Green Building Materials: Energy-Saving Glass for Buildings

Core Certification Content

The Green Building Materials Certification for Building Energy-saving Glass focuses on the green performance throughout the product's lifecycle, primarily examining the following four attribute dimensions:

• Resource Attributes: Includes indicators such as the comprehensive utilization rate of solid waste during production, the degree of raw material localization, and water resource consumption. It encourages enterprises to use recyclable materials, reduce environmental impact from transportation through localized procurement, and also pay attention to the environmental friendliness of raw materials. For products like coated glass, the utilization efficiency of key raw materials such as rare metals is also examined.
• Energy Attributes: Focuses on energy consumption per unit of product. The comprehensive energy consumption during glass product production should meet the requirements of relevant energy consumption limit standards, including energy consumption control in processes like raw material melting, forming, annealing, coating, tempering, lamination, and insulating glass assembly. Three-Star certification requires production energy consumption to reach the industry's advanced level, encouraging enterprises to adopt energy-saving production processes and clean energy technologies.
• Environmental Attributes: Covers indicators such as air pollutant emissions (nitrogen oxides, sulfur dioxide, particulate matter, etc.), workplace dust concentration, wastewater discharge, and noise control. Production enterprises must legally obtain a pollutant discharge permit and discharge pollutants according to its stipulations. Exhaust gas treatment from glass furnaces and the recycling of production wastewater are key focuses of the environmental attribute assessment.
• Quality Attributes: Based on relevant product standards, tests key performance indicators of building energy-saving glass products, including visible light transmittance, total solar energy transmittance (g-value), shading coefficient (Sc-value), thermal transmittance (K-value), and light-to-solar gain ratio (LSG), ensuring products possess excellent performance while meeting green requirements. Quality attributes also include key technical indicators such as mechanical properties, durability, and safety performance of the glass.

Certification Levels and Assessment System

Based on the standard T/CECS 10034-2019, the Green Building Materials Product Grading Certification divides products into three levels from low to high according to the level of evaluation indicators achieved:

• One-Star: Meets basic green assessment requirements and complies with national fundamental green building material standards. Enterprises must satisfy all control item requirements, with each evaluation indicator reaching the One-Star benchmark.
• Two-Star: Demonstrates good performance in resource conservation, energy consumption, and environmental protection, reaching an advanced industry level. Requirements for each evaluation indicator are stricter than for One-Star.
• Three-Star: Exhibits outstanding green performance, with minimal environmental impact throughout the lifecycle, representing the highest grade of green building material products. Three-Star requires per-unit product production energy consumption to reach the advanced value standard, with the strictest requirements for all evaluation indicators. Building material products that have passed China Green Product Certification are equivalent to Three-Star green building materials.

The assessment method also considers the application of bonus items, including: actively addressing environmental impacts throughout the lifecycle (e.g., conducting environmental declarations using scientific methods like LCA), using clean energy like green electricity, completing energy management system certification, and achieving green factory status.

Key Performance Indicators

The quality attribute assessment for building energy-saving glass focuses on the following energy-saving and optical performance indicators:

• Visible Light Transmittance (VLT): Represents the glass's ability to transmit the visible portion of sunlight, directly affecting indoor daylighting. General window glass requires VLT ≥ 70%, while privacy curtain wall glass requires VLT ≥ 30%. A higher value indicates better natural lighting.
• Total Solar Energy Transmittance (g-value): Represents the glass's ability to transmit total solar radiation energy, directly affecting building heat gain. Low-E glass requires g-value ≤ 0.50. A lower value indicates better thermal insulation performance.
• Shading Coefficient (Sc-value): Represents the glass's ability to block solar radiant heat, a key indicator for measuring the glass's energy-saving performance. Low-E glass requires Sc-value ≤ 0.55. A lower value indicates better shading and insulation effects.
• Thermal Transmittance (K-value): Represents the heat transferred per unit area under a unit temperature difference between the two sides of the glass, reflecting its thermal insulation performance. Insulating glass requires K-value ≤ 1.5 W/(m²·K). A lower value indicates better insulation.
• Light-to-Solar Gain Ratio (LSG): The ratio of visible light transmittance to total solar energy transmittance, a comprehensive indicator evaluating the balance between daylighting and energy efficiency of the glass. A higher LSG indicates better thermal insulation while ensuring good daylighting.

Basic Certification Requirements

Enterprises and products applying for Green Building Materials Certification for Building Energy-saving Glass must meet the following basic conditions:

• Compliance Requirements for Production and Operation: The production enterprise must have had no major environmental pollution incidents or major safety accidents in the past three years. The collection, storage, and disposal of general solid waste must comply with the relevant provisions of GB 18599; the storage of hazardous waste must comply with the relevant provisions of GB 18597 and subsequently be handed over to a unit holding a hazardous waste operation license for disposal.
• Compliance of Production Equipment and Technology: The production enterprise should adopt advanced technologies and processes encouraged by the state and should not use technologies, processes, equipment, or related substances that have been eliminated or banned by the state or relevant departments.
• Management System Requirements: The production enterprise should establish and operate a Quality Management System, an Environmental Management System, and an Occupational Health and Safety Management System in accordance with GB/T 19001, GB/T 24001, and GB/T 45001, respectively.
• Product Qualification Requirements: Product performance must meet the requirements of relevant product standards such as GB/T 2680 "Determination of luminous and solar characteristics of glass in building" and GB/T 11944 "Insulating glass". The product must be accompanied by a valid type test report issued within one year.

Certification Process

The Green Building Materials Product Grading Certification implements the mode of initial inspection + product sampling inspection + post-certification surveillance:

• Certification Application: Submit an application form (specifying the desired green building material grade), business license, product process flow chart, factory organization chart, list of key raw materials for filing, valid product type test report within one year, directory of management system-related documents, etc. The applying enterprise must pass the certification body's review.
• Document Technical Review: The certification body reviews the completeness, suitability, and effectiveness of the application documents. Review conclusions are categorized as: meets requirements and can proceed to on-site inspection; basically meets requirements but needs supplementation; does not meet requirements and cannot proceed to on-site inspection.
• Initial Factory Inspection: Includes factory assurance capability check, product consistency check, and verification of compliance with green assessment requirements. The on-site inspection focuses on the operation of the enterprise's energy management system, production energy consumption control measures, wastewater recovery system operation, pollutant emission control measures, solid waste disposal, etc.
• Product Sampling Inspection: Sampling and inspection are conducted by a laboratory with CMA (China Metrology Accreditation)资质 designated by the certification body. Inspection items, technical requirements, sampling methods, etc., should comply with the certification implementation rules and green building materials assessment standards. Inspection items for building energy-saving glass include visible light transmittance, total solar energy transmittance, shading coefficient, thermal transmittance, etc. Inspection reports meeting requirements issued by a CMA-accredited laboratory within the last 12 months may be accepted.
• Certification Result Evaluation and Approval: After passing the document technical review, on-site inspection, and product sampling inspection, the certification body conducts a comprehensive evaluation, approves the certification decision, and issues the certificate. The certification certificate is valid for five years.
• Post-Certification Surveillance: Surveillance is arranged after certification, with intervals not exceeding one year. Surveillance content includes factory assurance capability supervision inspection, product consistency supervision inspection, verification of continued compliance with green assessment requirements, and product supervision inspection. Enterprises must rectify non-conformities found during surveillance audits within the specified time limit.
• Recertification Audit: A recertification audit is conducted before the certificate expires to renew the certification qualification, typically with a five-year cycle.

Certification Value

• Enhances Product Market Competitiveness: Green Building Materials Product Certification is a nationally promoted voluntary product certification. Certified products can gain priority in government procurement, key projects, municipal public works, etc. Policies jointly issued by the Ministry of Finance, Ministry of Housing and Urban-Rural Development, and Ministry of Industry and Information Technology supporting green building materials in government procurement explicitly require priority procurement of green building materials. Starting in 2025, government projects (hospitals, schools, etc.) will be required to procure ≥80% green building materials, and uncertified products will lose significant market opportunities.
• Enjoys Policy Support and Financial Subsidies: Many provinces and cities provide financial rewards or support to enterprises passing green building materials product certification. For example, Shanghai and Shenzhen subsidize certification fees by 200,000 to 500,000 RMB. Certified enterprises can also enjoy preferential tax policies such as corporate income tax reductions (tax rates reduced to 15% in some areas). The policy supporting green building materials in government procurement has been implemented in 101 cities (municipal districts) including Chaoyang District, Beijing.
• Strengthens Bidding Competitiveness: The Green Building Materials Certification certificate can serve as a bonus point in project bidding and procurement, with Three-Star materials potentially adding 5 to 10 points in municipal projects. It helps enhance an enterprise's differentiated bidding capability and establish its technology and quality brand. Obtaining the green building materials label is a necessary condition and a bidding advantage for enterprises to participate in major projects, government-funded project tenders, and enter large clients' qualified supplier lists.
• Meets Green Building Development Needs: With the implementation of the "Assessment Standard for Green Building" (GB/T 50378-2019) and the promotion of green building initiatives, the required proportion of green building materials in new urban buildings is continuously increasing. As a key component of the building envelope, certified building energy-saving glass products can more easily enter the green building market.
• Addresses Dual-Carbon Strategic Requirements: In the context of carbon peak and carbon neutrality goals, energy and construction are key sectors. Green Building Materials Product Certification requires enterprises to conduct carbon footprint accounting, helping them meet carbon emission control requirements and plan for low-carbon development in advance.
• Promotes International Trade: Certification results can serve as a "green passport" for exports. Some standards have international mutual recognition, helping reduce green trade barriers. Green building materials labeling and assessment work is actively participating in international mutual recognition mechanisms, providing authoritative basis for Chinese building materials entering markets along the Belt and Road and globally.
• Establishes Corporate Social Responsibility Image: Certification demonstrates an enterprise's commitment and actions in resource conservation and environmental protection, enhances customer trust, elevates brand reputation, and meets consumer demand for upgraded green building materials.

Applicable Product Scope

The Green Building Materials Certification for Building Energy-saving Glass is applicable to various types of energy-saving glass products for buildings, including but not limited to:

• Coated Energy-saving Glass: Low-E (low-emissivity) coated glass, solar control coated glass, heat-reflective coated glass, etc.
• Insulating Glass: Standard insulating glass, gas-filled insulating glass (argon, krypton), vacuum glass, etc.
• Laminated Glass: Standard laminated glass, thermal insulation laminated glass, soundproof laminated glass, etc.
• Tempered Energy-saving Glass: Tempered Low-E glass, tempered insulating glass, etc.
• Building-Integrated Photovoltaic (BIPV) Glass: BIPV photovoltaic curtain wall glass, photovoltaic skylight glass, etc.