1. Project design: The construction project is generally divided into three stages: program design, preliminary design and construction drawing design. The scheme design documents shall meet the requirements for the preparation of preliminary documents, and the lightning protection parts generally have the contents of lightning protection and grounding. Special buildings should consider electromagnetic shielding.
2. Preliminary design: The preliminary design document shall meet the requirements of the construction drawing design document, and the design depth of the lightning protection part shall be:
1 Design lightning protection basis The design basis cited mainly in the preliminary design of lightning protection is “Building lightning protection design specification†GB50057-94, “Building electronic information system lightning protection technical specificationâ€, GB50343-2004 and “Intelligent building Design standards such as GB/T50314-2000 and other related design specifications.
2 Determine the type of lightning protection (length, width, height, environment, thunderstorm day, importance to be determined) Calculation of lightning protection category, site survey and calculation of lightning protection scope are for internal use and archiving only.
3 Measures against direct lightning strikes, side-impact lightning strikes, lightning strikes against electromagnetic pulses, and intrusion of high potentials.
a. Guard against direct lightning: the size of the roof grid, lead down line spacing, lightning rod or lightning protection zone.
b Side-impact protection: According to different types of lightning protection, the equalizing rings, railings on the external walls, and large metal objects such as doors and windows are connected to the lightning protection device.
c Anti-lightning electromagnetic pulse: Shunt, shielded, grounded, and equipotential bonding.
d High-voltage potential intrusion: All metal pipelines entering and exiting the building are connected to a total equipotential connection. Roof-forbidden lights, lanterns, etc. are recommended to wear metal pipelines and surge protectors are installed at the interface.
4 The types of grounding requirements and grounding resistance requirements for each system of the project.
5 Total equipotential and local equipotential setting requirements.
6 Other lightning protection measures:
a The top and bottom ends of the vertically laid metal pipes and metal objects are connected to lightning protection devices.
b All metal cases of uncharged equipment under normal conditions shall be grounded.
c. Non-metallic objects outside the roofing protection area shall be equipped with a lightning arrester and connected to the roof lightning protection device.
d Metal devices and metal components protruding from the roof should be reliably welded with the lightning protection strip.
e Satellite receiving antenna and other equipment shall be within the protection range of the air-termination device. The antenna feeder shall pass through the metal tube, and both ends of the metal tube shall be grounded.
f Reserve equipotential bonding pads in place.
Venous cannula is also a deep venous puncture catheter. The method is to select the appropriate puncture site and insert the needle under the skin, and insert the needle with negative pressure until the dark red blood is absorbed, indicating that the needle has entered the vein, and the guide wire is inserted. Withdraw the puncture needle to leave the guide wire in the blood vessel, and then insert the venous catheter that needs to be indwelled along the guide wire, then exit the guide wire, inject diluted heparin saline and fix the catheter, the deep venous catheterization is completed. The veins for puncture and catheterization are usually selected clinically, including the subclavian vein, internal jugular vein, and femoral vein. After the puncture catheter is indwelled, attention must be paid to the care of the puncture site to avoid infection with thrombus or catheter falling off.
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