ASTM C518-17由美国材料与试验协会 US-ASTM 发布于 2017。
ASTM C518-17 在中国标准分类中归属于: P31 建筑物理,在国际标准分类中归属于: 91.120.10 建筑物绝热。
ASTM C518-17 采用热流计仪器法测定稳态热传递特性的标准试验方法的最新版本是哪一版?
最新版本是 ASTM C518-21 。
4.1 This test method provides a rapid means of determining the steady-state thermal transmission properties of thermal insulations and other materials with a high level of accuracy when the apparatus has been calibrated appropriately.
4.2 Proper calibration of the heat flow meter apparatus requires that it be calibrated using specimen(s) having thermal transmission properties determined previously by Test Methods C177, or C1114.
Note 1: Calibration of the apparatus typically requires specimens that are similar to the types of materials, thermal conductances, thicknesses, mean temperatures, and temperature gradients as expected for the test specimens.
4.3 The thermal transmission properties of specimens of a given material or product may vary due to variability of the composition of the material; be affected by moisture or other conditions; change with time; change with mean temperature and temperature difference; and depend upon the prior thermal history. It must be recognized, therefore, that the selection of typical values of thermal transmission properties representative of a material in a particular application should be based on a consideration of these factors and will not apply necessarily without modification to all service conditions.
4.3.1 As an example, this test method provides that the thermal properties shall be obtained on specimens that do not contain any free moisture although in service such conditions may not be realized. Even more basic is the dependence of the thermal properties on variables, such as mean temperature and temperature difference. These dependencies should be measured or the test made at conditions typical of use.
4.4 Special care shall be taken in the measurement procedure for specimens exhibiting appreciable inhomogeneities, anisotropies, rigidity, or especially high or low resistance to heat flow (see Practice C1045). The use of a heat flow meter apparatus when there are thermal bridges present in the specimen may yield very unreliable results. If the thermal bridge is present and parallel to the heat flow the results obtained may well have no meaning. Special considerations also are necessary when the measurements are conducted at either high or low temperatures, in ambient pressures above or below atmospheric pressure, or in special ambient gases that are inert or hazardous.
4.5 The determination of the accuracy of the method for any given test is a function of the apparatus design, of the related instrumentation, and of the type of specimens under test (see Section 10), but this test method is capable of determining thermal transmission properties within ± 28201;% of those determined by Test Method C177 when the ambient temperature is near the mean temperature of the test (T (ambient) = T (mean) ± 1°C), and in the range of 10 to 40°C. In
本仪器参考标准:GB/T10295-88 (绝热材料稳态热阻及有关特性的测定 热流计法)及ASTM C518-04用热流计法测定稳态热通量和热传递特性的试验方法。...
参考标准:GB/T10295-2008(热材料稳态热阻及有关特性的测定热流计法)及ASTM C518-04用热流计法测定稳态热通量和热传递特性的试验方法。 二、主要技术参数: 1、导热系数范围与精度: 0.00001~3W/mk,可测量可至0.1mw/mk。 0.001~300W/mk2、测量精度:1%。...
该仪器参考标准:ASTM C518-04用热流计法测定稳态热通量和热传递特性的试验方法;GB/T10295-88绝热材料稳态热阻及有关特性的测定(热流计法)。(1)主要技术参数1、导热系数范围:0.002-2W/MK,精确度小于5%,2、热面温度:采用高数度数显表测温,0.2级精度,分辩率0.01℃。3、冷面温度:采用高数度数显表测温,0.2级精度,分辩率 0.01℃。...
两类方法的各种形式都各有特点和适用条件,不同材料根据自身的特性和使用条件,可选用不同的方法测定。根据稳态导热原理建立起来的方法,在国内外已很成熟。80年代末,我国已参照国际标准制定了一系列国家标准。防护热板法及圆球法导热系数测定仪也正式投入生产。...
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