GB/T 39749-2021Evaluation method and graduation for energy efficiency performance of insulating glass unit (English PDF)

1 Scope

This Standard specifies the terms and definitions, evaluation methods and gradation for energy efficiency performance of insulating glass unit.

This Standard applies to single-cavity insulating glass unit, multi-cavity insulating glass unit, and vacuum composite insulating glass unit for construction.

2 Normative references

The following documents are indispensable for the application of this document.

For dated references, only the dated version applies to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 2680, Glass in building - Determination of light transmittance, solar direct transmittance, total solar energy transmittance, ultraviolet transmittance and related glazing factors

GB/T 11944, Insulating glass unit

JC/T 2304-2015, The technical specification of energy efficient glass for building

JGJ/T 151-2008, Calculation specification for thermal performance of windows, doors and glass curtain-walls

3 Terms and definitions

Terms and definitions determined by GB/T 2680 and GB/T 11944 are applicable to this document.

Appendix A (Normative)

Characterization method of insulating glass unit A.1 The structure of insulating glass unit is characterized by the thickness and type of a single piece of glass or material, the film designation of the coated glass, the location of the film surface, the thickness of the spacer layer, and the type of spacer layer.

A.2 Each part of the insulating glass unit shall be characterized by the following methods:

a) The thickness of a single piece of glass or material is expressed in millimeters;

b) The type of a single piece of glass or material can be divided into colorless transparent glass, colored glass, Low-E coated glass, sunlight control coated glass, coated glass, laminated glass, tempered glass, glazed glass, fireproof glass, polycarbonate, sun shade, which are expressed by the names of various glasses or materials;

c) The film designation of the coated glass shall be named by the manufacturer;

d) The locations of the membrane surface from outdoor to indoor are represented as #1, #2, #3, #4,...;

e) The types of spacers can be divided into air, inert gas, and vacuum. Air is represented by Air (abbreviated as A); inert gas is represented by the molecular formula of inert gases such as Ar and Kr. For inert gas, the gas composition ratio or content shall be given; vacuum is expressed as V; the residual gas pressure (indicated by P, in Pascals), the radius of the support (indicated by R, in millimeters), and the distance between the supports (indicated by S, in millimeter) shall be given.

A.3 The structure characterization methods of common insulating glass units are as follows:

a) The structure characterization of single-cavity air-filled insulating glass unit is:

6 mm Low-E coated glass (×××, #2) + 12 mm A + 6 mm colorless transparent glass;