1. Material Selection for Frames
Frames are categorized into aluminum alloy, PVC, fiberglass, and aluminum-wood composite. The choice of frame material is primarily influenced by user habits, preferences, and budget, and of course, must match the architectural style. Qualitative selection is required for the frame material, glass, hardware, seals, and accessories. Thermally broken aluminum profiles include strip-type, glue-injected type, and hybrid type. Strip-type profiles have high strength but slightly lower leak-proof performance; glue-injected type has good sealing performance, but its performance deteriorates at high temperatures; hybrid type is superior to the first two, but is more expensive.
2. Door and Window Type Selection
The shape and size of the exterior windows, as well as the window type and exterior design.
3. Water Tightness Design
The water tightness of doors and windows refers to their ability to prevent rainwater penetration when the exterior doors and windows are normally closed, under the combined action of wind and rain, measured in Pa. The national standards *Classification and Test Methods for Air Tightness, Water Tightness, and Wind Pressure Resistance of Building Exterior Doors and Windows* (GB/T 7106-2008) and *Aluminum Alloy Doors and Windows* (GB/T 8478-2008) specify the water tightness classification for aluminum alloy doors and windows. The pressure difference value preceding the point of severe leakage is used as the water tightness classification index, with six levels from 1 to 6.
4. Air Tightness Design Air tightness refers to the ability of doors and windows to prevent air penetration when normally closed, expressed in m³/(m·h) or m³/(m²·h), representing the air permeability per unit opening length and per unit area, respectively. Air tightness is classified using the air permeability per unit opening length (q1) and per unit area (q2) under standard conditions with a pressure difference of 10 Pa.
5. Thermal Insulation Performance Design
The thermal insulation performance, simply put, refers to the ability of doors and windows to block heat transfer from the higher-temperature side to the lower-temperature side when the doors and windows are normally closed and there is a temperature difference between the two sides. The stronger the heat transfer capacity, the worse the thermal insulation performance of the doors and windows. The thermal insulation performance of doors and windows is expressed by the heat transfer coefficient K value [W/(m2·K)].
6. Shading Performance Design
Shading performance refers to the ability of doors and windows to block solar radiation heat in summer. Shading performance is expressed by the shading coefficient SC. The shading coefficient refers to the ratio of the amount of heat gained indoors by solar radiation passing through exterior doors and windows under given conditions to the amount of heat gained by solar radiation passing through 3mm thick transparent glass of the same area under the same conditions.
