GB/T 9775-2025 in English

Core changes in the standard revision

Product classification system

The new standard divides products into 6 categories, and the code system is as follows:

• Ordinary board (P): Basic model, suitable for dry environment
• Water-resistant board (S): Water absorption ≤10%, used in humid areas
• Moisture-resistant board (T): New type, water absorption ≤25%
• Fire-resistant board (H): Fire stability ≥40min
• 9.5Vertical 400/Horizontal 160≥70 12.0Vertical 520/Horizontal 200 15.0Vertical 650/Horizontal 250

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Implementation Recommendations

Precautions for Manufacturers

1. Raw Material Control: Building gypsum must comply with GB/T 9776, and facing paper must comply with GB/T 26204
2. Process Adjustment: Moisture-resistant products require improved gypsum formula and paper surface treatment process
3. Testing Capabilities: Equipped with dedicated testing equipment that meets the requirements of the new standard

Engineering Application Guidance

• For humid areas such as bathrooms, water-resistant board (S) or moisture-resistant board (T)
• Fire compartments must use the fire-resistant board (H) series products
• For suspended ceiling projects, it is recommended to select products with a thickness of ≥12mm to ensure rigidity

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Background of Standard Evolution

This revision (the third) mainly responds to the following industry development needs:

• Green Building: New moisture-resistant products are added to reduce drying energy consumption
• Fire Safety: Clarify the quantitative indicators of fire resistance performance
• Utilization of Industrial By-product Gypsum: Allow the use of recycled raw materials such as desulfurized gypsum