1 Introduction
Doors and windows are an indispensable part of a building. Not only are they affected by environmental influences such as wind pressure and rain and snow, they also have to withstand the gravity of the switches and weights in use. Among them, wind power is the main reason for the bending deformation of the bars (cross bars, vertical bars, window bars) and frames and fans of doors and windows. The three physical properties of aluminum alloy windows, namely wind pressure resistance, air permeability, and rain leakage performance, have gradually become one of the focuses of quality control in construction projects. Whether the windows and doors are safe or not mainly depends on their ability to withstand the wind force, which is usually measured in terms of the pressure of the gas per unit area (in Pa). In actual application and testing, the quality of aluminum alloy exterior windows does not meet the requirements of relevant national standards. These quality issues will directly affect the further development of aluminum alloy exterior windows.
2, aluminum alloy exterior window quality inspection control points
2.1 Strength of aluminum profiles
The strength and hardness of aluminum profiles have a certain quantitative relationship. In order to have operability during inspection, only the hardness test of aluminum profiles is required. That is, a hardness test is performed with a portable hardness tester or bench top hardness tester. . Vickers hardness HV ≥ 58 is required.
2.2 The wall thickness of the aluminum alloy profile
Aluminum alloy doors and windows of the force components include door and window frames, the upper and lower glides, sashes and vertical and horizontal stiffeners. The actual measurement size of the smaller wall thickness of these force members should not be less than 1.2mm. The inspection method uses a vernier caliper to perform on-site inspection of the profile of the examined window.
2.3 Component Connection
The connection of the components of the aluminum alloy outer window is a major issue in relation to the use performance and solid safety of the outer window. Components must be securely connected and have a reliable degree of attachment. The connecting part should also be sealed and waterproof and must not be short of parts or parts. During the inspection, connect the node diagram to the outside window and check whether the connectors, such as screws and stiffeners, are complete. Push the outside window components by hand, including the frame fan frame, to check for looseness and distortion.
2.4 Opening and closing of window sash
The opening and closing of aluminum alloy windows should be flexible. It is an important project that relates to the sliding and opening of aluminum alloy windows. It is determined by the structure of the outer window, the seal, the quality of the pulley and the correct installation. Therefore, measuring the sash opening and closing force is also an important indicator for checking the quality of doors and windows. During the test, it is installed on the test device according to the state of use of the external window. It is closed, and the spring scale with a range of 150N is used to push and pull the external window to move the edge of the fan and apply force in the direction perpendicular to the edge. Off, reads the force value when the fan moves.
2.5 Attachment Installation
The attachment of the installation window to the aluminum alloy window resistance to wind pressure performance, air permeability, rain leakage performance level. The requirements for attachment installation should be complete, correct, and securely installed. During the inspection, check whether the window lock, handle, pulley, sealant, top, seal, sealant and anti-drop fan accessories are complete. Whether the installation position is correct, the installation is firm, there is no off and loose phenomenon, strength is better, play their own role, should be flexible when opening and closing, blocking noise.
2.6 The quality of the attachment
Glass, hardware, rubber parts, plastic parts, sealants and other accessories should meet the corresponding quality standards. In addition to stainless steel parts, metal accessories should be preserved. During the inspection, the appearance of the attachment should be free from flashes and burrs. Metal plating should be complete, bright, no shedding and corrosion. The strip should be soft, elastic, non-aging and cracked. Tops should be siliconized or multi-stranded, and wool should be densely packed. Check the factory certificate and attachment inspection records.
2.7 Two adjacent assembly problems
The control of the assembly gap between two adjacent components of the aluminum alloy outer window is one of the foundations for guaranteeing the aesthetic appearance of the aluminum alloy outer window assembly and ensuring the air permeability performance and the rainwater leakage performance. The detection method is: using a feeler gauge to measure the width of the gap between the two components at the interior and exterior surfaces of the test piece, and take the larger value.
2.8 Lap width deviation
The control of the lap width of the frame and fan of the aluminum alloy outer window is the basis for ensuring that the aluminum alloy window does not leak through the air. During the test, place the test piece upright and close the sash. At the center of the fan's height and width, use a pencil to draw the mark of the lap joint on the frame of the sliding sash or on the frame of the flat window, and then take the fan. Lower or open, use the depth ruler to measure the overlap value and compare it with the design overlap dimension to find the deviation value.
3. Phenomenon, Causes and Preventive Measures of Aluminum Alloy Exterior Window Quality Problems
3.1 Insufficient strength of profile, variable type, unacceptable wind pressure level
3.1.1 phenomenon
In the deformation detection and repeated pressure detection, malfunctions occur, the switch is not smooth, and the amount of residual deformation is large. In the safety inspection, the large wind pressure cannot reach the design required wind pressure level.
3.1.2 Cause
The selection of aluminum alloy profiles is improper, broken, and the wall thickness does not meet the requirements: the thickness of the steel lining in the hollow space of the steel window cannot meet the requirements, and the steel lining and the inner cavity of the profile cannot be closely matched, and the combined section can not be subjected to force at the same time.
3.1.3 Preventive measures
Before material selection, load calculation shall be made according to the specifications of the external window structure. Standard profiles shall be used as far as possible. The wall thickness of the profile shall be determined according to the cross-sectional characteristics of the profile. The wall thickness of the aluminum alloy profile shall be based on the measured data of the entering material. Weighing the wall thickness, the measured wall thickness of the stressed component shall not be less than 1.2mm.
3.2 Casement window window lock quality is poor, installation is not strong, resulting in functional obstacles, unacceptable wind pressure rating.
3.2.1 Occurrence
Casement window in the negative pressure state of the wind pressure detection, the window lock deformation under a large wind pressure off, and some even off in the test pressure phase, so that the test is interrupted; bolts installed window lock under greater wind pressure Loss, loss of function, unacceptable wind pressure rating.
3.2.2 Cause
The window lock lock hooks are thin. In the negative pressure state, the wind on the flat windows is all concentrated on the window lock lock hooks. The strength of the lock hooks is not enough for one hundred deformation to disengage; the bolts for the installation of window locks can withstand the tensile load. insufficient.
3.2.3 Preventive measures
High-quality window locks are used. The wall thickness of the lock hooks is 2.0mm-2.5mm. The flat window window locks must withstand large tensile stress. The installation should use rivets with strong tensile strength.
3.3 aluminum alloy push-pull window detailed structural defects, poor processing accuracy, leaving the gas leakage channel, anti-air permeability performance failed.
3.3.1 phenomenon
There are more air-permeation channels between the aluminum alloy sliding window and the window frame and the window frame. The total air penetration is large and the air permeability performance is unqualified.
3.3.2 Cause
The stoppers on the left and right corners of the window of the aluminum alloy window are too small or not installed properly, failing to effectively close the upper rail; the intermediate space of the upper rail is not treated and becomes an air infiltration channel.
3.3.3 Preventive measures
The stopper on the aluminum alloy window is not affected by the derailment of the window. It does not affect the air permeability. The width of the stopper is the same as the width of the window. The height of the stopper is 2mm-3mm above the top of the upper rail. The separation zone is closed at the interface of the two window sheets (3cm-4cm) with a rubber block or waterproof sealant to block the air passage.
3.4 Aluminium alloy window sheet, window frame seams and combination window joint gaps are not properly handled
Remaining infiltrating gas and water seepage channels, the lower rail of the sliding window did not properly retain the drain hole, resulting in unacceptable air permeability and rain leakage performance.
3.4.1 The phenomenon of production
Aluminium alloy window sheets, window frame four-corner joints and combination windows are connected to the joints to leak water; rainwater splashes out of the window test piece interface from the discharge holes; the sliding window drains slowly, and water is accumulated at the lower rails.
3.4.2 Cause
Aluminum alloy window sheets and window frames have poor cornering accuracy. The seams are not closed with a waterproof sealant. The gaps at the splicing points of the combined windows are not closed with a waterproof sealant; the brush holes at the drain holes are loose or are partially loose. The head is not in place, leading to splashing of rain; the lower rail does not have a drain hole or a drain hole that is too small to drain.
3.4.3 Preventive measures
Aluminum alloy window window page, window frame corner seams and combined window contact points are filled with waterproof seals to be completed before all the windows are assembled. All the assembled joints are re-irrigated with a waterproof sealant; the role of the brush bar is to fill the window. The gap between the page and the window frame prevents the air from penetrating and prevents the rain from splashing. Therefore, select a high-quality brush bar and install it firmly in place. The size of the drain hole in the lower rail of the sliding window should be 4mm x 40mm, close to the window frames on both sides.
4 Conclusion
Aluminum alloy windows have advantages in light weight, high strength, rich decorative effects, and simple construction methods. The problems that aluminum alloy exterior windows exhibit in terms of three physical properties are mainly caused by inappropriate selection of profiles, insufficient strength, poor quality of hardware accessories, multiple structural defects, and poor processing accuracy. These quality problems are sometimes caused by a single cause. , Sometimes it is caused by many reasons, so the measures taken are not single and are the result of comprehensive measures. Should take comprehensive measures in materials, design, construction, use and maintenance, etc., and take measures to eliminate the quality problems caused by the three physical properties of aluminum alloy windows in the bud, and promote the development of aluminum alloy windows in the direction of health.