Tempered glass

When selecting tempered glass, you must prioritize surface flatness and edge treatment. Ensure the glass has a minimum surface compression of 10,000 psi to be classified as fully tempered. For safety applications, the fragmentation test is critical; a 50mm x 50mm area should break into at least 40 to 60 small pieces to minimize injury risks. Additionally, specify the tolerance levels, typically ±1mm to ±2mm, depending on whether it is for architectural or furniture use.

Compliance is non-negotiable in the glass industry. For the US market, products must meet ANSI Z97.1 or CPSC 16 CFR 1201. For the European market, the EN 12150-1 standard is the benchmark. If you are sourcing from China via Made-in-China.com, ensure the supplier provides a CCC (China Compulsory Certificate) and CE marking documentation to avoid customs clearance issues and legal liabilities.

Spontaneous breakage is often caused by Nickel Sulfide (NiS) inclusions. To mitigate this risk, you should require the supplier to perform a Heat Soak Test (HST). This process involves heating the tempered glass to approximately 290°C to force any unstable panes to break in the factory rather than at the installation site. While this adds 5-10% to the cost, it significantly reduces long-term liability.

Since tempered glass cannot be cut or drilled after the tempering process, all fabrication must be completed beforehand. You should provide detailed CAD drawings specifying hole diameters, notch positions, and edge polishes (such as flat polish, pencil edge, or beveled edge). For aesthetic or functional needs, inquire about silk-screen printing, acid-etching for frosting, or Low-E coatings for thermal efficiency.

Glass is fragile and heavy, making packaging the most critical factor. Insist on custom-made seaworthy plywood crates with cork pads or corrugated paper separating each sheet. Ensure the crates are fumigated (ISPM 15 standard) and secured with steel strapping. For high-value shipments, use Impact Indicator labels (e.g., ShockWatch) on the crates to monitor handling during transit.

Focus on yield rates and lead times rather than just the unit price. A lower price often indicates lower-quality raw glass (float glass) which has more impurities. Negotiate based on container-load volumes (FCL) to reduce the per-unit shipping cost. On Made-in-China.com, look for 'Audited Suppliers' and request a production video to verify their tempering furnace technology and QC laboratory capabilities.

Always use Trade Assurance or secured payment terms that link payment release to shipping documents. Before the final payment, hire a third-party inspection agency (like SGS or Intertek) to perform a random sampling test focusing on dimensions, hole alignment, and the fragmentation pattern. Never skip the pre-shipment inspection, as returning defective glass internationally is economically unfeasible.

Tempered glass is extremely heavy; therefore, you must verify the weight limits of the destination port and the inland trucking regulations. Use FOB (Free On Board) terms if you have a reliable freight forwarder who understands glass handling, or CIF (Cost, Insurance, and Freight) if you want the supplier to manage the risk until the destination port. Ensure the Marine Insurance policy specifically covers 'breakage' as a standard clause.