Question

Summarize the following info. Write them in your own words. Make it clear so I can read it. Break them into different key points.

5. Significance and Use 5.1 A need exists for accurate data on heat transfer through insulated structures at representative test conditions. The data are needed to judge compliance with specifications and regulations, for design guidance, for research evaluations of the effect of changes in materials or constructions, and for verifi- cation of, or use in, simulation models. Other ASTM standards such as Test Methods C177 and C518 provide data on homogeneous specimens bounded by temperature controlled flat impervious plates. The hot box test method is more suitable for providing such data for large building elements, usually of a built-up or composite nature, which are exposed to temperature-controlled air on both sides. 5.2 For the results to be representative of a building construction, only representative sections shall be tested. The test specimen shall duplicate the framing geometry, material composition and installation practice, and orientation of con- struction (see Section 7). 5.3 This test method does not establish test conditions, specimen configuration, or data acquisition details but leaves these choices to be made in a manner consistent with the specific application being considered. Data obtained by the use of this test method is representative of the specimen perfor- mance only for the conditions of the test. It is unlikely that the test conditions will exactly duplicate in-use conditions and the user of the test results must be cautioned of possible significant differences. For example, in some specimens, especially those containing empty cavities or cavities open to one surface, the overall resistance or transmittance will depend upon the temperature difference across the test specimen due to internal convection. 5.4 Detailed heat flow analysis shall precede the use of the hot box apparatus for large, complex structures. A structure that contains cavity spaces between adjacent surfaces, for example, an attic section including a ceiling with sloping roof, may be difficult to test properly. Consideration must be given to the effects of specimen size, natural air movement, ventilation effects, radiative effects, and baffles at the guard/meter inter- face when designing the test specimen. 5.5 For vertical specimens with air spaces that significantly affect thermal performance, the metering chamber dimension shall match the effective construction height. If this is not possible, horizontal convection barriers shall be installed inside the specimen air cavities at the metering chamber boundaries to prevent air exchange between the metering and guarding areas. The operator shall note in the report any use of convection barriers. The report shall contain a warning stating that the use of the barriers might modify the heat transfer through the system causing significant errors. For ceiling tests with low density insulations, the minimum lateral dimension of the specimen shall be at least several times the dimension of the expected convection cells. 5.6 Since this test method is used to determine the total heat flow through the test area demarcated by the metering box, it is possible to determine the heat flow through a building element smaller than the test area, such as a window or representative area of a panel unit, if the parallel heat flow through the remaining surrounding area is independently determined. See Annex A8 for the general method. 5.7 Discussion of all special conditions used during the test shall be included in the test report (see Section

Answer 1

Heat transfer through insulated structures at representative test conditions: The data required for testing and verification of the of the effect of changes in materials or constructions can be acquired by various methods:

1. ASTM standards such as Test Methods C177 and C518 provide data on homogeneous specimens bounded by temperature controlled flat impervious plates.
2. The hot box test method is more suitable for providing data for large building elements, usually of a built-up or composite nature, which are exposed to temperature-controlled air on both sides

Data obtained by the use of this test method is representative of the specimen performance only for the conditions of the test.

Important for large complex structure: Detailed heat flow analysis shall precede the use of the hot box apparatus.

• Consideration must be given to the effects of specimen size, natural air movement, ventilation effects,radiative effect
• For vertical specimens with air spaces that significantly affect thermal performance, the metering chamber dimension shall match the effective construction height. and  operator shall note in the report any use of convection barriers.
• For ceiling tests with low density insulation the minimum lateral dimension of the specimen shall be at least several times the dimension of the expected convection cells.