Steel scaffolding set up lightning protection
Erection of lightning in the wilderness area on the slopes of steel scaffolding to be set up in the storm season, Lightning protection, lightning protection devices include air terminals, grounding, grounding line.
First, air terminals or lightning rods, available from 25 to 32 mm in diameter, wall thickness of not less than 3 mm diameter galvanized pipe or not less than 12 mm galvanized steel produced in house on the corner of the scaffolding pole stand, a high degree of not less than 1 meter, and should top all of the horizontal pole connected to form a lightning network. Rack installed in the vertical transport in the middle of a lightning rod should be set to the side of the pole above the top of the access not less than 2 meters, the lower end of the stand pole ground wire, and hoist chassis ground.
Second, the grounding wire should maximize the use of steel. Vertical grounding can be 1.5 to 2 meters long, 25 to 30 mm in diameter, wall thickness of not less than 2.5 mm steel pipe with a diameter not less than 20 mm angle steel bar or 50 * 5. Grounding can choose the length of the level of not less than 3 meters in diameter from 8 to 14 mm round or thickness of not less than 4 mm wide and 25 to 40 mm flat steel. Also buried in the ground can also be used metal pipes, metal post, drill pipe, water pipe and into a reliable connection with the earth as a grounding metal structure. Scaffolding on the ground electrode by a continuous length of 50 meters within the set at one, and should meet the furthest point away from the grounding of transition within the scaffold does not exceed 10 ohms resistance requirements. Ground resistance shall not exceed 20 ohms. Grounding the highest point buried in the ground and under the ground is not light at 50 cm, when laying the new compacted fill. Steam pipe or chimney often heated air duct near the soil layer, located above the groundwater level of the masonry cinder or sand, the dry soil and in particular shall not be buried ground wire.
Third, the ground wire that is deflectors, can be not less than 16 mm cross-section of aluminum wire or a section of not less than 12 square millimeters of copper wire. In order to save non-ferrous metals can be used under the premise of a reliable connection is not less than 8 mm in diameter, round, or not less than 4 mm thick flat steel. Ground wire connection to be absolutely reliable contact, connect the exposed surface of the paint and clean oxide layer, exposing metallic luster, and painted a neutral petroleum jelly. Ground wire and the grounding connection is best to use solder, solder ground wire length should be more than 6 times the diameter or more than 2 times the width of flat steel. If bolted, ground contact surface not less than 4 times the cross-sectional area, splicing bolts of not less than 9 mm in diameter.
Steel scaffolding set up lightning protection must pay attention to the following:
First, the grounding device before setting the limits under the grounding resistance, soil moisture and conductivity characteristics of the design, selection and location of grounding, and grounding wire grounding and layout, material selection, connection, production and installation requirements be specified. After the installation of sheet resistance measurement to use for compliance.
Second, the grounding line position should choose the place people go is not easy to avoid and reduce the step voltage hazards, to prevent the ground suffered mechanical damage, grounding and other metals or cables should be maintained between the distance of 3 meters or more.
Third, the use of grounding devices in 6 months or more, should not be used in the ground as bare aluminum grounding wire or grounding wire. In a strong corrosive soil, use galvanized or copper grounding pole.
Fourth, in case of lightning strikes during construction, the steel scaffolding on the operator should be immediately evacuated