The green "hard constraints" of the curtain wall industry have been implemented! GB 38456-2025 starts a new journey of low carbon

When “good houses” become the core orientation of national housing development, the green upgrade of building envelopes reaches a critical juncture. In 2025, the "Energy Efficiency Limit Standard for Green Manufacturing of Building Curtain Walls" (GB 38456-2025) was officially implemented. This mandatory standard, which is called the "most stringent in history" in the industry, uses clear energy efficiency indicators and process red lines to delineate a hard boundary for green development for the curtain wall industry. It also opens a new chapter in the transformation of building curtain walls from "scale expansion" to "value creation".

Standards Breaking: Anchoring the “Double Carbon” Energy Efficiency Revolution

Driven by the dual drive of the "dual carbon" strategy and the upgrade of building quality, the introduction of GB 38456-2025 is no accident. The Ministry of Housing and Urban-Rural Development has clearly stated that a "good house" must have four attributes: safety, comfort, greenness, and intelligence. As the core component of the building's skin, the curtain wall's energy consumption level directly affects the overall energy-saving effect of the building. The core breakthrough of this standard is to transform green manufacturing from "advocative requirements" to "mandatory constraints", which directly addresses the industry's pain points of high energy consumption and high emissions.

Two key quantitative indicators in the standard set clear entry thresholds for the industry:

● Energy consumption hard indicators: The energy consumption of aluminum profile surface treatment is ≤0.85kWh/m². This value is about 30% lower than the average energy consumption of traditional processes, which means that companies must achieve a qualitative leap in energy efficiency through technological upgrading. Compared with the GB 21351-2008 standard widely adopted by the industry before, the new indicators focus more on the core production links of curtain walls, significantly improving the accuracy of energy efficiency control.

● Emission strict red line: VOCs emission ≤20mg/m³. This standard is in line with the ultra-clean emission requirements of the petrochemical industry and will promote curtain wall production from "end treatment" to "source control". It should be known that VOCs emissions from traditional solvent-based spraying processes often far exceed this value. This indicator will accelerate the popularization and penetration of environmentally friendly processes.

Say goodbye to chromate and embrace new green technology

If energy efficiency indicators are "quantitative constraints", then process innovation is a "qualitative breakthrough". GB 38456-2025 clearly states that " Compulsory elimination of chromate passivation process and comprehensive promotion of chromium-free pre-treatment technology ”, this requirement will completely change the industry ecology of aluminum profile surface treatment.

The chromate passivation process has been widely used due to its low cost and good protection. However, hexavalent chromium, as a known carcinogen, not only poses a serious threat to the health of operators, but improper wastewater treatment can also cause lasting environmental pollution. The chromium-free pretreatment technology uses zinc, molybdenum, titanium and other environmentally friendly ingredients to replace chromate, which completely eliminates the risk of chromium pollution while achieving the same anti-corrosion performance. It has accumulated mature application experience in the fields of automobiles and high-end building materials.

In terms of spraying technology, standard Focus on promoting the popularization of environmentally friendly processes such as powder spraying . Traditional powder spraying requires curing at around 200°C for 10-13 minutes, but new low-temperature fast-curing powder coatings (such as Defuson 09 system) can reduce the curing temperature to 160-180°C, shorten the time to 6-10 minutes, reduce natural gas consumption by 25%-30%, and increase production efficiency by more than 30%. What is more noteworthy is that this type of environmentally friendly process does not require large-scale modifications to existing equipment and can achieve compliance only through parameter adjustment, reducing transformation costs for enterprises.

Compliers survive, innovators win

The mandatory implementation of standards will inevitably lead to the restructuring of the industry structure. For enterprises, this is both a challenge and an opportunity. In the short term, small, medium and micro enterprises may face pressure to upgrade technology, but if they can seize the transformation window, they will achieve a leap-forward improvement in competitiveness. Combining policy guidance and technological trends, enterprises can make efforts in three aspects:

● Technical path upgrade: Priority is given to the combined process of "chrome-free pre-treatment and low-temperature powder spraying".

● Whole-process energy efficiency management and control: Establish an energy efficiency accounting system from raw material procurement to finished product delivery. We can learn from the experience of "production process energy efficiency classification" in the electrode foil industry, break down the energy consumption indicators into each production link, and achieve precise energy saving through intelligent monitoring.

● Leverage policy dividends: At present, governments in many places have introduced policies to support green building materials, such as providing floor area ratio incentives to projects using ultra-low energy consumption processes and expanding the scope of green building materials procurement subsidies. Enterprises should actively align with policies and reduce transformation pressure by participating in demonstration projects and applying for green credit.

Green curtain walls make buildings more beautiful

The implementation of GB 38456-2025 marks that my country's building curtain wall industry has officially entered the era of "green hard constraints". This is not only a standard for the production process, but also the implementation of the concept of "good house" - when the curtain wall is no longer just the "coat" of the building, but a "green barrier" with energy saving, environmental protection and safety attributes, the quality connotation of the building can truly be realized.

For the industry, this change is both a challenge and an opportunity. Eliminating backward production capacity and promoting green technology will promote the transformation of the curtain wall industry to high-quality development and lay the foundation for emerging fields such as building photovoltaic integration and smart curtain walls. With the in-depth implementation of the standards, a group of companies with leading technologies and advanced concepts will stand out and lead the industry to realize the beautiful vision of "homes are better for everyone".