall be vertically upwards. 4.7 Specimens shall be prepared in a manner consistent with the intended installation procedure. Products for pneumatic installation shall be pneumatically-applied (blown), and products for pour-in-place installation shall be poured into place. See 5.2 .