(1) According to the technical information about lightning protection and grounding combined with the experience of previous completion projects, we believe that glass curtain wall lightning protection must meet the following requirements in several important aspects:
The lightning protection design of the glass curtain wall shall comply with the relevant provisions of the current national standard "Code for Lightning Protection of Buildings" (GB500057-94).
The vertical main keel of the glass curtain wall shall be regarded as the down conductor, and the cross section of the vertical main keel shall be 100 mm2 when used for flat steel products.
In addition to the welding method, the thickness of the metal material should be 4 mm by crimping.
The length of the round steel overlap is 6 times of its diameter, and it is double-sided welded; the length of the flat steel overlap is 2 times its width, and the welding is performed on three sides; the welded joint is treated with anti-corrosion treatment.
Different metal crimping, anti-electrochemical corrosion treatment. For example, when steel is connected with aluminum, the steel should be tinned; or stainless steel gasket should be added between steel and aluminum.
After the completion of the construction, an authoritative testing organization is required to perform the test, and the grounding resistance value required by the design and specifications must be met.
(2) The method of lightning protection and grounding of a glass curtain wall of a building
The building has 22 floors above ground and 80 meters high. The exterior wall uses large-area granite hanging panels, glass curtain walls and composite aluminum panels. The following describes the specific practice of lightning protection and grounding of its glass curtain wall:
Starting from the sixth floor, nine floors, twelve floors, fifteen floors and twenty-two floors, each layer is laid with a 40×4 galvanized flat steel on the surface of the structural slab around the building, and with lightning protection around the building. The lower-row lead-out steel bar (Φ12) is welded, the welding length is 6 times the diameter of the round steel, and the double-sided welding and welding are used to brush two anti-rust paints (after the welding, two anti-rust paints are brushed), thus forming a uniform Pressure ring. In order to keep the glass curtain wall vertical aluminum alloy main keel to be grounded, one end of the 40×4 galvanized flat steel is welded with the equalizing ring, the welding length should be twice the width, and the three sides are welded, and the other end is used twice. M8 stainless steel is pressed against the vertical main keel by bolts. In order to prevent the electrochemical corrosion of galvanized flat steel and aluminum alloy, a 1mm thick stainless steel gasket is added between them, and a stainless steel flat pad and spring pad are added.
The joints of all vertical main keels are crimped with a retractable "ohmic bend" made of 40×4 aluminum alloy. The joints are crimped with two M8 stainless steel upper and lower bolts, and a stainless steel flat washer is added. Spring pad.
Set the joint of all vertical main keels and transverse keels on the floor of the pressure equalizing ring. Press the two bolts of M6 stainless steel through the 40×4 aluminum corners at both ends, and add stainless steel flat washers and spring washers.
The cover of the parapet wall at the top of the curtain wall is a lightning receptor that acts as a lightning guide. The φ12 galvanized round steel is installed along the circumference of the parapet wall and welded to the main structure lightning protection down conductor. 40×4×4 galvanized angle steel is installed on the inner side of the cover plate. Two pieces of angle steel (each length is 300mm) are installed on each aluminum plate, and the two sections are welded and connected by φ12 galvanized round steel. One end of the φ12 galvanized round steel is welded with the φ12 galvanized round steel at the top of the daughter wall, and the other end is welded with the angle steel. Each angle between the angle steel and the aluminum plate is crimped with four M6×20 stainless steel self-tapping screws (a 1 mm thick stainless steel gasket is placed between the angle steel and the aluminum plate), and a stainless steel flat pad and a spring pad are added.
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