Tempered double glass

When evaluating Tempered Double Glass (also known as Insulated Glass Units or IGU), you must prioritize glass thickness (typically 4mm to 12mm per pane) and the spacer width (6mm to 20mm). Ensure the unit uses primary (polyisobutylene) and secondary (silicone or polysulfide) sealants to prevent moisture ingress. For enhanced thermal performance, specify Argon gas filling and the use of Low-E (Low-Emissivity) coatings to reduce U-value and improve energy efficiency.

To ensure market access and safety, the products must adhere to ASTM C1048 (USA), EN 12150-1 (Europe), or AS/NZS 2208 (Oceania). Specifically for the tempering process, look for the CCC (China Compulsory Certification) mark if sourcing from China, and verify that the glass meets ANSI Z97.1 for impact resistance to prevent spontaneous breakage and ensure it shatters into small, blunt fragments.

Request a fragmentation test report to ensure the glass breaks into at least 40 to 50 pieces in a 50x50mm square. For the insulation, check the dew point temperature; a high-quality unit should have a dew point below -40°C to prevent internal condensation. Additionally, ensure the supplier uses 3A molecular sieve desiccants within the spacer bars to maintain long-term clarity.

This product is primarily used in curtain walls for commercial skyscrapers, residential energy-saving windows, and refrigeration display cases. For high-altitude or high-wind-load areas, you should specify heat-strengthened or fully tempered laminated double glass to provide extra structural integrity and sound insulation (STC rating of 35+ dB).

Glass is highly fragile; therefore, you must mandate customized seaworthy plywood crates with cork pads or rubber spacers between each sheet. Ensure the supplier uses steel strapping and includes Shockwatch or Tiltwatch sensors on the packaging. It is highly recommended to use CIF (Cost, Insurance, and Freight) terms or purchase independent all-risk marine insurance to cover potential transit damage.

Focus on yield rates and defect tolerances rather than just the unit price. Negotiate a Quality Guarantee Agreement that defines acceptable levels of bubbles, scratches, or inclusions (e.g., following ASTM C1036). For large-scale projects, request a staged payment plan (e.g., 30% deposit, 70% against BL copy) and ask for a factory audit or video inspection of the tempering furnace and automated sealing line.

Always use Secured Trading Services provided by platforms like Made-in-China.com to protect your funds until shipping documents are verified. Before the final payment, hire a third-party inspection agency (like SGS or Intertek) to perform a pre-shipment inspection (PSI) to verify the quantity, dimensions, and edge-work quality match your Proforma Invoice.

Check your local customs regulations for anti-dumping duties (ADD) which are sometimes applied to Chinese architectural glass in specific regions like the EU or USA. Ensure the supplier provides a Certificate of Origin (CO) and the correct HS Code (typically 7008.00) to facilitate smooth customs clearance and potentially benefit from trade agreements.