To ensure long-term sealing integrity, structural stability and thermal performance of insulating glass units (IGUs), all accessories — including aluminum/stainless steel spacers, corner keys, molecular sieve desiccant, butyl sealant, secondary sealants (polysulfide/silicone), warm edge spacers and sealing strips — must comply with the following quality control requirements.

1. Spacers and corner keys
Spacer dimensions (wall thickness, height, width) shall meet drawing tolerances (wall thickness ±0.05 mm). Cut ends must be burr-free and square. Aluminum spacers require anodized or anti-corrosion surface treatment, free from oil, corrosion spots or scratches. Corner keys shall fit tightly with the spacer; assembly gaps ≤0.3 mm are permitted.

2. Molecular sieve desiccant
Only 3A type desiccant for IGUs is allowed. Moisture content at delivery ≤1.5% (typically 1.0%-1.5%). Once opened, the package must be used within 45 minutes; any leftover shall be resealed immediately and never used overnight. Dust content ≤0.5% by weight.

3. Sealants

• Butyl sealant (primary seal): Extruded bead must be continuous, bubble‑free and uniform. Adhesion to glass and spacer shall remain intact from –30°C to +80°C without cracking or flowing.

• Secondary sealant (polysulfide or silicone): Two‑component mixing ratio shall be within ±5% weight tolerance. Pot life and tack‑free time must be tested batch‑wise. Cured hardness (Shore A 20–40) and UV‑aging resistance shall meet specification.

4. Batch traceability and documentation
All accessories must display clear labels: name, specification, batch number, production date, net content and storage conditions. Mixing different batches or suppliers is forbidden. Each delivery shall include a certificate of analysis (batch‑specific) plus a third‑party type test report (minimum annually).

5. Storage and handling
Store in dry (humidity ≤60%), cool (5–30°C) and shaded area. Desiccant and butyl must be kept away from volatile solvents (e.g., alcohol, acetone).

Non‑conforming accessories shall be rejected immediately. Regular process audits and incoming inspection records shall be maintained for full traceability.