thermal aging test
the accurate estimation of the thermal performance of insulation products used in buildings over their expected lifetime has been a recognized challenge for over 25 years. this is because the lifetime of such products is long, is caused by the diffusion of a multitude of gases, and the insulation product is not homogeneous. the task of developing a
standard test method for predicting long term thermal performance which applies to a variety of closed-cell foam products is even more complicated as diffusion processes occur at rates that depend on the type of polymer, the cellular structure, the temperature, the gas type, and its pressure. both classical approaches to accelerating diffusion controlled phenomena, namely aging at higher temperature and aging a thin slice, present challenges especially if a single method is desired for a variety of cellular foam products such as polyisocyanurate （polyiso） and extruded polystyrene （xps）.
though europe has favored standard test methods based on aging at elevated temperature, slicing and scaling techniques have been the leading approach in north america. lay, two prescriptive test methods, astm c 1303 in the usa and can/ulc-s770 in canada have emerged in north america. both are based on accelerating the foam aging process by slicing the foam into thin specimens. both methods use the projected thermal conductivity at five years of age to represent the insulation s long term thermal resistance value （lttr）. the two methods have many other similarities, such as use of fickian law for one-dimensional diffusion to calculate aging period, and use of a thin slice from the core and surface areas of the foam. however, they do vary in precisely how the long term thermal resistance is calculated. the c
1303 test method prescribes that the thermal resistance value of a stack of thin slices after aging for a calculated time is the long term thermal resistance value. the s770 test method calls for multiplication of an aging factor to an initial thermal resistance value to determine the five-year value. though the basic frameworks of the two methods are in place, the precise parameters are still being debated and balloted.
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thermal aging test
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standard test method for predicting long term thermal performance which applies to a variety of closed-cell foam products is even more complicated as diffusion processes occur at rates that depend on the type of polymer, the cellular structure, the temperature, the gas type, and its pressure. both classical approaches to accelerating diffusion controlled phenomena, namely aging at higher temperature and aging a thin slice, present challenges especially if a single method is desired for a variety of cellular foam products such as polyisocyanurate （polyiso） and extruded polystyrene （xps）.
though europe has favored standard test methods based on aging at elevated temperature, slicing and scaling techniques have been the leading approach in north america. lay, two prescriptive test methods, astm c 1303 in the usa and can/ulc-s770 in canada have emerged in north america. both are based on accelerating the foam aging process by slicing the foam into thin specimens. both methods use the projected thermal conductivity at five years of age to represent the insulation s long term thermal resistance value （lttr）. the two methods have many other similarities, such as use of fickian law for one-dimensional diffusion to calculate aging period, and use of a thin slice from the core and surface areas of the foam. however, they do vary in precisely how the long term thermal resistance is calculated. the c
1303 test method prescribes that the thermal resistance value of a stack of thin slices after aging for a calculated time is the long term thermal resistance value. the s770 test method calls for multiplication of an aging factor to an initial thermal resistance value to determine the five-year value. though the basic frameworks of the two methods are in place, the precise parameters are still being debated and balloted.
more knowledge ,pls contact with
二手mvr蒸发器的如何正确安装调试
噪声监测系统定制方案，为城市噪声污染治理
雷蒙磨几天加一次黄油
MBR污泥膨胀的处理方法
金属线材反复弯曲试验机做薄带测试时如何取样
thermal aging test
中国食品机械设备网答疑解惑之粉碎设备
塑料污染迫在眉睫治理，“以竹代塑”成首要方向
工具磨床的正确操作方法你可知
HUDAC贺德克EDS继电器产品简介
AS-3B微量水分测定仪
STAUFF过滤器选择要点
大鼠白细胞介素6（IL-6）ELISA
2019岁首将至 中智鲸工祝全国人民元旦快乐
离心分离机的工作原理及其应用
DMEM、MEM、F12、1640培养基区别在哪里?
阿米控WESTINGHOUSE 5X00226G02
日处理35吨地埋式生活污水处理设备
油压机之驱动系统说明
安徽无机渗透板设备生产线厂家