Key indicators of building membrane

According to the evaluation basis recognized by the international film industry, the evaluation practice of building film quality indicators

The key indicators are: SHGC (the smaller the better), TSER (the larger the better), UV barrier and visible light transmittance.

False indicator: infrared barrier rate

This is because the principle of building film insulation is to reflect some heat, isolate some heat and absorb some heat. When the sun shines, 49% of the main energy source is infrared light, and about 50% is visible light. The infrared barrier is only a part of the thermal barrier of too hot radiation, and many manufacturers selectively give the infrared barrier rate of a certain band, rather than the infrared barrier rate of the whole band. There is a common phenomenon of parameter fraud, which cannot be used as the main reference index. In addition, the infrared barrier ratio does not include the heat energy absorbed by the membrane, and the heat absorption part is also one of the important factors of the real heat insulation effect. This indicator is a commercial hype that attracts eyeballs, and has little practical value.

Solar heat gain coefficient SHGC (also known as total solar transmittance, heat gain factor, g value, which is called shielding coefficient in GB/T2680 in China, often abbreviated as Se or Sc): refers to the ratio of the heat of solar radiation energy entering the room through glass under the same conditions (including both the directly penetrating part and the heat released after absorption) and the solar heat entering the room through the same size but without glass opening. The smaller the sunshade coefficient is, the better the performance of blocking solar heat from radiating indoors is. That is, the lower the value, the better the performance of the membrane.

Solar barrier rate TSER: the index can actually reflect the real data of the film insulation capacity. Because it calculates the entire solar spectrum range. (Infrared only accounts for 49% of the solar spectrum.) It also contains absorbed energy. Therefore, for example, the Energy Star and other institutions, the U.S. Door and Window Assessment Commission, and the Canadian government only use the SHGC/TSER data as the evaluation criteria rather than the infrared barrier rate. The higher the value, the better.

Ultraviolet blocking rate: refers to the percentage of ultraviolet ray (300-380nm) in the incident sunlight blocked by the window glass system, usually expressed as a percentage. Ultraviolet radiation will make the skin produce a lot of free radicals, leading to the peroxidation of cell membrane, making melanocytes produce more melanin, which will be distributed upward to the cuticle of the epidermis, causing black spots. Causes skin wrinkles, aging, relaxation and black spots. The higher the value, the better.