What Are the Product Testing Standards of GRC Manufacturers? Quality Benchmarks from National, Industry to Enterprise Standards

Clarifying the testing standards for GRC (Glass Fibre Reinforced Cement) products is the sole objective basis for evaluating whether their quality is compliant, and also the foundation for suppliers and buyers to reach technical consensus. For a rigorous GRC manufacturer, its product quality control system is inevitably built upon clear, open, and strict standards. These standards constitute a hierarchical system extending from mandatory national requirements to general industry specifications, and further to stricter self-imposed enterprise requirements. Understanding this system helps you grasp the core of quality control when communicating with manufacturers.

Level 1: National Standards (GB) — The Bottom Line for Safety and Environmental Protection
National standards are mandatory minimum requirements, mainly concerning product safety, environmental protection, and basic general performance. Although there is currently no national standard specific to GRC products, GRC, as a building material, must comply with relevant general national standards, such as requirements for radioactivity and limits on hazardous substances. This is the “entry permit” for a product to enter the market.

Level 2: Industry Standards (JC/T) — The Core Basis for Product Performance
This is currently the most important and most direct basis for GRC product performance. The core standard is:
“Glass Fibre Reinforced Cement (GRC) Decorative Products” (JC/T 940-2022). Released in 2022, this standard replaced the previous version of JC/T 940 and is currently the latest authoritative industry standard. It specifies in detail the classification, codes, raw material requirements, technical requirements, test methods, inspection rules, as well as marking, packaging, transportation, and storage of GRC decorative products.
Among these, the technical requirements are the core of both manufacturer testing and user acceptance, mainly including: 1. Appearance quality: specifies the allowable range of defects such as cracks, chipped edges and corners, and surface bubbles. 2. Dimensional deviations: specifies the allowable tolerances for dimensions such as length, width, thickness, and flatness. 3. Physical and mechanical properties: the most critical part, including: ◦ Limit of Proportionality in bending (LOP) and Modulus of Rupture (MOR): key indicators measuring GRC's load-bearing capacity and crack resistance. The standard sets different minimum requirements according to service conditions (interior, exterior) and panel type (flat panels, profiled panels). For example, flat panels for exterior use are required to have higher MOR values. ◦ Impact resistance: reflects the toughness of the material; the standard specifies a minimum number of impacts or impact energy. ◦ Water absorption: an important indicator of material density and durability; the standard requires ≤14%. ◦ Frost resistance: products for exterior use must undergo frost resistance testing to determine strength and mass loss after a specified number of freeze-thaw cycles. ◦ Weather resistance (optional): colour and performance changes are evaluated through artificial accelerated ageing tests.

A responsible GRC manufacturer must ensure that 100% of its products leaving the factory comply with the requirements of the JC/T 940 standard, and periodically send products to third-party testing institutions for “type inspection” to obtain authoritative certification.

Level 3: Enterprise Standards (Q/) — Self-Imposed Requirements Beyond Industry Standards
Leading GRC manufacturers, in pursuit of higher product quality and market competitiveness, often establish internal enterprise standards that are stricter than industry standards (which must be filed with the local quality and technical supervision authority). For example: • Setting the factory control value for flexural strength far above the minimum requirement of the industry standard. • Controlling water absorption to a lower level (e.g. ≤8%) in pursuit of better durability. • Adding more stringent durability test indicators such as the chloride ion diffusion coefficient. • Imposing tighter tolerances on dimensional precision. When a manufacturer claims its products are “superior to national/industry standards”, you may ask it to present the specific enterprise standard text and corresponding test data for verification.

Level 4: Project-Specific Technical Specifications — Tailored Contractual Standards
For major engineering projects, the designer or owner usually prepares detailed GRC engineering technical specifications. Taking into account the project's specific environment (e.g. coastal areas with high salt mist, cold northern regions), special requirements of the architectural form (e.g. oversized or ultra-thin components), and the design service life, this document sets technical indicators that are more specific and stricter than general standards. For example, it may require “strength loss of less than 15% after 200 freeze-thaw cycles” or “chloride ion diffusion coefficient below a specified value”. Such specifications become the supreme basis for GRC procurement and acceptance on that project, taking precedence over industry standards.

Therefore, when you ask a manufacturer about its product testing standards, a professional reply should cover: 1. A statement of compliance with the JC/T 940 standard, along with the latest third-party type inspection report. 2. An explanation of the key indicators of its internal control standards and why they are superior. 3. A demonstration of the ability and willingness to meet project-specific technical specification requirements, with proof of past projects that met similarly stringent requirements. Enterprises like Qinglong GRC, which have participated in the revision of industry standards, generally have a deeper understanding of these standards and implement them more rigorously. Understanding these standards means mastering the “yardstick” for judging the quality of GRC products.