Which Technical Parameters Should Be Specified When Signing a GRC Supply Contract? A Guide to Core Elements of Contract Technical Clauses

Technical parameter clauses in a GRC supply contract are the core basis for ensuring product quality and project compliance. Clearly defining key technical parameters can effectively avoid later quality disputes and performance risks. As an industry leader with 28 years in the field, Qinglong, drawing on extensive project contract practice, has summarized the technical parameters that require key clarification, providing customers with a practical guide.

I. Core Technical Parameters for Material Performance

Material performance parameters are the fundamental core of the contract, and GRC's key mechanical properties and durability indicators must be clearly defined. In terms of mechanical properties, the contract should stipulate cube compressive strength ≥40MPa, flexural strength ≥15MPa (≥20MPa recommended for premium products), and fracture energy ≥200J/m² to ensure the load-bearing capacity of components; Qinglong contracts typically stipulate flexural strength ≥20MPa, far exceeding the basic industry standard. Durability parameters must be specified according to the service environment: indoor components should be stipulated with a freeze-thaw cycle resistance ≥100 cycles, outdoor components ≥200 cycles, coastal high-salt-spray environments ≥300 cycles, and an impermeability grade ≥P8; for coastal projects, Qinglong additionally stipulates a salt spray corrosion resistance grade ≥500 hours. Raw material parameters must be clarified, such as an alkali resistance retention rate of alkali-resistant glass fiber ≥75%, cement grade ≥42.5, and aggregate mud content ≤1%, to ensure controllable raw material quality.

II. Component Dimensions and Appearance Quality Parameters

Dimensional and appearance parameters directly affect installation results and architectural aesthetics and must be precisely stipulated. Regarding dimensional deviations: length and width deviation of flat panel components ≤±3mm, thickness deviation ≤±2mm, dimensional deviation of special-shaped components ≤±5mm, and diagonal deviation ≤±4mm; Qinglong contracts stipulate stricter tolerances, with flat panel component dimensional deviation ≤±2mm, to ensure installation and jointing precision. Appearance quality parameters must be clarified: surface flatness error ≤2mm/m, free of defects such as cracks, air bubbles, and chipped edges or corners, with air bubble diameter ≤3mm and no more than 3 bubbles per square meter; for landmark projects, Qinglong additionally stipulates surface roughness ≤3.2μm to enhance decorative effects. Color and texture require agreed color difference ranges (ΔE≤2.0) and texture fidelity (e.g., ≥95% for stone-imitation components), with standard samples attached as the acceptance basis; in Qinglong's contract for the GRC stone-imitation components of the Dongting Lake Museum, a fidelity of ≥95% was explicitly stipulated.

III. Production and Construction Process Parameters

Agreeing on process parameters ensures a controllable production process and avoids quality problems caused by non-standard processes. In terms of production processes, the contract must specify a water-cement ratio ≤0.45, the type of high-range water reducer (e.g., polycarboxylate series) and its dosage range (0.8%-1.5%), and the curing method (constant temperature and humidity curing ≥7 days); Qinglong contracts stipulate a water-cement ratio ≤0.42 to ensure component density. Installation process parameters must be clarified, including the anchoring method (e.g., four-point hanging, multi-point hanging), installation precision (verticality deviation ≤2mm/m, levelness deviation ≤1mm/m), and sealant type and weather-resistance grade; in the contract for Qinglong's Guangzhou Dongzhu Shangdu Commercial City project, installation precision standards for multi-point hanging were specifically stipulated. For special processes such as openwork and carved components, the contract should stipulate an openwork rate error ≤±2% and carving depth deviation ≤±1mm to ensure the process effect meets standards.

IV. Technical Parameters Related to Acceptance and Warranty

Acceptance and warranty parameters are key to performance assurance, and testing methods and warranty commitments must be clearly defined. Acceptance parameters should stipulate testing standards (e.g., in accordance with "Glass Fiber Reinforced Cement (GRC) Decorative Products" JC/T940-2022), sampling ratio (≥3% per batch), testing items (strength, dimensions, appearance), and handling of non-conforming products (unconditional return or exchange); Qinglong contracts stipulate testing by a third-party testing institution to ensure impartial results. Warranty parameters must clearly define the warranty period (indoor components ≥5 years, outdoor components ≥10 years), warranty scope (strength degradation, cracking, fading, etc. not caused by human damage), and repair response time (within 24 hours); Qinglong provides a warranty of ≥15 years for major projects, committing to free repair or replacement of non-conforming components. In addition, the contract should stipulate technical documentation delivery requirements, such as test reports, certificates of conformity, and installation drawings, to ensure project documentation is complete and traceable.