Metal double door

When selecting metal double doors, the choice of base material and surface treatment determines longevity. For exterior use, Galvanized Steel is essential to prevent rust, while Cold-Rolled Steel is suitable for interior applications. Ensure the surface is Powder Coated rather than spray-painted, as powder coating provides superior UV resistance and scratch durability. For high-humidity environments, prioritize 304 Stainless Steel to ensure the structure remains corrosion-free for over 15 years.

Security is the primary function of a double door. You should specify a Multi-Point Locking System (at least 3-5 locking points) to prevent prying. The door leaf thickness should be at least 50mm to 70mm, with a steel plate thickness of 0.8mm to 1.2mm for residential use, or 1.5mm+ for commercial security. Ensure the hinges are Heavy-Duty Ball Bearing Hinges capable of supporting the weight of both leaves without sagging over time.

Depending on the destination market, compliance is non-negotiable. For the US market, look for UL 10B or UL 10C fire ratings. For the European market, CE Marking and EN 16034 standards are required for fire-resisting performance. Additionally, verify the Sound Transmission Class (STC) rating if the doors are intended for office or apartment use, aiming for a rating of 30dB or higher for effective noise reduction.

Double doors require precise alignment. Always request CAD drawings from the supplier before production to verify the Rough Opening (RO) dimensions. Ensure the set includes an Astragal (the vertical strip that seals the gap between the two doors) to prevent air leakage and improve security. For smart building integration, confirm if the frame is pre-drilled for Electronic Strikes or Magnetic Locks.

Metal doors are heavy and prone to denting or scratching during transit. You must mandate Reinforced Plywood Crate Packaging rather than simple cardboard. Ensure the supplier uses Corner Protectors and EPE Foam padding between the door leaves. For bulk orders, specify Palletization to facilitate safe loading and unloading via forklift, reducing manual handling risks.

Never release the final balance without a Third-Party Pre-Shipment Inspection (PSI). Instruct the inspector to perform a Closing Alignment Test to ensure the two leaves meet perfectly without a gap. Also, conduct a Coating Thickness Test using a digital gauge to verify it meets the agreed-upon microns, and a Cross-Cut Adhesion Test to ensure the paint won't peel in transit or under extreme weather.

Due to the high weight-to-volume ratio, FOB (Free On Board) is generally recommended so you can maintain control over sea freight costs through your own forwarder. If you are a new buyer, searching for verified manufacturers on Made-in-China.com allows you to utilize Secured Trading Services, which protect your payment until the shipping documents are verified. Always clarify the Incoterms to avoid hidden port charges at the destination.