What do GB2 and GD2 mean for heating pipelines?

In the labeling of heating pipelines, “GB” and “GD” are typically used to classify or code pipes in different areas or with different properties within the pipeline system. Specifically, “GB” and “GD” may refer to different system or pipeline paths, but there is no standard national definition; their meanings can vary depending on the region, the design entity, or the specific requirements of a project. Generally, in heating systems, “GB” is used to denote a certain type of main pipe, while “GD” denotes branch pipes or other types of pipes. The number “2” in “GB2” or “GD2” may refer to a serial number, indicating that it is the second main or branch pipe, or it may refer to the number of the area or system served by that pipe. Therefore, to clearly understand the exact meaning of “GB2” and “GD2” in specific situations, it is necessary to consult relevant design documents or engineering specifications, or to ask the project manager, in order to obtain accurate definitions and uses. Without specific context, these abbreviations are not specific enough and can only provide general explanations. .

GB2 class refers to thermal pipelines, and it is divided into the following two categories: (1) design pressure greater than 2.5 MPa； (2) The design pressure is less than or equal to 2.5 Mh. GD2 class refers to power pipelines with a design pressure of less than 6.3 MPa and a design temperature of less than 400°C.

The installation qualification requires having GB2 and GD2 pipeline installation qualifications.

This post was last edited by AtlantisH on 2023-12-2 at 15:19. The code for power pipelines has been changed to GCD; it applies to pipelines in thermal power plants whose working medium is steam or hot water. For other flammable, explosive, toxic, corrosive, or gaseous media, the regulations for industrial pipelines shall apply. GB2 refers to thermal pipelines in public piping systems; it applies to steam or hot water pipelines ranging from the outlet point of the heat source to the inlet point of the end users (residential or industrial). The steam or hot water pipelines within the end users’ premises, such as those inside residential complexes or factories, do not fall under GB2. In a factory, it can be handled as industrial piping; having GC2-grade industrial piping or construction qualifications at the GCD level is sufficient, with GCD being an alternative to GC2.

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