First, wind pressure strength and water tightness:
Because steel doors and windows have low material strength and rigidity, they have been strengthened by adding linings, but their wind pressure resistance and watertightness are about two grades lower than aluminum alloy doors and windows. This is the case for the standard sample screen submitted by the company, and the sample for the construction site. Shanghai Construction Curtain Wall Testing Center adopts the average value of the “three performances†measured by the witness sampling method for aluminum alloy doors and windows and plastic steel doors and windows installed on the construction site; “In addition to airtightness, the watertightness and wind pressure resistance performance of plastic steel doors and windows are Compared with aluminum alloy doors and windows, this result is unexpected, but after further analysis, it reflects the important issues in the quality of steel doors and windows." Moreover, because the lining steel of steel doors and windows is not connected to the complete frame system at the corners of the inner corners of its profiles, the plastic welding angles of the window frames, the four corners of the fan, and the small-sized dots are relatively low.
Second, airtight performance:
Because the steel doors and windows are welded by the frame and fan components, their airtightness should be slightly better than the aluminum alloy doors and windows connected by screws. However, the aluminum alloy door and window profiles have higher dimensional accuracy, and the frame and fan are more closely matched, so the two are still in One level up.
Third, insulation performance:
Aluminum alloy insulation performance is not as good as steel doors and windows, but because, according to the thermal conductivity of the window calculation formula k=1/(1/ai+Rw+1/ae) window heat transfer coefficient k value depends not only on the form itself The thermal resistance Rw (reciprocal of the heat transfer coefficient of the form itself) also depends on the form. The indoor and outdoor surface heat transfer coefficients ai and ae; and according to another calculation formula k = k box f + k glass (1-f), the window heat transfer coefficient k value from the window frame, fan components and window glass The composition of the k-frame and k-glass of the second part is directly related to the ratio f of the window frame fan occupying the entire window area, while the frame fan of the aluminum alloy window accounts for about 10% of the entire window area than the plastic steel doors and windows, and the profile of the aluminum door frame and window fan is also Not solid, and the hollow aluminum wall thickness (actual thermal bridge) is about 40% smaller than the plastic profile wall thickness.
Fourth, lighting performance:
The steel doors and windows have poorer daylight performance than aluminum alloy doors and windows, and the shading area of ​​the frame sash components is about 10% greater than that of aluminum alloy doors and windows. The visual field and decorative effect are poor, which is not conducive to energy saving and consumption reduction of architectural lighting.
Fifth, sound insulation performance:
The sound insulation performance of the window is mainly the sound insulation effect of the glass that accounts for about 80% of the window area. The gap sealing level of aluminum alloy doors and windows and plastic steel doors and windows is basically the same, and its sound insulation performance is basically the same. Shanghai Institute of Building Sciences has conducted a series of sound insulation performance measurements and comparative experiments on plastic steel doors and windows and aluminum alloy doors and windows [6]; 5mm thick single glass steel doors and windows sound insulation volume is about 21~24dB; 5+12A+5 hollow single frame double glass steel doors and windows is 24~29dB; double glass sound insulation volume is 5dB larger than single glass; plastic steel doors and windows and aluminum alloy doors and windows "At least the thickness, the same structure, and the similar sealing conditions, the equivalent sound insulation RW value is similar."
Six, fire performance:
Fire-retardant pvc plastic doors and windows have better fire resistance than flammable wood doors and windows, but they are inferior to non-combustible aluminum doors and windows. Polyvinyl chloride plastic is a non-flammable material. Under the effect of fire, it will burn slowly after encountering an open flame, and it will self-extinguish if it is away from the fire. Its flame-retarding mechanism is the hydrogen chloride released when burning, with the ability to capture H, OH, free radicals, and become flame-retardant [7]. HCLCOCO2 and other toxic gases are emitted when burning. The hazard of smoke is the main cause of heavy casualties during construction fires. Therefore, some countries in Europe stipulate that public buildings must not use pvc doors and windows to avoid unnecessary harm. About the fire performance of doors and windows: steel doors and windows are relatively good, plastic doors and windows are relatively poor.
Seventh, on lightning protection and static electricity issues:
Aluminum alloy is a good electrical conductor, so when it is used as a building peripheral structure, effective grounding measures can be used as a lightning protection facility and can prevent the generation of static electricity; pvc plastic is a non-conductive insulator when it is used in high-rise buildings (a More than 30m of lightning-protection buildings, over 45m of Category II, and over 60m of Category III) cannot solve the problem of side-by-side lightning strikes. Moreover, if it is not used for antistatic treatment, it will be difficult to clean the electrostatic dust and dirt when it is used in civil buildings, and it will affect the appearance and decoration. For industrial buildings, it cannot be used in dust and other explosive shops, electronic or electrical assembly workshops and computers. Room and so on. According to information, electrostatic fire protection for plastics can be applied on the surface with an anti-static oil agent containing quaternary ammonium salt, which can absorb moisture in the air and increase the electrical conductivity. However, the current domestic plastic doors and windows are not treated with anti-static coating.
Eight, decorative:
Plastic windows and doors as the exterior of the building can only be white. Because white or light gray PVC profiles weather resistance and light stability is better, not easy to absorb heat. Coloring pvc profiles are greatly reduced in heat and weather resistance and can only be used indoors. Color decoration is crucial to the artistic effects of architecture. The single white color of plastic doors and windows is a huge flaw and cannot meet the needs of various types of architectural exterior decoration. Relatively speaking, aluminum doors and windows have a variety of surface treatment technologies such as powder coating, anodizing, electrophoretic coating, and woodgrain transfer processing. The surface color options are large, and there are white, green and other colors and wood grain, granite, etc. A variety of surface colors.
Nine, aging issues:
Aluminium profiles are durable, there is no aging problem, and pvc plastic profiles do age. At present, China's plastic doors and windows basically adopt the lead salt system formula of Germany and Austria, and some companies use the organic tin system formulation of the United States. Artificial accelerated photo-aging experiments in China have shown that all white lead-containing compounds can be easily colored and contaminated after photoaging, and their color changes to yellow after 1500 hours of light irradiation. The lead salt system is slightly lower in price, but its appearance color and durability are far inferior to organic tin stabilization systems. According to statistics, the weathering effect of German plastic doors and windows on the smooth surface of the product in the first year will become more rough, and the comparative photographs of more than ten years later indicate the weathering process of the pvc profile. The weathering layer is 0.3 to 0.4 mm thick. The decomposition of the lower layer of PVC will stop. Under the effect of ultraviolet rays, the polymer pvc resin breaks the chain of Oita and makes the surface of the material lose its luster, discoloration and powdering, and the mechanical properties of the profile are reduced. Steel windows and doors in similar buildings and doors are apt to rust, wooden doors and windows are easy to make, and their service life is generally not long.
Ten, deformation and expansion issues:
Plastic-steel doors and windows are susceptible to thermal deformation, brittle to brittle, and poor in dimensional and shape shift stability. It is often necessary to use the rigidity of the glass to prevent deformation of the window frame. Therefore, plastic windows are shipped abroad after the factory has installed the glass in order to prevent deformation during storage, transportation, and installation. In addition, a foamed plastic filled and cured elastomer seal is used between the window frame and the opening during installation. However, the construction habits of the construction industry in China cause plastic steel doors and windows to be shipped without glass. The cement mortar is used to fill the gaps and seals between the window frames and the openings during installation. “The thermal expansion coefficient of the PVC plastic window frames is far greater than that of steel, aluminum and cement. When the temperature difference between day and night and winter reaches 20~700C, the PVC plastic steel door/window frame will be “squeezed†so that it cannot deform freely.
Eleven, product weight:
Plastic steel doors and windows are lighter than aluminum alloy windows. Since the tensile strength of plastic profiles is 1/3 of that of aluminum profiles, the modulus of elasticity is 1/36 of that of aluminum. Therefore, the cross-sectional dimensions and wall thickness of plastic profiles have to be designed to be larger than those of aluminum alloy profiles. Reinforce steel linings should be added in the cavity of the profile to meet the wind pressure resistance of the window and the need for assembling hardware accessories. China's European window with improved steel doors and windows, profile thickness 2 ~ 2.5mm, profile consumption 9 ~ 12kg/m2, according to steel liner consumption is 85% of the profile weight, steel lining consumption is 7.65 ~ 10.2kg / M2. Therefore, the weight of the plastic window type plus steel liner has exceeded the weight of the aluminum window profile by 4.5~7.5kg/m2. In addition, steel doors, windows, and solid wood doors and windows are generally more bulky.
Twelve, production energy consumption and use of energy:
The ratio of production energy consumption per unit volume of aluminum alloy doors and windows and steel doors and windows is 8.8 times, but the ratio of production energy consumption per unit area of ​​profiles is 2.55 times. For the energy consumption of windows, the heat transfer measured under the condition of winter insulation is adopted. The comparison of coefficients can only be said that steel doors and windows are 27 to 31% lower in energy consumption than aluminum alloy doors and windows. Because the heat transfer coefficient of the summer window is different from that of the winter, it cannot be simply said that the effect of the air conditioning cooling energy consumption in summer is also the same. The window insulation performance in summer is not the same as the winter insulation performance and cannot be simply confused.
Thirteen, profile mold costs:
From the perspective of mold extrusion die cost, plastic windows are about three aluminum windows. The development and replacement of aluminum alloy doors and windows are more economical and flexible than plastic steel doors and windows.
XIV. Product performance/price ratio:
The performance/price ratio of aluminum alloy doors and windows is higher than that of steel doors and windows. The price of aluminum alloy doors and windows abroad is 1.5 times that of plastic steel doors and windows, that is, plastic steel doors and windows are 33% cheaper than aluminum doors and windows. However, the situation in our country is the opposite. In general, single-glazed steel doors and windows are 25~33% more expensive than aluminum alloy doors and windows; hollow double-glass plastic steel doors and windows are 36~44% higher than aluminum windows. Of course, these two types of steel doors and windows have better insulation performance than aluminum alloy doors and windows. Better, but other performance plastic doors and windows are not as good as aluminum alloy doors and windows. The price of hollow double glass aluminum alloy doors and windows is about 25% higher than that of single glass steel doors and windows. However, the former is better than the latter in terms of heat preservation, sound insulation, and other properties. For the same type of structure, the inner flat open windows are made of aluminum alloy windows. The insulation performance index (K=2.8) of insulating glass insulating glass reaches the level of hollow double glass window (K=2.7) of plastic steel doors and windows. The price of the latter is also about 24% higher than the former; however, the former has high strength and high Performance, excellent corrosion resistance (spray lacquer) and decorative effect (metal texture and non-metallic texture and other colors and frames, window frames can be both indoor and outdoor colors), long service life and other comprehensive performance is far better In the latter.
The Tape Measure can be rolled up because there is a spring inside the tape measure. When the measuring length is pulled out, the length of the ruler and the spring is actually stretched. Once the measurement is completed, the spring inside the tape measure will automatically contract, and the ruler will follow the action of the spring force. Shrink, so the tape will roll up.
Metric Tape Measure,Rolling Tape Measure,Automatic Tape Measure,Tape Measure Scale
Shangqiu Yusheng Tools co.,Ltd. , https://www.cnystools.com