How to Choose Specs for Insulating Glass Doors and Windows? What Are the Hard Requirements for Curtain Wall Glass?
In our years of making door and window glass, the two questions customers ask most are: "What specs are available for insulating glass doors and windows?" and "Can any glass be used for curtain walls?" As a glass factory, we'd say: the selection logic for these two is completely different—one depends on household needs, the other on the baseline set by codes.
Insulating Glass Doors and Windows: Specs Follow "Thickness + Gas Layer + Thickness"
Insulating glass is commonly written as "5+9A+5," "5+12A+5," or "6+12A+6," representing the thickness of the two glass panes and the air layer between them. For residential doors and windows, 5+12A+5 and 6+12A+6 are the mainstream choices, balancing thermal insulation and cost-effectiveness. The air layer isn't better the thicker it is—beyond a certain thickness, the gas inside creates convection, and insulation performance actually drops. Glass factory reminder: for mid- and high-rise doors and windows, tempered insulating glass is recommended; when a single pane exceeds 2㎡, 5mm is no longer enough and you need to upgrade to 6mm or thicker. If low-frequency noise from the street is severe, simply thickening the insulating glass has limited effect—laminated insulating glass is the right solution.
Curtain Wall Glass: Safety Is the Bottom Line, and Codes Are Strict
Curtain walls are not on the same level as ordinary doors and windows. Codes explicitly require safety glass for curtain walls, with thickness no less than 6mm, and rib glass for full-glass curtain walls no less than 12mm. When insulating glass is used for curtain walls, the gas layer thickness should be no less than 12mm, individual glass thickness should not be less than 6mm, and the thickness difference between the two panes should not exceed 3mm. In addition, curtain wall door and window glass must have edge treatment, and tempered glass surfaces must be free of damage. When a glass factory schedules production of curtain wall insulating glass, dual sealing is standard, and hidden-frame curtain walls also require silicone structural sealant—completely different from the weather-resistant sealant used for ordinary doors and windows.
In one sentence: when choosing insulating glass for door and window glass, look at the usage scenario; when choosing door and window glass for curtain walls, look at the code red lines. The glass factory gets the parameters right so you can use them safely.
