GB/T 13475-2008 in English

《GB/T 13475-2008绝热 稳态传热性质的测定 标定和防护热箱法》由TC191（全国绝热材料标准化技术委员会）归口，主管部门为中国建筑材料联合会。
本标准等同采用ISO 8990:1994(E)《绝热―稳态传热性质的测定―标定和防护热箱法》。本标准代替GB/T 13475-1992《建筑构件稳态热传递性质的测定　标定和防护热箱法》。本标准规定了装置的设计原理及测定建筑构件和工业用的类似构件的试验室稳态传热性质应满足的最低要求。由于各种要求的变化（尤其是尺寸方面），因此不能限定一个特殊设计的装置和将操作条件规定在较小的范围。本标准给出了装置，测量技术和必需报告的数据的描述。本标准不适用于测定特殊构件，如窗，此时需要附加程序，本标准不包括这些程序。本标准适用于在试验室测量大尺寸的非均质的试件。也适用于测定均质试件，这是进行标定和验证所必需的。本标准不适用于试验过程中有穿过试件的传质现象的测量。本标准与GB/T 13475-1992相比主要变化如下：
―――标准题目做了文字修改；
―――第2章规范性引用文件做了修改；
―――增加了局限性和误差源的相关规定（见1.6）；
―――增加了装置设计要求的相关规定（见第2章）；
―――增加了设备表面温度的相关规定（见第2章）；
―――平衡热电堆的输出功率、加热器及风扇等的输入功率的测量准确度做了修订（1992年版本的5.7；本版本的2.8）；
―――装置性能评价和标定的相关规定做了修订和补充（见2.9）；
―――修订了试件状态调节的相关规定（1992年版本的6.1；本版本的3.2）；
―――删除了原标准中的附录Ｂ、附录Ｃ 和附录Ｄ（见１９９２年版本的附录Ｂ、附录Ｃ 和附录Ｄ）；
―――增加了附录Ｂ参考文献；
―――增加了附录ＮＡ。

1 General

1.1 Scope

This standard specifies the principles for the design of the apparatus and minimum requirement that shall be met for determination of the laboratory steady-state thermal transmission properties of building components and similar components for industrial use. It does not, however, specify a particular design since requirements vary, particularly in terms of size, and also to a lesser extent in terms of operating conditions.

This standard describes also the apparatus, measurement technique and necessary data reporting.

Special components, for example windows, need additional procedures which are not included in this standard.

Also excluded are measurements of the effect on heat flow of moisture transfer or redistribution but consideration shall be given in the design and operation of the equipment as to the possible effect of moisture transfer on the accuracy and the relevance of test results.

The properties which can be measured are thermal transmittance and thermal resistance. Two alternative methods are included: the calibrated hot box method and the guarded hot box method. Both are suitable for vertical specimens such as walls and for horizontal specimens such as ceilings and floors. The apparatus can be sufficiently large to study full-scale components.

The methods are primarily intended for laboratory measurements of large, inhomogeneous specimens, although homogeneous specimens can, of course, also be tested, and these are necessary for calibration and validation.

When testing homogeneous specimens in accordance with this standard, experience has shown that an accuracy within ±5% can generally be achieved. However, the accuracy of each individual apparatus shall be estimated with reference homogeneous specimens of thermal conductance extending over the range to be measured using the apparatus. The estimation of accuracy for nonhomogeneous specimens will be more complex and involve an analysis of the heat flow mechanism in the particular types of inhomogeneous specimens being tested. Such analyses are not covered by this standard.

This standard does not provide for measurements where there is mass transfer through the specimen during the test.

1.2 Normative References

The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.

ISO 7345:1987 Thermal Insulation — Physical Quantities and Definitions

1.3 Terms and Definitions

For the purposes of this document, the terms and definitions given in ISO 7345:1987 and the following apply.

1.3.1
mean radiant temperature
appropriate weighting of the temperatures of surfaces "seen" by the specimen for the purpose of determining the radiant heat flow rate to the surface of the specimen (see annex A)

1.3.2
environmental temperature
appropriate weighting of air and radiant temperatures, for the purpose of determining the heat flow rate to the surface of the specimen (see annex A)

1.4 Symbols and units

The following symbols and units are used in this standard:

i Interior, usually hot side

e Exterior, usually cold side

s Surface

n Environmental

Foreword II
ISO Foreword IV
Introduction V
1 General
1.1 Scope
1.2 Normative References
1.3 Terms and Definitions
1.4 Symbols and units
1.5 Principle
1.6 Limitations and sources of errors
2 Apparatus
2.1 Introduction
2.2 Design requirements
2.3 Metering box
2.4 Guard box
2.5 Specimen frame
2.6 Cold side chamber
2.7 Temperature measurements
2.8 Instrumentation
2.9 Performance evaluation and calibration
3 Test Procedure
3.1 Introduction
3.2 Conditioning of specimen
3.3 Specimen selection and mounting
3.4 Test conditions
3.5 Measurement periods
3.6 Calculation
3.7 Test report
Annex A (Normative) Heat transfer at Surfaces and Environmental Temperatures
Annex B (Informative) Bibliography
Annex NA (Informative) Additional Remark