| Product and market compliance | Products should be assessed against the standards and building-code requirements applicable in the destination market. For example, EN 14351-1 covers performance characteristics for windows and external pedestrian doorsets in its scope. | Applicable test reports, declarations or certification documents, with the product type, configuration, and issuing laboratory clearly identified. | Requirements differ by country. A document for one market or product configuration may not establish compliance for another. |
| Thermal performance | Compare the whole-window thermal transmittance (U-factor or U-value) and, where relevant, solar heat gain data with project requirements. Values depend on glazing, frame, spacers, and window size. | Tested or calculated performance data for the specified glass build-up and frame. For the United States, check whether ratings are supported by NFRC procedures and documentation. | Thermal ratings help buyers evaluate energy performance and avoid comparing glass-only figures with whole-window figures. |
| Air leakage | Request a reported air-leakage result tested to the relevant market method, such as ASTM E283 where applicable. Acceptance limits should follow the project specification or local code. | Test report stating the test method, specimen dimensions, operating type, and measured leakage rate. | Air leakage can affect comfort, energy use, and indoor moisture control; results are meaningful only when the test conditions are clear. |
| Water penetration | Confirm the required pressure and pass criteria for the project. ASTM E331 is one method used to evaluate water penetration under uniform static air pressure difference. | Report showing the test method, pressure, duration, specimen details, and observed water penetration. | Rain exposure and wind conditions vary by location, so buyers should set a project-appropriate target rather than rely on a generic claim. |
| Structural performance | Check that the proposed window can meet the design wind loads and deflection criteria for the project. ASTM E330 is a structural performance test method used for exterior windows, doors, skylights, and curtain walls. | Test results or engineering calculations for the relevant frame, glass thickness, hardware, dimensions, and support conditions. | A result for a smaller or differently configured specimen may not represent a larger project window or a different installation. |
| Insulating glass unit (IGU) durability | For markets using European standards, EN 1279 addresses insulating glass units. Confirm that the proposed unit construction and applicable parts of the standard match the project requirements. | IGU test documentation, glass and spacer specifications, sealant details, production identification, and any applicable conformity documents. | Sealed-unit durability depends on the complete assembly and manufacturing process, not just the glass panes. |
| Materials and finish | Specifications should identify the frame material and relevant dimensions, glazing build-up, hardware, seals, and surface finish. Suitability should be assessed for the intended exposure and use. | Product drawings, material specifications, finish details, hardware schedules, and approved samples where color or appearance is important. | Clear specifications reduce substitutions and help buyers check compatibility with the building design and local environment. |
| Quality management and production control | A documented quality-management system, such as one certified to ISO 9001, can support consistent processes; certification alone does not prove that a particular window meets project performance requirements. | Current certificate scope and validity, inspection procedures, production records, and records for the ordered product batch. | Buyers need both process controls and product-specific evidence to assess consistency and traceability. |
| Inspection and traceability | Orders should have identifiable product configurations and documented checks for dimensions, appearance, operation, and packing before dispatch. | Inspection plan, measurement records, photographs or inspection reports, and labels linking units to order or batch records. | Traceability makes it easier to resolve defects, confirm the delivered configuration, and manage replacements. |
| Packaging and export readiness | Packaging should be appropriate for the window size, glass type, handling method, route, and expected storage conditions. | Packing specifications, loading plan, handling instructions, and confirmation of shipping marks and order quantities. | Glass can be damaged during handling and transport; packaging and loading details should be agreed before production is complete. |
| Commercial terms and after-sales support | Written terms should clearly state product scope, tolerances, inspection arrangements, lead time, warranty coverage, exclusions, and the process for reporting issues. | Quotation, approved drawings, purchase-order specifications, warranty document, and a named service contact or documented claim process. | Clear written commitments reduce misunderstandings across languages, time zones, and international shipping arrangements. |
