Lightning rod the setting law of lightning rod is generally: the highest point and protruding point, such as ridge, eaves corner, flat roof and wall corner…
The double-sided welding length of the weld shall be greater than 6D, and the lower end shall be welded with the two main reinforcements of the building pile foundation reinforcement and the foundation bottom beam reinforcement.
The welding of lightning protection grounding adopts lap welding, and the lap length shall comply with the following provisions: the lap length of round steel and round steel shall not be less than 6 times the diameter of round steel, and welding shall be carried out on both sides (when the diameter is different, the lap length shall be subject to the larger diameter); When the round steel is overlapped with the flat steel, it shall not be less than 6 times the diameter of the round steel, and it shall be welded on both sides; The overlap between flat steel and flat steel shall be that the flat steel shall not be less than 2 times of its width and shall be welded on no less than three sides (when the width of flat steel is different, the overlap length shall be subject to the width); When flat steel is welded with steel pipe or angle steel, it shall be close to the surface of 3 / 4 steel pipe or the two sides outside the angle steel, and the upper and lower sides shall be welded.
In architectural design, when the height exceeds the radius of the rolling ball (30M for class I, 45m for class II and 60m for class III), a grading ring shall be set every 6m.
3.
After the foundation grounding project is completed, the grounding resistance test shall be conducted at the outgoing line of each grounding electrode.
The process flow grounding device uses two diagonal main reinforcements in the inner (peripheral) corner of the building foundation ring beam to weld into a ring network (four main reinforcements must be used if the main reinforcement is less than ø 12), and the downlead is welded into one with the ring network.
After the welding of each lead down point on each floor and before concealment, the on-site constructor and supervisor shall be invited to carry out concealed inspection, and the concealed inspection records shall be filled in at the same time.
After welding, the coating shall be removed.
The equipotential equipotential method adopts the welding of two main reinforcements in the ring beam around the toilet, The surface reinforcement of the toilet bottom plate is welded into a grid according to 600 * 600, and connected with the longitudinal and transverse ring beam reinforcement.
When the main reinforcement in the structural column is used as the down lead, each down lead shall not be less than two main reinforcements, and the diameter of each main reinforcement shall not be less than Ф 16mm, the lightning protection downlead position should be symmetrical Down lead spacing: class I lightning protection building: ≤ 18m; Class II lightning protection building: ≤ 20m; Class III lightning protection building: ≤ 25m.
A – 25 * 4 galvanized flat steel is welded by the ring beam to connect the local equipotential box of the toilet (300mm from the ground).
1、 Foundation Grounding 1.
Lightning protection construction 1.
Find out the position of all main reinforcement according to the design requirements, mark it with paint, weld the disconnection clip at 0.5m away from the outdoor surface, weld it to the top layer in series with the reinforcement layer by layer, and weld a certain length of down lead on the roof Ф 12mm galvanized round steel for connection with lightning strip.
Except that the welding points buried in the concrete are not treated, the other welding points shall be taken with anti-corrosion measures: brush one layer of antirust paint and two layers of silver powder paint.
After the coating at the welding position is knocked clean, anti-corrosion treatment shall be carried out.
The grounding resistance R is required to be less than 1 ohm.
The grounding body (wire) shall be connected by welding.
Lightning protection test point 4.
Embedded grounding flat steel 1) water supply and drainage, cable, wire and gas inlet (if the installation height of inlet pipe is relatively high, its grounding terminal can be reserved in the ceiling) 2) cable, information wire The telephone line enters the pipe (see installation of equipotential bonding (02d501-2) P12) 3) high and low voltage distribution room (at least 2 points) 4) the distribution cabinet in the pump room (it is recommended to surround the pump room and connect the conductors within the arm, see the provisions of the atlas) 5) the temporary distribution box 6) the distribution box in the basement, Outdoor distribution box 7) basement machine room (ventilator room and civil air defense fan room) 8) outdoor distribution box (such as outdoor advertising distribution box and roof outdoor advertising distribution box) 9) the first distribution box introduced outdoors (such as civil air defense distribution box) 10) elevator shaft 11) temporary construction elevator 5.
In design, the grading ring can be welded into a closed ring by using two main reinforcements in the ring beam, which must be connected with all down conductors.
The weld at the welding position shall be full and have sufficient mechanical strength, and there shall be no slag inclusion, undercut, crack, false welding, air hole and other defects.
If it fails to meet the requirements, an artificial grounding electrode shall be added until it meets the requirements.
Country garden requires a grading ring on the 10th floor, and then a grading ring on every two floors.
The welds of the welding points shall be full without slag inclusion, undercut, false welding, air holes and other defects.
Its purpose is to facilitate the connection of metal doors and windows on the upper and lower floors within 6m height with the grading ring.
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II.
The downlead in the column shall be reliably welded with the grading ring in the beam, which adopts double-sided welding.
The construction quality requirements of lightning protection grounding.
Grading ring grading ring is a horizontal lightning strip around the building designed for side lightning protection of high-rise buildings.