4.1 As determined by this test method, the pipe insulation lineal thermal resistance or conductance (and, when applicable, the thermal resistivity or conductivity) are means of comparing insulations which include the effects of the insulation and its fit upon the pipe, circumferential and longitudinal jointing, and variations in construction, but do not include the effects of the outer surface resistance or heat transfer coefficient. They are thus appropriate when the insulation outer-surface temperature and the pipe temperature are known or specified. However, since the thermal properties determined by this test method include the effects of fit and jointing, they are not true material properties. Therefore, properties determined by this test method are somewhat different from those obtained on apparently similar material in flat form using the guarded hot plate, Test Method C177, or the heat flow meter apparatus, Test Method C518.
4.2 The pipe insulation lineal thermal transference incorporates both the effect of the insulation and its fit upon the pipe and also the effect of the surface heat-transfer coefficient. It is appropriate when the ambient conditions and the pipe temperature are known or specified and the thermal effects of the surface are to be included.
4.3 Because of the test condition requirements prescribed in this test method, recognize that the thermal transfer properties obtained will not necessarily be the value pertaining under all service conditions. As an example, this test method provides that the thermal properties shall be obtained by tests on dry or conditioned specimens, while such conditions are not necessarily realized in service. The results obtained are strictly applicable only for the conditions of test and for the product construction tested, and must not be applied without proper adjustment when the material is used at other conditions, such as mean temperatures that differ appreciably from those of the test. With these qualifications in mind, the following apply:
4.3.1 For horizontal or vertical pipes of the same size and temperature, operating in the same ambient environment, values obtained by this test method can be used for the direct comparison of several specimens, for comparison to specification values, and for engineering data for estimating heat loss of actual applications of specimens identical to those tested (including any jackets or surface treatments). When appropriate, correct for the effect of end joints and other recurring irregularities (4.4).
4.3.2 When applying the results to insulation sizes different from those used in the test, an appropriate mathematical analysis is required. For homogeneous materials, this consists of the use of the thermal conductivity or resistivity values (corrected for any changes in mean temperature) plus the use of the surface heat transfer coefficient when the ambient temperature is considered (for example, see Practice C680). For nonhomogeneous and reflective insulation materials, a more detailed mathematical model is required which properly accounts for the individual modes of heat transfer (conduction, convection, radiation) and the variation of each mode with changing pipe size, insulation thickness, and temperature.
在公安部《消防员普通防护服﹑隔热服性能要求和试验方法》行业标准中, 制订了防护服抗辐射热渗透性能试验方法。研制了织物热辐射性能测试仪和织物热传导性能测试仪 ,用于热防护性能的测试和评价。...
关于测试的样品不能够太大,应当避免它因为被挤压在试验箱的流通管道中,使其气流在堵塞的管道中无法增加其气流,且在后面而造成试验结果的误差性,从而导致其被测试样品与其周围的环境条件从而产生其不符合的传导性能。...
2、隔热板为两体式,固定隔热板垂直安装在机座上,中间开有一孔,孔边上有滑槽,滑槽内装有活动隔热板,活动隔热板在计算机控制的传动机构的带动下,可沿滑槽滑动,开启或关闭固定隔热板的中心孔,固定隔热板和活动隔热板均为多层材料复合而成,中间有一层冷却水管道。3、其主要性能指标达到国外同类产品水平,填补了国内空白,仪器造价仅为国外同类产品五分之一 。...
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