There are differences between domestic and international standard systems for pre-insulated pipes, manifesting across various aspects such as material properties, testing methods, and product requirements. Understanding these differences is valuable for both procurement and engineering design.
The most notable difference lies in the definition of thermal conductivity. In European standards, thermal conductivity refers to the value for the pre-insulated pipe assembly as a whole, accounting for the combined effects of the foam insulation and the outer casing. In contrast, domestic standards (such as CJ/T 114) define thermal conductivity based solely on the polyurethane foam itself. Since the objects and methods of testing differ, the numerical values cannot be directly compared; comparing data based on European standards with data based on domestic standards can easily lead to misunderstandings.
Differences also exist regarding material performance requirements. International standards impose stricter requirements and include more testing parameters for the long-term temperature resistance and aging characteristics of polyurethane foam. While domestic standards are gradually improving-with GB/T 29047-2021 marking a significant upgrade over the previous version-gaps remain in certain specific metrics.
Regarding manufacturing processes, the pre-insulated pipe industry in developed countries started earlier, resulting in higher levels of automation and production consistency. In recent years, leading domestic enterprises have invested heavily in equipment acquisition and technological upgrades, with some achieving production standards and product quality that rival or match the best international levels. However, the industry's overall standard remains uneven, and a gap persists between small-to-medium-sized manufacturers and advanced international counterparts.
Testing standards and methods also differ. International standards mandate more systematic testing for properties such as long-term thermal aging and creep, whereas domestic standards are relatively less detailed in these areas. This explains why some overseas projects require products to comply with both domestic and international standards; each set of standards has a different focus, and combining them ensures more comprehensive requirements. The differences between these standards are not a matter of which is superior, but rather reflect distinct technical approaches and engineering practices. For export projects or international engineering contracts, it is necessary to understand the requirements of both standard systems. For domestic procurement projects, however, ensuring that manufacturers strictly adhere to current national standards-such as GB/T 29047-is generally sufficient.