GB/T 28638-2023Heat loss test for thermal insulation structure and evaluation methods for thermal insulation efficiency of district heating pipes (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document replaces GB/T 28638-2012 "Heat dissipation loss test and insulation effect assessment method for urban heating pipe insulation structures" and is consistent with Compared with GB/T 28638-2012, in addition to editorial changes, the main technical changes are as follows.

---Changed the scope of application (see Chapter 1, Chapter 1 of the 2012 edition);

--- Added terms and definitions for the comprehensive thermal resistance of pipeline insulation structures (see 3.1);

---Added test methods for pipes laid in pipe galleries and tunnels (see Chapter 4, Chapter 6, and Chapter 7);

---Changed the heat flow sensor error (see 4.1.6, 4.1.7 of the 2012 version);

---Deleted the on-site test conditions for heat flow meter testing (see 4.1.8~4.1.10 of the 2012 version);

---Changed the test method of thermocouples [see 4.2.6, 2012 version 4.2.5.2b)];

---Changed the test method of thermal resistance (see 4.2.7);

---Deleted the ambient temperature test conditions for surface temperature method testing [see.2012 version 4.2.6a), b)];

---Changed the conditions for calculating heat flow density of external protective tubes (see 4.3.5, 4.3.4 of the 2012 version);

---Changed the sampling and testing methods for pipeline soil thermal conductivity (see 4.3.10, 4.3.9 of the 2012 version);

---Deleted the requirement of the heat balance method on whether the pipeline is leaking [2012 version 4.4.2a)];

---Changed the maximum temperature of the heating source of the laboratory simulation test system [see 4.5.3a), 2012 version of 4.5.3a)];

---Changed the on-site test section and measuring point layout method [see 6.2.2d), e), 2012 version of 6.2.2d)];

---Added on-site environment measurement methods (see 6.4);

---Changed the pipeline operating conditions during testing (see 6.5.1, 6.4.1 of the 2012 version);

---Added on-site test conditions (see 6.5.2);

---Changed the data collection methods of heat flow meter method, surface temperature method and temperature difference method (see 6.5.5, 6.4.4 of the 2012 version);

---Added data collection method for thermal balance method (see 6.5.6);

---Added thermal balance method test data processing method (see 7.1.4);

---Added the calculation method of heat loss rate of heating pipe insulation structure (see 7.2.9);

---Changed the basis for thermal insulation effect evaluation (see 9.1, 2012 version of 9.1);

---Deleted the conformity assessment of test results (see 9.2 of the 2012 version);

---Added the classification of heat loss rate levels of heating pipe insulation structures (see 9.2);

---Changed the cooling heat flux value correction method (see Appendix A, Appendix A and Appendix B of the 2012 version);

---The maximum allowable heat loss value of the heating pipe insulation structure has been changed (see Appendix F).

1 Scope

This document specifies the test methods, test classifications and requirements for heat loss testing and insulation effect assessment of urban heating pipe insulation structures.

Test procedures, data processing, test errors, insulation effect evaluation and test reports.

This document is suitable for testing the heat loss and insulation effect of urban heating pipes, pipe accessories and insulation structures at pipe interfaces. assessment.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

GB/T 4132 Thermal insulation materials and related terms

GB/T 8174 Testing and evaluation of thermal insulation effect of equipment and pipelines

GB/T 10295 Heat flow meter method for determination of steady-state thermal resistance and related characteristics of thermal insulation materials

GB/T 10296 Round tube method for determination of steady-state heat transfer properties of insulation layers

GB/T 27418 Evaluation and expression of measurement uncertainty

GB/T 29046 Testing method for technical indicators of prefabricated insulated pipes for urban heating

3 Terms and definitions

The terms and definitions defined in GB/T 4132 and GB/T 8174 and the following apply to this document.